I’m posting my experience to help others avoid what I encountered. It doesn’t matter how much knowledge, or experience you have with the subject. The right sequence and combination of problems can occur to mislead and confuse anyone.

Here is a history to set the scene. I started with a stock 3900 except for the reground camshaft, 216/214, 114 LSA, stock 9.8:1 compression, twin turbos (T3, 60/.48) and wastegates. The engine ran 7 psi, midgrade fuel, and 212 deg inlet temps with a poor tune without detonation under boost. The camshaft was advanced about 10 deg with intended VVT use to retard it.

I built a forged motor stroked to 4.2L and ~11.5:1 compression ratio and switched to a single T67 and installed water/meth injection. I used TunerproRT 4 for both motors. This engine was like a rocket off the line. Unfortunately TunerproRT 5 worked best for me with code59. I acquired a version 5 adx file for TP5 but the AFR table did not go into boost range and I didn’t realize it was very easy to modify. After a viscious 8 psi run, and failure to realize that under boost my bar graph AFR gauge should be reading in the rich zone, not close to stoich, the damage was already done. Here is a picture of what I couldn’t see then which burned the valves and rings.



I didn’t realize right away how bad the engine was damaged (5 cyl over 240 psi, one at 150 psi, still managed 33 mpg hwy though), so when occasional turbo smoke appeared I suspected the turbo because it did smoke a little when revving in the driveway shortly after it was installed.

I sent it off for repair and drove the car naturally aspirated until I was returned with a clean inspection and a gapless turbine ring installed as a good gesture.

I reinstalled it harmlessly bumping the knock sensor. I cranked up the engine and immediately the turbo started smoking. Turns out the engine was damaged further while the turbo was out for inspection and crankcase pressure was blowing oil out of the turbo.

I solved that problem by installing a Holley Black fuel pump as an oil scavenger blocking the oil return from crankcase pressure and the car seemed to run fine.

The next day and after I unwisely routed a hose from an extra oil pan drain up to the airfilter as a blowby vent area, I finally attempted to launch hard from a stop which threw oil to the back of the oil pan covering the drain fitting and crankcase pressure blew it up to the filter, about a half quart worth.. There was a stumble, a pop and the smell of burning oil and even after the hose was removed I would still experience an intermittent stumble and pop during early accel and mid. I figured the ingested oil damaged the engine and possibly the turbo since it passed through the blades.

I saw timing retard all over the place on logs associated with these events and figured there was excessive carbon build up coupled with possible oil from the compressor of what must be a damaged turbo contaminating the combustion mixture. I started pulling timing but without much success.



This went on until the engine was removed for later repair and the first motor which I’m glad nobody bought when I tried to sell it cheap was reinstalled. This motor received a second reground cam that was basically the stock cam with a little more duration, the stock 117 LSA and .520 lift since I planned to try to take basic advantage of VVT.

Same problem, intermittent stumbles and pops along with brief power loss under load then it would finally pick up and run okay. Now I know it’s not a mechanical problem because the engine was compression tested before install with 240 psi across all 6 cylinders, not to mention its abilities described in the second paragraph were augmented with 93 octane and alcohol injection and intake temps ~30 deg cooler.

While reaching for a wire on the engine block I bumped the knock sensor plug and when I started the car it finally set a code indicating a malfunctioning knock sensor.
I replaced the sensor and noted an immediate improvement and disappearance of peppered timing advance on the history table.

Here is the thread on that issue.
https://www.fiero.nl/forum/Forum2/HTML/118459.html

But, the occasional intermittent pop and brief power loss on launch and full throttle acceleration from cruise speed was still there. Long story short, the bad knock sensor caused me to chip away at my spark table to the point where this problem developed. Since it was gradual over time I didn’t realize it until I compared an early bin from when the engine was first installed to what I had currently for basically the same motor.

Here is a difference comparison showing the current spark table with the one during the trouble period subtracted from it to show how much the timing had been reduced in error.



The stumble and pop is gone (new plugs are in place also) and although my 7 psi spring can’t keep the engine below 10 psi there is no spark retard. The alcohol doesn’t kick in until about 9 or 10 psi but isn’t necessary although I leave it in place as added safety.

So as you see, when my troubles manifested, I had 3 simultaneous problems that could have been responsible, but I was only aware of one when it occurred and that was the oil ingestion. Not knowing about the knock sensor, or realizing that I had overly retarded timing, I could only assume that the trouble was a by product of the oil. What would you think if every time you experienced a stumble, pop and brief power loss and looked at the data log and saw timing retard?

Here’s what it’s hitting so far



Note the drop in air temps at around 180 kpa which must be the preturbo alky at work because the second nozzle is placed after the MAT sensor.


It’s richer than what I’d like but part of that is because the thermostat is stuck open (maxed out a safety stop during a recent overheat) so some of this is due to much cooler than normal engine temps. I prefer this to what happened to my masterpiece.



I believe the timing retard in the idle region of the table is the result of an intermittent connect disconnect during the datalog which manifests as spikes of timing retard on the monitor tracing with no detectable change in the way the engine is running when it happens, a new problem I need to address. Near engine stall and cranking with the datalog recording also cause this. Usually there is nothing but zeroes on the spark history table.

So far for the first time in quite a while the engine is running the way I expect a boosted 3.9L to run and I don’t want that to change so I’ll work slowly at raising the AFRs into the 12-11.5:1 range. I’ll add relevant progress updates if anymore surface.

This is my current spark table.



Here is the timing retard history table I mentioned the stray timing retard in above. Aside from this it is clean where I need it to be most.


If you're running Tunerpro 5 and you're boosted, be sure to optimize your history tables to see where your fueling and timing is to avoid what happened to my engine.

[This message has been edited by Joseph Upson (edited 10-09-2011).]

Thanks for the informative post.

Boost is still climbing above the intended 7 psi but the engine is staying out of detonation. Remember this is a stock 9.8:1 compression engine running on 93 octane and although I have meth injection it isn't necessary and doesn't come on until about 9 psi. I'm not planning to increase timing to take advantage of it on this motor. I have pre and post nozzle locations but as can be seen below the pre turbo nozzle doesn't appear to be doing anything for air temps but is supposed to improve compressor efficiency.



The outlet temps from the turbo don't jump to 300 deg when max boost pressure is reached, it climbs as boost pressure is sustained, in this case 4 seconds. Usually it hits about 170 and drops off because I don't normally hold boosted load that high that long. To add an exception to what I stated above, this is the first time I've seen temps above 215 deg so the alcohol may be at work preventing detonation under a sustained load. I plan to install a bullet style air to water intercooler in the near future hopefully.


Top to bottom: RPM, kpa & psi, air temp, afr, knock retard 0.00.

The AFR above 7 psi is very rich as low as 9 ish in some areas and I'm still trying to work that out of the tune. I haven't tested the camshaft in the retarded position under heavy load and that might help since the cam is running about 10 deg advanced at the moment. When the VVT is activated the cam will be retarded about 6 deg beyond the intake centerline so hopefully there will be enough efficiency increase at the higher rpm level above 4000, where the richest area is to lean it out some.

[This message has been edited by Joseph Upson (edited 10-15-2011).]

with the high intake temps and not sending the water meth in till 9 psi , i think the only thing stopping you from having problems is the low afr numbers .i would not go above 10:1 under boost until you get the intake temps down .good info , thanks for posting all this .

quote Originally posted by wftb: with the high intake temps and not sending the water meth in till 9 psi , i think the only thing stopping you from having problems is the low afr numbers .i would not go above 10:1 under boost until you get the intake temps down .good info , thanks for posting all this .

That's really circumstantial as every motor is different and in this case 10:1 and below is killing power, I can feel it in the form of pulses under load when it comes on which gives the impression of timing retard but is actually quenching of the combustion process. I did mention the alcohol is probably suppressing detonation under sustained boost high enough to produce those temps. I don't feel anymore comfortable running extremely rich than I do moderately lean as both have potentially adverse consequences.

212 deg temps without alcohol on mid grade fuel and a poor tune didn't cause any problems and the timing advance was a little more aggressive as well when the engine was first installed with a twin turbo arrangement.

The tune is much better now and I've been watching my exhaust temps also and it appears there's more than enough room to bring the afr up into a more practical region and still stay out of trouble with premium fuel, and a little less timing. I'll be sure to take baby steps in the process. I rarely hold boost long enough to produce temps that high and that is the first time I've seen temps greater than 212 since the motor was reinstalled.

[This message has been edited by Joseph Upson (edited 10-16-2011).]

I've decided the alcohol injection kit will be removed and sold and replaced with the liquid to air intercooler. The following results were achieved on 93 octane fuel and NO water/meth injection at all.



If the planned intercooler replacement is successful at reducing temps under the current boost conditions by at least 100 degrees 18 psi should be no problem with the current spark table. I watched the dash gauge post slightly North of 15 psi so it is apparent the MAP sensor is maxed out at ~14.5 psi.

Here is an example of the peak temps encountered during todays test drive.



The upper level boost AFR is not tuned as of yet considering I activated the VVT camshaft also during this run and when it retards it reduces the AFR by about .4 points and there was a noticeable increase in performance to go along with it. Once wired in completely the Zeitronix wideband controller will be programmed to activate VVT at about 4400 rpm consistently so that I can adjust the tune more accurately in that range.



Knock retard is still under control despite the compression ratio, boost level and intake temp combination. The spec on the table maybe false knock as it is normally absent in that area and my emulator/data logger is failing producing several errors in the form of signal blips in the log and will have to be sent in for repair for now.




I bet the oil spraying on the bottom of the pistons is very helpful under these circumstances. With the cooler ambient temps it's usually less the 200 deg F.
I'm looking forward to repairing the forged motor and getting it reinstalled.

[This message has been edited by Joseph Upson (edited 10-26-2011).]

quote Originally posted by Joseph Upson: I've decided the alcohol injection kit will be removed and sold and replaced with the liquid to air intercooler. The following results were achieved on 93 octane fuel and NO water/meth injection at all.

Insane idea, not going to happen, especially considering that decision was made with the stock motor temporarily in place. The forged motor was restored with some upgrades listed in the build thread and a slight reduction in compression down to about 11:1. It has about 2500 miles on it since the reinstall along with the new F40 to replace the failed unit.

I have the meth injection system up and running and recently switched form 100% water injection to a water/meth mix along with recomissioning of the pre-turbo injection nozzle along with the primary just ahead of the throttlebody.

I want to test for real benefits associated with pre turbo spraying and intend to compare non pre turbo spray air temps against 80% meth pre turbo spray. Since my primary nozzle is placed after the MAT sensor I'll still be able to run the same boost levels with and without pre turbo injection without a change in knock retard risk to avoid confounding any change in intake air temps due to tune changes between test runs.

I use TunerproRT5 primarily for logging and tuning, but the Zeitronix controller software will be better for this test because it allows the inclusion of EGT readings although I'll have to wire and setup the MAT sensor input into the data stream.

Fortunately the makers of Zeitronix regularly improve the software and recently added a User2 input to the controller for a total of two additional programmable user inputs.

Below is a function test of the controller software to verify proper function. The MAP reading at the bottom is actually the User2 input and the steady state User1 input is where the MAT data will be when I install it and set the sensor limits. In order to follow the screen shot disregard the values in the right margin since they represent the actual data point from the right margin as it is scrolling from right to left.

Focus on the four data points from left to right at the beginning of throttle tip in before going into boost and note that there is a lean tip in point where the AFR at the top of the screen is going lean briefly when it should be just the opposite. I can feel that stumble on aggressive throttle input and now that it's easily visible at pretty much the same location at several boost points in the datalog I know where to go in the tune to adjust what should be acceleration enrichment vs. TPS to correct it.

The preturbo injection is in place with this test and my EGT temps have dropped by about 100 deg since it was reinstated. I like to keep the EGTs at a max of about ~1200 deg and now they are around 1100 with sustained boost of about 4.5 psi. What I didn't realize was that the EGT continued to climb another 100 deg or so after coming off the throttle so in the instance it took me to glance away from the road to the display to check the EGT, it was actually reading higher than it was under load giving me the impression I needed to richen the AFR when as you can see by following the trace that the temps increased by another 150 deg after coming off the throttle from 1144 deg to over 1303 deg registered at the end of the trace. You can see a slight elevation before and above the end point indicating a higher temp than the last temp of 1303 registering.

I had some recent problems mentioned in another thread that were addressed. Loose exhaust bolts that caused popping under boost.

Spark blowout that was puzzling at first until an ignition coil trio swap helped identify it. One set of coils produced popping at about 5 psi with pretty much no spark retard and the other coil pack trio resulted in a misfire at about the same boost pressure without popping. I closed the plug gap down from .040 (to .028) where I previously had no problem and used copper plugs that cleared up all but an occasional bout that suggeted the problem was elsewhere.

It appears it's in the tune. The 8F code mask has a boost multiplier table that appears to have a different effect than desired at some point. Realizing I had changed it the most, I started stepping it back down and noticed that it didn't appear to have a noticeable effect on the AFR in log, kind of like the async tables that add small amounts of fuel. It appears that the PE RPM vs. AFR table is the one to go to for changes in boost level AFR as the blowout problem is just about gone altogether now. I'm backing it out a little at a time. Once all appears to be back to normal I'll reinstall The TR6 plugs with the .040 gap as the narrower gap takes away from city MPG in my experience.

I also turned the water injection nearly off (set to a high boost level) as it may have been contributing to the spark blowout given the much lower inlet temps and although it's variable injection it was still coming in at about 5 psi.

Current ambient temps are in the 40s-50s and the IAT runs about 10 deg above ambient at cruise. I'm running 89 octane now for conservative reasons. I didn't intend to run full boost with it but boost pressures have a tendency to climb as the temps drop and this morning despite the 60 mm wastegate boost pressure hit 8 psi without knock retard. I like the reserve given the compression ratio is 11:1. for nomal driving habits I'd have 93 in it.






No knock retard despite the mid grade fuel and absence of water injection.


AFR



Highest boost level so far with, air temps. 93 octane, less than 1% alc injection (nearly water only 20+ deg washer fluid) back in Sept when a loose bolt caused the gate to stick.





The liquid intercooler does a good job.

[This message has been edited by Joseph Upson (edited 11-17-2012).]

...
Rook to queen 4?

Ok, ok, you win.

quote Originally posted by Stubby79: ... Rook to queen 4? Ok, ok, you win.

Ha, Ha, not horn tooting. The problems mentioned above had me clueless for a while across all 3 installs involving the stock motor and the modded. I had been wrestling with spark blowout for over a year and didn't know it as well as the immediate cause of it. It didn't show up in the log from what I could tell either.

A thread like this describing problems with boost problems I had never encountered before (spark blowout, popping under boost etc...) would have been a big help so I'm trying to save someone else the trouble where I can by posting about it. I wouldn't have known right away the miss with one set of coils, was spark blowout were it not for the other set causing popping at about the same point, except for the searching all over the net that eventually described it as having caused one or the other in their experience.

I hadn't managed 8 psi on midgrade fuel without water injection before so it's a new accomplishment to show data for.

Finally got to the bottom of the spark blowout. I mentioned in a different thread that it's my understanding that in order to get the most out of the MSD coils you must use the complete MSD ignition system. They did not help the spark blowout problem at all when installed and many have arrived at the same conclusion.

I swapped in a set of OE coils and put the module assembly back in the stock location and the motor reached ~10 psi with small episodes of misfire but never a complete blowout, eventually reaching 13 psi with intermittent pulses of misfire. Finally after one hard run a few days later, the engine started going into a strong misfire around 4 psi and within minutes of that incident the progressive rate meth injection controller quit working which wasn't a problem because the motor does not need any liquid injection to run through 13 psi. The meth injection makes the motor run very smooth under boost and with a higher percent of meth makes the intake manifold cold to the touch so I like to use it anyway.

I swapped in a second set of OE coils to make sure as I started to think the module was giving out. Upon ohm checking the current set at the time I found the secondary to coil #3 open. The backup set of coils ran the motor clean through the boost range without a hiccup. That was the second coil over a period of time that I discovered had gone bad and that combined with the lower module B+ voltage prior to hot wiring it and a likely weaker ground due to relocating the assembly plus running 100% water for injection (increases spark gap resistance because it's not flammable) for a while all contributed to the problem. I realized the latter after mixing in alcohol and noticing the blowout got better and finally reading an article that pointed out that can happen. With several things contributing to the same problem it makes it harder to resolve.

Along with the coil swap I bypassed the controller to restore the meth injection to basic on/off function and also connected up the preturbo injection nozzle. The difference was with all else the same was that the efficiency increase from injecting in front of the turbo took boost pressure up from ~13.6 psi to just over 15 psi according to the gauge. The 2 bar MAP sensor maxes out at 14.7Psi. Air temps reached 120 briefly on a 90 degree day at that boost pressure but that's before the methanol injection. The intake manifold is actually seeing cooler temps as the meth evaporates.

I'm running 2 deg more advance now with and without the alcohol injection beyond 7 psi where before any additional advance would cause spark blowout even earlier. The motor pulls strong up top and I have to let up before I get going too fast so the dyno will have to identify the cutoff point and I hope to have that done at the end of the month now that the blowout problem appears to be resolved. I have a set of new Delco coils on the way. I'll have to switch to code59 since it's clear that there's more boost range left in it than the 2 bar MAP can measure.



The frayed plug at the knock sensor I discovered after a code 43 set, was actually causing false knock retard. Once repaired even on hot days in the 90s the spark table looks like this:

It'll be very interesting to see the dyno numbers and a data log.

OMG Joseph, That made my head hurt.

Wow, what did you use to get all that great tabulated data?

quote Originally posted by pttransamdriver: Wow, what did you use to get all that great tabulated data?

TunerproRT5.

I also have Tunercat RT although in my opinion Tunerpro is far better in that it has several more functions as well as the cell follower to help keep track of what area the data is being read from in a particular data table.

The data posted is straight from a history table in the program, another benefit it has over Tunercat, which allows you to setup a history table for nearly every data stream in the program to help with tuning.

You can download it from the net.

I sent some info via private message also so check your inbox.

[This message has been edited by Joseph Upson (edited 09-22-2013).]

A couple of questions:

Are you still using $59...It uses a 3 bar map, not a 2 bar map.

If so, did you use the tuning assist, Autotune? It only works with Tunerpro4, but I found it to be very good. You have to sanity check the results, but for the most part they were very good.

Are you using the wideband 02 capture in $59 via the ecm? If so, make sure they jibe with what your 02 sensor is sending out...the ecm nubers and my zeitronix numbers are a bit different, the Zeit is a bit richer, so it's on the safe side.
Chay

quote Originally posted by Slowbuild: A couple of questions: Are you still using $59...It uses a 3 bar map, not a 2 bar map. If so, did you use the tuning assist, Autotune? It only works with Tunerpro4, but I found it to be very good. You have to sanity check the results, but for the most part they were very good. Are you using the wideband 02 capture in $59 via the ecm? If so, make sure they jibe with what your 02 sensor is sending out...the ecm nubers and my zeitronix numbers are a bit different, the Zeit is a bit richer, so it's on the safe side. Chay

I have not been able to use code59 without problems since I switched to the Turbo Grand Prix 727 style ECM, I know they are supposed to be interchangeable with the code but recently Robertsaar found some variations between the three, the 727 and its two variants and I believe that's causing the problem. I could not tune out the idle hunt with and without Quasi mode active which many have been successful with and for some reason the cooling fan would not be commanded on when the A/C was turned on, but would work properly when the 8F TGP code mask was reloaded. I also received frequent logging errors that went away when 8F was reloaded. 59 ran without a problem or idle hunt when I used it initially with the 730 and 749 ecms. It's ashame because I'm running more boost now than I can monitor with 8F.

I did try autotune with TP4 but after a certain point I was going in circles with it. I like TP5 much better because of the history tables and the ability to create them with ease. I run the Zeitronix wideband and it differs slightly from the Tunerpro dash but it tends to read a little on the high AFR side at times and I believe that is mostly the refresh rate as the data update is slower on the Zeitronix display where at the time of power up the AFR is reading instantly in the log while the display is taking its 30 seconds to warm up.

My misfire problem is pretty much resolved and I found the new misfire threshold on pump gas alone to be about 15 psi around 4800 rpm on a hot motor in the 11.5:1 AFR ratio. I turned the alcohol injection back on a couple days ago to cover the occasional swings above 15 psi and eventhough the AFR has dropped into the mid 10s to high 9s in some areas near 15 psi, there was no misfire. I can't explain it as gas at that ratio will blackout the exhaust as well as misfire. I run about about 1/3 water and 2/3 methanol mix. I'll be purchasing a new variable meth controller to restore AFR to the proper range. The Snow unit failed and I found a new alternate from Canada for about half the price, no sense in buying a second of the same kind that has let me down once already, it's a good thing I didn't need the meth. I like the way it smoothes the motor out and the added safety. I inject pre and post turbo and that's what causes boost to swing a little north of 15 psi. The motor runs great despite the added richness fro the alcohol.

http://www.hpcontrols.ca/?item=101005

[This message has been edited by Joseph Upson (edited 09-22-2013).]

quote You can also see the need for a variable rate controller.

Nope. Its flat, with an obvious misfire around the middle of the low rpm pull.

Joseph..thanks for the info on the $59.

Some explanation required on the last stuff here...trying to learn...

Dark, how did you determine there is a low rpm misfire?

Joseph..it's interesting that in the 180 range you seem to have dropped .2-.3 AFR, but in the 190 range you dropped more than that...maybe it takes time for the meth to get to the cylinders and/or register on the 02? It's even more pronounced at the 200/210 levels.

Chay

quote Originally posted by Slowbuild: Joseph..thanks for the info on the $59. Some explanation required on the last stuff here...trying to learn... Dark, how did you determine there is a low rpm misfire? Joseph..it's interesting that in the 180 range you seem to have dropped .2-.3 AFR, but in the 190 range you dropped more than that...maybe it takes time for the meth to get to the cylinders and/or register on the 02? It's even more pronounced at the 200/210 levels. Chay

The values are not consistent enough to draw any real inference from other than the need for the variable controller when you look at the stability of the data without meth vs the one with. The reason being that at 200 Kpa boost is still building but the ECM is no longer adjusting for it because it can't sense it.

Although dark might be right, the car does not feel flat anywhere under acceleration in those areas and actually feels as fast or faster with the meth on but my understanding is that an actual spot on tune feels slower than one that is not. I'll see once the spark booster is added to eliminate any chance of there being insuficient spark.

A lot of the stray rich points down low are the result of off throttle rich condition where the AFR takes a dive and then comes back up so it's not as rich globally since the methanol does not shut off like a light switch. The meth doesn't come on until ~10 psi which is around 170 Kpa, yet the lower cells are still richer with methanol injection on although they have not been adjusted. Variable control will allow me to limit how much is injected up top so that should it fail my AFR on gasoline will still be safe up top as opposed to pulling more fuel to accomodate the meth instead.

[This message has been edited by Joseph Upson (edited 09-23-2013).]

Misfires show up as lean hits on the wideband.

quote Originally posted by darkhorizon: Misfires show up as lean hits on the wideband.

Yep, mine usually show up to be an occasional 12.9-13 AFR spike in a cell that is normally ~11.5.

So you're thinking that the 3200rpm range where it goes higher may be misfire?

Interesting...

Thanks for explaining.

Chay

quote Originally posted by Slowbuild: So you're thinking that the 3200rpm range where it goes higher may be misfire? Interesting... Thanks for explaining. Chay

That's probably the result of the gear I was in at the time, 4th or 5th at a relatively low speed allowing the rpm area to hold longer and subsequently being affected by the methanol excess coming off throttle at the time. With the variable controller in use I had injection set to come on at ~7psi and varied up to the limit instead coming all on at once in excess.

How did it accomplish the variable injection...pwm valve? Multiple nozzles?

I have thought about doing this myself (I can build electronics); it's always the hardware side that's difficult...to find a valve, for example, which will vary, but keep the droplet size small still. I haven't tried it...looking for any real world information.


Chay

[This message has been edited by Slowbuild (edited 09-23-2013).]

quote Originally posted by Slowbuild: How did it accomplish the variable injection...pwm valve? Multiple nozzles? I have thought about doing this myself (I can build electronics); it's always the hardware side that's difficult...to find a valve, for example, which will vary, but keep the droplet size small still. I haven't tried it...looking for any real world information. Chay

Look at the link I posted in response to your second post I believe. Variance is controlled with voltage reduction and step up at the injection pump.

I've pretty much gained control of all of the boost related problems I've been plagued with and am maintaining a pretty consistent boost performance so I'll recap here.

Erratic and seemingly inappropriate knock retard, suspect the knock sensor, or pigtail connection, I had a problem with both.

Spark blowout;

Check plug gap first and make sure it is practical for boost levels and engine characteristics. I've read of gaps in use as little as .015 but I personally believe anything below .020 is too small. Some may argue but I believe the overwhelming consensus is that copper plugs are the best at resolving these issues. I use Bosch Super Plus copper plugs.

When water injection is involved, check the time at which it is being injected, if that's okay consider the water/alcohol ratio, the greater the water content, the greater the chance of blowout in a sensitive system (like high compression).

OE ignition coils are the best performers with coil only upgrades. MSD coils made my spark blowout problem worse because MSD coils are intended for MSD ignition systems. If you do not have a multiple discharge spark ignition (MSD) system then it stands to reason that MSD coils will not be utilized at their intended and maximal potential. Where the MSD coils choked on my motor the stock coils excelled and I would take a junk yard OE coil over a new MSD coil based solely on my experience with both on my motor.

With high compression engines and persisting blowout at a certain rpm with all else corrected which was ~15 psi for me and .020 plug gap, you'll need to look for dwell tables in the code for extra help. Robertsaar set the tables up in 8F code mask for me and after researching ignition coils and stumbling across a table that paralleled spark intensity with dwell time I set mine to the suggested range of 7 ms and my spark blowout problems were history even up as high as 19 psi.

I installed a new set of plugs a week ago and gapped them a little wider at .030, to test the limits of the dwell changes. I also installed a new wastegate as seen in another thread and smaller turbine housing. The blowout problem returned at 15 psi but the nature of it is very similar to what I experienced just before finally resolving the problem months ago when all was going well and suddenly out of nowhere misfire started occurring at a much lower boost level than before but was consistent.

Turns out one of the coils had failed and when they were tested with a multimeter the bad coil gave an open reading although it still fired up to about 4 psi. I haven't checked for the bad coil yet because the misfires don't occur until double digit boost. The higher dwell time along with the wider gap problem took its toll on the old coil assembly so I may drop the gap back down to .020 as there were no apparent side effects to engine performance at the level.

[This message has been edited by Joseph Upson (edited 05-30-2016).]

In reference to the immediate post above, I'm going to take a step back and say that I don't know for sure that the dwell changes in the chip made a difference because I can not say for sure I did not have a malfunctioning part present aside from the failiing coil that would have continued to limit performance despite dwell changes.

What I have found to date after FINALLY achieving consistent performance without misfire is this; OE ignition parts all the way.
Props to all those who have said MSD and other aftermarket alleged performance parts are not better than OE and that I should be able to accomplish stable performance with GM stock ignition parts.

I've gone from one misfire problem under boost to another in short order leading to frustration and settling on far less than the performance potential available. The last weak link that may have been part of the problem for more than a year are the MSD plug wires. The 8mm diameter and attractive red color is the best thing about them and says nothing about performance potential and reliability. Removing them from the engine is one of the best performance improvements I made.

I replaced them with a standard diameter wire set of Premium Bosch plug wires and AC Delco plugs spec'd for the Turbo Grand Prix and have not had a hiccup from the engine since consistently boosting to 15 psi and holding through 5000 rpm without the misfire noted in the dyno run at 4100 rpm. The coils and module are AC Delco. The Premium Bosch plug wires were picked up from RockAuto for one of the early 3800SC applications and I consider them OE in this case because of their OE manufacturing experience.

My plugs were gapped to .015 before discovering the MSD wires were the persisting trouble makers.

So, I recommend without compromise OE ignition parts end to end and plug gap changes as needed.

That's a must in my opinion before any aftermarket performance ignition part based on customer testimony, rather than cold hard data (which big name aftermarket companies never seem to have) is purchased.

MSD wires unless otherwise stated do not meet OE guidelines for our computer controlled cars which should have RFI suppressed wires not only for noise free radio play back but also to avoid the possibility of PCM/ECM performance. Low resistance, one of the selling points for MSD wires does not necessarily mean better performance and neither does the 8 mm wire diameter which says nothing about the quality and thickness of the core which delivers spark energy.

Buyer beware.

[This message has been edited by Joseph Upson (edited 05-30-2016).]

It is well documented that the 3800 SC community has had problems with MSD plug wires. I do not think the issue is due to the low resistance core of their plug wires, but rather, their insulation or their construction/design.

Low resistance wires don't pose much of a problem for the electronics in the Fiero, including whatever ECM/PCM you are using. I use Crane Firewire spark plug wires which are 25 ohm per foot resistance in my own car + some I've done swaps to and never had an issue with them. I think the particular set of FireWires I have in my personal Fiero have been in there since 2003 and they still work great. No radio noise either.

I've also used Taylor RFI Suppressed aftermarket wires in a few swaps for those customers who preferred some different color spark plug wires other than black (which is all the Firewires are available in). Never had any issues with the Taylor wires either.

I would like to add that I have worked on numerous cars that came to my shop with running problems due to defective aftermarket ignition components (ignition boxes, coils, etc). In all cases, replacing the aftermarket components with OEM / OEM-replacements cured the problems. The aftermarket "high performance" coils and ignition boxes just don't seem to tolerate daily driver use very well. I think they are only designed for limited racing use, not frequent street use.

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quote Originally posted by Darth Fiero: It is well documented that the 3800 SC community has had problems with MSD plug wires. I do not think the issue is due to the low resistance core of their plug wires, but rather, their insulation or their construction/design. Low resistance wires don't pose much of a problem for the electronics in the Fiero, including whatever ECM/PCM you are using. I use Crane Firewire spark plug wires which are 25 ohm per foot resistance in my own car + some I've done swaps to and never had an issue with them. I think the particular set of FireWires I have in my personal Fiero have been in there since 2003 and they still work great. No radio noise either. I've also used Taylor RFI Suppressed aftermarket wires in a few swaps for those customers who preferred some different color spark plug wires other than black (which is all the Firewires are available in). Never had any issues with the Taylor wires either. I would like to add that I have worked on numerous cars that came to my shop with running problems due to defective aftermarket ignition components (ignition boxes, coils, etc). In all cases, replacing the aftermarket components with OEM / OEM-replacements cured the problems. The aftermarket "high performance" coils and ignition boxes just don't seem to tolerate daily driver use very well. I think they are only designed for limited racing use, not frequent street use.

I believe the most important of what you've pointed out is aftermarket performance ignition parts causing problems that are remedied with OEM parts. We are programmed to think "Racing performance" parts are some how automatically better than OEM and that's likely untrue more often than not because as you've alluded to, they're designed for race applications, not daily driven/frequently driven applications and therefore tend not to hold up well under continuous use.

In the additional literature I've read, I also discovered that low ohm wires do not necessarily translate into better spark, otherwise the MSD wires would have resolved if not greatly improved the misfire problem I had when they were installed new. They didn't make a difference but they did interfere with my radio and possibly the ECM in between and that's quite suggestive going from thousands of ohm resistance OE wires to less than 200 ohm each Performance/MSD wires. It's clearly not as simple as the measured low resistance and on the level we are seeing it, it is more a selling claim than a dependable performance improvement. I'm certain an approach from an electrical engineering standpoint would bear that out.

Whatever the case, I've thrown in the towel on the aftermarket performance craze and need to track down a backup set of wires like the ones I already have. I'd love to have the money back for that noisy Walbro fuel pump that many spoke so highly of. If it can't withstand OE duty, it's worthless to me, that noisy thing ran hot and left me stranded at the gas pump where a cop had to help me push my car into a parking space. Right now the most common brand name on my engine is GM/AC Delco/Delphi.

[This message has been edited by Joseph Upson (edited 06-02-2016).]

quote Originally posted by Joseph Upson: I believe the most important of what you've pointed out is aftermarket performance ignition parts causing problems that are remedied with OEM parts. We are programmed to think "Racing performance" parts are some how automatically better than OEM and that's likely untrue more often than not because as you've alluded to, they're designed for race applications, not daily driven/frequently driven applications and therefore tend not to hold up well under continuous use. In the additional literature I've read, I also discovered that low ohm wires do not necessarily translate into better spark, otherwise the MSD wires would have resolved if not greatly improved the misfire problem I had when they were installed new. They didn't make a difference but they did interfere with my radio and possibly the ECM in between and that's quite suggestive going from thousands of ohm resistance OE wires to less than 200 ohm each Performance/MSD wires. It's clearly not as simple as the measured low resistance and on the level we are seeing it, it is more a selling claim than a dependable performance improvement. I'm certain an approach from an electrical engineering standpoint would bear that out. Whatever the case, I've thrown in the towel on the aftermarket performance craze and need to track down a backup set of wires like the ones I already have. I'd love to have the money back for that noisy Walbro fuel pump that many spoke so highly of. If it can't withstand OE duty, it's worthless to me, that noisy thing ran hot and left me stranded at the gas pump where a cop had to help me push my car into a parking space. Right now the most common brand name on my engine is GM/AC Delco/Delphi.

It is worth mentioning that GM installed spiral core / lower (than standard) resistance wires on all production 3800 Series 2 and 3 Supercharged engines at the factory.

quote Originally posted by Darth Fiero: It is worth mentioning that GM installed spiral core / lower (than standard) resistance wires on all production 3800 Series 2 and 3 Supercharged engines at the factory.

Good to know, I have Bosch Premium for series 1.