Thats when your decklid is open and you are idling .... do you see this pressure when running on the road driving ... sound like engine starvation (gas) if ya accelerate it sputters and backfires ... not enough gas or ignition ... My V8 had the same symptoms on the highway ... at idle everything was normal.
Hmmm will check tomorrow. I can give it gas with the decklid open and watch the fuel pressure. I am running a fuel pump out of a Silverdo. Before I out the regulator in place to bring it down to 52 PSI, it was pushing almost 100.
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Originally posted by wgpierce: Just an extreme shot in the dark, but what did you gap the plugs at? I just recall years ago putting a supercharger on my LS1. Forgot to re-gap the plugs, idled fine but the second you were into a tiny bit of boost BAM no sparky
I do not remember the gap off hand, but it was looked up for a 2004 Pontiac GTP 3800 SC.
[This message has been edited by JohnWPB (edited 06-30-2017).]
Originally posted by tshark: John, I'm thinking of a nickname for your car. Is your ESP working?
Does a person that shares this nickname, live in Colorado, and does a Fiero calendar each year?
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Originally posted by tshark:
Dunno, but I forgot what I was thinking on this.
I thought sure you were referring to "Christine", as this car has much spite towards me.... It just has failed, as Christine did, to repair itself! LOL
Ok, been getting LOTS of advice, and ideas as what to trouble shoot. I want to put everything I can into one single post, as I have gotten the same advice many times, and advice to do stuff that has already been done and posted about several times.
I have a Series III 3800SC. It has a Gen 5 blower. I have a Series II throttle body and adapter plate. I just had the computer programmed by Ryan (Darth Fiero) at Sinister Performance to the exact specifications of my setup.
The car will accelerate slowly, and smoothly and I can cruise along at 75 MPH no problem. If however I try to accelerate to quickly, the car will cough and sputter. It happens JUST at the point where you can feel that the super charger would kick in. If I continue to accelerate quickly, it will buck pretty bad, and I get black smoke out the exhaust. If I back off the accelerator, it will return to accelerating slowly and smoothly.
Saturday Morning, I thought to myself, I have AAA, so I headed out on a bit of a road trip. almost 200 miles round trip. I could only accelerate slowly, but at speed it ran well. Of note, I did burn almost 2 full tanks of gas! So obviously there is something wrong. One should be able to get around 300 miles on a full tank, verses 100 miles per tank. I got a chance to fill the car today, and come to find out, , I actually burned 11 gallons going there, and on the way back, only around 4 gallons. So that just complicates things as far as trouble shooting
I have replaced the MAF sensor, (03/05/16) (Ryan programmed for the one that I have) I also checked it today and the filament is nice and clean. The MAP vacuum line goes directly to the port just under the snout of the super charger I have 52 PSI of fuel pressure, that stays steady as I advance the throttle on the throttle body with my hand, both when doing so slowly or "blipping" it. The spark plugs are new and are properly gapped to .45 per this engines specifications The wires are Accel, and are one year old. Though they only have a few hours run time on them The injectors are stock, cleaned on my bench with a 9 volt battery and brake cleaner, and were programmed for in the tune.
With all the advice I have gotten so far, a lot of people were pointing to both the coils and the TPS as likely candidates. I replaced both tonight: I have replaced the coils (07/03/17) I replaced the throttle Position Sensor (07/03/17)
After changing the TPS and the coils, the car is now idling VERY high. I started it, and quickly put it into drive and went around the block hoping it was a matter of the computer re-learning the new TPS. I drove it for around 5 minutes, and It is still idling at just around 3,000 RPM!
I FOUND THE IDLE PROBLEM SEE THE NEXT POST BELOW
Anyhow, even with the high idle, I was able to try to accelerate quickly, and nothing has changed. It still coughs and sputters. At least I have ruled out the TPS and the coils.
[This message has been edited by JohnWPB (edited 05-09-2021).]
Ok, everyone has talked about not enough fuel but how about too much. 2 (full?) tanks in 200 miles?? Sounds like its just dumping it in. Bad injectors or something?
Originally posted by phonedawgz: Try bringing your plug gap down to .45. Are your injectors stock?
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Originally posted by JohnWPB: The injectors are stock, and were programmed for in the tune. The spark plugs are new and are properly gapped to this engines specifications
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Originally posted by wgpierce:
Ok, everyone has talked about not enough fuel but how about too much. 2 (full?) tanks in 200 miles?? Sounds like its just dumping it in. Bad injectors or something?
It is a possibility.... I do not mind some little parts here and there, but I do not want to toss handfuls of money at the car, such as 6 new injectors would cost. I attribute the bad gas mileage to something still being wrong with something. Would it be possible that many of the injectors have gone bad? Would it not normally be just one, and just cause a slight miss instead of the car coughing and sputtering at acceleration?
Oh, I now have the ability to read just about every sensor on the car now thanks to Ryans write up in another thread. I do not know what a lot of the values of the sensors mean. I can create a log or video of sensors that people know would help diagnose the problem. I just need to know what information from the scanner would be helpful. Manifold pressure? Intake Temp, MAP ect....
Also, PLEASE reply here in the thread. I have gotten quite a few PM's with advice, the same advice quite a few times. Post everything here "out in the open" so to speak so everyone can follow along and see what has been done, and has been suggested.
I sincerely appreciate all the advice and help from everyone!
black smoke is normally from to much fuel. I honestly would look at injector pulse width. It is something set from the tune of the computer. Injectors that are bad are bad at light acceleration and heavy acceleartion. Is there a dyno/tune shop close that you can put the car on? Probably cost you 100 to 150 but they should be able to tell you if all the sensors are workng and if the computer is set to rich or if the advance is off. Just a thought...
You have a mismatch somewhere. Yes great advice! Now that you can read all sensors you will need to teach yourself a little about ECM tuning to learn what everything means and try to diagnose were the problem could be. Some here can tell you what to look too if you get lazy. The problem you have is under load. It is definitely something wrong with spark/timing or fuel or both. You need to read what is the timing doing once engine gets under load. A chart of MAP vs timing vs RPM is key. If that looks ok then yo need to check fuel delivery. Also you need to be able to read misfires. Under that bucking yo should get them. If above is ok then maybe your Accel wires (crap to me) or plugs may have some issues. All SC engines are super sensitive to spark. Will run perfect at idle but put a little boost and all can go crap. Have seen it on my SC Fiero ad on my SC F-150. Definitely an incorrect/bad sensor could create havoc. But it may not be that. Now going back to that heavy fuel consumption cold mean some injector issue (all incorrect) or incompatibility or car running on some limp mode. But it is weird that it does not throw a code. Are you 100% sure you got the right injectors for that engine? Again, it will idle fine but will go crazy under load. Use that scanner to your advantage before throwing more $$ at it. Good luck.
Couple of things, When doing any sensor replacement you are resetting the computer correct? Also have you been to a physical tuning shop? Talking to someone who wrote a tune over email or phone is great but its all guessing. Spend the money throw the car on a dyno and let someone read the values being put out and they should be able to exactly tell you where the problem is. Odds are there is an issue with AFR when you get into it, they should be able to adjust it to atleast make you happy, or point you in a direct sensor wise that may not be reading correctly.
I edited the message above.... come to find out my little road trip, I used around 10 gallons on the way there, and only around 4 on the way back. Strange, yea I know.....
I like the idea of having it Duno'd. Not that I am too lazy to figure it out myself, it's just that I honestly do not know what I am looking for in all of the sensor data. A Dyno could hopefully nail it down to some specific thing to replace, or what would need to be changed in the tune.
[This message has been edited by JohnWPB (edited 05-09-2021).]
I edited the message above.... come to find out my little road trip, I used around 10 gallons on the way there, and only around 4 on the way back. Strange, yea I know.....
I like the idea of having it Duno'd. Not that I am lazy, as mentioned above, just that I do not know what I am looking for in all of the sensor data. A Dyno could hopefully nail it down to some specific thing to replace, or what would need to be changed in the tune.
I was doing some research of good shops in Florida there was one a few towns away from you that specialized in LS and EFI. They would be the route I would go. Honestly for a few hundred bucks its better than taking random shots in the dark. Just call around and find someone who is familiar with the 3.8, realistically though any good tuner should be able to help you with a Dyno sheet telling them exactly whats going on. But once again Ryan can't be sure with any suggestions as he doesn't have a read out. You'll also make quite a bit more power and run better on a dyno tune. (Not saying Ryans tunes are bad, just this is a specific situation)
Originally posted by Phirewire: I was doing some research of good shops in Florida there was one a few towns away from you that specialized in LS and EFI. They would be the route I would go.
Yea, I found one shop fairly close to me. I emailed them with all the details and asked if they are familiar with the 3800SC and what their rates are. I want a lot of info before I do anything with them. Their web page has 3 YouTube videos, that just show cars parked in a parking lot. No tuning, no equipment, no shots of the shop ect.
I just took the Fiero up to the store. Today, after the new coils and TPS, it is running slightly better. I can accelerate on a faster curve before it starts choking. I can actually start to hear the whine of the SC and if I maintain that throttle, it accelerates fairly decently. So at least the coils and TPS was not a waste.
I am headed to meet CaptnDean to grab a bite, and watch the fireworks on the inter coastal down town. It will be the first time he has seen the car running LOL!
HAPPY FOURTH OF JULY EVERYONE!
[This message has been edited by JohnWPB (edited 07-04-2017).]
I edited the message above.... come to find out my little road trip, I used around 10 gallons on the way there, and only around 4 on the way back. Strange, yea I know.....
I like the idea of having it Duno'd. Not that I am lazy, as mentioned above, just that I do not know what I am looking for in all of the sensor data. A Dyno could hopefully nail it down to some specific thing to replace, or what would need to be changed in the tune.
Sorry. Didn't mean to offend you with the comment. Engine swaps require you to learn the ropes or pay someone else to get things right. If you have the $$ then a dyno shop can tune your car. Do not expect it to be the regular dyno sheet fee. Specially if they find issues to fix and you may need to go back. Again, trying to help. Good luck either way.
Dyno is a great idea. My first look would be at O2 sensor data vs dyno, that will tell you instantly how rich it is when you get on it. Any good dyno shop will have a wideband O2 that will tell you outside of what the ECU thinks the A/F ratio is so you can compare them. Even if they know nothing at all about a 3.8.
I agree with taking it to a good auto repair shop. They can scan the computer while they are driving it and freeze the scanner when the problem starts to act up. Then they would review that data. That should zero you in to the problem
Originally posted by Alex4mula: Sorry. Didn't mean to offend you with the comment.
Alex, no way... I was not offended in the slightest. I appreciate and and all feedback, especially from someone I know personally, and has been through this on more than one occasion.
The Dyno seems to be a good idea from the feedback I am getting. I will have to see what the shop hours are around here, as I work till 6am ~ 3pm M~F and have weekends off.
I will look into the spark plug gapping and see. It most certainly could be part of it, but I do not think that it is the root of the problem. I say this because, when I drove the car tonight, it accelerated better than it has in the past... FAR better. I did a 0 to 60 in probably 10 seconds tonight with slow steady acceleration from a light. It would have been 0 to 60 in 30 seconds a couple of days ago. It still will cough when you accelerate, but I have to accelerate harder / faster for it to do it now. All I have done in the past 6 days is replace the coil packs and the TPS. That only helped slightly, but now it is getting better gradually. A Dyno I think is definitely in the forecast to get to the bottom of this.
On a side note, CaptainDean got to ride in my Fiero tonight, and we went and caught the fireworks downtown on the water.
[This message has been edited by JohnWPB (edited 07-04-2017).]
If I missed it, what are the factory spark plug gaps for these 3.8s? .050 or more still sounds big to me for a supercharged application. My factory supercharged 5.0 Ford running 6lbs boost has a spec of .9 mm (.035) which sounds more correct to me.
BTW, IMHO adding strong coils with a hotter spark to a supercharged engine that was experiencing blow out because the gap was too large to begin with would make it run a little better.
[This message has been edited by wgpierce (edited 07-05-2017).]
If I missed it, what are the factory spark plug gaps for these 3.8s? .050 or more still sounds big to me for a supercharged application. My factory supercharged 5.0 Ford running 6lbs boost has a spec of .9 mm (.035) which sounds more correct to me.
BTW, IMHO adding strong coils with a hotter spark to a supercharged engine that was experiencing blow out because the gap was too large to begin with would make it run a little better.
You would think that. My SC Harley F-150 must run at .035 to .040 at 12lbs boost. But these 3800SC are different. I think I ran .050 with one step smaller pulley. To be safe maybe you could start at .045. I agree that buckling/missfire under load could be caused by too much plug gap too. I like this post from another thread from a very knowledgeable member here.
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Originally posted by Darth Fiero:
I run a 0.055" - 0.060" gap on Iridium plugs in stock or mildly modded 3800 SC engines.
I run a 0.045" - 0.050" gap on copper plugs in stock or mildly modded 3800 SC engines.
On my turbo 3800 Series 2, I run Denso Iridium plugs with a 0.050" gap (had to decrease the gap to prevent misfires at higher boost levels but it runs fine otherwise).
The amount of plug gap you are going to be able to run is going to depend on boost/power level. Also, I recommend to everyone who is running a 3800 SC or Turbo engine to NOT run the stock heat range plugs in these engines. If you have a 100% bone stock 3800 SC engine, you will probably be "safe" using the stock 41-101 heat range plug. Stock Delco 41-101 plugs are Iridium and a very hot heat range. I recommend running the coldest plug you can get away with (and not have fouling problems with it), especially if you have done/installed any mods whatsoever. See heat range chart below:
DO NOT run platinum plugs in any SC or turbocharged engines. I've seen the high combustion temps generated by such engines blow the platinum tips right off these plugs and those pieces can wedge between the piston and cylinder wall causing damage.
-ryan
[This message has been edited by Alex4mula (edited 07-05-2017).]
Originally posted by Alex4mula: I like this post from another thread from a very knowledgeable member here.
Yes, he is very knowledgeable. He is the one that programmed my PCM. I will check the plugs and see what they are gapped at just to verify. Oh! Lou says hello, I stopped by his house today to say hello. Dean said to also say hello, and he had no idea you even moved.
Yes, he is very knowledgeable. He is the one that programmed my PCM. I will check the plugs and see what they are gapped at just to verify. Oh! Lou says hello, I stopped by his house today to say hello. Dean said to also say hello, and he had no idea you even moved.
Darth did my PCM too. Didn't even had to touch it. Ran perfect from day 1. Yes I miss a lot my FL Fiero friends. Say hi to Dean too!
Darth did one for me for a V8 as well, very good quality. Ryan is also a good guy.
Jason, Darth & Ryan are one in the same
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Originally posted by nosrac:
What year/car MAP are you running as that isn't from 1998-2003 SC Grand Prix version? It looks like a NA and NOT a SC MAP sensor.
Uggg.... I just replied to your PM in length, not knowing you posted here about it as well.... Let me copy the PM here: . .
.
"Do you still have your old PCM that DAN programmed 4 you? If so If you send it to me I can reprogram the correct MAF in it 4 free. (to eliminate possibility of a bad PCM) You can always just sell the extra PCM. Also, if you have a Bluetooth OBD II scanner can you get some logs and email them to me. I can look to see if there is anything majorly off. Did you perform a case learn? If not please do so as it may help.
I do have the old PCM, but not sure if a MAF tune would help it. Ryan said there were 2 different MAF's for the series II TB. He had me take it out, and send pictures from multiple angles so he could make sure he was programming for the correct one. I also unplugged the MAF, and took it for a test drive, relying only on the "backup tables" in the PCM and it acted the exact same way, with no noticeable changes. am going to try to take the car for a spin later this evening, and capture a good log.
I have not done a case learn as of yet, as Torque Pro does not seem to be able to do that over Bluetooth. I need to get it to a shop to trigger it with the proper wired scan tool. I have made sure to not go over 50% ~ 60% of the throttle till this is done.
Thanks for the help, it is very much appreciated!
[This message has been edited by JohnWPB (edited 07-06-2017).]
Uggg.... I just replied to your PM in length, not knowing you posted here about it as well.... Let me copy the PM here: . .
.
"Do you still have your old PCM that DAN programmed 4 you? If so If you send it to me I can reprogram the correct MAF in it 4 free. (to eliminate possibility of a bad PCM) You can always just sell the extra PCM. Also, if you have a Bluetooth OBD II scanner can you get some logs and email them to me. I can look to see if there is anything majorly off. Did you perform a case learn? If not please do so as it may help.
I do have the old PCM, but not sure if a MAF tune would help it. Ryan said there were 2 different MAF's for the series II TB. He had me take it out, and send pictures from multiple angles so he could make sure he was programming for the correct one. I also unplugged the MAF, and took it for a test drive, relying only on the "backup tables" in the PCM and it acted the exact same way, with no noticeable changes. am going to try to take the car for a spin later this evening, and capture a good log.
I have not done a case learn as of yet, as Torque Pro does not seem to be able to do that over Bluetooth. I need to get it to a shop to trigger it with the proper wired scan tool. I have made sure to not go over 50% ~ 60% of the throttle till this is done.
Thanks for the help, it is very much appreciated!
What about the MAP sensor? It looks like a NA one.
It was the pair of them that was bolted on this Series III SC When I got the engine.
So you are not sure if it is a NA or SC one? Does a Series 3 have 2 MAP sensors? I assume one for the computer and one for a Gauge? Get some good logs to so I can see your vac & boost numbers.
Your intake temps are high as hell. You may want to put that filter in the quarter panel. Also, where did you get that FPR? Does it work like the stock FPR on a S2 fuel rail but adjustable?
Can anything ever go right..... I spent a half hour setting up Torque Pro and selecting what to log. I set it to start logging when the app starts. I hopped in the car, got up to the corner, and started the app. All the gauges in torque registered perfectly, so the Bluetooth is working. I could read the gauges I have set up on the screen for Coolant Temp, MAF, RPM ect ect...
I get back to the house, and Torque absolutely REFUSED to upload to Google Drive. It did create the folder I told it to save to..... So half an hour later after dealing with RootBrowser, and copying files around, I was able to email the logs to myself (No SD card slot in this tablet). I open the log and all the column headers are there GPS Speed, Altitude, RPM's, Coolant Temp and so forth. All of the GPS and sensor data from the tablet recorded in the respective columns, but all of the OBDII Data is completely empty. I will now have to trouble shoot a problem, so I can trouble shoot another problem.... It never ends hahah!
Here is a cap of the dashboard I have set up to monitor, you can see it is connected and showing data perfectly:
