thank you for offering your lower intake manifold for free, this is very nice! Of course shipping costs are very expensive from USA - Austria, but in the end the shipping costs will still be cheaper than buying a LIM form a German or Austrian junkyard. I think total shipping costs are somewhere in the neighborhood of $70-75.
However, I hope that my Fiero also works with the 3.4L Firebird LIM without any problems. I´ve already invested so much time for cleaning, porting, sandblasting and painting the Firebird LIM, therefore I would prefer to use it. (furthermore the stock Firebird LIM has slightly larger intake ports than the Fieros LIM)
IAC and air tube: I´ve used/misused the EGR tube for solving this problem!
Basically the working principle of this “throttle body to EGR inlet” is the same as with the OEM CSI air tube hose. The only difference is, that the modified EGR-pipe supplies all six injectors with fresh air through the IAC valve, instead of supplying the CSI only (which is not available anymore due to the LIM swap).
BTW, soon I´ll finish the engine work on my Fiero and then I try to fire the engine up and will let you know, whether all is working or if there´re any issues with these mods.
Stay tuned!
Update, 23th July:
In the meantime I have bought some new Fieros, a red ´88 Fiero GT and a ´87 Fiero GT as a donor car. On the ´88 Fiero I have made the same modifications and everything is working perfect!
One important thing you should know about the custom TB bypass EGR pipe for the IAC is, that you should use a thick and rigid gasket (~ 2 mm) on the fitting with a 5 mm hole in the center. If you use the stock EGR gasket, then the diameter would be too big, which results in too much air flow through the IAC valve -> high idle speed. In my case, a 5 mm hole is sufficient, cold idle is about 1100-1200 rpm and warm idle ~ 900 rpm. (TB adjustment screw is still in stock position).
I recommend this mod to everyone with a broken lower intake mani!
[This message has been edited by Moar (edited 07-23-2015).]
After this I got some starting problems related to the ignition system. The distributor caused some big problems, because there was a worn carbon contact pin (in the center of the dizzy), which couldn´t transfer the spark to the rotor anymore due the big gap btwn. these parts. For a quick fix, I´ve sacrificed one of my old ballpoint pens and have used the spring inside the pen for pushing down the carbon pin to the dizzy rotor for ensuring proper spark transfer.
Finally she started up without hesitation!
Today I´ve set the ignition base timing to 10° BTDC and tried to adjust idle speed to a reasonable value between 800 - 900 rpm (closed loop / warm engine). (acc. quick online research this should be the stock idle speed for V6 Fiero's with manual trans?).
For the idle adjustment, I grounded the ALDL terminal (diagnostic mode), switched ignition to "ON" position and disconnected the IAC connector. Then I removed the jumper from the diagnostic connector and started the engine for adj. idle to 650 rpm. Now I get an idle speed of ~ 1000 rpm with the IAC connected again (@ warm engine). 1000 rpm is still a bit too high, but acceptable for the moment (@ cold start idle is btwn. 1500 - 1800 rpm).
BTW, the drop in idle speed from 1800 -> 1000 rpm (from cold start to closed loop operation) confirms, that the "IAC EGR pipe mode" is working!
FYI: I think, the high idle speed on my engine has nothing to do with all these modifications I´ve carried out, because the idle was already not adjusted correctly as I´ve bought the car. Idle speed was about 1500 rpm as I´ve bought the car. (@ cold start it was even 2500 rpm!)
Perhaps something is wrong with my IAC and/or TPS!?
I think, the high idle speed on my engine has nothing to do with all these modifications I´ve carried out, because the idle was already not adjusted correctly as I´ve bought the car. Idle speed was about 1500 rpm as I´ve bought the car. (@ cold start it was even 2500 rpm!)
Perhaps something is wrong with my IAC and/or TPS!?
Has the "tamper proof" idle speed screw on the throttle body been messed with?
Yes, some previous owners have already messed up the TB screw setting. One owner has set the TB butterfly position to get a 5 - 7 mm gap btwn. TB bore and butterfly (@ fully closed TB)!
Perhaps he wanted to compensate a dirty air filter with this!??
@f85gtron: You'll carry out the Firebird/Camaro LIM swap, too?
In case you also want to use the EGR tube for the IAC valve air bypass, you should use a torch for bending the tube. Otherwise it may break or crack, because you will need to bend it quite a lot!
For a sealing connection btwn. EGR tube and TB IAC hole, I used a short connection tube in the right diameter (a plastic tube which fits the O-ring in the IAC hole) and glued this plastic tube into the EGR tube with RTV sealant. (of course, on the TB side I haven´t used RTV, because there is the O-ring which seals to the plastic pipe)
Did I see that right? The p.o. routed a vac from the intake to the plenum? He must have had some kind of idle issue bypass the iac like that. Hmmm. Yes, I'm thinking of doing exactly what you've done. It appears the 3.4 lim is more open for moving air. I'm thinking it would breath better without those exaggerated humps before the injector ports. Although, there are arguments in here about the effects of removing those humps, so I'm on the fence about that one. I'm interested in what you'll report about driving behavior......
check out my old post from 05-04-2015 04:11 AM on page 1. I´ve updated this post with pictures and a I have also included a Youtube link from a Cobra tuner regarding porting / grinding LIM humps.
As far as you don´t grind away these humps completely, you shouldn´t get any problems. Try to grind these humps into small ramps like the Cobra tuner did it. I think the Cobra tuner knows what he does!
Unfortunately, I can´t say anything about my car´s engine performace or driveability now. At the moment my car is not insured / registrated and I´m living in a big city (Linz) with too many cops out there.
I checked it out. I understand it. Time to get out the grinder again! I didn't notice it before, but the coil button on the dizzy cap is missing in all the photos. I see where you've mentioned a repair using a ball point pen.....what else do you have up your sleeve?! Also, cool thumbs up in the polished valve cover pics
In these pictures from the post on page 1, you see the dizzy cap directly after painting. (original color was gray)
Therefore, you still see the small piece of tape in the center of the cap which should keep away the paint from the center hole.
Inside the cap´s center hole there was only a small, already too short carbon contact pin.
I don´t know, whether any parts are missing here, but obviously it hasn´t worked for me. For this reason, I tried to find something which pushes this carbon pin down to the dizzy rotor for assuring proper spark transfer btwn. contact pin and moving rotor.
I figured out, that a simple spring from a ball pen fitted perfectly!
Today I have removed a lot of unnecessary junk from the Fiero´s engine bay (another 5 kg saved!). I will give you some detailed updates with pictures tomorrow.
Here is a picture before cruise control and EVAP delete:
In above picture you can see, that I´ve already routed the vent line from the gas tank directly to the throttle body´s EVAP vacuum port for preparing removal of all this junk.
In this vent line I´ve also incorporated a check valve, which ensures that no humid air or other **** can flow backwards into the gas tank. (The Fiero´s gasoline tank can´t build up any vacuum, because there is a vacuum/vent valve in the gas cap.)
The check valve allows fuel vapors to escape out of the tank. Gasoline vapors will then be sucked into the TB´s EVAP opening port and will be burned.
Furthermore, I recommend to use a check valve which needs a certain cracking pressure to relief the fuel vapors (cracking point of ~ 50 – 100 mbar would be sufficient). Otherwise fuel vapors could escape permanently (but only very small amounts)!
$2 Check valve from China (Aliexpress):
Clean engine bay after cruise control and EVAP delete:
My Fiero garbage bag so far - 5 kg of junk:
BTW, I also have removed all the old carpets. Driver + passenger side carpets scale about 26kg – remove this **** !!!
I always remove all the junk of my cars!
Weight reduction not only gives your Fiero a better power-to-weight ratio, it also makes the car more responsive / better handling.
[This message has been edited by Moar (edited 05-12-2015).]
Clean engine bay after cruise control and EVAP delete...
I don't understand the benefit of removing the EVAP system. There's a Fiero guy locally who promotes this practice and all he accomplishes is stinking up the air with the smell of raw gas.
[This message has been edited by Patrick (edited 05-11-2015).]
When you use a check valve, which has a certian cracking point (~ 50 mbar or 100 mbar), then you won´t smell any raw gases in your garage. The fuel fumes will only escape when there is some pressure build-up in the gas tank (e.g. sun shines on you car), then these vapors will vent into the TB. After starting the car, all these vapors will immediately be sucked into the engine.
You can also ask the other way around - Why someone sould keep the EVAP system with all these vacuum hoses, hard lines, brackets and the big EVAP canister? IMO it´s just unnecessary emission related junk, which messes up the engine bay and adds additional weight to the car.
I also don´t need cruise control in my Fiero, because for longer journeys I usually drive with my Jag.
[This message has been edited by Moar (edited 05-12-2015).]
You can also ask the other way around - Why someone sould keep the EVAP system with all these vacuum hoses, hard lines, brackets and the big EVAP canister? IMO it´s just unnecessary emission related junk, which messes up the engine bay and adds additional weight to the car.
So GM put their EVAP system on millions of cars just for fun? I suspect not.
The local Fiero guy I referred to earlier who removes all the emission related hardware on his Fieros is convinced that he gains more power and increases his gas mileage. Other than his Fieros smelling obnoxious, I doubt he's experienced any difference.
Well, they did it because the government made them. But pointlessly letting hydrocarbons escape into the atmosphere to make your engine bay look pretty or in pursuit of phantom horsepower is just wrong.
So GM put their EVAP system on millions of cars just for fun? I suspect not.
Of course car makers don´t install EVAP systems just for fun. They install it, because they are forced to install it by emision legislations since 1970/1971.
This also applies to the EGR, basically it was introduce for reducing NOx emissions.
The local Fiero guy I referred to earlier who removes all the emission related hardware on his Fieros is convinced that he gains more power and increases his gas mileage. Other than his Fieros smelling obnoxious, I doubt he's experienced any difference.
Of course, deleting the EVAP system won´t give you any power gains! It only makes your engine bay cleaner and slightly improves power-to-weight ratio - that´s all.
Running your car with or without EVAP shouldn´t influence gas mileage.
But pointlessly letting hydrocarbons escape into the atmosphere to make your engine bay look pretty or in pursuit of phantom horsepower is just wrong.
I also wouldn´t recommend an open fuel vent system, too. Basically, my modified fuel vent system works similar to the stock EVAP system, just without the charcoal canister.
If there should be some pressure build-up in the gas tank, then vapors will escape into the TB and will accumulate there in very small amounts. As soon as you start the engine, fule vapors will be sucked into the engine and all hydrocarbons and other pollutants will be burned.
[This message has been edited by Moar (edited 05-12-2015).]
Of course car makers don´t install EVAP systems just for fun. They install it, because they are forced to install it by emision legislations since 1970/1971.
This also applies to the EGR, basically it was introduce for reducing NOx emissions.
Perhaps I should've rephrased my question... Did governments mandate these air pollution measures "just for fun"? That's a rhetorical question, but seriously, is it a bad thing to want to reduce air pollution?
I'm not trying to give you a hard time, but when items such as EGR valves and EVAP systems do not affect a car's driveability in any manner, any cosmetic advantage to removing them is far outweighed by the negative effects that result.
That's a rhetorical question, but seriously, is it a bad thing to want to reduce air pollution?
Reducing pollution is not a bad thing, as far as it doesn´t reduce engine performance. But honestly, people who really want to protect the environment with low-emission cars, shouldn’t drive an old Fiero. (For environmentalists a Tesla would be the way to go, as far as the utilized electricity isn´t produced by a coal-fired power plant!)
[This message has been edited by Moar (edited 05-12-2015).]
I can't see that the fuel vapors will be stored in the air intake. While the car is sitting, if the temperature warms, the fuel and vapors in the tank expand, forcing fuel vapors into the air intake, they will migrate downward and exit to the atmosphere through the side intake, what with gasoline vapors being heavier than air. I can just imagine what might happen if the car should backfire through the intake when starting it.
I recently removed my evap canister, and have my tank vent plumbed to the intake ducting, just ahead of the throttle body. Just upstream from that is a cone type air filter. (This is a 4.9 install.) My car sits in a closed garage - frequently with the decklid open. I can walk up to it and not smell a bit of gas. As it was before, with the regular evap system in place and connected to the throttle body, as stock, a few thimble-fulls of gas would actually puddle in the intake plenum. This certainly can't be any worse. If I get really concerned, I'll put a check valve inline, in the vent hose.
[This message has been edited by Raydar (edited 05-12-2015).]
I know that my modified fuel vapor vent setup can be improved. This is just an initial test setup now. I also thought about venting the fumes into the intake ducting or into the OEM air filter box. This will be more save in view of more or less possible intake backfire problems.
However, I also think, that the fuel vapors can´t easily enter the plenum with my current vent setup (with engine off). Because the gasoline vapors are heavier than air, and will therefore flow down to the air filter and escape through the side intake. But maybe, I will re-route the vent line to the intake ducting, too (like Raydar did it).
If I would live in USA, then I would order the following purge valve used by 2.8L V6 Firebirds: Firebird vapor canister purge valve / vacuum actuated (GM #17074286): http://www.rockauto.com/cat...1155&jnid=439&jpid=0
With this purge valve, the venting system will work equivalent to the Fiero´s EVAP system, just without this annoying charcoal canister. For the vacuum signal, I would use the vacuum port, which was used by the cruise control (on UIM near TB). Then the vapor purge line could be connected to the small port under the TB (like stock) without any risk of backfire. (Fuel venting is ported by vacuum signal –> no accumulation of fuel vapors in the intake).
I think I will re-route the purge hose into the air filter box. There is a non-used opening in the air filter box, which was plugged by Pontiac´s recall.
No matter whether you route the purge hose to the TB or to the intake duct, I think backfires caused by fuel vapors from the gas tank are very improbable for following reasons:
Prerequisites for intake-backfire caused by fuel vapors from gasoline tank: 1. Pressure build-up in gas tank 2. Cracking point of check valve exceeded 3. Continuous fuel vapor saturation from TB down to the cylinder head´s intake ports 4. Concentration of fuel vapors need to be inflammable (flammability range 1.4 - 7.6%) 5. Incorrect ignition timing causing ignition of fuel vapors 6. Spontaneous ignition temperature of gasoline reached (~ 260 - 280°C)
Prerequisites 1, 2, 3, 4 and 5, or 1, 2, 3, 4 and 6 must be fulfilled simultaneous in order to cause backfire!
Therefore, it is very pessimistic to say, that I could get intake-backfire issues.
@ Raydar: Do you have experienced any intake-backfires on your 4.9 V8 conversion so far?
@ Raydar: Do you have experienced any intake-backfires on your 4.9 V8 conversion so far?
Not since I made the change. But I've only driven it a few times since then. I've really only ever gotten it to backfire a couple of times. Usually when I got a bad chip program, and it was running in limp-home mode.
If I do, I'll post here. If the thread hasn't made it to the archives by then...
This would be a useful mod, in addition to the digital cruise mod, to completely eliminate the rusted vacuum lines running along the trunk. Hmmm. If it works well, I'm all in. Be careful the first time you crack the fuel cap!....just in case......
I have been testing the fuel vapor venting mod (EVAP delete) for several weeks now without any issues. No pressure build-up in the gas tank, no smell of raw gases, no back-fires and no increase in fuel consumption!
With the EVAP delete the engine bay looks much cleaner and performing engine related repair jobs will become easier without EVAP and cruise control canister (due to the additional space).
Like f85gtron already said, this mod is useful especially in combination with the digital cruise control upgrade, in order to delete some old and ugly vacuum lines.
This is a pretty cool mod to clean up the engine bay, and still not hurt the environment or yourself. How about some part #'s for the valve and hoses for us to duplicate
I recommend ordering a check valve from AliExpress (cheap & nice quality)!
Go to the Alibaba website and search for “Aluminium Fuel Non Return Check Valve One Way” This is the 8mm check valve which I have ordered (USD 2.75 incl. shipping): http://www.aliexpress.com/i...ose/32303774597.html
Hoses and clamps:
The hoses which I have used are coolant hoses from an old scooter engine. Maybe you can find a longer single hose at the junkyard which fits even better. (you will need a staggered diameter hose setup) The small hose btwn. the vent line and the check valve is the Fiero´s stock hose. (was connected to EVAP canister)
The hose clamps (stainless steel) I have ordered from Aliexpress, too. Keep in mind the long shipping time for orders on Aliexpress (can take several months)!!! :sleep:
Alternatively, I think you can get equivalent parts in a hardware store somewhere in US.
[This message has been edited by Moar (edited 07-10-2015).]
I suspect not.
