3.4 idles bad and runs rich

[jeep3.4]

Here is the deal, i have an 84 jeep Cherokee that originally had a 2.8 Gm v6 in it. That motor was a POS and was replaced about 3 times so i decided to swap in the 3.4 SFI motor from a 95 camaro(exact same block so it bolts to the jeep ) The engine won't idle. (Surges like carb engine). Runs smooth for first 10 15 seconds on start., then rough idle starts. When doing the idle set-up with the car in drive engine starts to surge then I get check engine light after 2-3 minutes. Any help would be appreciated. Runs off idle.

[southern94]

check the IAT(or is it AIT?) sensor it is on the throttle body on the side if u uplug the plug in it has two screws in it just undo those screws. put a new one it that might do it. the sensor regulates air intake to the computer and might be messed up

just a thought :D

[GordSipko]

Do you have the SFI computer as well?

It sounds like the engine is switching to batch fire mode after 15 seconds. This can happen when the signal from the cam position sensor goes missing. Check to see that it's connected. The cam position sensor sits on the top of the block just forward of the front intake manifold rail.

[EyeOutThere]

It is probably the IAC (idle air control) valve.

It is located on the top of the throttle body, and is held in by 2 hex screws.

It could also be the IAT, which is located on the intake. It is a sensor with 2 wires right before the elbow.

[Fin]

IAC was my guess, although I posted that in the original post. I'd like to see some pics of the setup in the Jeep.

[jeep3.4]

dont know if you guys read this but it was in the original post that got locked.

The motor is a pull out from a 95 camaro and I was told that t had 60K on it. I was going to transfer the carb from the 2.8 but decided what the hell i have the injection stuff, and i paid for it, so i used the SFI system. I have replaced almost every sensor on the motor or checked it with the ohm meter(in fact checked the IAC valve today and it was within spec). I also have replaced the plug wires and plugs along with ignition coils and base plate. Im using the harness and computer from the camaro but modified by a place called fuel injection specialties in san antonio. I have no clue what the problem is and really need to get this thing running right. I hope you guys can help.

Thanks, Tealv6 ill try to take some pics later this week

[jeep3.4]

anything guys?

[southern94]

if you want to invest in it buy a software that can tell u whats up it is 300$ let me know and i will send u a link gotta have a laptop for it

[GordSipko]

The check engine light is telling you there is something wrong. You need to find out what it is. FIS should be able to help out or perhaps you can rent/borrow a scanner from a local parts house.

southern94... What software are you talking about?

[jeep3.4]

here are some pics as promised, I couldnt get the pics to work, so here are links:

http://www.imagestation.com/picture/...1/fdc10bae.jpg

http://www.imagestation.com/picture/...2/fdc10bb3.jpg

[ May 07, 2002: Message edited by: jeep3.4 ]</p>

[Backfire]

Man, I wish I had that kind of room to work on my 3.4. Would make life alot easier [img]smile.gif[/img]

[Tiago]

hell yea it would make things easyer :eek:

[OnixV6]

my guess, not enough fuel pressure.

gotta find me a Jeep Cherokee. what years used the GM 2.8L V6 motor?

[jeep3.4]

I just checked the fuel pressure a few days ago and it was fine so thats not the problem, but thanks for the help. This thing is starting to piss me off.

[ May 07, 2002: Message edited by: jeep3.4 ]</p>