skarpenz

My jeep will not start or stay running unless I'm giving it throttle. I replaced the TPS (this was already causing a problem) and it still does the same thing. If I start it while I'm giving it gas it cranks right up but will NOT idle. If I just try to start it normally then it won't run at all. Someone help me out, I need to get this thing fixed TODAY.

96 XJ Sport

When you're giving it throttle, does it run smoothly? I'm not a techie, so others will jump in, but a possibility could be that your idle air control valve is stopped up or sticking. If so, when you let off the gas and the throttle plate closes, ZERO air is coming through which kills it.

BlueXJ

Could it be fuel pressure or is the vacuum line loose somewhere. The fuel pressure regulator needs a vacuum sorce to keep the presure up in the rail. Try those things skarpenz!!

skarpenz

Will do. It runs like a champ when I'm giving it gas. Can I pull the idle control valve off and clean it out or something?

BlueXJ

Don't think you need to but it won't hurt anything.

skarpenz

I took the throttle body off and removed the IACV and it has carbon CAKED all over it. I'm getting my wife to pick up a new one at my work now. Think this could be the problem? If it doesn't fix it I'll return the part, but this is the only thing I can come up with. The vac line on the fuel regulator is good. Any other ideas?

THANKS GUYS

BlueXJ

Just clean the IAC you have and replace it. If that cures the problem then you save the bucks on the part. Try brake cleaner and a toothbrush.

skarpenz

Well I don't have anymore carb or brake cleaner so my wife is picking that up too. If my old one will work then I'll return the new part. Like I said, I just need this thing running today before I go to work, haha.

BlueXJ

OK let us know if that fixes it!

skarpenz

Will do. Is there anything else it could be in the meantime? I mean, the TPS is new and the IACV will be new or cleaned. What else might cause it? Like I said, the truck runs great when I'm holding the throttle or revving the engine it just won't start or idle on its own.

skarpenz

This just happened on the first cold (cool) morning we had in south Georgia BTW. Not sure if that has anything to do with it, but thats when it started doing this.

BlueXJ

If it has good fuel pressure and it is obviously firing fine so the only other thing is the air intake. Does it idle with the intake hose removed from the throttle body (after cleaning the IAC) That should be all that comes to mind.
Make sure you have some good contact where the wires plug in to both the IAC and TPS.

skarpenz

I checked all the plugs and connections so I'm sure thats all gravy. Thanks for the help so far Blue.

skarpenz

Replaced IAC and it cranks right up. Thanks guys!

BlueXJ

That's what we are here for. Jeepers helpin' Jeepers.