Ok this problem has been going on for quite some time now.

Sometimes when I start the car it idle like it’s already warmed up, at 650, yet it surges like a...... It'll go from 650 to 200, and while I’m driving I hate hitting the brakes because I risk stalling it out.

But 75% of the rest of the startups are perfectly fine. No problems of any sort until I turn off the car, then maybe something will happen.

I took out egr just before this happened, and painted my valve covers and what not.

Does EGR have any way of making my problem happen? If so, how can I fix it without adding egr again?

I live in Florida and we have no emissions testing so there is no need for it...


Thanks.

PS, i knwo you;d think, just turn the car off and restart, well everytime this startup happens, when your restart it comes again as well. If i leave for 10-15 minutes and come back, normally its good again, but who wants to wait?

 

Need to know the make, model, engine, and transmission

 

without even reading the thread...


vacuum leak.

 

i have a similar problem, mine is in a v6, have a digital egr so thats not a problem. when i posted my question someone suggested that it might be a leak leading to the MAF. i dont have one, so again no help for me, but if your cars an 8 its a possibility for you....

 

vacuum leak of sorts is what came to mind also. Check IAC, and also the TPS.

 

Ditto.

 

It could be all kinds of things Not just a vac leak. We don't even know what engine it is. OP didn't come back to answer questions.

Could be the IAC on a TPI.
Worn out engine
Dead cyl. (bad wire, plug or injector)
Worn out dist.

And then some....

 

305 TPI. And he said that he removed the EGR, which would require disassembly of the intake system, which if done improperly (probable with this particular user ) will typically have a vac leak, which would match his discription.

 

Where did he say he had a TPI engine? I read it a few times and can't tell if he has a carb, TPI or TBI.

 

Wouldnt a vacuum leak cause it to idle high?

 

Yes it surely would. So would some of the things I mentioned. Just want to give the guy enough stuff to test. Hopefully he reports back on the problem. So many folks do that and leave folks in the search with nothing.

Please explain how the problem was fixed folks. Would help others.

 

That really irritates me.

 

i don't think he'll be replying anymore, he's been banned.

 

even though skinny man has been banned, i just read this post have have somthing to add.
You will actually hurt the car by removing the egr system. First of all, the cars computer uses that to advance timing when the car is moving, and help keep a smooth idle when cold. So, by removing the Egr you will actually hurt the car more than you could possibly help it. I say leave it on the car if it isnt built for the strip, and if u plan to use it as a daily driver.

 

i have a similar problem on a new rebuild, so how does one find a potential vacuum leak? wouldn't there be an audible hiss or something? supposedly my iac is set correctly, not to single it out, though. this, btw, is on my '91 5.7 TPI... a guy had it on his analyzer or scanner, whatever he uses, and said the surge was because my fuel was lean at idle...

KAM

 

Look first. If you can't find anything you can go around hoses/intake area with a unlit propane tourch or a can of starter fluid. Idle will change when you hit a leaky area.

 

ok - i'll check that. next question, is how can i correct a lean idle condition? advance timing?

KAM

 

My car was some lean at idle, especially when cold, some hesitation off idle. Helped a bit to plug PCV valve so I put a new valve in from a 2.8 V6, more restriction at high vacuum at idle, full flow above that. Might try this if you have problems.

 

My surge was TPS sensor being out!

 

well i guess i'll get back in there and recheck everything. and probably gonna answer my own question here, but if fuel pressure is 43.5 stock for a 5.7 TPI, i guess with a bigger cam i need to bump it up? i've got it set at about 42 now by recommendation, but may be too low? and how do you know what to set timing at with a bigger cam? i've got the LT4 hotcam in there now w/1.6 roller rockers, so making about .525 on the lift (int & exh). thanks...

KAM