It's Long, sorry


This is gonna be kinda long, sorry

My car is a 1988 IROC-Z, 5.7L L98 with 65,000 miles. All stock besides K&N's and a Flowmaster cat back. This has been happening since I got the car.

If it is around 65 Degrees or above:

When trying to start the car from sitting overnight, It cranks and cranks and cranks the first try. On the second try it will catch and stumble/Chug for a very short time (5-7 seconds), then go to idling normally.

After driving the car, If I let it sit anywhere from 15-30 Minutes. When I start it, it fires up the first time, very fast with no chugging/stumbling.

After driving the car, if I let it sit for an hour or two. It starts like it does when sitting overnight. Takes forever to start(usually two to three times). And when it starts, it chugs a bit, then idles normally. But when it starts, it does not blow any smoke out the back. No black/blue/white smoke.

The ONLY way I can get it to start fast when its warm out and has been sitting more then 45 minutes, is to hit the gas when its turning over, then it catches the first time and starts with less chugging but still a bit of it.


Now heres the wierd part!!!!

If its 60 degrees or colder (More or less)

The car starts PERFECT! If it sits overnight, it will start on the first try, very quickly, no stumbling/chugging what so ever (Dont need to hit gas when starting at all). If I let the car sit for a few hours after driving it, it still starts super fast and perfect.


So pretty much, if its warm out, the car dosent wanna start fast. When its cold, it starts very very fast and perfect! It cranks just as fast when its warm as it does when its cold.

Sorry so long, but I felt details were essential. Thanks for any input guy/gals

Other then that, the car idles perfect, runs perfect, and definitely has all it's ***** and is not throwing any codes. I was thinking leaky injectors, but it should start crappy all the time, not just when its warm out.

 

Did I stump you all?

 

Hmmmmph, I had the once in a while no crank BS, and a starter fixed that but I don't know about this. That starting better at different temps is something, mine usually started better when warm, but sometimes its the same.

 

I was thinking leaky injectors also but maybe something with the cold start injector? I would try a 89 TPI prom and disconnect the cold start injector to try to rule that out.

 

Uhh hmmmm, perhaps it's one of those rare '88's with a carb'd 350 and the choke needs a little nudge...

 

I got Tuned Port



Its really starting to **** me off Im gonna clean my IAC tomorrow.

 

I agree!! Think of it like this:
If you drive the car for 15-30 minutes the computer knows that the engine is warm. The cold start injector will not fire. The cold start will use fire when it has been sitting over night. If it is below the temp that you said, then the engine will need the fuel from the cold start injector! That is my $.02