If the engine has been running a while, is stopped for several minutes (allowing the heat in the engine compartment to build up) and is restarted, it frequently dies. It will start fine and run for 15-30 seconds, then try to die for a minute or two. After a couple of minutes it is fine!

If the rpms are high enough when it starts to die, I press the accelerator about half way to the floor, rpms will continue to drop for a second or 2 then it will roar back to life. If the engine dies, I hit the starter and it cranks right up! Most of the time the 15-30 seconds is enough time for me to pull out onto the street and start to accelerate then it will falter. The few times it has died while idling, it takes ~3 seconds to die ... like it's flooded or maybe starved for fuel. I originally thought it was dying as if the ignition had been turned off but the rpms don't drop THAT fast.

The engine was connected to a fuel pressure gauge one time when it died and the pressure was fine. I replaced a bad pre-cat O2 sensor. I borrowed a MAF sensor and I've replaced the IAC unit. Nothing I've done has made any difference.

I have a laptop and AutoTap on loan so I can monitor sensors. What are some possible problems, what sensors do I record and what values should I expect.

The problem is not a show stopper but I'm getting REALLY tired of it! <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

Danny

 

Sure sounds like a fuel problem. Thought about pulling the injectors/fuel rails/damper and checking them out?

 

I wonder if its vapor lock.

 

Couple of good ideas/suggestions!

I haven't heard the term "vapor lock" in a long time. I associate that problem with carbed engines and high altitude because that's when my dad experienced the problem. I don't really know what a "vapor lock" condition is.

My problem certainly appears to be heat related. My guess is that when the car was already at operating temp and is restarted, it goes from "open loop" to "closed loop" much quicker and some sensor (due to heat) is telling the PCM to make a significant adjustment to the fuel flow ... either too lean or too rich?

This problem has been bugging me for over 3 weeks and I'm pretty tired of it.

Thanks and PLEASE keep the suggestions coming!

Danny

 

Apparently, my problem is unusual considering the lack of responses. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

Can anyone suggest possible causes? ANY help would be greatly appreciated.

Danny

 

your best bet would be to hook up atap and go make it die and record it to tell us the readings i would think maf readings, throttle position ,ltrims, misfires, o2's would be a good start. good luck and keep us uptodate.

 

ttt

 

I see you have aftermarket heads/cam. Your motor may be asking for more air at idle. Hook your car up to AutoTap ONLY when it is FULLY WARM and check the IAC counts. They should preferably be around 30 to 40, give or take a little. If they are too high like around 50+, drill the hole in your TB bigger, but do this SLOWLY, a little bigger at a time until the IAC counts drop to the preferred level. Too big of a hole (IAC=0) will set a code, I think.

Evan