This problem has slowly changed to "all the time". It used to do it infrequently and now, nearly every time.

When cold, it fires right up, when hot, it takes maybe 3-4 seconds.
Fuel pump replaced about one year ago. New fuel filter, Cleaned EGR valve, new plugs, cap rotor, coil, MAP sensor, MAF sensor. Computer replaced with unit from salvage yard, no change.
What else to check?

Thanks,

GLB

 

uh, anyone?

 

3-4 seconds does seem a bit on the long side. How is the performance of the vehicle once you get it started?

There are a number of things that could cause this.

As suggested in one of the threads linked to in the Related Threads table below, a leaking fuel injector could cause a rich condition. Reason it does not impact cold start up time is because any fuel that has leaked from the injector would dissipate over time. When starting after sitting only for a few minutes, the additional fuel would cause a rich condition. To check for this, you could hold the throttle open some when trying to start it hot and see how that impacts things. A fuel pressure gauge may also help diagnose this type of problem.

 

Vehicle runs smooth as butter once started. Idles perfect. No missing at all. MPG is around 20 like its always been. It starts, but not split second like it used to. Sometimes 2 secs, sometimes 3 secs.

I'd like to ask about the MAF sensor. I put one on it from the salvage yard in order to troubleshoot an earlier problem i was having. Question: Do they just simply wear out? I cleaned it thoroughly with the CRC MAF cleaner. I was wondering if it may be sending the wrong signal to the computer indicating that the vehicle is cold and not hot, therby flooding. And does it also control a signal related to the upshift to OD? I'm having some lock up issues and wondered if the MAF may be related to both. I see new ones for around $70.00 and that would surely be easier than replacing the spider.
What else tells the computer that the engine is cold? I wanted to explore that line of thinking before going to something else as sensors are easy things to "parts replace". I'd really rather not go down the road of injectors and spiders right this moment.

I ran two cans of Seafoam through the tank at the stronger mixture in an effort to clean injectors.

What type of test can I do with the pressure gauge? I have one.

It just starts perfect when cold.

Thanks,
Gary B
VBFD

 

The MAF does not tell the PCM whether the engine is hot or cold. If the coolant temp sensor were malfunctioning, you would probably get a code. It could be checked with a high feature scan tool though.

With the pressure gauge, hook it up to the schrader valve on the main fuel line on top of the motor. The pressure should climb to 55-60psi after turning the key on, engine off. If you turn the key off and find that the pressure bleeds off more than 2-3 psi in the first minute, then there is a leak somewhere in the system.

 

Ok, thanks. I've done that pressure check before when getting ready to replace the fuel pump. I just wanted to know what specifically we would be looking for with respect to the hot start issue.
Today, out of maybe 6 starts, 2 were near perfect. One was perfect and then the others were 2-4 seconds. When hot. I would think that if it were an injector issue, it might be doing this each time.
I did find one other thread with this EXACT issue on the net. But there was no resolution. I've found not threads here with this issue. Mine does start every time, just takes 2-4 secs.

Thanks,

Gary B.

 

Ok, getting back to this issue now as it has gotten a bit worse and has thrown some codes. It threw a rich condition and multiple misfire. Taking a bit longer to start when hot. Slight hesitation on take off and actually cut out completely (then refired), for just a second crossing an intersection.
Just did a pressure check. Starts out at 62psi with key on engine not running but slowly drops to 30psi within about 1 minute. Once started it is 62psi solid. I replaced the pump about 3 years ago. Runs nice once started. Starts perfect when cold.


In reading some threads I see that that a possible issue is the pressure regulator. I understand a diaphram that cracks and leaks.

And maybe even a leaking injector. So I have to take the top part of the plentum off (96 4.3litre) to get to both issues. So if I have it off, shouldnt I replace anything to do with leaking fuel issues? Like the entire spider/injector system AND the pressure regulator?

And clearify this for me please. I dont have to take the entire intake manifold off correct? Just the plastic upper part? Is that right?

Thanks,
Gary