Need help with starting problem after slight cool down

[RH802001]

Hey, i have a 2001 Tahoe with the 5.3 motor.
First thing in the morning, it fires right up, at normal operating temp, it fires right up, everytime. If i let it sit and it starts to cool down it just cranks and cranks for nearly 8-10 seconds then it starts and then runs fine. It will start everytime after that. Its only when it starts to cool down. Where should i start as far as checking or replacing parts? I haven't changed plugs, wires or fuel filters. I figure if it were anyone of these things, i would have the starting problem all the time, no matter what temp. Has anyone had this problem? Please help! Thank you!

 

[RH802001]

I guess this is an uncommon problem? Lol.
I'm not familiar with these engines, all of my other
cars were older carb engines. Almost seems like my problem
is a choke sticking? Or some type of temp sensor? I'm clueless

 

[clkelley]

Welcome to the neighborhood!

Go ahead and clean the throttle body and see if that helps things improve.

 

[RH802001]

Yeah..I cleaned the throttle body and the blade about a month ago. I was having problems with my idle dipping...this fixed my idle problem!

Now im just trying to figure out this issue.
I was told fuel pump..i havent run a pressure test yet
I would think if it was the fuel pump, i would have problems starting it
no matter what the engine temp was.

Like i said.. it fires right up in the mornings...i can make about a 100 short trips a day, and it will fire right up, everytime. But if it sits 30min-1 hour, it will crank alot longer than normal.

But if i let it sit until it cools completly down...it will fire right up.

I checked the vaccum line to the fuel reg. and no sign of fuel in it..

Im lost. LOL

 

[RH802001]

So..I have figured out instead of cranking it over
for nearly 10 seconds, all I have to do is crank it
for about 3 sec, stop, re-crank and it will fire right up.
I'm still lost as to why I have this problem

 

[clkelley]

Take it to Autozome if you don't have a code scanner, see if there are any codes that aren't making the CEL come on. That is an odd issue. But it does sound as if there is a fuel pressure issue. The pressure regulator may be getting hung during the cool down process. So when you crank for 3 seconds stop and then recrank you are actually starting and stopping the pressure fast enough to get it working again. Maybe...

 

[RH802001]

Yeah..I guess I will do that.
It looks to have the original fuel pump relay...
I'm guessing its not a problem since it starts fine
any other time.

 

[clkelley]

It seems/sounds like a fuel issue. But it is definitely odd if there is no issue with it actually turning over. If it is turning over and just not starting then it has to be fuel related in some way.

 

[RH802001]

Yeah..it is weird. If you had to guess, would say
the regulator is more likely the problem rather than the pump?

I only ask because I was told it was the pump.
but I never have any problems with it starting cold or hot.
It never acts sluggish and has plenty of power.

 

[clkelley]

If I HAD to guess I would say regulator. I have seen plenty of pumps go bad and they usually just quit. When they do either the pump itself is bad or there is faulty wiring around the pump somewhere...

 

[RH802001]

Ok. I will try replacing the regulator first since its
the easiest of the two jobs.

I told him the situation I'm having now and he says
'You are forcing a double prime' but he had no answer
As to why it opperates flawlessly any other time.

 

[delta579]

I always try the cheapest fix first. I have seen many fuel pumps pass a pressure test and still not FLOW enough fuel to the injectors. Change the fuel filter first. Clean the IAC seat in the throttle body and the IAC itself. Try cleaning the MAF next. Hope this helps.