8.1 LITER STARTING PROBLEM

[toored]

Truck: 2001 GMC Sierra 2500HD, Crew cab, 4X4, 8.1L with Allison Trans. 140K miles.

 

Whenever the engine is shut down at operating temp and sits for more than 5-10 minutes, it does not want to restart. It turns over just fine but acts as if it is not getting fuel (like it's vapor locking). If I restart it within 10 minutes, it starts just fine. The engine always starts immediately when it's cold.

 

I have noticed that if I try to start it and it won't start, if I turn the ignition off, then back to the ignition-on position and wait a few seconds it will usually restart OK. However, the problem seems to be getting worse lately as sometimes I have to repeat this procedure 3-4 times to get it to restart. This is very frustrating.

 

It seems as if maybe a fuel shutoff solenoid or fuel pump relay is sticking closed or the fuel pump is not operating when it's hot and sits for more than 5-10 minutes.

 

I would greatly appreciate anyone's help in sharing your similar experiences or suggestions to resolve this issue.

 

Thanks for reading and any help y'all can provide.

[Swimmer8366]

Sounds like check ball is sticking in the pump. Time for fuel pump.

 

Sent from my Z981 using Tapatalk

Do a fuel pressure bleed off test. Your losing pressure.

 

Sent from my Z981 using Tapatalk

[Raptordude]

Does your fuel pump sound ok? As said, I would bet it's the pump. It's a good time to replace the fuel filter as well, if it's clogged it can wear out your new pump

 

 

Sent from my iPhone using Tapatalk

[toored]

Thanks a million for the replies!

 

The pump sounds fine - no noise. It makes sense that the pressure is bleeding off. I am planning to replace the pump soon because my fuel quantity guage has been going nuts for years and I'll be in the tank to replace the sending unit for that issue.

 

When I get a chance, I'll do a bleed down test and/or just replace the pump and see what happens. I'll post the results.

 

Thanks again!

[dewfpo]

If the check ball is sticking, before you go replacing anything or spending any money. Go buy a bottle of Techron or BG fuel System cleaner or equivalent good brand and run that thru a full tank of fuel. It the check ball is sticking, that should free it up. At least then you'll know and you'll only be out a few bucks.

 

DEWFPO

[davester]

maybe check the fuel pressure at the fuel rail to check that this is actually happening? I would check first, as it sucks to change the FP. And the FP isn't that cheap either.

[Bmz72]

My 2 cents.... does it start better if you key it up and wait... letting the pump build pressure?

... or scenario 2 ... are the injectors leaking fuel after shut down and flooding the cylinders?

 

Good luck

 

 

Sent from my iPhone using Tapatalk

[Arth]

Had this issue with my 05 suburban with the 5.3 except it would have that issue after sitting for 5 minutes.

 

Checked the pressure at the rail and it would start to slowly fall off as soon as the truck was turned off. New fuel pump is what it took for me.

[Raptordude]

Not sure if this can cause this problem, but takes 2 seconds to check.....pull the hose off of the fuel pressure regulator up near the fuel rail. If there's fuel in that breather hose, the diaphragm in the regulator is shot. If it's dry, you're good

 

 

Sent from my iPhone using Tapatalk

[toored]

UPDATE:

 

I replaced the fuel pump/sending unit assembly and it appears to have fixed the problem. I have started it several times while hot after sitting for 30 minutes to an hour and she starts right up!

 

Thanks a million to all who read my post and/or offered advice!!

 

Thanks again!