starting problem with 02

[seu174]

I had posted a few weeks back about a starting problem with my 02 surburban. It had all of the symptoms of a bad pressure regulator. It started fine cold but not when it was hot. I replaced the fuel pressure regulator but it did not fix the problem. Still starts fine cold but not when its hot. Do anyone have any other suggestions?

[maxwedge]

So what do you do when it is hot to get it started, what is the FP when this happens?

[seu174]

It will start but it turns over a few seconds first. When it is cold it starts as soon as you turn the starter. Cold it takes maybe 3-4 seconds to start. Hitting the gas pedal helps.

[maxwedge]

Get FP readings during both events.

[seu174]

The fuel pressure is 51psi during both events. During both cold and warms starting is hits 51 psi as soon as you turn the key on. Cold starting it cranks right away and the pressure drops to around 47 psi. During warm starts it takes a few seconds to start but the pressure stays at 51psi until it starts then it also drops to around 47psi.
I hope this helps.

Thanks

[rockwood84]

try throttle position sensor

[seu174]

here is an update on the problem. Thanks for the reply but I think that I ruled out the throttle position sensor.

The first suggestion that I got some time ago was the fuel pressure regulator, and I replaced it. It did not fix the problem. Today I pulled all of the spark plugs and they all looked pretty good, gray in color, except number 3. Number 3 was black and gummy looking. I was thinking that the number three injector may be leaking, causing it to flood when it is warm.

If I'm correct then it would explain why it cranks when its cold (fuel has time to evaporate) but it takes a few seconds to start when it is warm (gas leaking in a flooding)

What do you think? Am I on the right track? Would a leak cause the plug to look like I described?

Thanks for any help.

[maxwedge]

Normally one cylinder flooding wouldn't cause a hard start, if your FP gage is accurate the FP is way too low, 60-65 psi is required with the Vortec. Pumps are a common problem with these trucks.

[j cAT]

Originally Posted by seu174

here is an update on the problem. Thanks for the reply but I think that I ruled out the throttle position sensor.

The first suggestion that I got some time ago was the fuel pressure regulator, and I replaced it. It did not fix the problem. Today I pulled all of the spark plugs and they all looked pretty good, gray in color, except number 3. Number 3 was black and gummy looking. I was thinking that the number three injector may be leaking, causing it to flood when it is warm.

If I'm correct then it would explain why it cranks when its cold (fuel has time to evaporate) but it takes a few seconds to start when it is warm (gas leaking in a flooding)

What do you think? Am I on the right track? Would a leak cause the plug to look like I described?

Thanks for any help.

the number 3 injector could be the problem to check after fuel pump shuts down does fuel pressure hold for 5min and if not pull #3plug if wet when engine hot replace that injector. this is how it is described to check in shop manual.....if ok check ect for proper resistance engine temp sensors could cause hard start as well as maf/IAT sensor...