[ChaosEnvy]

1997 Suburban C1500 350 Vortec.

It will start in the morning fine.. drive for a few miles then just die. If it sits for a few minutes it will start back up. Drive for a mile then dies. Now I have to wait 20 minutes... then is will start again.. Repeat.

I can hear the Fuel pump, and if it sicks overnight or just for an hour it will start right back up no problems, good idle.

At one point the CIL came on. I checked the code, came up as MAF sesnor. The CIL went off and never came back on.

When it is running it isn't lacking any power or showing signs of fuel starvation.

I tried changing the MAF sensor just to be safe.. It didn't make a difference.

Someone suggested pulling the Ignition Module and have it tested. I have removed it and will be having it tested at least 5 times after work today. I want to make sure they can build some hear in the module.

Anyone have any experience with the problem that can maybe lead me to where I can look.


Big D

 

[MrShorty]

Certainly sounds electrical in nature.

After changing the MAF, did you clear the MAF code from the computer's memory? If you did, is it coming back with the MAF code still, another code, or pass? Remember that codes point to problems in circuits, of which the sensor is only part. If your MAF code is consistently coming back, you probably need to look at the rest of the MAF circuit between the PCM and the MAF. It also might be time to take a trip to the library to get the official diagnostic procedures for the specific MAF code you are getting.

Even though you can hear the fuel pump, I would probably put a fuel pressure gauge on the fuel line to make sure you are getting the correct fuel pressure. It might also be useful to verify that the fuel injectors are opening to let fuel into the cylinders. Of course, because it is intermittent, these all need to be checked when the engine is stalling/not starting.

Let us know how the ICM checks out.

 

[ChaosEnvy]

Certainly sounds electrical in nature.

After changing the MAF, did you clear the MAF code from the computer's memory? If you did, is it coming back with the MAF code still, another code, or pass? Remember that codes point to problems in circuits, of which the sensor is only part. If your MAF code is consistently coming back, you probably need to look at the rest of the MAF circuit between the PCM and the MAF. It also might be time to take a trip to the library to get the official diagnostic procedures for the specific MAF code you are getting.

Even though you can hear the fuel pump, I would probably put a fuel pressure gauge on the fuel line to make sure you are getting the correct fuel pressure. It might also be useful to verify that the fuel injectors are opening to let fuel into the cylinders. Of course, because it is intermittent, these all need to be checked when the engine is stalling/not starting.

Let us know how the ICM checks out.

I'll let you know, I hope that it is the ICM. FYI Though, the Fuel Pump, Pick up, socks, and Fuel Filter were all changed less than 6 months ago. The CIL has never came back on, just that once.

Thanks,

Big D

 

[Holy Smoke]

Could it also be heat related? Putting it out there. no need to answer.

 

[ChaosEnvy]

The ICM checked out as good.. Passed six times. What next??

 

[HI-TORQ]

Is it bitter cold where you are? If so, maybe frozen fuel line.


If not carry an squirt-type oil can with gas in it. The next time it happens, open the hood, remove air filter cover, and spray air filter with gas(no need to remove air filter). If it starts up then you know it's a fuel problem. If it doesn't, pull a spark plug. Not enjoyable to do on the road though. What happens if you let it run outside?