Back in May while towing my 24' fifth wheel, my check engine light came on and the truck went into limp mode. I pulled over shut down the engine and opened up my toolbox to find that i did have my code reader with me. It was P0093, Fuel System Leak Detected, Large Leak. I reset the computer after looking for a leak and found nothing. Had no problems again for several months. Now, just about every day the light is on and off, sometimes hitting the limp mode. same code, only code. I have read just about every thread on here and several other forums about this and results seem to vary. I have talked to the local GM service center manager and we both agree it needs to have diagnostics run on it.

Had that done 2 weeks ago, It showed a bad Fuel rail pressure sensor, I replaced that today, $207.00 Easy swap out. However I took it for a hard run, and it threw the p0093 code again and hit limp mode. Now i'm stumped again (not to mention pi$$ed off after spending the $207.00).

I'm looking for a little imput on this. According to the Service manager, he does not feel the injectors or pump are bad. My mileage is still fairly good, 16-20, It is not smoking , the oil level is staying the same. Pump is making the proper pressures.

Truck has 118k miles, it is all stock. Fuel filter was replaced about 1000 miles ago, air filter too.

Not sure where to go from here. I am going to go get a beer.... I need it.

 

When hot and shut off does it start right up or take a few seconds of cranking time. What I have found is large amounts of fuel injector return when hot or a pressure relief valve that is weak.

 

Starts the same cold or hot. it happens under a load...

 

I see you say the pump is making proper pressure. How did you check the rail pressure? What was the rail pressure at?

 

That i can't answer, The local GM dealer did the diagnosis. I'm just passing along the information i was given by them.

 

Do you know if they took the truck for a drive when they checked the pump?

 

no. I dont. I called the Dealership yesterday, The service mgr is on vacation til monday. Cant get anymore answers til then.... Sorry.

 

p0093 was one of the codes i was pulling on my truck for a fuel leak i had the same problems and i took it into the shop it turned out to be that my return lines and injectors were bad you need to get that fixed as soon as you can because it dumped fuel into the pan the best way to find out if it is your return line is to check you oil drain it all and see if you have fuel in it i had 5 gallons in my oil pan i was told and three of that was fuel hope that helped if you need information about it let me know and i will talk to a close buddy of mine that did all the work to my truck when this was happening

 

I was told that when i bought the truck to watch the oil level because of the injectors, I have not been "gaining" oil. But that is in the back of my mind...

Thanks

Tim

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Just talked to the Service mgr. He dosent remember if they drove it or not... Nothing in the tech's notes. Tech dosent remember either. So my guess is it didnt happen... He is looking through thier TSB's to see if there is any other info from GM on this.

One would think this would have been done while in the shop.

 

Had another shop check the codes yesterday. however he didnot have a pressure gauge that would check the rail pressure. his OTC scan tool came up witha P0093A code. Does that help anyone?