I have an 02 Duramax with 86/M miles.
I got fuel in the oil issue and took to local dealer. I was informed that they would fix the injectors but that I also had low compression in one cylinder.
It was at 335#, other holes were over 400. I was told by the service manager that the new injector in that hole would be damaged by the lower compression and they would not warranty again.
My question to him was if the bad injectors that I have now caused the low compression.
By the way, my truck went out of warranty on June 1st!!!!
Have already made the call to GM. Should be getting a call today.:mad:

this maybe the same problem I'm having????? I have the smell of fuel, rather strong and have the same smell in the oil????? I noticed the fuel going down a bit faster than it ever has in the past. I have 80500 on the clock???? Please let me know what they are going to do. Did you have any DTC's that made you take it in? How did you come up with the problem?

Low compression will not hurt a fuel injector as far as I understand.
Have never seen a fuel fuel injector bad enough(or heard of one) to cause low compression in a cylinder....yet.

Min compression is 300 psi, with a max variance of 50 psi from the average compression of all other cylinders.....I wonder if they did the low one last and cranking rpm was down,(min cranking rpm is 40 rpm) also was it at operating temp when they did the test, also if a injector is leaking bad enough could it cause wall wash and lower the compression reading?? it is possible i guess...I would recheck the compression after the new injectors, a oil change and a good road test, then see whats up with the compression...good luck I hope it works out for you!!

I just got off the phone with the GM Customer Rep. I was told that they will not do anything about my low compression issue. I asked if a bad fuel injector could cause the problem. They told me to talk to the service manager at the dealer. Also there was nowhere else for me to go except to write a letter to GMC. Will be doing that shortly.
How I discovered the problem is that I noticed that the oil pressure was running slightly lower than normal. When I arrived home and checked the oil it was way overfull on the stick and the bottom of the truck was covered with oil/fuel mix and was dripping all over the driveway.

Listen to what kgt said, you probably do not really have a problem at all....except for a idiot service manager and mechanic working on your truck.

There are varibles built in, and allowences, just like the aircraft industry a plus or minus is common, and it is still good as long as it falls in the window.
Sonds like the compression should be 350 +/- 50, so you fall in the minimum, I know it being the minimum is not a good feeling, but other varibles play in the compression like stated above. Cranking rpms, engine temp, ect....
get it all fixed, and then do a compression check, but make sure you are there with the knoledge so the stealer does not try to pull a fast one on ya! Now that you are educated on the matter, they are going to be alittle pissed when you prove them wrong.

I have not seen the book, and do not know what the tolerances are for the compression, but I think at this point I would get a second opinion, if needed

Minimum crank speed is 140 rpm.