jhanratt
01-11-2013, 11:17
I have a 2003 Chevrolet CC 4X4 Duramax Allison LB7 with 198,000 km on it. It is stock and I have had it since new. The injectors are original. It has been a great truck but now have a difficult to diagnose issue. The problem started last winter.
When it is cold outside and the truck is warmed to operating temperature it will not restart. It will either crank for an extended period and then start or will sometimes fail to start at all. If you let it sit for a few hours until it cools it will start no problem. Also if you give a shot of ether it will start and run fine. I know this is not healthy for it but when I am stuck in the woods with a dead truck it has been attractive on a few occasions.
All summer when it is warm outside there was no issue.
I immediately changed the fuel filter. It made no change at all.
I ran a code reader and came up with nothing.
I took it to the GM dealer in town. They scanned the fuel injectors and return rates at my request. They stated that all was normal and diagnosed a faulty glow plug relay. I paid for a relay even though I knew it was unrelated. Not surprisingly the new Glow plug relay made no change at all.
I then went to a local mechanic who owns the same truck and will take the time to talk to you in person. He said try priming for a while before starting and see if that makes a difference. I primed until it was hard and started for a while. This also made no change.
I left the truck with him for three days so he could check it cold warm etc. He checked the injectors and determined they are fine. He found the fuel rail pressure was way low especially when warm. He also checked the fuel pump and determined it is fine. He did find some codes but we did not get in to specifics. He is recommending a new ECM and estimating $3,200.
Any advice?
Thank you all in advance for your help.
When it is cold outside and the truck is warmed to operating temperature it will not restart. It will either crank for an extended period and then start or will sometimes fail to start at all. If you let it sit for a few hours until it cools it will start no problem. Also if you give a shot of ether it will start and run fine. I know this is not healthy for it but when I am stuck in the woods with a dead truck it has been attractive on a few occasions.
All summer when it is warm outside there was no issue.
I immediately changed the fuel filter. It made no change at all.
I ran a code reader and came up with nothing.
I took it to the GM dealer in town. They scanned the fuel injectors and return rates at my request. They stated that all was normal and diagnosed a faulty glow plug relay. I paid for a relay even though I knew it was unrelated. Not surprisingly the new Glow plug relay made no change at all.
I then went to a local mechanic who owns the same truck and will take the time to talk to you in person. He said try priming for a while before starting and see if that makes a difference. I primed until it was hard and started for a while. This also made no change.
I left the truck with him for three days so he could check it cold warm etc. He checked the injectors and determined they are fine. He found the fuel rail pressure was way low especially when warm. He also checked the fuel pump and determined it is fine. He did find some codes but we did not get in to specifics. He is recommending a new ECM and estimating $3,200.
Any advice?
Thank you all in advance for your help.