Hard starting when hot - Chevy and GMC Duramax Diesel Forum
01-04.5 LB7 Duramax Powertrain Discussion of components that are directly involved in the power production and all that is needed to get and keep the truck moving . Engine , Transmission, Etc.

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post #1 of 3 (permalink) Old 03-04-2011, 12:37 PM Thread Starter
Join Date: Aug 2010
Posts: 8
Hard starting when hot

i have a 2003 gmc 2500 hd lb7 w/cal.emmissions completly stock 75000 miles
about 5 months ago i had a check engine light
code said glow plug
replaced "all 8 glowplugs" i cant be sure. After that it was hard starting.the dealer said they would diagnose it for free. In 3 hours first it was the fuel regulator then they called and said it was the injection pump and if i put up $1500 they would replce it and if that wasn't it they would give me my money back.i won't pay for parts changers
i took the truck home and found the short fuel line off the filter was cracked i replaced it and all was good for 2 months
now it starts cold after 5 second of cranking but when its hot it will crank but not start
any ideas out there
thanks for reading
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post #2 of 3 (permalink) Old 03-04-2011, 05:04 PM
Join Date: Dec 2006
Posts: 2
Having the same problem, dealer changed all injectors . No help with the start issue.
Added megafilter and lift pump. No help with start issue.
Changed most rubber fuel lines. No help yet.

2003 GMC 2500HD utility stock
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post #3 of 3 (permalink) Old 03-05-2011, 02:25 AM
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mijdirtyjeep's Avatar
Join Date: Sep 2008
Location: West Michigan
Posts: 5,212
ZBM2's sounds like a classic case of injectors.

Personally I would put up the $1500 and let them put an injection pump in even though it might not be bad "they said they would not charge if it did not fix, and you get a new pump for nothing "

The reason they think the pump is bad is it probably will not reach commanded Mpa of at least 158-160Mpa. Shoot I put a new injection pump in a truck that at idle was around 26Mpa "3900psi", and at WOT could only muster 39Mpa "5800psi, that is just a little shy of the commanded 23000psi" Shoot this truck at WOT could only max out a little over what mine does at idle, and it never had a hard start condition

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