Hi all! First time poster. I have a 2004 express cargo 2500 with a 6.0. I put in a remaned motor last year along with ALL the sensors, full tune up, and a new fuel pump. Fuel pressure is good. Even replaced the ecm. Had it a a mechanic for over a month and he could not figure out my long start when warm. First start of the day, pops right off. But if I shut it down and try to start within 30 min (is running errands) it cranks forever before it catches. Anyone else have this?

Thanks!

 

Welcome from Florida. Is the check engine light on? If it is what is the code?

 

Thanks oldchevy! No. No check engine lights. No codes.

 

I had something similar happen on a similar vintage Malibu. It ended up being the fuel pump assembly. It's all one assembly with lots of stuff in there. I think it was the check valve built into the regulator or pulsator that is the problem but you replace it as a whole unit. Don't go cheap. Get factory if testing sends you down that path.

 

What brand of pump?
Does the fuel pressure bleed off once you shut it off?

Will it start more quickly if you hold 1/2 throttle?

 

Hi triaged! Fuel pump is a Delphi. Got hosed on an airtec once, now I only use brand name. Don't recall bleed down, but will check this weekend. Injectors were replaced. There was no difference. Pumping, holding throttle down, holding part way, seemed to make a difference, but may have been wishful thinking. Almost seems like vapor lock.

 

This is a common problem with these high mileage engines. Both my '96 (5.7 L / 350 ci) and my '99 (7.4 L / 454 ci) have done the same thing. Both were a result of the fuel injectors. The problem was corrected in the 5.7 L by replacing the "spider injector" assembly (between the plenum and intake manifold). Not a terribly difficult DIY job.

I currently have the same issue with my '99. Not going to do it myself this time and am pricing it out at the Chevy dealer. The 454 has individual individual injectors. It doesn't have the spider assembly like the 350.