Jump to content
  • Sign up for FREE! Become a GM-Trucks.com Member Today!

    In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience. 

1997 K2500 Running Rich, Rough Idle, & No Start

Recommended Posts

Hey all,


I drive a 97 k2500 p/u w/ 5.7L. I'm trying to diagnose all the problems listed above, but don't have a lot of experience (or money for that matter). As far as the no start problem, it will sit and crank forever, but the only way I can get it to start is by applying the gas pedal and even then it still struggles. In addition to all that, it struggles and stutters and just generally has no balls.

I thought it might be the fuel pressure regulator so I got a fuel pressure gauge and attached it to the schrader valve. When I turned it to accessory and let the fuel pump run, it shot up to 60 psi and then down to between 15 and 20 psi after a couple of seconds. When cranking it, it's at 60 psi as well.

Does anybody have any advice or idea what it could be or where I should look next? I'm kind of new to troubleshooting vehicles so any help would be great.

Link to comment
Share on other sites

dropping to 15 and 20...

it may be dumping into a flood for some seconds.


bad injector(s)?


can you check engine codes?

checking spark plugs can narrow down which cylinder(s) are rich

Link to comment
Share on other sites

If it is at 60-psi while cranking, that should rule out the fuel pump. It should hold pressure for a few minutes after turning the engine off. If it drops, you could have a leaking fuel line, bad regulator or leaking injector.


To check for a leak at the intake, you'd need to pull the upper intake manifold. Disconnect the coil's electrical connector, reconnect the fuel lines at the injector assembly and cycle the ignition switch a few times without cranking it. You should be able to spot a leak then.


But, since you're already there, it would be a great time to upgrade the spider to the MPFI unit.



Sent from my iPhone using Tapatalk

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.