1997 GMC Sierra Hard Start After Sitting

Avatar
BGLASS998
  • MEMBER
  • 1 POST
97 GMC Sierra 1500 with 5.0L and 180,000 miles.

For the last several weeks my pickup has had a hard time starting on Monday morning. It seems related to whether I start it every day or not, because I some times don't drive it on the weekend.
It cranks over fast, not acting like a low battery. For the first 10 seconds of cranking it doesnt seem to fire. It then seems to act like it fires a couple of times then will act like it is misfiring enough that it stalls out the cranking. It may take 30-40 seconds of this funny cranking with mis-firing and near starting before it starts. It starts rough for the first 5 seconds or so then runs great and starts and runs fine all week.
BTW a normal start on this is just a 2-3 second turn over so something is clearly different after it has sat for a while.
I am wondering if I have a computer/electronic ignition problem but seems odd that I am not seeing any other bad effects.
Feb 5, 2007 at 12:32 AM
Advertisement
Avatar
2CARPRO JACK
  • ✓Experienced Mechanic
  • 11,533 POSTS
That is a CPI engine.They had all sorts of injector and fuel pressure regulator problems.Sounds like the reg is blown, or the pump is weak. Install a manual fuel pressure gauge.The press. should jump up when the engine is revved, if not the reg isnt working
Feb 5, 2007 at 4:41 AM

Suggested Repair

Install a manual fuel pressure gauge on this CPI engine. Pressure should rise when the engine is revved; if it does not, the fuel pressure regulator is not working. A weak fuel pump is also possible.

Conversation Summary

The owner of a 1997 GMC Sierra 1500 with a 5.0L reports hard starting only after the truck sits, such as on Monday mornings. It cranks quickly but takes 30-40 seconds of misfiring and near-starts before running, then starts and runs normally the rest of the week. The expert says CPI engines commonly have injector and fuel pressure regulator problems and recommends a fuel pressure gauge test; pressure should jump when revved, otherwise the regulator is not working, and a weak pump is also possible.

Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Frequently Asked Problems for This Vehicle