1998 GMC Truck wont start

185,000 MILES • 5.7L • V8 • 4WD • AUTOMATIC
Avatar
DET61
  • MEMBER
  • 3 POSTS
Over the last year My truck would run rough sometimes, It has new fuel injectors, fuel pump, upper manifold, distributer cap, plugs, wires, cap, rotor, coil, throttle position sensor ad every other sensor has also been replaced, So I replaced the ECM and it would fire for about 1 second then dye, I put the old one back in for now so that I can drive it, What do I need to do to make it run with the new ECM,
Oct 23, 2014 at 10:24 AM
Advertisement
Avatar
JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,248 POSTS
The new ECM may need programmed. How bad is the rough running? Is this the original engine? Have you checked engine compression?
Oct 23, 2014 at 10:44 AM
Avatar
DET61
  • MEMBER
  • 3 POSTS
It is the original engine, I have not checked the compression, It runs really rough but at around 60 mph + on the highway it will run great most of the time,
Oct 24, 2014 at 2:17 AM
Avatar
JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,248 POSTS
I question if it deals with the ECM. Have you ever cleaned the injection system? Also, with this many miles, you may want to check compression.
Oct 24, 2014 at 3:48 AM
Avatar
DET61
  • MEMBER
  • 3 POSTS
I put in all new fuel injectors, I'll try to check the compression this weekend,
Oct 24, 2014 at 8:50 AM
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