my 93 gmc sonoma with the 4.3 doesnt' want to start in cold weather anymore. I can hear the fuel pump turn on when i turn the keys, there is spark, but odly the injectors aren't firing. Is this a problem with my fuel injectors or fuel pump? I heard if the fuel pump isn't giving enough pressure then the injectors wont fire. I also heard that it could be my injectors. Any input is appreciated, thanks.

p.s. it's a throttle body

-Chris

wouldnt be injector problem

check pink wire from coil to distributor, have had one break inside the insultation at the plug end and it caused no injection of fuel

injectors fire off the timing

fuel pressure has nothing to do with the injectors pulsing. But if you have spark, maybe faulty ecm. Try tapping on it when your trying to start the truck(its behind the glove box). I've seen the screens plug up from rotten fuel before so not enough fuel gets let in. Try looking at the fuel spray with a timing light hooked to #1 plug, that will give you a good idea whats happening.

up.

I'm still having problems with this. i replaced the fuel pressure regulator and it starting up. A week later, same problem. Does anyone know what are more common reasons for no starting? The engine does have 110,000 on it so it could be an age factor. Things like, loss of compression, general tune up, and timing could be off. If someone can give me common reasons for cold starting then that would help a lot. thanks for the help so far.

-Chris

Use a scanner and check to see if you are missing any data or if any is skewed. especially check coolant temp value. Just my .02

Sounds like the pickup is weak or the module is no good. See it all the time. Repl the module and pickup and see what happens. Either the pickup is not strong enough to fire the output of the module to the ecm or the module sees the input and fails to report to the ecm that the eng is cranking. Good luck. DB

do you still have spark and no fuel spray when cranking? help us out.

i can't explain it, the 4.3 starts up no problem in 30 degree weather. I really didn't do anything. Maybe the computer corrected/adjusted for cold weather driving and starting. Thanks for all the help and input.

-Chris