Cranks but won't start, unless you are diagnosing it!

[papajon13]

Hello Everyone,
This is my first posting so, please forgive any errors. I have a '90 Chevy 1500 with a 383 stroker (under 5k miles on the motor/tranny). It has been running strong, other than a rough idle that goes away when I re-seat all of the electrical connectors around the TBI (it returns in a couple weeks or so). A week ago I got in it and it would crank & crank but, no start. It would run as long as I shot fluid into the TBI. So, I checked all the fuses etc. I found nothing wrong. Long story short, I put a couple gallons of gas in the tank & it started so, I figured the gauge was bad. When I filled it I found the gauge was fine so, I thought it had vapor locked. Then, after running fine again a week later it left me stranded and nothing I did would get it to start so, I towed it home. Same symptoms; it would run with starter fluid sprayed into the TBI etc. so, I checked the fuel pump relay and it bench tested bad so, I replace it; no change. That night a friend came to help and as soon as he was listening for the fuel pump when I turned the key on, the pump was going and it started. It has not failed again yet. I am thinking I have an intermittent fuel pump, any thoughts? I am disabled & on a fixed income so, I don't want to just keep throwing parts at it.

 

[RedLeader289]

Maybe a bad ground somewhere? With it being intermittent like that it sounds like an electrical gremlin.

 

[papajon13]

Good point, thanks, I will check the grounds.

 

[eyesi]

Good point, thanks, I will check the grounds.

papajon13
pcm grounds are in one of the two thermostat housing bolts

ignition control module inside distributor fails sometimes not delivering spark signal, sometimes not delivering injector pulse signal, sometimes failing intermittently prior to fail out

fuel pump must deliver 9 to 13 psi regulated fuel pressure
aprox 18 psi overhead pressure

 

[jasons99hoe]

i had an issue with mine doing that and it was the connection of the fuel pump relay prongs. mine wasnt making good connection and melted the plastic block all the fuses and relays mount to. take out your relay and see if anything is melted. try taking a knife or something to sand the connection inside the fuse block. i had to remove some plastic and bend the tab so it was a tighter connection. wiggle the fuel pump relay and see if the truck fires and when its running if you tap the relay it will die or sputter then you know you have a loose connection.

 

[papajon13]

Thanks to everyone. Responding to the Relay suggestion; I did replace the pump relay and all the connections looked good. I will check into the grounds tomorrow after all the goblins, witches and assorted candy seekers have gone back to school. LOL, no use in trying to get anything done tonight!

 

[papajon13]

I finished checking all the grounds & connections; everything looked fine. The beast is still starting and running fine so, I guess I will have to wait until it dies hard before troubleshooting again. Thanks to everyone for your ideas.

 

[papajon13]

Just to let everyone know; I finally got this fixed. It turned out to be the fuel pump. The bottom line symptom was every time it COMPLETELY (like a couple cool days) cooled off it would start and start until you ran it for a half-hour or so. Then you would have to let it completely cool again. Thank you everyone for your input.