truck cranks but isnt starting?

[jparkhurst27]

hi everyone,

my name is Joe im 16 and just bought my first fullsize truck its a 1987 gmc jimmy TBI 350. when i first bought it it ran awsome but as soon as i got it home 2 days later and tryed to start it, it wouldnt start it only cranks (but deffinitly has spark cause of a little starter fluid test!) it has been like this for a couple months now. i took a couple tests for voltage at the throttle body and nothing even when trying to start it. also the fuel pump will no longer turn on when the key is turned i dont know if the 2 problems are linked togethor or different. (if the fuel pump is riged up from the battery it will turn on) as you can see im not a mechanic but i also dont wanna halfass my truck so if anyone has any ideas or suggestions it would be greatly appreciated.

 

[big83chevy4x4]

welcome to ck5 /forums/images/graemlins/waytogo.gif

have you tried replacing the fuel pump relay?

 

[jparkhurst27]

it did cross my mind a couple times theres just a lil bit of a problem and thats where is it located? my manual doesnt show a spicific area in where it should be.

 

[big83chevy4x4]

i think its on the fire wall. my trucks aren't tbi so i dont know where they are at.

 

[Emmettology 101]

I bet it is the Module in your distributor! This has happened to me a couple times!

 

[slimlynn1]

Sounds like the puel relay to me also. It should be located on the firewall on the passenger side. It is a little square thingy. If you can hot wire the fuel pump and it works, this is your problem.

 

[dyeager535]

Fuel pump will work regardless of the relays condition, as it has an oil pressure switch wired into the circuit. It will take a little bit of additional cranking before it fires, (VERY little oil pressure required to make it switch)but a bad fuel pump relay won't result in a no-start condition UNLESS the pump doesn't work, or the oil pressure switch is bad. And you've already ruled out the pump.

 

[jparkhurst27]

i looked for the relay today but it isnt on the firewall if anyone knows where else it would be located let me know thanks.

 

[Emmettology 101]

The relay will be on the passenger side firewall almost above the passengerside valve cover(about 8") It is a rounded black box with a connector or two going into the bottom of it.

Have you check your oil pressure sensor? It is located on the back of the block on the drivers side of the distributor. It screws down into the block with a connector plugging into it. When I swapped the TBI back onto my truck I didn't have one of these and it wouldn't start. SImilar senario as yours. But at the same time I swapped out my disty module also.