spark/fuel pump question
 

hi,
i replaced the fuel pump relay on my 87 k10 (with 350 motor, throttle body ignition) six months ago. the truck was running at the time. it's been sitting for over five months.
now it has no spark, and the fuel pump isn't running.
if the fuel pump has failed, would that also cause no spark?

also installed a new coil and ignition control module. fuses are good.
i'm ok with replacing the fuel pump for reliability, the current pump has a lot of miles on it. but if that's not going to solve the no spark problem, i'd rather not drop the tank.
thanks for any input.

Re: spark/fuel pump question
 

as a follow-up, i do have good voltage going into the coil and coming out of the coil. the distributor module is a new ac/delco unit.

Re: spark/fuel pump question
 

The fuel pump should come on briefly when you turn the key on, without cranking the engine. I'd start with that.

Re: spark/fuel pump question
 

check your computer fuse./ fuel pump not working has nothing to do with spark.
off your fuel pump relay, there is a wire connector hanging loose, you can put 12v to that to bypass the relay and the fuel pump should run.

Re: spark/fuel pump question
 

thanks guys i will check the pump as suggested, both ways.
the distributor coil pickup wires are in bad shape so i got a new ac delco unit and right now i'm taking the distributor out to install it.

Re: spark/fuel pump question
 

well i'm sort of baffled with the no start situation.
i put power to the fuel pump at the relay and it runs. it does not run for a few seconds with the key on.
replaced the distributor pickup coil and the starter switch.
pulled and cleaned all the fuses in the square panel under the dash left of the steering column.
there's not a separate fuse, in another location, for the computer is there? wondering if the problem is the computer itself.

Re: spark/fuel pump question
 

one other thing,
is it correct that you can have a bad oil pressure sensor (the one next to the distributor) but that will not stop an engine from cranking, because the sensor is wired in parallel with the fuel pump relay?
i would change the sensor without thinking twice about it, but i've read that it's easy to snap the brass elbow between the sensor and the manifold.

Re: spark/fuel pump question
 

Scroll down to post 10 in this thread. I posted the troubleshooting charts from the service manual

http://67-72chevytrucks.com/vboard/s...d.php?t=811599

Re: spark/fuel pump question
 

hi 44th, thanks for those charts - very helpful and i will use them.
i'm facing the reality that i will actually have to learn this tbi system instead of just changing parts and hoping.

Re: spark/fuel pump question
 

It’s really a simple system, that most don’t take the time to learn. Good luck and if I can help in any way, let me know