The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 10-27-2020, 11:19 AM   #1
hjs
Registered User
 
Join Date: Feb 2018
Location: Arnoldsville GA
Posts: 15
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.
hjs is offline   Reply With Quote
Old 10-27-2020, 01:18 PM   #2
hjs
Registered User
 
Join Date: Feb 2018
Location: Arnoldsville GA
Posts: 15
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.
hjs is offline   Reply With Quote
Old 10-28-2020, 07:51 AM   #3
Katrina/10
Registered User
 
Katrina/10's Avatar
 
Join Date: Oct 2010
Location: Ocean Springs, MS
Posts: 1,746
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.
__________________
Gary

1971 Chevrolet C/10
1951 GMC 100
1977 GMC C15
1955 Chevrolet 3100
Katrina/10 is offline   Reply With Quote
Old 10-28-2020, 07:29 PM   #4
v30crewcab
Registered User
 
v30crewcab's Avatar
 
Join Date: Apr 2012
Location: Chatt Tn
Posts: 982
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.
__________________
88 military v30 crewcab shortbed 5.9 cummins, nv4500, 205
86 k30, 89 diesel burb, 76 gmc pathfinder
71 longbed 5.3 4l80
http://67-72chevytrucks.com/vboard/s...d.php?t=522535
v30crewcab is offline   Reply With Quote
Old 11-02-2020, 07:28 PM   #5
hjs
Registered User
 
Join Date: Feb 2018
Location: Arnoldsville GA
Posts: 15
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.
hjs is offline   Reply With Quote
Old 11-08-2020, 05:31 PM   #6
hjs
Registered User
 
Join Date: Feb 2018
Location: Arnoldsville GA
Posts: 15
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.
hjs is offline   Reply With Quote
Old 11-08-2020, 07:56 PM   #7
hjs
Registered User
 
Join Date: Feb 2018
Location: Arnoldsville GA
Posts: 15
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.
hjs is offline   Reply With Quote
Old 11-09-2020, 11:03 PM   #8
44th Miss Inf
Registered User
 
Join Date: Sep 2002
Location: Liberty, Mississippi
Posts: 672
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
44th Miss Inf is offline   Reply With Quote
Old 11-10-2020, 12:00 PM   #9
hjs
Registered User
 
Join Date: Feb 2018
Location: Arnoldsville GA
Posts: 15
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.
hjs is offline   Reply With Quote
Old 11-10-2020, 08:02 PM   #10
44th Miss Inf
Registered User
 
Join Date: Sep 2002
Location: Liberty, Mississippi
Posts: 672
Re: spark/fuel pump question

Quote:
Originally Posted by hjs View Post
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.
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
44th Miss Inf is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:34 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com