Full Size K5 (1969-1991) GMT415 (1992-1994) Tech Discuss any and all full size K5 general tech topics here.

No power to fuel pump???

  #1  
Old 09-15-2014, 09:57 PM
damadtech's Avatar
Beginning Member
Thread Starter
Join Date: Dec 2012
Posts: 14
damadtech is on a distinguished road
Angry No power to fuel pump???

Okay, have a 1993 Blazer Sport 4X4 with the 5.7L. Drove it home running fine and shut it off and then the next day it wouldn't start. Plenty of fuel in the tank, strong spark to the plugs but it just spins. On the first few items I checked, I found no pressure at the injectors in the top of the FI unit. Pulled the cover under the hood on the passenger side firewall and there was no power to the fuel pump fuse (gray wires). Checked the fuel pump relay beside it and there is constant 12V power on the orange wire as there should be. However, in the "Start" or "Run" position, no power shows on the black/white wire to the fuel pump or the red wire to the prime circuit. Also never shows any power off the gray wire which should be to the pump fuse if I traced the diagram correctly. All the fuses under the drivers side of the dash by the brake release are fine but I only found one full size fuse marked for the Eng/ECM although the book wiring chart references two 20A mini fuses under the hood also for the ECM1 & ECM2 circuits. I supposedly have a PCM but it shows it should be where my anti-lock brake controller sits on the driver's side inner wheel well. I can also find no pink power wire anywhere that is supposed to power the PCM in any of the visible harnesses to follow and try and locate the actual module.

Any ideas about:

(1) where to find the PCM so I can verify power (although the idiot lights work which should mean it's powered up),

(2) where the mini ECM1 & ECM2 fuses referenced in the wiring diagrams can be found under the hood, or maybe elsewhere,

(3) or any ideas on another possible area to check such as ignition switch?, neutral safety switch?, or something that controls the power to the fuel circuit (ECM maybe) that I haven't found in the pages of wiring diagrams?

Thanks in advance for ANY ideas or personal experiences that may help me get this thing fired back up!!!
 
  #2  
Old 09-15-2014, 10:04 PM
Starting Member
Join Date: Sep 2014
Posts: 1
chugger7 is on a distinguished road
Default

Check the oil level. Just had same problem with 1987 K5 with 5.7. Oil was low, there is a low level sensor of some kind that blocks signal to fuel pump.
 
  #3  
Old 09-15-2014, 10:13 PM
damadtech's Avatar
Beginning Member
Thread Starter
Join Date: Dec 2012
Posts: 14
damadtech is on a distinguished road
Default

Fresh oil change a month ago and never got a light but I'll go pull the stick. Maybe that sensor could be the problem???? Thanks for the tip!!!
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
BouncingRadical
2nd Gen S-series (1995-2005) Tech
14
11-27-2015 12:30 AM
jfrust64
1st Gen S-series (1983-1994) Tech
0
07-15-2012 06:41 PM
Klturi421
2nd Gen S-series (1995-2005) Tech
1
06-29-2012 10:20 AM
cide
2nd Gen S-series (1995-2005) Tech
1
11-07-2009 01:26 PM
mytruck2
2nd Gen S-series (1995-2005) Tech
11
12-13-2006 04:50 PM


Thread Tools
Search this Thread
Quick Reply: No power to fuel pump???


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.