1992 6.5 lift pump sometimes not getting power - Diesel Place : Chevrolet and GMC Diesel Truck Forums
 
Home Forum Market Place Garage Tuning Library DTC Tool Register Vendors
Go Back   Diesel Place : Chevrolet and GMC Diesel Truck Forums > GM Diesel Engines > 6.5L Diesel Engine
Register FAQ Forum Rules My Replies My Threads Mark Forums Read Advertise

6.5L Diesel Engine Discuss the 6.5 GM diesel engine & associated components. Automatic transmission questions & problems belong in the 4L80/85 - 4L60E - 6L90 Transmission Forum

DieselPlace.com is the premier Duramax Diesel Forum on the internet. Registered Users do not see the above ads.
Like Tree1Likes

Reply
 
LinkBack Thread Tools
Old 07-22-2014, 09:04 AM   #1 (permalink)
atikovi
Diesel Fanatic
 
Join Date: May 2006
Location: Suburban Washington DC
Posts: 139
iTrader Score: 0 reviews

1992 6.5 lift pump sometimes not getting power

Bought this truck 3 years ago and replaced the lift pump before I could even drive it home because it would run a few minutes, die, and wouldn't restart. Managed to drive it home 100 miles after that but parked it because of a transmission problem.

Fast forward 3 years and I think I fixed the transmission issue, bad TCM, and went for a test drive. a half mile down the road the engine quits. Cranks fine but no start, so I roll onto a parking lot and walk back to get some tools. I disconnect the fuel lift pump and put 12 volts directly to it from a jump box. I can hear it working so I get in the truck and it starts up fine, and also notice the water in fuel light on for the first time. Reconnect the fuel lift pump and manage to drive it back.

Any ideas why the pump isn't getting power periodically? I've started up the truck a dozen times in the past few years and let it run 10 minutes with no problem. The last 2 times it's quit like this time, but if I leave it and try a week later, it starts right up?

Offline  
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 07-22-2014, 09:10 AM   #2 (permalink)
90GMC62L
Diesel Expert
 
90GMC62L's Avatar
 
Join Date: Nov 2009
Location: Nebraska
Posts: 2,978
iTrader Score: 0 reviews

Old School Oil Burners (Old SOBs) Member

Could be quite a few things.

The lift pump gets power from the Oil Pressure Sensor and the relay inside goes bad, the gauge will still work but won't supply power to the LP. Search the OPS relay mod. If you don't do the mod, at least replace the OPS with an AC Delco only.

Also, check ALL of your fuel lines for air leaks and it would be good advice to drop the tank and either replace or completely remove the pickup sock.

__________________
Aaron

1983 Silverado K10 RC/LB 305 700R4 119K miles:
1993 Formula Firebird LT1 6-speed. 119K miles:
1995 GMC K2500 LB/EC 6.5L 4L80E 167K miles:
DE 4" no muffler exhaust, OBD-I high idle mod, 285s, Walbro FRC-10 lift pump, Custom FTB mod, stock FFM delete, '82 6.2 Diesel fuel filter setup with filter heater.
2002 Chevy 2500HD Duramax/ZF6 CC/SB
Link to my build thread ----> https://www.dieselplace.com/forum/63-...liability.html
Offline   Reply With Quote Quick reply to this message
Old 07-22-2014, 09:23 AM   #3 (permalink)
atikovi
Diesel Fanatic
 
Join Date: May 2006
Location: Suburban Washington DC
Posts: 139
iTrader Score: 0 reviews

Yes the oil pressure gauge does work. I also replaced the fuel filter above the IP when I replaced the lift pump. OK I'll replace the OPS as it's cheap. Is the fuel pump relay known to go bad? That's pretty cheap to and would eliminate 2 unknowns in the circuit, even though I hate to just throw parts at a problem. Would the truck even run at all if these were bad, or is it an intermittent situation?

Last edited by atikovi; 07-22-2014 at 09:23 AM.
Offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 07-22-2014, 09:41 AM   #4 (permalink)
Tr00b
Diesel Boss
 
Tr00b's Avatar
 
Join Date: Oct 2013
Location: Scales Mound, IL
Posts: 1,261
iTrader Score: 0 reviews

Intermittent power.... check grounds. Pull the black lift pump ground wire out and find where it is grounded to the frame... and likely you will find issues. This is how I fixed mine...
__________________
1996 GMC K1500xcab 6.5 3.73 4L80E rear bags Bought at 99k 12/13 now 138k 9/17
Repairs:
BWD OPS 1/14 Heath PMD kit 3/14 Airtex boost solenoid 6/14 Lube Specialist cooler lines and cooler, rad support mounts, Pro Comp ES9000 Shocks, rear brakes 7/14 Interstate Batts, Cooper AT3 tires, Hummer H3 rims, stepper motor 4x4, coolant flush 11/14 Stabilizer bar links, soot trap gasket 9/15 Dorman tank, sending unit/sock delete, filler neck, filler neck, hose, Leroy's Tank Barbs, SAE30R9 lines, WIX filter head and prefilter with brackets by paleyjim, intake manifold gaskets 3/16 Used transmission, dipstick tube, fluid flush, drain plug pan by paleyjim, power steering fluid flush, transfer case seals and fluid 9/16 Duraterms 11/16 Ball Joints and wheel bearing drivers side. Powerstop pads, lubed sliders 4/17 AD244, Leroy's Flight Systems PMD 9/17
Performance:
Ashland Muffler 2.5 X-over 12/13 FTB FFM by paleyjim, ported upper egr delete S-code, lower F-code, ported IP fitting, FASS DRP-02 lift pump 3/16 Transgo Shift Kit by paleyjim, Energy Susp. engine+trans mounts 9/16 Ported GM8, Diamond Eye, Quadstar tune 11/16 K47 Box, Glowshift 3-1 1/17 Leroy's Billet Crank pulley, Fluidampr. 9/17

Last edited by Tr00b; 07-22-2014 at 09:42 AM.
Offline   Reply With Quote Quick reply to this message
Old 07-22-2014, 09:59 AM   #5 (permalink)
racer55
6.5TD Post Addict
 
racer55's Avatar
 
Join Date: Jul 2010
Location: Scugog Island Ontario Canada
Posts: 9,885
iTrader Score: 0 reviews

Ontario Diesel Place Chapter Member

Old School Oil Burners (Old SOBs) Member

AC Delco ONLY for OPS replacement and OPS relay mod should be mandatory for long term reliability:
https://www.dieselplace.com/forum/63-...y-install.html
__________________
No longer a 6.5 owner
2005 Chev K3500 CCLB Dmax

Diagnostic Checklist 2.0
OBD1 Codes
OBD2 Codes
6.5 FAQ
Carcode & TDCO Instructions
Offline   Reply With Quote Quick reply to this message
Old 07-22-2014, 11:34 AM   #6 (permalink)
FloridaHorseman
Diesel Specialist
 
FloridaHorseman's Avatar
 
Join Date: May 2011
Location: Lakeland, FL
Posts: 3,217
iTrader Score: 0 reviews

Quote:
Originally Posted by atikovi View Post
Yes the oil pressure gauge does work. I also replaced the fuel filter above the IP when I replaced the lift pump. OK I'll replace the OPS as it's cheap. Is the fuel pump relay known to go bad? That's pretty cheap to and would eliminate 2 unknowns in the circuit, even though I hate to just throw parts at a problem. Would the truck even run at all if these were bad, or is it an intermittent situation?
Good idea to do the LP relay mod with all new items so you know where you stand with those. Letting the truck sit for a long time is an open invitation to vermin nesting and chewing on wire insulation. With the intermittent nature of the problem I'd do a VERY close inspection of the wiring and even run some new ones if in doubt. ~FH
__________________

1994 Chevy K1500 Z71, 6.5L TD 145,000 miles, bumper mount PMD, LP relay mod, filter sock delete -SOLD-
1998 Chevy K3500, 454 horse hauler , 175,000 miles, tuned flow-through exhaust, pillar gauges (vac, trans temp, volts), electric cooling fans, external trans cooler & fan, manual TCC lockup mod, limo tint, front & rear brush guards, B&W G/N flip hitch, spray-in bed liner, chrome wheel inserts


Engine "No Start" Checklist
Diagnostic Checklist
OBD1 Trouble Codes
OBD2 Trouble Codes
Offline   Reply With Quote Quick reply to this message
Old 07-22-2014, 12:02 PM   #7 (permalink)
Freddyack
Lead Moderator
Diesel Guru
 
Freddyack's Avatar
 
Join Date: Jul 2011
Location: Denver, CO
Posts: 9,491
iTrader Score: 0 reviews

CT Smoke Member

Old School Oil Burners (Old SOBs) Member

DieselPlace.com Lifetime Premium Member

The Suburban Club Member

Use this guide to make sure all your grounds are clean and tight: https://www.dieselplace.com/forum/63-...d-grounds.html

This is a good mod, too: https://www.dieselplace.com/forum/2755252-post5.html
__________________
Offline   Reply With Quote Quick reply to this message
Old 08-08-2014, 04:35 PM   #8 (permalink)
atikovi
Diesel Fanatic
 
Join Date: May 2006
Location: Suburban Washington DC
Posts: 139
iTrader Score: 0 reviews

Just getting back to the truck now. I powered the lift pump directly by a jumper wire in the relay connector. It ran fine in the parking lot for 10 minutes idling, then I drive out to the street and it quits. Crank and no start. Got it started after about the 5th try. Drove it back in and it quits again, feels like it runs out of fuel. Idles a little rough then dies. Got it started again and parked it. What else to check? When it runs, it runs great, nice and smooth. I see in the wiring diagram a fuel shut off valve. If I remove the pink wire while the engine is running it quits immediately. Any problems with that valve?
Offline   Reply With Quote Quick reply to this message
Old 08-08-2014, 05:38 PM   #9 (permalink)
Freddyack
Lead Moderator
Diesel Guru
 
Freddyack's Avatar
 
Join Date: Jul 2011
Location: Denver, CO
Posts: 9,491
iTrader Score: 0 reviews

CT Smoke Member

Old School Oil Burners (Old SOBs) Member

DieselPlace.com Lifetime Premium Member

The Suburban Club Member

Quote:
Originally Posted by atikovi View Post
Just getting back to the truck now. I powered the lift pump directly by a jumper wire in the relay connector.
What relay connector?

Quote:
Originally Posted by atikovi View Post
It ran fine in the parking lot for 10 minutes idling, then I drive out to the street and it quits. Crank and no start. Got it started after about the 5th try. Drove it back in and it quits again, feels like it runs out of fuel. Idles a little rough then dies. Got it started again and parked it. What else to check? When it runs, it runs great, nice and smooth.
Did you replace the Oil Pressure Switch with an AC Delco D1808A? If you replaced it with an off brand you wasted your money. Put an AC Delco OPS in.

Did you do the OPS Relay Mod: https://www.dieselplace.com/forum/63-...-install.html?

Do you have a diesel rated fuel cap? If you are not sure, then get a new one. Stant 10591D for example.

Until you can pass the lift pump test (explained here: https://www.dieselplace.com/forum/63-...-pump-ops.html) you will continue to have fuel flow problems.

Quote:
Originally Posted by atikovi View Post
I see in the wiring diagram a fuel shut off valve. If I remove the pink wire while the engine is running it quits immediately. Any problems with that valve?
The Fuel Shut Off Solenoid must be powered or fuel is shut off to the Injection Pump. That is why the engine stopped when you disconnected the pink wire.
__________________

Last edited by Freddyack; 08-08-2014 at 05:41 PM.
Offline   Reply With Quote Quick reply to this message
Old 08-08-2014, 05:55 PM   #10 (permalink)
kerrye
Diesel Boss
 
Join Date: May 2013
Posts: 1,165
iTrader Score: 0 reviews

I'm not seeing where you've determined that the lift pump is not getting power when the engine stops running. Have you? Are you sure it's not still running but not pumping fuel?

__________________
93 GMC 2500 pickup
107k miles
4WD Xtra cab.
New Optimizer 10/14
Rebuilt Central Plains Diesel IP 10/14
Offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Diesel Place : Chevrolet and GMC Diesel Truck Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

PLEASE READ! You must check your email inbox for the confirmation link to complete registration. Please check your spam box if you do not see the email in your inbox.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Insurance
Please select your insurance company (Optional)

Log-in


Thread Tools

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Lift pump not getting power sskp1 6.5L Diesel Engine 31 12-24-2011 09:00 PM
Question: lift pump no power gmcdetroit 6.5L Diesel Engine 9 06-06-2011 10:11 PM
1992 6.5 IP pump overkill375 Closed / Archived Marketplace Ads 4 03-23-2011 11:37 AM
No power to the Lift pump zodiak12 6.5L Diesel Engine 5 08-16-2009 08:06 PM
6.5 no power to lift pump snowmanw9a 6.5L Diesel Engine 21 01-18-2008 09:51 AM


All times are GMT -4. The time now is 11:11 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Shoutbox provided by vBShout v6.2.1 (Lite) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd. Runs best on HiVelocity Hosting.
© AutoGuide