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View Full Version : Lift pump not working/ops? fuse?



ff43sc
05-13-2004, 16:01
My 95 k2500 6.5l recently stalled pulling out of driveway, got it to restart after a few attempts, no power to pump, there is power to fuel pump at relay(main power terminal) but no power out. I read all the posts about the OPS and went to both parts stores here(advance auto/autozone) neither carry the item but can have in 1 day. I ordered one since sounds like very common problem.
I manually powered the pump and it works, truck will run without it, but if i open drain valve engine dies.... Not sure I'll trust it to venture down the highway. A few other posts talked about a fuse for the lift pump, I found nothing on r firewall, and no obvious fuses of any other kind on the firewall. Anyone know where there is one, Does the 95 have a lift pump fuse? Nothing marked as such in L side of dash fuse panel. and only fuel fuse under hood(in power/relay center) is fuel solenoid(which is IP shutoff solenoid, right). any help would be appreciated. Thanks for your time.

whatnot
05-13-2004, 17:19
Put it in D with the engine off and turn the key to START. If it doesn't run the lift pump then it isn't the OPS. (or not only the OPS)
If it does, you can take the plug off the OPS and jumper out the outside 2 pins. If it runs the pump then the wiring is all ok and the OPS is the problem.

ff43sc
05-13-2004, 17:33
Thanks for the tips, I jumped the two outside pins and the pump runs....that was music to my ears....
on the relay idea, do I simply splice into the gray wire from ops to relay(switch terminal), run power to relay, and gray wire that goes to pump then goes to power out of relay. anything else that needs to be done? thanks whatnot for your help. I appreciate it..

whatnot
05-13-2004, 21:31
I don't know how other people wire a relay but this is how I would do it. I don't know what color the wires are.
http://www.rsixray.com/junk/pumpcircuit.jpg

tom.mcinerney
05-14-2004, 16:54
Nice diagram, Whatnot.
ff43sc~ Are 3 wires fr ops. Pretty sure the output to LP is grey, possibly striped....

ff43sc
05-14-2004, 18:05
thanks for the info Tom mac..got it figured out...I replaced the OPS like dozens of other DP users and it's alive again...thanks again. funny asked a gm diesel mechanic who had worked on my truck in the past and he was totally clueless about what could be wrong...DP users save the day again...