stalling after idling/update,now what

[mad rad]

I have an 94 6.5 td,5 speed,and after I let it idle while sitting still( 2-3 minutes)it'll die when I go to take off,this time when it happened IT wouldn't start up until I removed the filter and put more fuel in there,(I've already changed the filter)it cranks good just no start.had to jump it after adding fuel.thanks for help,mike.

[ 07-11-2004, 01:41 PM: Message edited by: mad rad ]

[whatnot]

Is the lift pump working? To check it, open the bleeder on top of the filter with the engine running. If noting comes out and the engine dies then it is either the pump, OPS or wiring.

[mad rad]

ok,part of the problem was that one of the batteries was bad,installed new battery,checked all grounds,did the battery posts with bolts,now it cranks great,but while I was trouble shooting I never got any fuel to come out of the bleed port on the filter or the drain by the t-housing.does that mean the lp is bad or am I doing something wrong.

[MTTwister]

mad - search on posts related to this - OPS / Lift Pump. There's a quick way to bypass the OPS and hot wire the lift pump to see it it works, versus the OPS buggering you up. Should hear the lift pump running during the iitital glow polug cycling, but evidently that doesn't mean it's pumping evidently. Good Luck

[mad rad]

ok, I'll try to hot wire it,I've never heard any kind of pump at warm up,is the lift pump the small pump on top - front of the IP?when I hot wire it do I just run a hot wire from batt to + and ground to - ? thanks for the help,working 2 jobs don't leave much time for troubleshooting and searching,luckly I have 2 trucks.again thanks

[ricksheldahl]

Mad Rad,

The lift pump is on the rails by the rear tires. Very easy to get at if you have access to a lift.

I am going through a similar troubleshooting process and from all the sites I visited they said the OPS (oil pressure switch) is the first thing to replace (34.95 from the dealer). This component senses oil pressure and then allows the lift pump to send fuel to the injector pump. No oil pressure (or a failed switch) and the lift pump does not operate, thus no fuel getting to the engine. Results in very difficult starting and excessive wear on the injector pump.

[Imteam]

I just went through the same issue with my '95 K3500. I replaced the OPS ($29.99 from NAPA) and the lift pump (a little steep at $114) and the problem is solved. Buy the OPS socket for 10 bucks while you're at it. It saves a lot of frustration.

It took about 10 minutes for the OPS swap and about 20 for the lift pump.

Good luck.

[Barry Nave]

Lift pump, many times I have read that when one open's the water drain from the filter with Eng running the truck will stop running when lift pump is not working.
When I first start Eng. when cool and run for a couple of sec. then shut down I can hear pump run till oil psi goes down. Still has psi to the ops for a couple of sec.
When runing you can feel the lift pump working.
Also check that the fuse is OK :D

[norm]

2 ways for lift pump to get power:
[1] key in "start" position (while cranking or bypass cranking by putting shifter in gear to lock out starter but not LP - easy way to prime new filter), and
[2]while engine is running oil pressure will switch in power (through OPS). This is why you hear the lift pump running after shutting down your cold engine.

I don't think that power can get to it during glow plug cycle, unless there are model year changes.

[George McGuire]

I have put a bypass on many lift pumps on the older years. Go to the firewall by the coolant tank, locate the fuse for the lift pump, remove fuse and put power from terminal strip to the terminals in the connector, try either side, if the pumps does not start, it is finished. I have a switch wired in permanent on mine so that when it is time to change the filter, you simply change it, open the bleeder, flick the switch and let it pump until air is gone, close the bleeder and then shut off switch. This saves alot of time and unnecessary engine cranking.

[mad rad]

thanks for all the info,I'll be working at the truck on saturday,good idea on the switch for the lift pump.got to try to find the ops now so I'll be ready on sat.