Truck Won`t Start/Long Story...

[C.K. Piquup]

I had the Peninsular 300hp motor from my wrecked`95 installed in my`92.The`92 had 250,000mi.on everything:IP,injectors,glow-plugs,lift-pump...like I said,everything.My son had it since 200K and when I got it back it was smoking and stalling,but still had it`s power.It just needed the new fuel delivery.When I picked the truck up with the 12,000mi.motor it was smoking alot and the shop said it was probably from the roll-over in the accident.Although it had been sitting upright for three months,I figured could be trapped oil.It really didn`t feel any more powerful than the original motor,though.The`95 had a service body,ladder racks,285/75s,and 3.73s.Both trucks are 5spd.The`92 is an empty pickup,255/85s,and 4.10s.If anything,I figured it would run like a hot rod compared to the`95.I took a 400 mile(1 way)trip in it last spring and by the time I got to my destination it was stalling at idle.On the way back,it was stalling any time I let off the throttle,a real PIA.I had to keep the throttle on and ride the brakes or stall,pull over,crank and crank,pull out while speed shifting with the throttle down.I had asked the shop to swap-in the lift pump from the donor`95 since I had replaced it not long before the new engine.They said they did,but it didn`t work so they put the original back.Not true,I had a new one for the`92 I had bought before totalling the`95 and when I installed it,the origial was obviously untouched.This seemed to be the obvious problem.With everything on the engine new(12k)and the lift pump being with the old truck,I went about replacing it and the fuel filter.Well,it won`t start now,just cranks.I`ve either got trapped air or somehow the OPS is bad.What should I do?I tryed a while back and couldn`t find the testing procedure for the OPS or the one for getting air out.

[JohnC]

Did the '92 come with an electric lift pump? If so, it should run while cranking regardless of the oil pressure switch. Find out if it is running and pumping fuel first. Your description of the problem sounds like a clogged filter or failed lift pump, so I think you're at least on the right track

[moondoggie]

Good Day!

To test the lift pump on my daughter's 89, I got out the factory (Helms) shop manual (I have one for every vehicle I own) & found the relay that runs the lift pump during cranking (it was on the firewall, passenger side). I figured out which terminals to short & was able to power the lift pump to test it.

Interesting tidbit: It turned out the 89's lift pump was fine, & the relay was providing power to the lift pump during crank, but the oil pressure switch/sender was partially open-circuit during run - it provided ~ 8 or 9 volts to the lift pump, which it turns out wasn't enough.

Blessings!

[C.K. Piquup]

My`92 is a first 1/2 year 6.5TD with DB2.I think I need to test for power at the lift pump.Should it run with the key on?

[moondoggie]

Good Day!

Sorry about long delay. I only have Internet access at work, so no Saturday or Sunday; I also limit myself to lunch break (the Page is my drug of choice - I'd be on here all the time if I could).

My weak understanding of these systems is that there are two circuits to power the LP: a relay during cranking, & the OPS (oil pressure switch/sender) during running. I guess I'd check it during both conditions.

Blessings!

[C.K. Piquup]

I looked over the truck yesterday.I had a fresh filter,so I put it in after draining and cleaning housing.This was a new filter that I replaced.The lift pump is also new.The engine has 12,000 miles with everything new,a complete Peninsular motor just installed in this truck.Ok,I cracked an injector fitting and get no fuel seapage after cranking.I get fuel into the filter,but won`t pump through hose on bleeder into a can.The lift pump is running while I crank because I hear it for a few seconds after cranking.It does not run with key "on" before cranking.So,how do I go about checking power to the lift pump?what color wire am I looking for for key "on" power,grey?How do I find this OPS relay on firewall(`92 6.5TD)?Before,when it was running,it smoked alot and smells fuelish and I really don`t think it was at full power.When this motor was in the other truck it made black smoke under full throttle because of the modified pump and no wastegate set-up..It doesn`t in this truck and acts just like the old motor did before pulling.Since the lift pump was the common denominator,I have to suspect it.So,it`s a brand new GM part,must be circuitry or relay,right?Or,if that checks out,OPS?

[a5150nut]

How is the fuel shutoff solinoid? Is it working or even hooked up? Just a guess......

[C.K. Piquup]

Yeah,I forgot to mention that,It`s operating.

[JohnC]

Originally posted by C.K. Piquup:
I get fuel into the filter,but won`t pump through hose on bleeder into a can.That doesn't sound right. The bleeder simply drains the bottom of the filter can. If fuel is coming in, it should drain out.


The lift pump is running while I crank because I hear it for a few seconds after cranking.This would seem to imply that the oil pressure switch is working and you are cranking long enough to build oil pressure. Otherwise, the pump should stop as soon as power to the starter solenoid is removed.


It does not run with key "on" before cranking.It shouldn't. Figure out why fuel doesn't come out of the bleeder.

[C.K. Piquup]

Fuel does come out of the bleeder,cartridge-type w/bleeder on top.It didn`t pump through a hose into a can when I tryed the 15 second test.I need to get someone to crank it for me while I check under the hood during cranking.
JohnC,I appreciate your responses.It`s real helpful.