Oil pressure guage over the top

[C.K. Piquup]

I`ve never had to replace an OPS.Is this a typical sign of a dead OPS?I was already suspecting a bad lift-pump.My son had this truck for two years,where nothing was done to it.When I got it back,it cranked long(original inj-pump/injectors/G-plugs)and didn`t want to idle,I figured to change them.I haven`t yet.The Fuel Filter light was also on,so I replaced filter,still on,still stalling.Now no start,don`t here lift-pump,and I notice oil-pressure guage pegged when energized.I know ALL these parts need replacing(incl:pulling heads/stuck glow-plugs),I want to start it first and it probably will with possibly as little as just replacing OPS.I want to be able to pull it into the shop.This is a`92TD.

[CleviteKid]

Hard-wire +12 Volts to the lift pump, pull it into the shop, then fix everything. ;)

Dr. Lee :cool:

[gmctd]

To enhance Dr. Lee's suggestion, oil pressure gage pegs high when OPS circuit is open, or has lost it's ground. Pegs low when shorted to ground.
If lift pump is non-functional, also indicating open circuit, the OPS connector may have fallen off.

For the rest of it, sounds like bare knuckles and bad blood time. ;)

[C.K. Piquup]

Thanks for satisfying my curiousity,fellers.These parts don`t owe me a thing.It`s amazing how good this truck treated me,through the time I knew so little about the diesels.Didn`t need to know,just strict preventive maintainence.My truck before,an`84K30/6.2,taught me alot about glow-plug(non-solid state shorts)systems and what a MFI pump can act like when it`s goin`south(@123,000mi).Oh yeah,bad head gaskets(using water/bubbling water in radiator).Then came TheDieselPage.I bought my`84 in`89.