Fuel Problem?

[gbrecke]

I just bought a 1992 3/4 ton, 6.5 Turbo, Auto trans, 2WD, mileage and history is not really known. This looks all stock, mechanical pump, etc..

The Air Filter was really packed with junk, so I doubt this vehicle had much
maintainance.

I have changed glow plugs, wired in a manual system for the glow plugs, changed the oil, the lube filter, and the main fuel filter on the intake manifold.

There's now a new air filter in place, and I verified the turbo freely turns.

It will now start and run smooth from the twist of the key, but if I let it come all the way up to temp (200F), and then floor it, I will get 200 feet up the road, and bog.. it is as if somone shut off the fuel. I think it does the same cold too, just wanted you to know It does it warm in case that is required.

I was thinking I'd try the pre filter next, heard there was one on the frame?

Any advice as to what is typically foudn would be greatly appreciated, I know little about thes engines.

thanks in advance for any pointers!

George B.

[Hubert]

I was thinking I'd try the pre filter next, heard there was one on the frame?


???? Not sure what you are referring to. I only know of 1 fuel filter on the 6.5 equipped trucks. On the frame is an electric lift pump.

Lift pump, oil pressure switch, and fuel filter are the big checks to do any and every time it acts up having to do with fuel.

I'd run some fuel additive for a couple of tanks too.

[gbrecke]

I'll follow the fuel line form the tank forward, and locate and check the 'lift pump'

As for the oil pressure switch, I'll look around..

It appears I'll need a manual at some point, but don;t ewant to make a mistake of buying junk, some manuals don;t tell you much about how it works.

thanks for your time and advice.. I'll be back :-)

George

[a5150nut]

Fuel pump should be under foot from the drivers seat. Looks like an inline fuel filter sept with wires into it.

Oil presure/fuel pump switch in the valley at the rear of the motor. Remove fuel filter housing and loosen glow plug relay and it will be easyer to get at the switch. Black cylinder looking switch with 1/8 pipe fitting into top rear of block, wire plug into top.

[tommac95]

Determine for sure if the mechanical FIP has a LP or not.
Determine for sure if you only have the single filter stock on most all 6.5Ls.

If more than 1 filter , change all -- be sure to Drain & Bleed !

If LP , check pressure/flow , renew OPS as 5150 suggests ... consider pre-LP fuel filter installation ; may need drop/clean/renew fuel tank. Could be crud in tank that confounds LP, and clogs filter.

[gbrecke]

Added some addatives to the fuel, added another 5 gallons of fresh fuel..

got warm, took down the road.. full throttle didn't die, doesnt; seem to have as much power as I'd expect to hear the turbo doing something, but heck, I have no boost gauge yet..

Took to the bottom of a 6% grade. floor boarded it, and went about 650 feet up 6% grade and did not die! went around the block, slow way down, then wide open throttle till abotu 55-60, and no die no bog!

So it seems the symptom has changed for the moment, maybe it'll come back, maybe not.. I do notice, that I can not get any black smoke when I'm really in the throttle, so maybe the pump is turned down, or still a fuel delivery problem.

One guy told me that the lift pump either works or it doesn't, so maybe I break the connection at the injectionpump and see what's coming out ??

some of the acroynyms used by you folks, I don't know..

One question, anyone know what lead carrys the normal temp to the glowplug controller to cancel the cycle on of the glow plugs? Seems the glow plug dash light and the glow plugs get a shot of juice from the controllerlong after the enigne is hot, and thye are cycling all the time.

Got Chilton manual for 1988-1996 chev Pickups.. no very helpful, in fact I'd say it sucks..

found the temperature switch on the intake manifold bad.. (reads wide open) hot or cold. went to Napa parts and they couldn't find same for the 1992 2500 6.5 Turbo AT 2WD ! Took the switch with me.. went thru his books, found nothing. BTW, I shorted these leads, and the idle picked up, apparently, these leads shorted raises the idle as part of the cold idle scheme, but when the leads are shorted, the glow plug controller still thinks the engine is cold, so in the 1992 6.5 mechanical system, maybe it gets the signal from elsewhere?

thanks for your help and ideals.

George

[Bnave95]

http://www.thedieselpageforums.com/tdpforum/showthread.php?t=20598
Now if only you can remember them. Some times we do use to many short cuts.

[Hubert]

I don't know much about the early 6.5's but think you have the electric lift pump and mounted in rear of engine valley fuel manager/filter/waterseperator.

Easiest test is with truck idling warm open water drain near front passanger valve cover. If it dies lift pump is not working. Catch some fuel in a clear container and let it sit look for crud / contamination. It should fill a pint container in a couple of seconds. If not investigate further.

Use the search feature and read the proper way to change the fuel filter don't just take my word for it or the owner's manual instructions. You have empty the filter bowl completely and clean it out then install a new filter. Look for any crud in bottom (there will be some). A poorly maintained fuel system may stop up a new filter pretty quick or at least partially plug it. Fuel should circulate all the time with engine running.

I'd suggest Alldata.com for service info or helminc.com for the official shop manual (not sure how far back you can get printed books) may can find one on ebay. The diesel page has a book too.

Not sure this is exactly correct on early mech IP's but there 2 coolant temp sensors one for dash gauge and 1 for the PCM. Yes the PCM (or mech. IP) somehow adjusts timing and idle for cold operation. I think the PCM controls the glow plug time according to coolant temperature sensor too. Not exactly sure about early models.

Go to Kennedydiesel.com for a trick to reading any on board diagnostic codes. He is also a preferred vendor for parts pieces and supports the page.

[JohnC]

The glow plugs are controlled by the controller bolted to the rear of one of the heads. It senses key on sequences and engine temperature. There is a coolant temp swwitch that disables them when the engine is warm. Replacement switchs are just a jumper so that the glow plugs run even if the engine is warm.

Another coolant switch controls the fast idle and cold injection advence. There is also a separate sensor for the gauge.

The lift pump relay (under cover on firewall) controlls the lift pump while he starter is engaged. The oil pressure switch on the rear of the block below the driver's side head controls it while the engine is running. They fail frequently.

There is no PCM. If you have an automatic, there is a transmission control module, but it has no connections to the engine beyond the throttle position sensor.

[gbrecke]

Became a member, finally have some infromation to go by, and posts here we helpful as well, and I thank all of you!

oil pressure switch is not exactly closed at idle, I see a flicker in my test light.

Also found the 20 amp lift pump fuse blown..

Fitted common radio shack relay, Oil pressure switch operates relay, and lift pump operates thru relay.. lift pump now working well, fuel delivery good.

Still doesn't seem to pull as strong as I would expect, but no stalls now..

As for the glow plug controller, it will continue to cycle forever! Now I know this needs no external input to cancel! problem internal to the controller

I'm starting to suspect the injection pump has an interanl problem.. but I'll study more..

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There's a major tranny fluid leak, and it appears to be coming out of the LARGE connector that plugs into the drivers side of the auto tranny (1992),
I have no clue how this plug is removed, or if there's a seal that goes bad or what.. any clues as to whether others have had a leak here will certainly be appreciated..

This is a rust free Washington Truck , I will be selling it cheap, and buying a duramax, but first, I want to get stuff sorted, and learn a little about this 6.5 turbo.


thanks for the help!

George B