OBS powerstroke fueling issues, keep it or not?

NDCjeepsmith

NDCjeepsmith

Red Skull
Joined
Dec 8, 2021
Member Number
4600
Messages
926
Loc
SW Mo
Nabbed a 96 Powerstroke last year. Guy disappeared before delivering ***le so I haven't been using it except to do brush and ditch clean up around the property.

I originally bought it after buying a 30ft lowboy and starting to haul 2 jeeps.

Havent got to use it for that since it ain't tagged yet but I'm going thru that cluster **** now.

Today I was loading it up with burn pile **** and after 15 mins of idling it started to idle rough, then slowly got rougher. Gave it a little throttle and it cleared but as soon as I came to a stop it died. Didn't restart. Fuel is in the filter housing so that kinda tells me my original thought of fuel gauges maybe ain't right and it ran out off fuel in rear tank, isn't what it is.

This is my first diesel so not up to par with them. What are some tests to do to narrow down the issue?

When I got it I did take it to local diesel shop and they inspected it and gsve it a once over.

Guy said it's the least amount of blowby he's seen in an OBS and other than brakes was in good shape.

It does sit for periods, I put Howe treatment in it every few months and hoping that isn't the issue but I did fill both tanks over a year ago. Think the rear is close to empty.

I did pull the batts to charge and one was 25%, the other was 90%+

What's the deal there? It was the drivers side batt, is that main batt?, are they not "tied" together?...
I'm thinking it's the head unit that's in it

Pointers on where and what to test greatly appreciated
 
30ft goose and two jeeps will be a slow ride in that old girl. It will get it done.

Have no direct experience with your issues. Injectors are fired off oil pressure, so check you have oil first.
 
Gravy said:
30ft goose and two jeeps will be a slow ride in that old girl. It will get it done.

Have no direct experience with your issues. Injectors are fired off oil pressure, so check you have oil first.
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Yeah had most people tell me they'd rather haul that in my 2010 Power Wagon. Which is what I've been doing and it's done fine this year. I know it taxing it hard tho.

Good to know about the injector/oil relation, that's good... also sounds like a damn good way to have a safety built in to make sure you don't run a motor getting no oil.
 
Oil condition is important. I can tell by the way mine starts when it needs an oil change, esp when it's cold outside.

Fuel filter, I had one clog on me back in October, but it looked fine when it was pulled so don't go by the visual inspection.

If you think it's out of fuel but the gauge is still showing a quarter tank then the screen probably broke. They're pretty tall on the 7.3 sending units. You can buy a replacement screen from Dorman, you don't have to replace the whole sending unit.

The OEM battery cables will corrode instead the big lug on the passenger side battery, and just like that you're not using the driver battery anymore. The IDM won't fire the injectors unless you're over 10v.

The screen in the IPR can get clogged, or the nut on the back side can come loose, which will cause low oil pressure to the injectors.

Having a scanner to check the actual high pressure oil psi along with the IPR % will help with troubleshooting.
 
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Get the electric system up to snuff 1st. New cables and whatever else you have to do. The IDM pulls a lot of amperage 1 battery can barely get you buy. I do highly recommend that you use connector gell. Use it liberally. Bare clean grounds everywhere and liberally coat it all with connector gel.

You may need to clean out the filter bowl below the heater. My IH sits and it took oven cleaner and a pressure washer to get the built up gunk, Algae and muck out. I cleaned the entire thing including the screens and orifices'. My truck runs 1000 times better.

My issue was similar to yours. truck would run find then stall. Start right back up. Then after a while it took a touch longer to restart. After i cleaned the fuel system it starts like it did when I 1st got it years ago.

If the truck is that mechanically sound Id keep and never forget what year the truck is when you tow. It will tow like everything else does that was made in 96.
 
Check the fuse for the fuel heater, IIRC it's #22, when you are leaning over the driverside fender it's the furthest one back, one of those big fuses. If it's blown the fuel shorted, just unplug the heater and replace the fuse. If that's not the problem you need a scanner, guessing gets expensive.
 
Doesn't that fuse also power the PCM? If so unlikely it would run at all if it popped.

I haven't run the fuel bowl heater in mine for 20 years because of that. Not really needed anyways I don't think; I don't even plug my block heater in unless it's below 0°f.
 
Got to mess with it today. Charged batteries in but the batt light stays on and nothing happens when key is turned.

Test light says I'm not getting power to fuse #22, TFI module, coil, dizzy pickup, and EEC relay coil.

Anyone have a wiring schematic handy while I dig?

Im assuming it'll be in the power distribution block itself, so fun wiring ahead
 
Fuse 22 is Fuel Line Heater, 200a Generator/Voltage Regulator, PCM Power Relay Coil, Glow Plug Controller.

Thats a key hot fuse. Power comes direct from ignition switch to that fuse.
 
Yep, thanks for that... it's GTG...

These were the only two codes thrown and the first is most likely from sitting with no batts id say.

20250112_121042.jpg


I did an injector test and things fired off, so whether or not that means they're working properly...
 
She's runnin... really didn't replace anything but the fuel filter and starter solenoid.

Think it was mainly old fuel and priming.

Need to pull cluster and check the temp and fuel gauges, they're both dead, everything else works fine tho.
 
NDCjeepsmith said:
She's runnin... really didn't replace anything but the fuel filter and starter solenoid.

Think it was mainly old fuel and priming.

Need to pull cluster and check the temp and fuel gauges, they're both dead, everything else works fine tho.
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Cluster/PSOM are common failures.
 
Yeah I've had 2 PSOMs fail now, while the speedometer itself continued to work. Had a couple gauges fail. Never a fuel gauge, every time for me it was a failed float in the tank, or the inlet screen broken off the fuel pickup in the tank.

If you've never replaced the EBPS before, then it's safe to assume the supply tube for it is clogged with soot and needs replaced as well.
 
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