Bringing non-runner M1165A1 REV back to life!

[GMVguy]

I bought this “non-runner” M1165A1 REV Truck (SN 315k) as a “parts truck” to salvage some things for my GMV, but decided to try and get it running. I’m chasing down all the problems and hit a wall I could use some help with.

When it arrived from GP, the serpentine belt was wrapped around the fan drive and the tensioner was missing, so I replaced those.

With fresh batteries, the truck started up, but ran very rough and blew white smoke (unspent fuel), as if glow plugs were bad. It lives! I was encouraged…

Sure enough, 2 out of 8 glow plugs tested bad (no continuity), and the start box was not supplying voltage to the glow plug wires. Replaced & tested all 8 glow plugs with Wellmans and put a brand new Nartron S3 start box in. Verified 24v to known good glow plugs and reconnected the batteries...

See the video at this point. The truck started up quicker, but still runs very rough and blows white smoke. (I also noticed oil pressure gauge doesn’t move). I’m hoping there isn’t a major internal engine problem, but am not sure what the above steps lead to at this point.

Any ideas?

 

[87cr250r]

Even without glow plugs the engine should smooth out within a few seconds if you're above 40°F. That engine is making some unhappy sounds but they don't sound like bearings but there is something seriously wrong with the engine. Is it blowing bubbles in the cooling system? Have you done an oil filter cut? What does it look like under the valve covers? You may need some injectors.

 

[GMVguy]

Haven't removed the valve covers yet but I did change all fluids and there were no obvious issues. I still have the old oil filter, so will cut it open and check the element with a magnet.

No bubbles in the coolant.

Would any of the above, or injectors, cause the engine to run so rough and shake like that, blowing unspent fuel out the exhaust?

 

[Mogman]

I would put an oil pressure gauge on it and confirm it had oil pressure before continuing, you can simply screw a gauge into the 90 that the sending unit connects to.

 

[tomelroy]

Hopefully you have oil pressure and good compression on all cylinders. If you do I would check the fuel system. Maybe injectors. Could also be injection pump or timing (lots to check on the injection pump) . Did you drain the tank and start with fresh fuel? Did you change the fuel filter? How are you fuel lines looking (including return lines off each injector)?

Does you throttle move smoothly? Is the small pin on the side of the pump frozen (rusted in place) or is it moving in and out as you apply throttle manually at the pump?

Eliminate the cheap and easy stuff first.

 

[GMVguy]

Hopefully you have oil pressure and good compression on all cylinders. If you do I would check the fuel system. Maybe injectors. Could also be injection pump or timing (lots to check on the injection pump) . Did you drain the tank and start with fresh fuel? Did you change the fuel filter? How are you fuel lines looking (including return lines off each injector)?

Does you throttle move smoothly? Is the small pin on the side of the pump frozen (rusted in place) or is it moving in and out as you apply throttle manually at the pump?

Eliminate the cheap and easy stuff first.

Good stuff, thanks. Checking oil pressure and compression tomorrow. Yes, fresh fuel and the fuel filter/separater was removed, cleaned and new element installed.

Throttle moves smoothly. Will check the small pin on the side of the pump as well and report back.

 

[tomelroy]

I would also disconnect the exhaust before the cat and see if it runs any better.

 

[Gamble]

Remove the check valves from the fuel lines also.

 

[GMVguy]

Remove the check valves from the fuel lines also.

Which ones do you recommend removing? In the TM, there are several shown.

 

[Coug]

just in front of the fuel tank there are 2 check valves in short rubber sections of hose. Those are the ones that normally cause trouble.

 

[Gamble]

just in front of the fuel tank there are 2 check valves in short rubber sections of hose. Those are the ones that normally cause trouble.

Exactly. Remove those two check valves and your issue very well could be resolved.

 

[GMVguy]

Update... I wanted to confirm engine was healthy, so I compression-tested the cylinders and all are consistent at 420psi so I’m good there.

Drained the motor oil and cut the oil filter open… no sign of metal anywhere.

After installing a new filter and filling with fresh Rotella T6, I connected a mechanical pressure gauge to the sending port and confirmed good oil pressure 30-40 at startup).

No change, so I will remove those two check valves tomorrow. Seems I’m running out of options here…

If it still runs rough with no check valves, what’s next? Injectors? Injector pump? Flux capacitor?

 

[Maxjeep1]

I have had good luck using Diesel Kleen when my truck was running ruff and dying when I let off of the gas. It fixed and I add it about every 3rd tank. I know people say that it’s hiding the problem but it worked for me and it’s been over 2 years.

 

[tomelroy]

I am not 100 sure, but I think if you remove the return fuel line off the top of the injection pump and put a longer piece of fuel line on it and run it into a catch can, that would simulate open check valves...if that works..then dig into the check valves.

Then,
Check to see if the small pin on the bottom of the pump is not frozen in the in position?
Bypass the cat
Injector clean or replace.
Rebuild injection pump

 

[Maxjeep1]

I have had to replace the fuel pumps on both of my trucks. I don’t think that’s your issue but I am sure that it needs to be done! I had fuel in my oil

 

[GMVguy]

- Checked compression at all cylinders and they’re all consistently 410psi.
- Removed both check valves (one was blocked!).

Started it back up and it runs a little better but still sounds like it’s running on six cylinders.

Fuel Injection Pump rebuild next???
Or try new injectors before removing the pump?
Or something else?

 

[TOBASH]

- Checked compression at all cylinders and they’re all consistently 410psi.
- Removed both check valves (one was blocked!).

Started it back up and it runs a little better but still sounds like it’s running on six cylinders.

Fuel Injection Pump rebuild next???
Or try new injectors before removing the pump?
Or something else?

Open and close each injector to let out air, but also to see which one or which ones are the offending the bad ones

 

[Mogman]

- Checked compression at all cylinders and they’re all consistently 410psi.
- Removed both check valves (one was blocked!).

Started it back up and it runs a little better but still sounds like it’s running on six cylinders.

Fuel Injection Pump rebuild next???
Or try new injectors before removing the pump?
Or something else?

The IP is a "distributor" type of pump, while possible it is not very likely it would be able to "fire" some cylinders and not all of them.
Break each line loose and see if you can figure out which ones are not firing, this would be indicated by a lack of RPM drop when the line is "busted loose"

 

[Mogman]

This will also let you see if any IP lines are not getting any fuel, you will not be able to tell if there is enough pressure to fire the injector but you should see similar results as far as how much fuel comes of of each line.
If it has always had the "mis" you might want to make sure all the lines are installed correctly, it would not be the first time someone found them switched.

 

[GMVguy]

During the takedown process of removing the power steering reservoir, intake manifold, turbo crossover, etc I noticed some damage to the engine harness, including the main ground wire (3C) as well as the three wires to the TPS (Throttle Positioning Sensor). The TPS wires were severed completely. Would a disconnected TPS cause the rough idling in the video I posted above? Wondering if that's been my culprit all along...