1986 M1009 - Fuel problem/Injection pump maybe?

[derekrayhall]

I bought a 1986 M1009 and I can't seem to kill the gremlin that's plaguing it. Here are the symptoms... and what I've done to fix them...it starts and runs perfectly, always. I drove at high speed (75) and long distance 60 miles... it ran great, then out of the blue it turned sluggish like it was starving for fuel above 45mph... one mechanic replaced the small fuel pump and fuel filter...it ran perfectly for about 200 miles... then the exact same problem returned. The next mechanic said it was sludge in the fuel tank... which made sense... replacing the fuel pump and filter allowed it to run great, for a while... so we replaced the fuel tank and fuel filter (again) and it ran great for about another 200 miles... now today, I drove to the neighboring town to get some tires mounted, and guess what happened on the way home??? Same symptoms.... and it stalls at red lights. Wtf???

Please... please tell me someone can diagnose this online...

Could it be a 30 year old rubber fuel line releasing (chunks)? Could it be a line sucking in air??? I'm at a loss...

 

[kc5mzd]

Try using a good fuel additive and driving much slower. Also you may go through a few fuel filters. Sometimes when you use Bio Diesel it will "clean" everything out and clog filters for a while...

 

[Mg84648]

I it "always starts and runs perfectly" I would eliminate air in the fuel or lines deteriorating. You would have issues starting the motor due to fuel drain back. Assuming the other two sides of the combustion triangle, air and heat are good then it's a fuel supply problem. I would spend $300 more to have my IP redone. It literally works miracles having a fresh injection pump on your motor.
There are several companies mentioned in previous threads that do IP's, just do a search for them. You'll get to read some spirited debates on your way to choosing a company, lol.
As long as you changed the fuel filter sock in the tank then you did all the small stuff, IP and injectors are all theta left really.

 

[doghead]

Might be your IP. Might just be the shutoff solenoid.

Try dumping cold water over the IP next time, see if it helps.

 

[firefox]

I have been under the impression that running these engines much over 55 will
shorten their life very rapidly. Could someone enlighten me?

 

[kc5mzd]

How long ago did you buy the truck? I have put diesel trucks that sat for a long time back on the road. I have seen that problem where the truck would drive fine until I tried to take it on a long freeway trip then it would clog filters for a while. Once you get all the buildup out of the lines they usually last progressively longer between filter changes. When it sits for a long time diesel gets bacteria growing in it. When you start using the vehicle it clogs filters until everything clears out. Diesel additives help dissolve the bacteria and make your filters last longer.

 

[kc5mzd]

Its more the RPM that kills the engines. When you run a diesel at high rpm it will greatly shorten their life. Overdrive transmissions allow you to go faster while keeping the rpm's down.

 

[Tinstar]

All of the CUCVs seem to have fuel tank cleanliness issues when purchased from the government.
Almost all sat idle for years before being sold.

Agree with doing fuel filter changes, along with checking/replacing tank pickup sock.
Run some SeaFoam, or whatever you prefer, fuel system cleaner for a few tanks.
I might also change the lift pump. It might be fading. Unlikely but possible.

If all that does not improve issue, new IP time.

Im assuming you already replaced all the old rubber fuel lines.
That is one of the first things you should do when you get truck home.

 

[glaser06]

Might be your IP. Might just be the shutoff solenoid.

Try dumping cold water over the IP next time, see if it helps.

What exactly does this do? I'm assuming cool something but how does that help and wouldn't water on the solenoid cause a short (and the solenoid to cut out)?

Sent from my SM-G930T using Tapatalk

 

[doghead]

Yes it cools the solenoid.

It is water/fuel tight. Water will not infiltrate it.

It will prove if the solenoid is failing from heat(needs replaced).

Remember, it's energized/activated all the time your engine is running.

 

[glaser06]

Yes it cools the solenoid.

It is water/fuel tight. Water will not infiltrate it.

It will prove if the solenoid is failing from heat(needs replaced).

Remember, it's energized/activated all the time your engine is running.

Just avoid getting it in the connector if it looks like mine with bare wires, lol.

Great troubleshooting tip. Thanks doghead!

Sent from my SM-G930T using Tapatalk

 

[porkysplace]

Just avoid getting it in the connector if it looks like mine with bare wires, lol.

Great troubleshooting tip. Thanks doghead!

Sent from my SM-G930T using Tapatalk

That sounds like a lack of maintenance on your part , either shrink tube or liquid electrical tape would solve that problem . It would only take a few minutes and a few dollars to fix.

 

[cucvrus]

DC current and water. No effect that I am aware of. I know it affects hot light bulbs on my boat trailer. But if water effected any DC connections we would all have problems. DC is different then AC in that aspect. I do not have a scientific explanation. but I am sure we will learn one quickly. Sounds like internal injection pump issues to me. A fresh injection pump sure does cure a lot of CUCV ill's. That is assuming you did all the other things you mentioned in your post. Good Luck. Keep us posted. IMHO a fresh injection pump is needed. Works for me when I get a poor running CUCV. You will be pleased with the results of spending $350. and 4-5 hours labor. Report back. Thank you.

 

[glaser06]

That sounds like a lack of maintenance on your part , either shrink tube or liquid electrical tape would solve that problem . It would only take a few minutes and a few dollars to fix.

Don't like to use either unless necessary, that's a temporary fix. Haven't really looked for a new connector to fit that 10 (maybe 8?) gauge wire as the truck came to me that way 6 years ago.... the insulation of much of my wire is old and cracked but she still runs.

Sent from my SM-G930T using Tapatalk

 

[cucvrus]

You don't need that insulation. A dab of dielectric grease and a tight connection. They were never water tight from new on a CUCV. I literally run mine under water a few times and it never shut off. I had a snorkel on the air filter. I don't recommend that to anyone. but we experimented with them. Rubber hoses and PVC tubing tightly sealed. More of a PITA then it was worth. Its not a boat so I stay out of deep water. In DC current a tight/snug connection is all that needs to be there. Good Luck.

 

[kc5mzd]

More info than you wanted to know...
24 volts DC acts very similar to 24 volts AC in regard to water. DC is where electrons flow one direction only. AC flows one direction then the electrons turn around and come back. The US standards and safety people determined around 24 volts is the maximum safe voltage for the human body to be exposed to without risk of electrical shock. Water is a conductor and a major component in the human body. Knowing this I would say 24 volts is the maximum safe voltage to use around water. Your house is 120 volts or 240 volts and very dangerous when wet. 240 volts DC around water WILL kill you!
You are right though it is reasonably safe to use water around 24 volts DC.

 

[kc5mzd]

I do not have a scientific explanation. but I am sure we will learn one quickly.

Sorry I just couldn't help myself.

 

[The FLU farm]

Don't like to use either unless necessary, that's a temporary fix. Haven't really looked for a new connector to fit that 10 (maybe 8?) gauge wire as the truck came to me that way 6 years ago.... the insulation of much of my wire is old and cracked but she still runs.

Okay, I'll bite.
So shrink tubing and liquid electrical tape are "temporary fixes". But not having any insulation (although not needed in this case) for six years is....a permanent solution?
As a frequent user of shrink tubing and liquid electrical tape, I don't get it, sorry.

 

[glaser06]

Okay, I'll bite.
So shrink tubing and liquid electrical tape are "temporary fixes". But not having any insulation (although not needed in this case) for six years is....a permanent solution?
As a frequent user of shrink tubing and liquid electrical tape, I don't get it, sorry.

I knew ya would. I'm replacing the wiring throughout the truck as I can/need to. With new wire (insulation included even! ). Tape degrades over time and although shrink tubing holds up with wire loom, I've found repeated exposure to hear cycling can loosen the tubing over time. The best use for shrink tubing is stiffening the area around a solder joint, imo and under some sort of wire loom/loom tape.

This spot hasn't produced a problem yet so I haven't replaced that particular run of conductor but I'm glad you asked.



Sent from my SM-G930T using Tapatalk

 

[firefox]

Just an fyi. 3M makes a shrink tubing with glue on the inside. The stuff is fantastic for
all kinds of things besides just wire. For example: I had a pair of large nail clippers that used to slip and produce copious amounts of blood. Thae shrink tubing I put on the handle part is still there and functional after 20 years. I put this stuff on all kinds of things. It really stiffens up
connectors so that they don't end up with the wire flexing back and forh and breaking.

I don't own stock in the company.