What are the symptoms of a dying IP?

[Napoleon_Tanerite]

I suspect that my injector pump is on its last legs. Here's what I have experienced:

--An overall lack of power (I know the 6.2 is a dog, but we're talking unable to accelerate from 35-40 on a reasonable hill)

--Poor fuel mileage (~12mpg)

--Hard starts when cold (cold is a relative term in August in GA, I mean the first start of the day is usually an affair. The truck will start, idle for a few seconds, sputter and die if not revved up, then require ~10 seconds of cranking before re-firing)

--Noticeable black smoke in exhaust with no load, significant black smoke when under load (such as towing)

--Noisy (I have insulated the cab with two layers of FatMat, rubber floor mat, carped, and a hood blanket, windows rolled up, air conditioner on, and it's STILL louder than a friend's bare bones M1009 with windows down cruising along with my feet burning on the metal floor)


I've changed the fuel filter, run several tanks through it treated with Diesel Kleen, changed the air filter, changed the oil, run it hard, all the tricks I know of to clean anything out of the system with no improvement. I'm left pointing at the IP through process of elimination. What else should I look at before taking it to the shop?

 

[Matt1031]

Have you pop tested the injectors?

 

[txmytx_catahoula]

Is the IP still on it's Timing mark? I've had many of the symptons and they were fixed when I put the IP back on time.

 

[Matt65]

.... air conditioner on...

AC ON?! - I envy you!

Based on what you have said I would verify timing. Are you running any alternative fuel WMO, WVO etc?

 

[Chief_919]

Take off the check valve on teh return line coming from the IP, inspect it, and clean it.

 

[ranchhopper]

Does it smoke excessivly a sure sign of fuel or air starvation?

 

[emr]

Just an fyi, I have a good one for 250 plus ship in NJ, just in case, last one I have... Good luck I really hope U do not need one though

 

[Napoleon_Tanerite]

AC ON?! - I envy you!

Based on what you have said I would verify timing. Are you running any alternative fuel WMO, WVO etc?

Nope, normal diesel with the occasional tank of commercially sold biodiesel. What page in the TM covers working the IP? I looked for it, but can't find anything that references it.

 

[Wolf.Dose]

Life could be easy! However, with your pump some things are possible: The return valve at the fuel pump of the IP does not close propperly. Or the return valve in the pump head at the selenoids will not close properly. Or there is some air succing location in the stock fuel filter assy.
If an IP starts really to die, the start to make noise or they fail without announcement. Ex. the spring plate at the pistons brakes and blocks the pump. The shaft will say good by. Needs a new pump in general.
However, this is without summing up all problems, but the most reasenaable for your case after 14 years with a CUCV.
Wolf

 

[Napoleon_Tanerite]

What about an air leak in the fuel system? The reason I say that is that it fires right up no problem, runs for a second, then sputters and dies if I don't give it gas, but only on the first start of the day after sitting overnight. i haven't noticed any indication of a fuel leak though. Is there a check valve in the fuel system that may have failed and is allowing fuel to backflow back to the tank?

 

[roboconcept]

I had a guy do an odd repair for me when my CUCV lost all power on a road trip: He removed the check valve, and rerouted fuel into the new 'port' created by the check valve's absence. Anyone heard of this? That was a year ago and it's been running fine since, going to replace it when I get the cash.

It might work for you as a temporary fix.

 

[Barrman]

That "port" is the fuel return port. Fuel leaves the pump that way and goes back to the tank.

 

[Brett09]

Have you pop tested the injectors?

If its free to breath that's where I'd put my money. Loud could be bad timing too.

 

[Napoleon_Tanerite]

I'm thinking its glow plug related, or electrical in some other way. I watched it yesterday and it died when the GP kicked back on after start. Today I waited about 15 seconds after the wait light went out and had no issues.

 

[Napoleon_Tanerite]

Ok, here's an update:

The issue has gotten WORSE. Now on 100% of starts the engine will start crank right up, run for about 5 seconds, and die. No amount of throttle play will fix that. Truck will restart after about 20 seconds of cranking with my foot on the floor. Most troubling is the puff of WHITE smoke as it dies, and another puff of white smoke followed by black smoke when it finally restarts. Following that affair the truck runs fine, and will restart without trouble until it sits about 4 or 5 hours, after which it requires the process above to be repeated.

I'm thinking it may be either a fuel pump or a check valve. I need a good place to start, and am desperate for ideas.

 

[ranchhopper]

I vote for the check valve the engine will not run if the fuel is obstructed on either the intake or return side you can pinch the fuel hose on the pump and it will shut down the engine. There is a plastic washer in the pump when it degrades and comes apart it obstructs the check valve on the top of the pump shutting down the engine.

 

[skark_burmer]

It sounds like your engine is sucking air and the problem is getting worse, ie the hole is getting bigger.
Are you still running the stock square fuel filter? Those are a likely air introducing source.
You run biodiesel? Sweet! So do i! However all your fuel lines are rubber and will soften and fail with the use of BioD over time. Replace your lines with silicone, even the connecter lines that go from injector to injector.
Boostcontroller.com has the best price i have found as of a year ago when i ordered bulk and replaced all my lines. I also ditched the crappy box filter for the spin on wix filters, but that is not a popular mod for the purist MV'ers around these parts.

Just FYI...
My experience with a dying (but still running) IP is the problems get worse with heat and better when cold.

 

[skark_burmer]

Of yeah, i am also a big fan of installing an electric lift pump in place of the block mounted mechanical pump.

A few benefits.
Fuel filter change/air purge is a snap.
Circulate/pressurize your fuel system to find air or fuel leaks.
Its obvious when the electric lift pump fails, not so much the mechanical.
Plus they are cheap and fit nearly anywhere.

More info.
http://www.steelsoldiers.com/533403-post10.html
http://www.steelsoldiers.com/533766-post17.html

Enjoy.

 

[acesneights1]

Check the throttle shaft seals. Very common. Mine is doing exactly what you describe. it's called drainback. I'd bet around the throttle shaft of the IP it's soaked with fuel. If so...well theey can be changed in truck but not for the inexperienced. If you put the top of the IP back together wrong it will run away. Check that shaft. I agree with what everyone else has said but check what i said as well.

 

[acesneights1]

If you can try parking the truck on a downhill angle overnight and see if that helps any.