Possible to flush IP?

[Mark3395]

Got a deuce that had been in USAF lot for years... and the fuel is the nasties smelling varnish I've ever sniffed.

Truck turns over well but is getting no fuel to the injectors. It's getting to the IP. Doesn't come out of the whatever-it's-called plug on the side of the head. Seems that the IP is clogged up.

Is it possible to loosen the lines and pressure feed some sort of solvent through the IP to clean it out, then reflush with fuel to fire up?

Or is there any way at all to clean that IP short of full disassembly?

Thanks in advance.

Mark

 

[Westech]

I would bet the injection pump head is frozen.... its replacement time. we had to do that to my last deuce.. it took about 30 min.

 

[mcmullag]

similar story

I won a deuce off GL that came out of the air force at Peterson AFB and the fuel system was in terrible shape.
The fuel tank had about 1 inch thick of brown goo on the bottom of it and all the fuel filters were just full of this brown gooo. I changed all the filters but evidently some had gotten thru to the injection pump or the fuel sitting in there for years went bad. I also took off the fuel tank and cleaned it out.
A member of our MV club whom is a supervisor of a freight company's truck shop, and a deuce owner, advised me to have the truck's fuel tank half full, then add 5 gallons of ATF (like Dexron II) and let the electric intank pump run for a couple hours and clean everything out.
I did that except I only put in 4 gallons of ATF ( $9.77 a gallon at Wally world).
Had the truck on a 24 volt charger and the electric switch on the dash turned on so that the intank pump was
circulating the magical cleaning fluid for about 4 hours.
I then cranked the engine for awhile with the stop engine thing pulled
out on the dash so that it would not start, but get the engine oil up where it was supposed to be. I did this
especially because the truck likes to go to full throttle (2,500 rpm) after it has been sitting for days, and then die.
So I did about 3 sessions of that cranking. Then I started the truck and this time I let it go to full throttle.
Well actually it ran up to about 2000 rpm and then slowed down to 1000 then started climbing back to 2000. It 'hunted' like this
for about 2 minutes then slowed down and died. I let it sit for awhile and it did the same thing again.
My buddy that owns and maintains 4 Kenworths ( the truck has been sitting in his yard for about 6 weeks)
suggested that it was acting like it was sucking air into the fuel system somewhere.
Sure enough, I went over all the nut fittings on the fuel system and some could be tigthened
at least a 1/4 turn and some a 1/2 turn (nuts at the secondary filters and going into the IP).
I got it started again and this time it settled down to 1500 rpms with the
on dash throttle thing pulled out, go any lower and the truck just died, and while it was running at these high rpms,
the throttle rod connected to the foot pedal and dash dingus made no difference, they acted like they were not
connected to the injection pump.
We let it run for about 1/2 hour at 1500 rpm, then slowly worked the dash
throttle dingus down, notch by notch, 1200 rpm for awhile then after about an hour, maybe more it could idle at 800 rpm.
It had been running an hour and now the IP reacted to the foot throttle movement, so I drove it about 10 miles, worked fine.

 

[gimpyrobb]

Couple things to check. First, pull the plug in the center of the hydraulic head. Make sure you have a trap or sumptin down, in this step fuel leaks a lot. Find a wooden dowl, a drinking straw, or plastic pen and hold it inn the space the plug was at. Have someone get in the truck and crank it over. Just so you know, when they turn the power on, the in tank pump turns on and fuel starts to flow out of that hole you have the straw in. When they crank the motor over, the straw should bounce up and down. If so, that tells you the plunger is moving correctly, if not, you might want to find a dowl to tap on the plunger to see if you can free it up. If all checks out there, its time to pull the "fuel shut off" cover off and make sure the lever under that cover moves backward and forward on its own. If you push it toward the firewall, it should spring back to the 7:00 position on its own. If not you need to clean it up. Do those tests and let us know.

 

[gimpyrobb]

Real quick, I don't know of anything on the side of the head that should be removed to test it. ATF is a good cleaner. If you still have my number and have questions, feel free to use it. If not, I can send it in a PM. Even when I have ran my truck out of fuel and it died on me, I have not had to crack the injector lines to get it to run again.

 

[armadillofz1]

i wonder if dropping it into an ultrasonic tank for half an hour would do the trick.

 

[gimpyrobb]

To tell the truth, I'm not sure he was looking for fuel in the right area.

 

[WillWagner]

Simple things first, I'd do the shut off then the mess making plunger check.

 

[nk14zp]

 

[Mark3395]

We checked the shutoff and find it working.

I love the idea of flushing with ATF. Will extract the fuel from one of the trucks, put in some fresh fuel and ATF, and see if it'll start. This particular truck looks like it'll be worth restoring... seems to have a nice engine.

The other on is a nice '88 and should come out of it. Will get to it later.

We'll be working on it this weekend and I'll report what I learn.

Might be able to unplug the in tank pump, block the line and pump clean fuel into the primary filter with a pressurized tank... would save a lot of fussing with the fuel tank. Issue is: What pressure should that tank be pressurized to?

Gimpy, I ran over my cellphone so lost your number after you helped me with the 97 109A3 that I couldn't get going. Removed the fuel density compensator stop plate and really revved the engine up. Knew I had to drive it carefully or I could blow the head gasket. Made it a whole 6 miles befoe it blew. Papabear and team helped recover it and Troy found that the bolts hadn't been properly torqued. He fixed it and it's the truck I drove to the GA rally in '09. Good shakeout cruise. Runs like a striped assed ape now.

Mark.

 

[Mark3395]

Time for an update.

A friend I gout out in ince weather yesterday to work the IP issue. Verified fuel is getting thru the filters and to the head by removing the stop/plug on the top fo the head and sticking a rod down in to verify that it was shoved up and down... pump is working in there it seems, and fuel comes out the hole.

Loostened 4 injecter lines and found no fuel getting up them..

So now what do you think is wrong, and will tapping some kind of solvent into the IP and lines clear it?

And BTW,. what's the fuel prssure going into the IP?

Thanks much.

mark,

 

[gimpyrobb]

Have you checked the fuel shutoff valve? That will be next. I will PM my cell # in a sec.

 

[derby]

I think he removed the fuel metering plug. Make shure you tighten it properly. I broke one off by over tightening it

 

[Mark3395]

I forgot to say that we checked the fuel cutoff and it was apparently working fine. And when the plug was remived we got good fuel flow out the hole, so we've got fuel going up that far.

So it seems to be somehow blocked from getting up the lines to the injectors. Sure hate to replace the head if there's a way to unjam it or clean it.

Mark

 

[Mark3395]

BTT.

Still questioning what flushing technique might work to unclog an IP... especially the head. Or is it a waste of time?

Still thinking of using ATF, but intend to disconnect the IP lines at the Injectors so that I could flush the system with a solvent that normally wouldn't be useable to run through the injectors.

Still trying to figure what pressure I should introduce the stuff into the IP at. Figuring on turning over the engine to distribut it out the lines... if I can get past whatever's holding diesel up from exiting the head now.

Any ideas... or success/failure for this sort of operation? Ideas for technique to test?

Mark

 

[gimpyrobb]

I'd just disconnect the fuel line going under the frame and hook you flushing mixture feed up there. It will run through the filters and to the IP. The fuel should just dribble out of the injector line ports. Make sure you wear protective measures.

 

[mcmullag]

Let us know how it goes. I pulled the thing off the side of the IP as someone recommended and cleaned that shaft thingy, and I also did the pen test and that all tested ok but my truck would not run right, just run to full throttle and then when I killed it so it would not blow-up, it would not restart.

I recommend the flush using 25% ATF (half tank clean diesel and then add 5 gallons ATF), running just the fuel pump for about 4 hours (do this by having the lever switch on the dash thing turned on but do not crank engine) to circulate this mixture thru the system and letting new filters catch the bad stuff as it gets pumped thru system again. My truck is running great now. I had a 24 v charger hooked up to run the fuel pump for 4 hours. I have painted the truck too, maybe that's why it runs so good. A clean truck is a happy truck.