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-   -   IP Rack Stuck? (http://www.peachparts.com/shopforum/showthread.php?t=407211)

smiffy6four 08-05-2020 06:57 AM

IP Rack Stuck?
 
I'm having trouble getting fuel to the injectors on 1985 OM 617,in a 1985 GD300



I have worked on many diesels in my career, but his one has me stumped.


So far, I have:


rebuilt lift pump
new primer
verified pump drive shaft is keyed to vacuum drive gear
spline coupler to IP pump is present
replaced all fuel lines from tank to engine


I get good fuel flow when priming,to the fuel filter, but very little from the outlet from the IP(on the block side of the IP). Even cracking the fitting, to bypass the check valve doesn't help.


Am I looking at a stuck IP rack? The vehicle has been sitting for almost 5 years.

Diesel911 08-05-2020 12:07 PM

What is a GD300?

"I get good fuel flow when priming, to the fuel filter, but very little from the outlet from the IP(on the block side of the IP). Even cracking the fitting, to bypass the check valve doesn't help."

This seems to imply that your the spin-on Fuel Filter is plugged. Or some other obstruction from the filter to the Fuel Injection Pump.

When you pump the hand primer or the Lift Pump is working and the fuel flows into the fuel injection pump housing and back out that is a separate system; the fuel supply system. The Rack has nothing to do with this part of the system.

You should be getting out as much fuel as say the hand primer moves.

You might try taking the fuel supply line at the fuel supply/lift pump and running a longer hose into a container of clean diesel fuel and running long hose from the return back into the container so you can get a really good idea of what is going in an coming out.
If things improve when you do that it may be that there is some restriction in the Fuel Line on back to the fuel tank.

Diesel911 08-05-2020 12:26 PM

Was the vehicle run on some alternative fuel like Waste Vegetable Oil or?

Inside of the Fuel Injection Pomp the individual Elements (plungers and barrels) has a small feed hole or holes. Even old dried diesel fuel can plug them up.

Need to know if you have an MW or an M Fuel Injection Pump.

Please note if your vehicle has an MW Fuel Injection Pump at the top of the pump there is 10 nuts that a 13mm wrench will fit. Don't loosen those nuts or you will change the amount of fuel each element puts out. And, the pump would need to be recalibrated.

So the mentioned fuel feed holes on the elements can be plugged.

Even with clean diesel I have seen Fuel Injection Pumps that sat in a shop get plugged and also I have seen when the Fuel Injection pump is rotated the plungers get stuck in all the way up and don't come back down to so they could get filled with fuel. And, that is in a shop clean fuel and on a shelf.
With fuel from the thank it is possible for there to be water and the plunger go up and stick from a combination of rust and dried up gunky Fuel.

Sticking rack: If the plungers in the elements or ever one element is stuck the rack won't move. The other way a rack won't move is if there was lots of sticky gunky oil that dried up inside of it.

If you remover the vacuum shutoff you will find it hooks onto the rack and you can see if the rack moves back and forth. Look up re-installing the shutoff because if you stick it in the wrong slot the engine runs away and you have to block off the air or stop the fuel supply as the shutoff is not going to work.

smiffy6four 08-05-2020 05:49 PM

Thanks for the input.

Was never run on anything but diesel fuel.

The fuel filter was new, but the fuel tank had major leaks when I first put the engine in six months ago, and was full of old fuel; so yes, a new filter would be in order.


I had the tank rebuilt by a specialist outfit, she's as good as new, with a half full of clean fuel.


All the fuel lines to the tank were changed along with the tank repair.


I'll have a squint at the pump and see which one it is...

smiffy6four 08-05-2020 06:09 PM

Fuel filter not clogged, same flow as input side.
Was able to get a minor amount of fuel at injectors 4 & 5, but the rest were bone dry.
Pulled vac shutoff to see if rack moves, it's pretty stiff, doesn't respond to throttle lever, can drag it back and forth, with a length of coat hanger..
Pump is MW type, pulled it, flushed body with ATF, left it to soak...

smiffy6four 08-05-2020 07:50 PM

300GD Photo
 
1 Attachment(s)
This is what the 300GD looks like.

Diesel911 08-06-2020 01:01 PM

Quote:

Originally Posted by smiffy6four (Post 4079637)
This is what the 300GD looks like.

Thanks.

Diesel911 08-06-2020 01:06 PM

What I find interesting about the lack of fuel delivery issue is that when I worked in a Fuel Injection Shop I would remove a Fuel Injection Pump from the test stand and do my best to drain all of the calibration oil out of it including rotating the pump to get the calibration oil out of the elements.

And I would sit that pump on the Counter and go to get something and in the mean time some Customer would wonder up and rotate the pump by hand and get spurted in the eye; and that from a pump I tried to drain completely.

Diseasel300 08-06-2020 01:23 PM

Rack stuck or not, you should be able to push fuel through the fuel rack. It is essentially an open gallery surrounding the various pumping elements. Failure to move fluid through indicates a clog somewhere. Check your banjo bolts to make sure they are in the right spots and the correct type (IE: not a relief valve stuck where an open bolt should be)

smiffy6four 08-06-2020 01:25 PM

Is ATF the best thing to free up the IP rack? I am leery about putting any kind of solvent in there; don't want to trash any seals, etc.

smiffy6four 08-06-2020 01:30 PM

Quote:

Originally Posted by Diseasel300 (Post 4079781)
Rack stuck or not, you should be able to push fuel through the fuel rack. It is essentially an open gallery surrounding the various pumping elements. Failure to move fluid through indicates a clog somewhere. Check your banjo bolts to make sure they are in the right spots and the correct type (IE: not a relief valve stuck where an open bolt should be)


The relief valve is on the side of the IP nearest the block, and the ball in there moves as it should.


The banjo's on the filter housing are different size, and can't be transposed.



I get good fuel flow from the outlet of the filter housing, and the inlet to the IP pump. Just very little seems to pass through the pump, when cracking the banjo with the relief valve on it.

Diseasel300 08-06-2020 02:23 PM

Try removing the relief valve entirely and see if you can get good flow. If you do, it means the relief valve is plugged up or stuck, or your primer pump can't develop enough pressure to overcome the 10-15PSI required to adequately lift the ball off its seat in the relief valve.

801mbz 08-06-2020 04:51 PM

on a 6 cyl 280se that sat for years the pump plungers got stuck so fuel only came out of 3 pump fittings I sprayed carb cleaner and penetrating oil in the pump fittings rotated motor and forced air into the plungers if plungers are stuck up fuel can't go in or out. It took time but all 6 were working eventually. What are the steps to timing? Remove #1 fiting valve and spring fuel should flow till motor rotates to 24 btc?? It has been awhile. It needs to be drip timed?? Help I can't remember. It has to have fuel to #1 to time it. Does it??

801mbz 08-06-2020 05:00 PM

can the plungers stick ? it needs to be drip timed. does fuel flow to #1 to drip time? I can't remember the exact procedure. Help.

Diesel911 08-06-2020 07:44 PM

Quote:

Originally Posted by 801mbz (Post 4079837)
can the plungers stick ? it needs to be drip timed. does fuel flow to #1 to drip time? I can't remember the exact procedure. Help.

I am on another computer that does not have my notes so I cannot give a description of the timing. But yes you use number one for the drip timing but you would be best off reading up on the procedure.

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I mentioned the sticking plungers and plugged up fuel feed holes as some possible issues.

On an MW type fuel injection pump once you remove the parts need to do the drip timing you can look down inside and rotate the Engine (or the Fuel Injection pump if it is off of the engine) and you can see if the plunger is going up and down. It also allows you to spray penetrating oil down inside of the plunger to try to free it up if it is stuck.

Do one at a time because the Delivery valves are lapped to an individual part down there and only on one side of that part. You would also need new crush washers and I believe an inch pound torque wrench.


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