Resealed my injection pump, stalling issue.

[Gunfreak25]

I'll try to keep this short. Posted on 2 other boards, with no replies.

Does anyone know if the throttle shaft can be installed on the min-max gov linkage incorrectly? I know the top cover of the Db2 pump itself can be installed on the wrong side of the gov linkage (causing a run away) but this is not my problem.

Truck runs great at WOT, mid throttle, good timing, good power, no air in the system verified by a clear IP return line. Truck runs perfect.......

It just WONT idle after reasealing the IP. I had to bottom out the low idle screw to get it to 500 rpm ish. Idles kind of rough, but is smooth if I hold it open a little further.

So i'm thinking 1 of 2 issues. I either goofed installing the throttle shaft on the governor shaft (shaft has 2 steps) or tank sock is plugged. I know the Db2 pulls fuel well at higher RPM but not much at idle which may be enough to cause it to keep stalling unless the throttle is opened a tad. I'm pushing through a 10 micron and 2 micron with a 12v lift pump and flow "seemed" okay during initial bleed.

 

[Gunfreak25]

I never started the truck before the IP reseal so there's no way of knowing if it was having this stall issue before hand. It would make sense.....because it came to me with 2 replacement filter screens in the glovebox when I towed it home. This truck used to be mine 3 years ago and at that time it ran like a raped ape. It would occasionally stall offroading from rust sediment plugging up the filters.....

So I'm going to say the issue just got worse when it changed hands, he didn't do a darn thing to the entire truck except buy those replacement filters which he never put on.

 

[richingalveston]

I would rule out the fuel sock. your fuel pump should pull/push the fuel not the IP. The IP will pull fuel but should not be required to.

check your fuel pump if you think it is a fuel delivery issue. a stopped up fuel sock will let it idle but not run good at WOT.

I would place my bet on the IP. if you had to go into it then it had a problem. I would have it rebuilt if it has not been. if it was then send it back for warranty.

my best guess from this distance
rich

 

[richingalveston]

by the way, what is an IP re-seal? did you replace the throttle shaft o-ring? gasket on the top cover?
never heard of some one call it a re-seal.

Thanks

 

[Gunfreak25]

I put a seal kit In it, a complete teardown minus the head and rotor. New drive shaft seals, top cover seals, throttle shaft seals, advance plunger seals, etc. It was leaking pretty bad just sitting.

I was out driving around more today. I have my 12v lift pump on a toggle switch. Turning the pump off driving has zero effect on the power output. Idling however, the engine will retard a little and the idle drops a bit lower when switched off.

I'm going to blow the tank sock off tomorrow and also blow out the return line just in case.

Sent from my SM-G955U using Tapatalk

 

[cucvrus]

It has been my experience from talking with the rebuilders that the head and rotor is the root of the trouble in most pumps. I never disassembled a pump to rebuild it. I disassembled one just to see the pieces inside it. After that I said no thanks. No user friendly parts inside and left it up to a professional. They have the knowledge and equipment to do the rebuild. Less than $400. and I have a perfect running engine every time. There is a lot of precision parts and adjustments to get a perfectly smooth running diesel engine. And blowing out the sock may do more harm then good. Like I say it's NOT my truck. But take your time and do it the right way. Or NOT. Good Luck. Have a Great Day.

 

[ken]

Turning off the lift pump is not a good idea. This causes cavitation in the IP. The IP can pull fuel but it shouldn't. It will seem to be running fine but with the noise the 6.2 makes you can't hear it. This will destroy the IP. Also not all 12V pumps are created the same. Do you know how many PSI it is feeding to the IP? It might not be sending the IP what is required at a givin engine RPM/load. IE over pressurizing the IP at engine idle. Might I sudjest returning the mech pump? It feeds the IP more or less as the engine speed goes up or down. The IP is designed for this variance in supply.

 

[porkysplace]

I put a seal kit In it, a complete teardown minus the head and rotor. New drive shaft seals, top cover seals, throttle shaft seals, advance plunger seals, etc. It was leaking pretty bad just sitting.

I was out driving around more today. I have my 12v lift pump on a toggle switch. Turning the pump off driving has zero effect on the power output. Idling however, the engine will retard a little and the idle drops a bit lower when switched off.

I'm going to blow the tank sock off tomorrow and also blow out the return line just in case.

Sent from my SM-G955U using Tapatalk

I never started the truck before the IP reseal so there's no way of knowing if it was having this stall issue before hand. It would make sense.....because it came to me with 2 replacement filter screens in the glovebox when I towed it home. This truck used to be mine 3 years ago and at that time it ran like a raped ape. It would occasionally stall offroading from rust sediment plugging up the filters.....

So I'm going to say the issue just got worse when it changed hands, he didn't do a darn thing to the entire truck except buy those replacement filters which he never put on.

So you already know there is a rust problem in the tank and now you want to blow the sock off so it can plug your filters faster ?
You need to drop and clean the tank to fix that part of the problem . As for the IP issues this is one of the few times I agree with cucvrus send the IP out for a rebuild.

 

[Gunfreak25]

I don't mind if the filters do the work, I buy em' buy the case. I opted to redo my IP seals on my own rather than send it off not to conserve costs but to learn how the pump works which was totally worth it. I dont know for sure if the tank is causing the issue as pinching the line on the frame by the lift pump doesn't do anything to the idle. I'm going to pop the top cover off today and see if I didn't install the idle spring on the front of the min-max backwards or if my 4 year old didn't play with it while it was on the bench. Little booger.

 

[Gunfreak25]

Backed the governor nut out 1 full turn. Truck is back to normal, idled a little too high but a little backing out on the external low idle screw got it in the sweet spot. She runs like she did 3 years ago, and with all the new seals is leak free.

It was a great learning curve completely re sealing this pump, I would do it again in a heart beat. They are really simpler than the shops let on. Big thanks to DieselPro and all the Stanadyne manuals.