Problem with injection pump on 6.9

[hazardc]

To be clear, I'm not very adept when it comes to diesel engines and fuel systems, but I think I can do my best to explain what is going on


I have a jayco RV with a 6.9 in it and just under 70k miles on the whole setup. There is a definite problem with the injection pump where I'm getting very poor fuel economy and power loss since it was purchased years ago

This is what i do know. It starts up, cold idles fine, then the idle drops down. If i drive it, problems start.


I don't know what the thing is actually called, but there's a metal lever that pushes in on a plunger type thing on the right side of the pump (right side if you're facing the engine from the hood) If i take a screwdriver and pry out on this lever, the truck seems to return to normal. I can't say I know exactly what this thing does, i've been trying to do as much reading as possible but haven't found my answer. There is no fuel leaking anywhere that i can tell. Is this simply something that is somehow gummed up and getting stuck? The truck did sit for a long period of time.

I'm obviously trying to get this thing back on the road and in good running condition. I've looked at some diagrams of injection pumps but can't find any good information on what this part is even called, so i've dubbed it "sticky lever thing that's making my life suck"

When it gets stuck the truck idles like crap and smokes a lot. Any ideas? suggestions on solutions (possibly without removing the pump??)


Any help is appreciated, and I'm gonna eep trying to read up more to see if I can find my answer

Thanks for any help

 

[Brianedwardss]

That's the throttle advance lever, the more the throttle is pushed in, the more that lever should be sticking out. Sounds tho that your timing is retarded. Look up how to advance your timing a dimes width, probably make a world of difference. These trucks tend to need a little bit of advance as they age.

 

[Brianedwardss]

But also heed all precautions that you'll read on those pages. To advance the pump, you'll be tipping it towards the passenger side a hair/dimes width.

 

[hazardc]

I was planning on adjusting the timing at some point.

I'm almost positive that this piston is getting stuck, though? it seems that it gets stuck "in" and if i pry out with a screwdriver at idle that the truck starts running "normal" again and runs normal for a bit until this lever/piston thing gets stuck and then it returns to running and idling like garbage.

Would it be beneficial to run some fuel treatments through it? ATF?


Like i said, i may be totally off base, I work almost exclusively on turbo 4 and 6 gas setups, and while this is foreign to me, i'm enjoying the learning experience (that hopefully has a positive outcome)

i could take some pics/vid sometime tomorrow i suppose.

 

[hazardc]

should i be able to actively watch this thing move while manipulating the throttle from under the hood? you're saying it should move outwards as i add throttle and back in as it returns to idle?


While it has low miles, it has been sitting for a while.

Another symptom that popped up today is it will idle fine, but when i rev it, it will die. i'm assuming air in the system or something. both of the tanks are pretty much on empty right now though, so i'll get more fuel and some sort of fuel system cleaners today. i read that someone reccomended filling the fuel filter with atf?


Once i can verify that there's no weird mechanical issues going on, id like to adjust the timing. I think this forum has enough information on that to where i can manage to not screw it up.

 

[Brianedwardss]

With everything off, pull back on the throttle, and you should see that advance lever move. When you rev it and it dies, is it dieing while rev'd up, or dieing when it returns to idle...?

 

[hazardc]

Dying when returning to idle. This was not part of the issue before, so this is a new thing. The fuel in the truck is old and the tanks are both riding on empty. It's a low mileage unit that's still in good condition, it's just been neglected over the past couple years for various reasons and i'd like to have it back in operating order by summer time



is there a decent write up on adjusting the timing? I'm far from mechanically inept, but like i said before, diesels in general are a bit foreign to me.

 

[TWeatherford]

Sounds like you need a new injection pump. Dying when returning to idle is a symptom of impending ip death. And you have the other "sticking" issue. Even though its low mileage, although I don't know how old your RV is, its 20+ years old at this point. If it were a pickup I would suggest you play with running fuel additives if you want to try to get a few more miles out of it. But since its an RV, getting it towed would be very expensive, plus it would be likely to happen away from home (if you travel very far with it) with the whole family along. Not a fun thing to have happen. You could give it a set of injectors and a return line kit too, and a mechanical fuel pump while your at it and you'll have a new fuel system, have better power, mileage, and peace of mind.

 

[icanfixall]

Addd some good fresh fuel to a tank... Also add some atf or fuel additive... Read the doesage and double that. Or remove the fuel filter and replace it but be awear that you will have some air to bleed out of the fuel system.... Usually some air is trapped in the filter change... If you fill the new filter with atf just run the engine for about 1 minute.... This will get the atf fluid into the injection pump and hopefully unstick all the problem areas. You may end up needing a rebuilt injection pump too. With 70,000 miles on the system it would seem like you still have plenty of miles left in the pump but. Sitting and gumming up the pump internals kills these pumps. Stanadyne performance formula or hoews are fine fuel additives. Power Service is another fine fuel additive...

 

[gandalf]

It sounds very much like your metering valve is sticking. The symptom there is that the engine dies when you let off the throttle.

1) Put some fresh fuel in one of the tanks, and run off that tank.
2) Pull the fuel filter. If it has brown sludge in it, you have an algae problem (see my pictures below). Replace the fuel filter.
3) When you replace the fuel filter fill it with full strength additive--Stanadyne, Howes, Power Service,...even ATF. Yes, ATF, it will burn. Put the filter back on. Buy plenty of additive.
4) Put a double dose of additive in the tank you're using.
5) Start the engine. Let it idle for a while. Run it up to speed, ease off the throttle slowly--exercise the metering valve.
6) Once the engine is up to running temps, pull the fuel filter again, fill it again with full strength additive, run the engine more. No need to drive, just run the engine.
7) Report back on results.

If you have algae life will get very interesting.

I see Gary posted while I was thinking. He's a bit quicker that I am. Combine the two posts.

 

[hazardc]

Very good advice. I'm going to try that all out sometime this weekend


Luckily I have no problem cruising this thing around, and I'm in my 20's without a family (well, at least for a little while longer) so if I get stranded, it's not as big of a deal.

The fuel is very old in this thing.



Could you possibly elaborate more on what would happen if there's algae in the system? wouldn't there need to be light getting into the system for algae growth to occur? I'm assuming most of the fuel system will need replaced if algae is the issue.

 

[gandalf]

...

The fuel is very old in this thing.



Could you possibly elaborate more on what would happen if there's algae in the system? wouldn't there need to be light getting into the system for algae growth to occur? I'm assuming most of the fuel system will need replaced if algae is the issue.

Old fuel is never a good thing. I've discovered that little gem of information the hard way. It's more likely to have water in it, and of course it looses it's cetain rating with age (That's the diesel equivalent to gas octain). The algae grows on the water/diesel barriers. Once you have algae in your tanks, you've got to get rid of it, but you can never be sure you're entirely successful, so you must keep treating your tanks forever. Also, carry several spare fuel filters, and plenty of fuel additive.

Start reading here: The Joys of Algae I think it may be easier, quicker, and less painful to do a frontal lobotomy on yourself.

I'm just finishing (I hope) the cleaning process.

 

[TWeatherford]

Luckily I have no problem cruising this thing around, and I'm in my 20's without a family (well, at least for a little while longer) so if I get stranded, it's not as big of a deal.

(SNIP)

Could you possibly elaborate more on what would happen if there's algae in the system? wouldn't there need to be light getting into the system for algae growth to occur? I'm assuming most of the fuel system will need replaced if algae is the issue.

Oh, well, if thats the case than its time to head out on a cross country road trip! Thats what I did with mine, 5 months after buying I hooked up a horse trailer, loaded up the horse, and headed from KY to CO. My truck was not in very good shape at that point either. Ended up toasting the engine after 1425 miles, 25 miles shy of my destination. Swapped in a low mileage 6.9 a few days before time to go back to KY and drove it back. Got back to KY and the IP died on me literally in my parents yard. Now its got a new fuel system and is doing very well.

If you have algae, which is likely especially due to it sitting, the fuel conditioners will likely kill it and it will plug up your filter. And then it will plug the new one, and likely the one after that. Also, sometimes fuel conditioners will turn waxes loose that have built up in the tank and lines, plugging your filter.

 

[hazardc]

I really appreciate all the help so far. This forum seems really mature compared to a lot of other automotive related forums.


When i manipulate the accelerator, the piston/arm thing on the driver's side moves inward, when the throttle cable is released back to idle position, the piston does not move back outwards, and this is when the problems usually start. If i start it with the piston almost all the way out (using a long screwdriver to pull it back out), it cold idles correctly, and then after a few minutes drops down to a normal idle. If i give it any major throttle, that piston gets stuck in and if it doesn't stall when returning to idle the engine starts bucking and blue-ish smoke comes out of the tail pipe like a mosquito sprayer.

If it's stumbling and i turn the truck off, and then move the throttle cable manually, i do hear what sounds like air, but not always. I'm going to assume there is some air in the system

I have taken some videos that i will upload tomorrow to youtube that might better elaborate on exactly what i'm talking about. I don't want to do much more to it without a) getting more advice and b) getting some basic maintainance items. The way I see it at this point is all i can do is mess more crap up by messing with it without having the right stuff

Right now on my purchase list is
a) couple quarts of atf
b) fuel filter
c) few gallons of diesel
d) fuel treatment (which one is the best?)


Anything else i should look into? I'd like to exhaust the cheaper options before just buying a new pump right now, as the RV needs a bit more maintainance before hitting the road as it is already, but at the same time i'm a "do it right and do it once" kinda guy. Either way, i wouldn't mind playing with a wmo setup, so if i'm going to trash a pump, id rather trash this one then a new one, so getting this one functioning properly would be preferable.


Thanks for any and all help guys

 

[hazardc]

Ok, i just removed the stock fuel filter and dumped it out, filled with atf, ran the engine for a minute or so and revved it a few times


That piston still sticks, but i haven't given it much time. Here are some videos i took for youtube... I'm not sure i did a good job of conveying what i was trying to with this.


This is what the truck runs like when the piston gets stuck in, i pry it out with a screwdriver in the video. The stalling issue in this vid has went away.

http://www.youtube.com/watch?v=9g8e2VkV3Cc



This next video is what the truck runs like once i pull that piston out (i still have to push it in a tiny bit to idle correctly. I can then rev the truck SOME but once the piston gets depressed a majority of the way in, it gets stuck and the truck returns to being a very high quality mosquito deterrent.



http://www.youtube.com/watch?v=sIO8XXc5wZM



as far as i know, the injector pump should have a good amount of ATF in it right now. should i just let this soak for a while? how do i work this piston into wanting to move back and forth again? Would dumping some fresh #2 diesel in the tank with a few quarts of atf and some treatment and letting it idle for a while help this situation?


Do you guys with more experience with this stuff think this is salvageable without a rebuild/replacement pump? it seems like my only issue is this arm getting stuck in.. i looked on my other 6.9 dually and it moves in and out freely when i move the throttle cable