Mep 803 a fuel injector problem ?

[alex bonaire]

Hello ,i have a mep 803a with about 1000 hours on it ,
it starts up rough i have to adjust the fuel injector and then it picks up and runs great black smoke
i had it under load and still runs good still black smoke but not as much ,when schutting down it taks a while it sputters and rumbles okay so far
then when i start it up again same problem adjust the fuel injector to the sweet spot and it runs good ,
so is it the fuel injector or is it the injectors .

Proud owner of another 803a and this runs great starts and stop direct and thanks to kurt klopp with wifi

 

[Ray70]

I believe you are most likely correct in your assumption about the injector, you probably have an injector stuck open, but need more investigation.
By "adjust the injector" I bet you are talking about the metering pump on the side of the motor with the rubber lines going in and steel lines out the top?
The actual injectors are up on top mounted into the cylinder head.
You really should not be playing with the metering pump adjustment because you are going to cause imbalance between cylinders.
I would push all the metering pumps counter clockwise until the rubber fuel line is just about to touch the adjacent pushrod tube.
Then restart and see if you have issues still.
If it still smokes, crack 1 injector line ( at the metering pumps ) until you find the cylinder that is smoking.
Most likely that cylinder has an injector stuck open ( although there are other causes for the black smoke )
Also look for discolored paint on the block or head on one particular cylinder, a stuck injector will quickly overheat that particular cylinder, which you may also see if you check with an IR thermometer.
You can pull off the top cover and swap the injector with another cylinder and see if the issue follows the injector.
Not long ago new injectors were available on the internet for about $50 for aftermarket, which is about the same price as a nozzle kit.

 

[alex bonaire]

I believe you are most likely correct in your assumption about the injector, you probably have an injector stuck open, but need more investigation.
By "adjust the injector" I bet you are talking about the met on the side of the motor with the rubber lines going in and steel lines out the top?
The actual injectors are up on top mounted into the cylinder head.
You really should not be playing with the metering pump adjustment because you are going to cause imbalance between cylinders.
I would push all the metering pumps counter clockwise until the rubber fuel line is just about to touch the adjacent pushrod tube.
Then restart and see if you have issues still.
If it still smokes, crack 1 injector line ( at the metering pumps ) until you find the cylinder that is smoking.
Most likely that cylinder has an injector stuck open ( although there are other causes for the black smoke )
Also look for discolored paint on the block or head on one particular cylinder, a stuck injector will quickly overheat that particular cylinder, which you may also see if you check with an IR thermometer.
You can pull off the top cover and swap the injector with another cylinder and see if the issue follows the injector.
Not long ago new injectors were available on the internet for about $50 for aftermarket, which is about the same price as a nozzle kit.

Hello Ray ,
thanks for the quick response ,
So i switched the injectors on the cilinder Head no change
when i crack the line direct from the metering pump there is a small change little more rpm
but not enough to pul it to run on all 4 cil ,i think the metering pump is not working correctly
sometimes it picks up good and then it runs like it suppose to do ,so the thing to do is get a other pump
maybe it is stuck or just busted .

greetings Alex

 

[Ray70]

It could also be as simple as a metering pump adjustment problem too.
When running under no load the internal fuel rack just barely opens the metering pumps.
All 4 pumps need to be synchronized or you will be getting inconsistent fuel from 1 cyl to the next.
Before swapping out a pump I think we need more testing.

So have you identified which cyl is smoking? or is it more than 1?
A good way to tell is to remove the muffler and the exhaust manifold and run it without the manifold.

Once you find the bad cyl. we should test a few other things.

Any way you could take a video or pictures of the smoke and the position of the 4 metering pumps?

 

[alex bonaire]

Hello Ray,
so fare i found out that it is the cilinder closes to the radiator ,
even after changing the top injectors it still was not running on al 4 cil
all metering pumps are in the same position ,
when i crack open the line coming from the pump diesel is sputtering out so it getting diesel on top but maybe not enough
all top injectors react when opening op the fuel lines ,but nr 1 barely react when opening up no change in rpm as of now it runs on 3 cil

you can download the video's with this link : https://we.tl/t-PKKPZ7vjR9

best regards,

 

[Ray70]

Hi Alex, yes I was able to open your files.
First off, hide those cans of starting fluid! If Guy sees them he will ream you an new one!
Seriously though.... don't use starting fluid on that machine. If you have to use anything, use WD-40 or carb clean, anything less volitile than ether.
Next thing, why is that machine idling so low, is that the fastest it will run, or are you intentionally idling it?
If intentional, don't do it! Rev it up to 60hz before going any further.
If that's all she's got then you should first pull the fuse ( if you have one ) immediately to the left of the voltage regulator.
You don't want to continue letting it run at that low speed without the voltage regulator shut down.
A good metering pump only puts out a small amount of fuel with every other stroke of the engine, you can compare the amount of fuel to a good cyl. and see if it seems less.
You can also try moving that metering pump to a different location and see if the problem follows the pump or stays with cyl. 1
If you remove it, look at the spring on the bottom and see if it is stuck fully or almost fully compressed.
A free pump will measure 2 1/4" from tip to the underside of the mounting plate. Substantially shorter means it's stuck partially compressed.
You can push it against a workbench etc. and you should be able to "Pump" it with your hand.
But first we need to know if it will rev. up to 60hz. on the gage?

 

[alex bonaire]

Hello Ray ,
i did not use the cans of starting fluid for starting i did a bit of cleaning work on the injectors ,
when i had them out ,no brake clean or carb clean on site .
and i was in the marine corps for 8 years so send Guy over whahaha .

the reason the machine is or was idling so low is because it was running on 3 cil
normale it runs and is set on 60 hz i cant Rev it up in this case ( 3 cil )
i will take out the metering pump and do some measuring i still think it is the pump
but that is a thing for Monday , the weekend is for the beach and diving lol

also have a good weekend talk to you soon alex

 

[Ray70]

Ah, good to hear you didn't use ether!
Now, I must say, I'm having a hard time believing that a single dead or weak cyl. on a 4 cyl. is causing the motor to not build RPM with no load and causing the black smoke. Have you checked for restrictions in the air inlet and air cleaner?
I would also remove the muffler and run it open to rule out a severely choked muffler.
As mentioned earlier I would actually remove the entire exhaust manifold so you can get a good look at the exhaust from each cylinder as well as check the head for carbon buildup in the exhaust ports.
I had a 2 cylinder with a dead cyl. act like that once, but doubt a 4 would act the same given the 2 extra pistons that ARE making power.
While you have the pump removed, stick your finger down the pump hole and grab the fuel rack that runs front to back ( and accepts the pin on the underside of the metering pump ) make sure it moves freely back and forth while holding the fuel shut off lever all the way to the right.

 

[Guyfang]

Alex,

CWO's eat Marines for breakfast!

I agree with what Ray is telling you. One dead jug should not slow the engine down that much. And do remove the muffler. I have seen some that were choked up so bad, the engine was about stopped. The same with air filters. If you have the IP out, then cleaning is not a bad idea.

Also, the L5. Is it extending/retracting correctly? If the rack doesn't move well, that may be also be a factor in the low RPM. Sadly I can not open your video.

 

[alex bonaire]

Hello Guyfang and Ray ,

i did remove the muffler no change stil smoking , when i loosen the metering pump it wil pick up and runs on al 4 cil
i let it run for an hour or so even with a 50 % load it is still smoking more then normal
output is good 220 v and 110 v 60 Hz
when i shut it down it sputters and rumbles ,when starting up again it runs on 3 cil
sometimes it takes a minute and it wil run on al 4 cil again ,

new air filter / new filters fuel and oil / clean the lines from metering pump to injector cleaned the injectors
new diesel fuel / clean diesel tank .

it did it from the day i bought it ,

thanks again for all the advice Oorah

 

[Guyfang]

Ray,

Bent rack? Or maybe the shim pack missing/improper? Look at TM 9-2815-253-24P, figure 4, Items 6&7, Thrust Cup and and Tappet. Could one of them be damaged? If Alex loosened the IP and it runs on 4 jugs, and I seem to remember Alex said he had moved the IP's around and had no big change in operation, maybe the problem lies here?

Alex, have you taken the IP's apart and soaked them in something to clean them?

 

[Ray70]

Dunno... The shim pack determines the injection timing. I have seen sets with too thick of a shim pack cause white / gray smoke due to late timing and cold ( lack of fire ) exhaust, but I don't think missing shims ( early timing ) would cause black smoke, but maybe it does??
Alex moved the injectors if I recall, but don't think he moved metering pumps at all.
I think next step is to remove and inspect the pumps as well as the rack and rack movement.

I still want to see what cyl. is smoking and the best way to check is remove the exhaust manifold. It's simple to do, wish Alex did that when he removed muffler.

 

[Guyfang]

I think it would be easier to pull the IP's first, disassemble and clean, before trying the rack. The rack is something that can intimidate folks. Lots of moving parts. Back in the OLD, OLD days, the rack was a big problem. But in the early 90's the Army got that taken care of. Very, very few problems later on. And the fact that when Alex loosened the IP, it ran right. That asks me if the IP, and then I would go farther down to the cup and tappet, could be the problem? Its only one jug. If all 4 were acting up, yeah, the rack might be a better bet. But its one jug.

 

[alex bonaire]

Hello Guy and Ray ,
it runs on all 4 cil but not the rpm it need to run nice ,took the metering pump out ,and let it soak in break clean for a day or so
or can i take it apart it looks like it has some marks on it from tools
and i can move the rack there are 3 shims sins nobody fooled around with it ( i hope ) it must be original
when it runs no reading on the HZ meter sometimes it jumps a bit

 

[Guyfang]

Alex,

Hertz is in direct proportion to AC volts. What is the AC meter telling you? Also measure at the 120 volt outlet.

I would take the IP apart. If there are tool marks on it, that could also be your problem.

 

[Ray70]

can you post a picture of the pump as well? Tool marks don't sound nice.. maybe we will notice something else wrong. Bent pin, stuck plunger etc....
3 shims sounds about right and should at least be in the ballpark.
Out of curiosity how much do you loosen the pump before it runs better? are we talking barely loosening the hold down nut a turn or less, or letting the pump lift up 1/8" off the block?

 

[alex bonaire]

Hello Guy ,
the ac jumps between 160 / 180 volts ,
is there a diagram how to pump suppose to be on the inside ,
so when i take it apart i can check if it is correct ,
maybe the person before me did not installed the richt way

when i just lossen the bracket that holds the pump it starts running beter ,
but now i has no effect .

Alex

 

[uniquify]

Alex, I had a stuck metering pump a while back. Here are some pictures from when I had it apart to clean it. See post #21. It wasn't the same problem you're having, but might be helpful if you end up cleaning your metering pump.

 

[alex bonaire]

Hello ,
thank you for the picks now i,m confident in taking the pump apart ,
and find out what is going on inside haha

Alex

 

[Guyfang]

Uniquify,

Very nice pictures!