MEP-005A Running Smokey

[Krc002]

Hello Everyone,

I apologize in advance for the long post and i hope you will stick around to read the whole thing as this project could benefit military generator users. ive been trying to get this thing running right for a long time to use as a test engine on my senior capstone project regarding biodiesel and its effects on non-modified diesel engines. I picked up an MEP-005A set from gov liquidators about a month ago now and have been working to get it running. The Set was complete when i picked it up, however the injector pump was not pumping so it would not start. got a new pump from down at Delks army navy, William has been helpful and i appreciate it. so i had the new pump sent to me and returned my old one for the core charge.

I put the new pump on and aligned the timing marks to 16 degrees per william, the set would miss and pop from time to time but otherwise ran. The real problem here is the amount of smoke the set produces while at idle and at load. it will carry about 90% load and i have run it at that for around an hour and a half to clean everything out thinking maybe the set was wet stacked. didnt help, upon returning to idle the smoke comes right back. So i started trouble shooting, the following list is in order more or less and starting with the basics that didnt change any of the characteristics after working on them.

1) replaced fuel filters
2) Removed air filter
3) checked to make sure return lines were free
4) went to john deere dealership to try and come up with something, they thought timing so we adjusted the timing as per the book which calls for 20 degrees, this helped the missing a lot but still ran smokey. we also advanced the timing to the point that the smoke went away, but the set begins to hunt and surge which is unacceptable.
5) pulled all the injectors and pop tested them on the bench tester and found them to all be opening around 2600 psi and having a uniform spray pattern.
6) while i had the injectors out i also ran a compression test, i hadnt been burning any oil but had them out so thought i would try. it took round 30 seconds to build up 400 psi or so on each cylinder, i was concerned about the amount of time here, but if it was compression related i would think that it wouldnt carry load and id burn oil.
7) Used dial indicator to verifiy the markings on the flywheel correspond to the piston top dead center. this is verified correct.
talked with william at delks and he thought the pump was 180 degrees out of time, so i set the pump out 180 degrees and it wouldnt start at all.
9) My fuel consumption is through the roof, i burned 26 gallons in around 5 hours of run time, most of which was running with no load.
10) talked with william, he sent me a new rebuilt pump, which i recieved today. i had considerably more trouble with this pump, the o-ring that seals the eccentric fuel pump inside the injector pump was clearly too small, and fuel ran out when i hooked the pump to the engine, luckliy i just swapped the oring from the old pump and this seemed to seal it right up. the scree on the front of the pump close to the mounting flange was also loose, i tighened that a little buit but high pressure fuel still seems to spray out. when i installed the pump i couldnt get 1800 rpm and had to mess with the screws on the throttle arm, i can get 1800 rpm when i back the one closest to the genend back, however once i do this, the set will not shut down on its own and it still runs as smokey as it ever did.

This is all for my senior capstone project to graduate in less than four weeks and the paper for the project was due wednesday, however my professor has been understanding and has given me an extra week thinking this new injector pump would solve the problem. now i just have more leaks and dribbling fuel and lots of smoke. im running out of things that i think could be wrong so i thought id get in here to see if anyone had any ideas.

Here is a youtube video of the set running, maybe it will help. the load is alternated from 90% to zero and thats where you will start to see the white smoke.

[media]http://www.youtube.com/watch?v=0tQv4f63uE8[/media]Any help is appreciated, i am running out of time and ideas!

Thanks in advance if you read all that,
Ken

 

[Ken_86gt]

from the TM:
Engine exhaust smoke excessive:

a. Fuel injection nozzle holders out of adjustment, dirty or defective
b. Worn, broken, or stuck piston rings
c. Worn valve guides or seals
d. Burned valves
e. Defective head gasket

Several of these will also result in low compression- which it sounds like you may have. I am leaning torwards the rings or burned valves. I don't know, but if it was mine I may leave it as is until it gets worse, but if you need it to be right pulling the head would be where I look first since you can eliminate most of these possibilities right then.

I am curious- does your oil appear to be contaminated by diesel fuel?

 

[Krc002]

This was one of my original theories, however i got to thinking about it and decided to hold off on pulling the head, maybe it is where i am headed next.

As far as the head gasket goes i havent noticed any indication of mixing between oil and coolant and vise versa. the smoke is definitely diesel fuel smoke, lingers and burns the eyes, couple guys who are familiar with diesels came by and agreed that its unburnt fuel. the burned valves are something to check i would think since i havent messed with them much other than checking valve tappet clearance. i would also think that if i had burnt or stuck piston rings that this wouldnt be the case for all 6 cylinders, however all of the cylinders acted the same during compression test, could this be an accurate assumption?. is there a way for me to see if i have burnt or stuck rings without pulling the piston but removing the head, indications on cylinder walls or the piston itself??

Im starting to wonder about oil contamination from the seals on the injector pump, i know they are on correctly but perhaps they are still leaking. i wouldnt think that would explain all of my lost fuel though.

I looked through the depot manual a little more too. when i got the pump today, the o-ring was the wrong size for the transfter pump end plate and decided to switch the o-ring from the other pump, and the screw on the front of the pump, which i have come to find is the governor arm pivot shaft, was 3 to 4 turns loose, i tightened this with a wrench at the time thinking it might be a problem, but looking at it and knowing what it is now, lends me to believe there is probably a procedure for this. i did not want to over tighten it though, and this is one of the places the pump leaks from.

My thought right now is to take the pump to a diesel place near by and have them put it on a flow bench and run through the testing procedure listed in the book to make sure the flow values are accurate. im wondering how well this pump was put together. my indications being this loose governor shaft and the smaller than spec o-ring. i would figure that if the guy took the time to rebuild the pump and calibrate it, he would have noticed that the pump leaked from these places and made the needed corrections to prevent such leakage. ruling out the pump would go a long way on diagnostics i would think. Any thoughts on this?

Thanks, Ken

 

[Krc002]

Also with this new pump, when i first started the set, it would not come up to speed, stayed below 50hz so i undid the throttle cable and attempted to move it by hand, the lever would not go back any further to allow the set to come up to speed so i adjusted the screw closet to the generator end on the throttle lever and eventually found my needle on the gauge and played with it till i got 60 hz and put the throttle cable back in place. when i did this, the set would no longer shut down when i hit the stop switch unless you return it to idle, im thinking this is because it is holding the governor open and not allowing the set to shut down. does anyone have any recommendations to this problem or do i just have the screws out of adjustment? the first pump i recieved from delks went on and did not have this problem and the throttle cable controlled it as it was meant to from what i have seen and read.

Thanks,
Ken Coffey

 

[Isaac-1]

Knowing that your in a crunch, I would go with the option that could be fixed in time, namely having the injection pump tested and rebuilt if need be. Sure it could be some obscure crack in the block or glazed cylinders, but those are things you are not likely to fix in the allowed time. So bet on the fixable things, even if they are not the most likely.

Ike

 

[ETN550]

Some thoughts..

Take the injection pump and the injectors to a diesel shop. The video shows the following. Blue intermittant fuel smoke at high idle and black smoke at load. The black smoke is lack of air and or poor fuel injection / spray with all cylinder firing and heavy load.. Blue smoke is raw fuel.

How well do you know the value of the load? Are you above 2,500 ft elevation? I found a shop rag in an inlet manifold once.

The blue fuel smoke may be poor injection due to either the delivery valve on the pump or injectors. You mentioned spray pattern and VOP. What about dribbling and pressure holding right before opening?
While the pump is in the shop pull the valve cover and verify the cam timing and lift at the valves to make sure the cam is okay and not worn down.

On a diesel compression is normally only a problem if it cannot start and it uses excess oil or has so much blowby that it cannot be tolerated. Low compression is of no consequence (or virtually no consequence) to performance when hot and up to speed. Lack of compression is often over stated as an operational problem in a diesel.

If a valve was burnt or bad you would get a steady miss and hissing when cranking with the fuel off.

Your smoke is not constant and it is not repeated with every combustion cycle. What is likely happening is that the engine is missing on a stroke then when it fires on the next stroke in the same cylinder it lights the wet cylinder.

Fuel delivery to the injection pump or lack thereof could cause this. Air in the fuel supply to the pump could as well. Trace the primary side of the fuel system and repace any bad lines that are cracked. I have seen a fitting that is cracked suck air and not necesarily leak fuel.

This is aggrevating but I believe the core engine is okay.

This is a fuel related problem.

Try running out of a clean fuel tank with treated fuel. The stanadyne fuel treatment will help poor combustion in the distributor style pump.

Be antiseptically clean when opening up the fuel system downstream of the filter.

Please post any conclusions.

 

[Krc002]

Thank you for your comments, while it is aggrivating, having someone actually give me support on the engine being alright is nice. tomorrow i will fit up my test fuel tank that i will be using for the project, which will consist of the gear needed to bypass the belly tank and a long glass column to measure volume of fuel consumed over time. i would think having the graduations on this will help me a lot in determining if the fuel pump is calibrated as i will be able to see exact volumes im guessing it is just blowing fuel by because the shims are out of whack or something. im tired of seeing my diesel/money get blown into the atmosphere. hopefully i can work all this out soon, i will run the pump to the injection shop soon as well, need it as is to complete project on time sadly.

Thanks for your help!
Ken

 

[PeterD]

... which will consist of the gear needed to bypass the belly tank and a long glass column to measure volume of fuel consumed over time. i would think having the graduations on this will help me a lot in determining if the fuel pump is calibrated as i will be able to see exact volumes ...

Do not forget to consider the 'recirculating' nature of the injection pump and injectors when doing your computations. The fuel return lines would need to flow back into your improvised fuel system, otherwise the apparent fuel consumption will be much higher than it really is.

 

[Ken_86gt]

Also for your reference, in case you didn't find it- this generator is supposed to use 2.85 gal/hr at 30kw.

 

[Krc002]

Thats the plan, i have a large graduated cylinder type glassware deal that i plan to use, return will either be piped into the top of it, or back into the inlet line of the pump to help cut back on fuel mixing. the load bank i built will run at a 85 to 90 amps depending on which leg you are looking at, which comes out to around 18 - 19 Kw. ill include some photos after a bit and see what you all think. the load bank uses hot water heater elements so its hard to get exactly 30 kw. in the long run im glad i didnt rent a load bank, it would have been nice to try and pull closer to 30 kw, but for all the trouble shooting i have done and days i needed a load bank total, that bill would be up in the thousands of dollars range by now.

Thanks, Ken

 

[Krc002]

Hey guys, quick update that i was hoping to get some of your thoughts on, i did my test last night, i found that with an 85 amp load, i burn 3.76 gph and with no load i burn 2.55 gph. according to a previous post, and the manual, 2.85 gph is my expected fuel burn at full load, so i think i am getting extra fuel.

When i had the injectors out several weeks ago, they were all pop tested and verified ok, he also did the hold test and didnt find anything wrong with them holding for several seconds just before the pressure was brought up and they popped. is there anything else that could cause fuel consumption to be so high other than the pump? timing, bad camshaft, poor compression?

Thanks,
Ken

 

[RichardR]

Ken,

I am far from a diesel engine expert so don't rely on my opinion too much. I tend to agree with one of the possibilities brought up by ETN550, that there is a restriction in the air supply such as something caught in the inlet manifold or air filter. That COULD explain much of what is happening, and it shouldn't be very hard to check.

Regards,
Richard

 

[PeterD]

If your research project is to compare different fuels, then you must do that comparison--not rely on design or specified fuel consumption numbers. If one of my students came to me and presented a comparison based on book values to alternative fuel values, I'd make him do it properly.

 

[Krc002]

Hey guys,

Thanks for the input, it is a comparison experiment, the values for biodiesel and petrodiesel were the basically the same, 4 minutes 22 seconds for petro and 4 minutes 23 seconds for biodiesel to burn 1000 mL of fuel. thats why im not too worried about the smoke for the project. my concern is the amount of smoke and the high fuel consumption for after the project when i want to use the set for running woodworking equipment. the project was a twofer for me as i enjoy the notion of biodiesel and also the idea of having a 30kw set to run my shop and a couple choice pieces of equipment i dont own yet.

I have also had the intake off of the set before i ran it to make sure there were not any nuts and bolts dropped down into it that would destroy the engine. non were found.