MEP-802A Starts Intermittently

[kloppk]

My 802A has developed an intermittent starting problem. It has me baffled.
I've had it for about 4 years and has always promptly started. It gets used almost weekly to test products I build for the 802/803 such as the Remote Start and an "new" product.

Today I was using the 802 to test products. Started and stopped it numerous times this afternoon.
Shut it down to switch products being tested.
When to start it and the engine cranks just fine at normal cranking speed but will not fire and no puffs of smoke.

I checked...
Fuel tank is full
Fuel Shutoff solenoid is fully retracting and lever on governor rotates full from stop position to run when cranking.
Removed the fuel tank cover and disconnected the fuel return.
Set S1 to Pime/Run and got a healthy stream of diesel. Had pressure and sprayed as I put a finger over the return line.
Hook return line back up.
I let the system prime for a good minute. Cranked it again and no start.
Let it sit for 10 minutes.
Came back and it started just fine.
Let it run for about 10 minutes as I put the fuel tank cover back on.
Shut the set off.
Tried to start it again 3 minutes later and back to cranking but not starting.
Waited 10 minutes, tried again, cranks but will not start or fire.

A few weeks back while testing products it did the crank and no just start once amongst numerous of normal starts and stops.
Cranked it again and it start and ran fine and continued my testing and did more normal starts & stops.

Thoughts?

 

[Ray70]

Hey Kurt, I know you said you had fuel pressure but which pump do you have? I'm wondering if you have a fuel pump about to fail. I've seen once or twice where the pump would sound fine, but wasn't pumping fuel intermittently. I changed out the pump and problem went away. Maybe you could rig up a down stream pressure gage to confirm constant fuel pressure is present, then go from there?
The other thing that comes to mind is oil pressure ( too much to be exact ) If the cranking sounds strange you may have a sticking pressure relief valve that is over pressurizing your oil system and locking up your lifters which causes no compression until they bleed back down again. If you get it to start again, see if the oil pressure seems abnormally high, like above 60 psi cold.

 

[kloppk]

It has the original Facet cube fuel pump. That failing was my first thought that's why I checked for good flow at the return line.
I do have an Airtex E1074 as a spare so I could try popping that in and see.

I'd expect the set to at least fire a few times when I get the no start issue due to residual fuel being in the lines though.

My oil pressure has always been normal and run around 50 PSI at startup and drops to about 40 when warm. Haven't touched the oil lately. Oil level is correct.
The no-start so far has always happened when the set was already warmed up so the oil would be thinner. It's got 10W40 in it.

I'm suspecting that once the fuel solenoid pulls in and the fuel lever on the governor rotates to the run position that something is prevent the fuel rack from moving. Anyone had that as a no-start issue?

 

[Light in the Dark]

I assume no fault lights. Have you tried holding in the fault light reset button while cranking? If you do that, and she fires, go into battle short and see if it keeps running.

 

[kloppk]

No fault lights when cranking. All fault lamps good.
Will try pushing Fault Reset while cranking and let you know.

Fuel solenoid pulling in as it should and have fuel flow so there shouldn't be any other electrical reason it won't start.

 

[kloppk]

Tried starting it this afternoon. No love...
Tried starting with Fault Reset pushed. Same result.
I cracked one of the hard lines on one of the IP's and cranked it via S1. No spray.
Fully removed the nut and made sure line was free from IP. Cranked it via S1. No fuel at all.
Stop solenoid retracting as it should.

I removed the plug that accesses the droop adjustment screw and I can see what looks to be end of the fuel rack.
I cranked the engine with the solenoid pulled in and didn't see any movement of the fuel rack.
Currently poking around with a borescope to see if I can spot anything thru the plug hole.

 

[kloppk]

Found that the fuel rack isn't sliding right when the shutoff solenoid retracts to the run position.
If I reach thru the hole for the droop adjustment and push a bit on the rack it pops to the right.
Seems there is a bit of friction for a fraction of and inch and then it slides free.
I can get the engine to now start using that trick but now it's only running on 1 cylinder. Cylinder near radiator not firing.

 

[kloppk]

Just keeps getting worse. Now the rack won't move to the right even when pressed upon.

 

[Guyfang]

Kurt,

Sorry i haven jumped in here sooner. I have a grandson in the hospital, and watching the other grandson is now a full time job. So time has become a problem. Hope all will be better by the weekend.

Long ago, these sets were famous for "Jumping out of the fuel rack". I would pull the IP's out, inspect them and reinstall them correctly. See if that gets you some joy. I know its a PITA, when both are out, to reinstall them. But you need to start from ground zero. Once you know they are in right, and it still wont move or start, then you need to start looking deeper. And that is even more work. So start with the IP's. In the bad old days, IP's jumping out of the rack, and bent racks were a major problem. Mostly fixed with some small changes a long time ago.

 

[kloppk]

Guy,
I hope the grandson is on the mend.

Thx for the info on the possibility of the injectors jumping out of the rack. Will pull them, inspect and post up what I find.

 

[kloppk]

Guy and others following...
It runs again!

I ended up popping the top cover off, muffler and air cleaner for better access to the injectors and IP's.
I then marked the sides of the IPs and the top shims with nail polish to mark where they were adjusted to.
When it last ran I knew the IP on the left wasn't working so I disconnected the lines from it and removed the IP.
IP looked good.
Removed the lines from the other IP and loosened it's clamp so that it could rotate freely.
One done I moved the shutoff solenoid slightly and saw the rack was again moving as it should. Yeah!
The second IP rotated back and forth as I allowed the rack to move back and forth to confirm it was still aligned with the rack.
Then tightened the clamp on the second IP using alignment marks and again verified the rack moved as it should.
The installed the left IP and aligned it with the rack.
Again verifying it rotated as the rack moved.
Tightened the second clamp using the alignment marks.
Again verified the rack now moved smoothly with no binding. Psych'd!
Buttoned it up temporarily, primed it well. Moment of truth! Cranked for about 5 seconds and it roared back to life. Happy dance!
Did several starts and stops to verify all seemed good. Now just need to put a bazillion screw back in the top cover.

Many thanks to our man Guy for his insight into this bizarre issue!!!!

 

[Guyfang]

No thanks to me Kurt. I just listened to good NCO's tell me about the early days of these sets. Where ever I went, when working with gen sets as a contractor, I talked to the older NCO's. And never hesitated to jump in and turn a wrench with them, and their young soldiers. The TQG came in just as I retired. By the time I had worked 10 years as an electrician here in Germany, and started learning the TQG, lots of these guys had immense knowledge. Sharing. That's how it should work. That's why I enjoy the Forum. Its all about sharing. Glad you got it fixed. And do not sell yourself short. You would sooner or later found the problem. Lots of folks would have given up, or paid someone to fix it for them.