MEP-802a 803a glow plug removal question

[dependable]

My 802 only fires on one cylinder cranking in cold temperatures, so, no start. My first guess is to check the "glow plugs" though that is not what they are called in TMs on this. I suppose it is possible a wire is loose or broken on heater relay also.

I probably have missed something, but the only references I have found in the TMs is to the "heater relay" in the gen set TM and a reference to the motor TM about testing and replacing of intake manifold heater plugs, which is brief and lacking in details. Not a lot of info that I could find.

Any one have some tips for getting at these? I guess I am going to try to get to them without removing top covers (I just re sealed them with calk a couple mouths ago).

The unit runs well once started, so it is not fuel or timing related.

Probably not the right thing to say, but if motor heater is down, and you need to start it, bend the air intake hose on air cleaner out of the generator housing and give it a very, very light squirt of either, without having used motor pre heat system (glow plugs). It is important to understand about pre ignition, piston fracture at the ring grooves, and the like, so you know just how small the squirt of starting fluid should be.

 

[dangier]

I had a 002a that had been subjected to ether. Not good. Broke both pistons at the ring area. Luckily, I found nos pistons for replacements. WD40 works and is safer sprayed in the intake while turning it over. Some also use a rag with a LITTLE (few drops) gasoline in the intake and light it. Just make sure the rag isn't sucked in.

David

 

[Guyfang]

I use diesel instead of gas. Burns slower and its in the gen set tank anyway.

Dead giveaway to a loose wire on the glow plugs, is a melted end of wire, and/ the wire insulation burnt back on the end of the wire. Sometimes the K-18, (preheat relay) gets stuck in the closed position, and the glow plugs stay energised. Then both wires are burnt, because the glow plugs are in series.

As they are in series, if only one works, then its almost a sure bet, that the non functional one needs to be tossed out. It can't be a loose wire on K-18, because, once again, its a series circuit. If one glow plug gets electricity, both will be getting electricity. They may not work, but will still be getting juice.

Go to TM 9-2815-252-24, look at the troubleshooting diagram. Page 3-3, and I would start with fault #3 and work on down the list. If you KNOW the glow pug is bad, skip down to that testing procedure. It sounds like you were just using the gen set manuals, and not the engine manual.

 

[dependable]

I used both engine and generator TMs, but may have missed something. It fires on one cylinder, that is what leads me to believe one plug was dead also.

On the emergency no glow start procedure, the air intake, which is rubber, does not lend itself to the rag on fire method as well as an 002, or most other machines. As a frequent mechanic on 6.2s, OM-617s, & other indirect injected diesels, I can not emphasize too much how little either I use, and only if glow system was not recently cycled. Perhaps it is better just to say "never use either" on a forum like this.

 

[dangier]

**I use diesel instead of gas. Burns slower and its in the gen set tank anyway.**

Yea, you are right on with that one. My error in suggesting.

David

 

[glcaines]

It's normally not that hard to check glow plugs if you have an ohmeter. Make sure you use anti-seize with copper on the threads of the new glow plugs to assure good electrical contact.

 

[Guyfang]

1. Remove glow plug.

2. Set multimeter for ohms and test heater plugs. Normal reading is 4 to 5 ohms. Zero resistance indicates ashorted heater and a high reading indicates an open heater.

 

[dependable]

Thanks, most of my original question had to do with accessing them for removal without taking a lot of panels off. Before I get too deep in taking it apart, I figured I should get some new plugs on hand. I have not found a source yet. If any one has any ideas, please let me know. Am I right in assuming the civilian applications of the LPW2 motor uses 12V plugs? This may be why a couple of Lister-Petter suppliers have not gotten back to me. My guess is the plug is not unique to the 802, 803, . I guess I'll dig in today and get them out and see if any MFG numbers are on them.

 

[Guyfang]

NSN: 4520-01-359-8114
Part Number: 186-6264
Try the link below.

http://listerengine.com/smf/index.php?topic=7776.0

 

[dependable]

So they are 12V, according to the link above. Guess them being in series makes that work. I did look though the 2815-252-24P manual, and did not find them, must have missed it again. What section are they listed in?

 

[Guyfang]

Look at figure 1, item number 1.