MEP 003 won't start, fuel solenoid not operating

[m16ty]

I've searched the TMs for two days and I'm sure I'm overlooking it but for the life of me I can't figure out how to troubleshoot my fuel solenoid.

When I first got the MEP 003, I test ran it using a slave cable (it had no batteries) and it fired right up and ran fine. I then parked it in the shop and it sat for a couple of weeks. I finally got some batteries and tried to fire it up again but it would just crank with no smoke. Upon further inspection I discovered that my fuel solenoid wasn't working. I was going to just run a 24v jumper wire to the solenoid to see if the solenoid was bad or it wasn't getting power but I'm unsure which wire is 24v and which wire is ground.

Correct me if I'm wrong but the way I understand the wiring diagram, 24v goes through the temp switch and the oil pressure switch before it gets to the solenoid. I guess what I'm wondering is where the solenoid picks up it's 24v?

 

[johnray13]

I just put my meter on the stop solenoid while my son bumped the starter. The post closest to the blower is the positive post.

John

 

[storeman]

The A1 in the upper right hand corner of the control box tells it to open, I believe (no wiring genius, me). Have a member I'm dealing with at present who is trying to sort out A1 and solenoid.

Jerry

 

[1800 Diesel]

I've searched the TMs for two days and I'm sure I'm overlooking it but for the life of me I can't figure out how to troubleshoot my fuel solenoid.

When I first got the MEP 003, I test ran it using a slave cable (it had no batteries) and it fired right up and ran fine. I then parked it in the shop and it sat for a couple of weeks. I finally got some batteries and tried to fire it up again but it would just crank with no smoke. Upon further inspection I discovered that my fuel solenoid wasn't working. I was going to just run a 24v jumper wire to the solenoid to see if the solenoid was bad or it wasn't getting power but I'm unsure which wire is 24v and which wire is ground.

Correct me if I'm wrong but the way I understand the wiring diagram, 24v goes through the temp switch and the oil pressure switch before it gets to the solenoid. I guess what I'm wondering is where the solenoid picks up it's 24v?

Can't really address the source of the 24v as installed, but my idea would be to pull the solenoid off & "hot-wire" it directly across the two batteries to test basic function. If it works sluggishly, I would remove (or partially move) the boot to clean & lubricate the shaft. I recently worked on an MEP002A that had a poorly functioning solenoid and after cleaning gunk off of the shaft and applying a light PBB spray and some marvel oil, it worked like a champ.

As to the source of the 24v, maybe it comes from the start switch while starting and maybe from a relay off the oil pressure circuit while running? I have not learned the electrical side of these units--still in training myself....

 

[storeman]

1800, aren't we all? Every day a new experience in the MEP world. Today, I scrapped a rebuilt 002 and a rebuilt 003 engine which I had stripped, along with one frame and some other alum for $247. Who says junk doesn't pay?

To keep on track, I believe the lower of the two identical relays in the control box originates 24 volts to the A1 and also the heaters, solenoid, etc. The upper relay is the starter and can be jumped to force the starter as can the lower to force its feeds.

Jerry

Jerry

 

[Harleyd315]

Put a meter or a test light on the solenoid to check if you have current first. I have had a few that were a bit slugish at first but worked theselves free with a little wd40. Sometimes just prying up lightly with a screwdriver will be all the help it needs

 

[m16ty]

The solenoid rod moves freely so I don't think it's sticking.

Correct me if I'm wrong but the way I'm reading the wiring diagram is that you send power to the solenoid when you hit "start" on the switch. After it starts, the oil pressure comes up and sends power to the solenoid in the switch "run" position. If that is true, it will be a two person job to check power to the solenoid. One to hold the switch in the "start" position and one to check power on the solenoid with a test light or meter.

It also looks as if the power in the "run" position goes through the the temp and oil pressure switch. The temp switch is normally closed and the oil switch is normally open.

This is just the way I'm seeing things and want to make sure I'm right before I go adding jumpers and such to try and troubleshoot the problem.

I also read in another post where I could somehow energize the solenoid in the control panel but it didn't give any details on how to do this. It somehow "tricks" it into thinking the generator is starting or running when it really isn't so you can perform test on things such as the solenoid.

I'm going to dig through the TMs some more to see if I can get a little more info.

 

[Harleyd315]

Yes or have really long arms!!!!!! I am working on one of these right now and can tell you it doesn't matter what terminal is pos or neg doesn't matter for testing. Remove the wires from the solenoid (so you won't back feed or hurt anything) and attach some jumper wires to the batteries, hook up the pos to 1 side of the solenoid and neg to the other side, the solenoid should snap into place. If not try pushing it up with a screwdriver, sometimes it has enough power to hold open but not engage from the off position. This way you don't need another person and don't have all the noise of the engine trying to start. Like I said before I had a couple like this that I jumped and worked up and down a few times with the jumpers and they freed up nicely.

 

[m16ty]

Thanks for everybody that gave suggestions. I installed jumper wires from the battery to the solenoid and got nothing. I then worked the rod up and down several times by hand and then it started working when power was applied. Put everything back together and it fired right up.

Now on to figure out why the charging system isn't working.