MEP-004A Oil Fault Indicator Light Problem

[1800 Diesel]

OK guys--different set, different fault indicator bulb problem. Oil light will not come on when power switch is turned on (DC circuit breaker pushed in). Test mode shows bulb is good. 1st thing I will test is the S/R/S switch. Anything else come to mind from anyone? I did a search in the TM and found nothing for this scenario. Also searched the SS site but found nothing either.

Thanks in advance.

Kevin

 

[PeterD]

I'd do an ohms (continuity) check of the sender first.

 

[1800 Diesel]

I'd do an ohms (continuity) check of the sender first.

Sounds like a good plan. Also trying to sort out what I believe is a double problem of the starter needing some work and/or the engine (or maybe the generator bearing??) having some sort of hard spot. I can turn the engine over with a half-inch drive ratchet (not breaker bar) but then it gets to a hard spot, which I can overcome but it's still noticeably harder to get past it. And it's a little harder than normal resistance from compression... Could be some ring groove rust maybe?

 

[1800 Diesel]

I'd do an ohms (continuity) check of the sender first.

Peter,

Since I had a known-good sender, swapped out the existing and no change. Also ran through the TM test procedure for the start/stop/run (S/R/S) switch & it checked out with all terminals showing correct open or continuity. Also swapped out relay inside fault indicator panel with no change. And last--I swapped out the wiring harness connected to the fault indicator panel. (Didn't think this would matter since all lights come on in test mode.)

Edit--I forgot to mention that I also tested for 24V coming into the fault indicator panel & the same wire showing 24v on the working unit also showed 24v on this unit.

I did locate a possible clue when I tested the 4 leads connected to the sender. After checking a known-good harness & assuming one of the leads had to be 24v (which I verified with the working unit) none of the four leads on this unit had 24v. (I figured out which position is the "feed wire" from the working unit, but checked all on the unit not working.) So, somewhere in the system, the sender is not getting 24v so the indicator light will not come on when S/R/S switch is in the run position. I'm not the greatest at reading schematics but will take a look at the TM tonight to look for possible causes.

If anyone has any ideas, don't be shy. These electrical gremlins are eating my lunch!!

 

[bimota]

I've got one coming back from a customer - runs for 20 minutes then throws an oil pressure light. Not sure if you learned anything from the above - I'm assuming it is the sender, highly unlikely a real oil pressure problem.

 

[1800 Diesel]

I've got one coming back from a customer - runs for 20 minutes then throws an oil pressure light. Not sure if you learned anything from the above - I'm assuming it is the sender, highly unlikely a real oil pressure problem.

Could be the sender, but if that doesn't correct the problem a couple other possibilities (these not common but are possible):

1. Check oil filter & hardware is installed properly...don't want oil bypassing filter and showing low pressure.

2. Check oil pressure with a known good mechanical gauge. Connect via pipe tee at oil switch connection.

3. If pressure checks out good, you may have a drain-back issue where some trash is clogging gallery in the head & oil is not returning to the sump quick enough & the pump is sucking air. This will drop oil pressure & cause a low pressure fault & shutdown.

4. If pressure shows low with mechanical gauge, then more work is needed-check oil pump screen for blockage, oil pump gears & end clearances & last thing is main, rod & cam bearing clearances.
All said-I'd bank on a bad sender or a bad wiring connection or bad harness.