Parked M923A2 and now it won't start

[Fatty]

I have a 90 BMY M923A2 parked it went to start it a couple days later and nothing just cranks over the emergency shutoff doesn't suck back in can't seem to find the problem any ideas fellas thanks

 

[tobyS]

Air getting into the fuel line. Or: you haven't manually pushed the electric emergency cutoff solenoid into the energized position and let the arm go into the open position...thus fuel not on.

Weak battery(s) seems to make those solenoids a problem, but they stay in as long as you leave the master switch on and the start switch in the run position. Once you turn off, it goes back out. PITA but with fully charged battery does not seem to have the problem.

 

[Fatty]

I have a battery tender on the batteries and in the manual it sez to tie the plunger back in and it should run but it's not thanks

 

[tobyS]

Then I would suspect a fuel line is letting air in. I would put a fuel tank and line that feeds directly to the pump, bypassing all other fuel lines. The usual spot for a crack is by the fitting that attaches to the pump, because the engine vibrates making small crack in old hose that loses prime. I cut mine off and used a hose clamp, poured fuel into the line and re-assembled, to get by, but had to replace the line eventually.

 

[tobyS]

If you wire the solenoid in, you cannot turn it off with the switch. It will stay in on it's own (until the switch is turned off) if you manually push it in each time and do not wire it. But if you've wired it in....it's not that issue.

 

[Evil Dr. Porkchop]

I would try to bleed the air out at the fitting on the backside of the injection pump. If it starts after that I'd look at replacing rubber fuel lines, they're a somewhat common problem on the a2 series.

 

[doghead]

Are you on rt 189?

 

[74M35A2]

Hi Fatty, love the name. Use a 10mm end wrench to remove the two solenoid mounting bolts. Unplug the 3 wire connector, and remove the solenoid. Engine will start and run properly. Use emergency stop cable to shut off engine. Nothing needs to be reset on the a2 8.3L.

Your batteries are weak due to age. They will seem to crank the starter OK, but as the voltage drops during cranking, the solenoid is the first thing to degrade with the voltage drop and it will not retract.

Replace the batteries with new (several options), then reinstall the solenoid, and you'll be all set. My recommendation is two group 31's, common semi-truck batteries. More than enough power for the 8.3, cheap, and frees up a lot of room under the seat.

 

[ibkickinit]

Just wanted to share what works for me... Mine does this frequently, I haven't fixed the leak that lets air in. Here is what I do and it hasn't failed me yet!

Try to Start and it doesn't....
Leave ignition in RUN position...
Hop out and hand prime until you hear the squishies.... 10-50 pumps usually.
Manually retract the plunger, it should stay retracted.
Hop back in, crank engine and it should start.

Its my understanding (Correct me if I am wrong) that the plunger wont retract itself if the fuel sensor doesn't sense pressure). Two circuits on the fuel solenoid - RETRACT and HOLD OPEN.

This is how I sometimes have to start mine. Need to check the fuel line and the pickup straw at the tank as both are known the cause issues.

 

[74M35A2]

The fuel cut solenoid has 2 coils in it, a pull and a hold coil. It takes a lot more energy for the pull coil, and when batteries are below spec rating, cranking voltage quickly drops, and the solenoid does not have enough power to pull back. It is the drop in cranking voltage from old batteries that causes this. You will not hear the starter going slower when this occurs, so everything will seem ok, but the reason is voltage drop. Fresh batteries maintain higher voltage when cranking. The fuel cut solenoid was designed to work with new batteries only. Does not help that the pull coil power feed comes directly from the motor side of the starter, adding even more voltage drop.