-
Coach Won’t Start or Crank
-
On our coach the DPDT front-rear start switch was intermittently bad and the key start switch would fail to make contact once in a while as well. Made trouble shooting problematic but after replacing both all issues went away. As cheap as it is to replace both I would do that on any late 90s to early 2000s Prevost. along the way the starter was also replaced but I doubt it was bad.
Jerry
-
Remember folks, he has a 8V92, so things are different than 60s and later buses
-
But he does have a front/rear start switch and a DDEC II that will shut down with low coolant level.
-
DDEC III started in 1992. Coolant level sensor was most problematic. when coolant level is high enough the sensor completed the signal. When to low the switch showed open circuit ..simple test with jumper(paper clip) will show the positive result.as if the coolant level is above the switch. This is a emergency road test. low oil pressure.low coolant level, high engine temp (Coolant or oil) lot of problems are created by open grounds or just weak ones. Also it takes 11.6 V for ecm to even operate. The ECM has it’s own dedicated power source and direct ground to battery seperate of chassi ground. FWIW we have no idea what others of done to system as our coaches age..Don’t use tape on sensors if you replace any..= bad ground possible(happen to me) and sensor can’t complete it’s function of measuring resistance or simple open /close function.. Most of this info comes from hands on experience with DDEC Ecm.. Bob
-
Just an update….. still not started!
Thanks to everyone who commented to help. I am yet to get the coach to turn over at all and I am looking for a vendor to come out. I need to get it started so i can get it to Jeff’s for something unrelated anyway so I have to get it going.
I feel like I have been over it 100 times with no luck but I am sure I am missing something simple.
-
Was the starter solenoid finally replaced? Doing so will eliminate it once and for all. We also experienced similar symptoms and that was problem. FYI…they do get very warm (hot) when they’re acting up.
-
Ran a jumper across the starter last night like I would a car or mower and it wont move or make a sound so I assume that’s indicative of a bad starter.
-
Starter is confirmed bad and I have a replacement.
Thanks everyone for the comments and help!
-
“Starter confirmed bad”
Very profound statement.
It looks like John removed the starter and took it someone who could bench test it. Without taking this step, John would never know if the starter was really “bad” or not. A local starter/generator/alternator guy told me that the scrap yard has many still “good” starters/generators/alternators because they got tossed without the bench test being done.
-
That is why we proactively replace ours with the newer version. Geo
-
Excuse me for butting in but I have a problem that I cannot diagnose and noone else seems to have a clue. I shorted the batteries when re-installing them with the master toggle switch on, after a charge up and after that, I could turn the engine (Series 60 (6 Cyl) over but it would not fire up. All of the lights come up & I checked all of the breakers and they’re not tripped. and I have 24 V.
Any guidance? Mine was a tour bus with no house batteries or wiring
David Wertheimer
-
you’re talking about the switch with the key in the dashboard? You replaced that? Could you only turn over the engine from he engine switch but not from the key?
David
-
In addition to needing power to spin the engine you need power to the DDEC circuits. You need to check the voltage to verify I am right, but you need 12V to CB19, CB20, and CB21. If you have that the no-start issue could be a sensor.
-
Jon–prob has it. The ddec requires seperat fused power all the time even with master turned off. Did you get all wires back on bat?
Log in to reply.