Skip to main content ↑ ↓
Topic: No start (Read 791 times) previous topic - next topic

No start

Ready to leave this morning, coach won't start. Turns over about one rev per second. Scangauge shows voltage at ecm is 12.0. Meter shows coach batteries at 12.4. Have been parked 5 days, battery maintainer connected. House batteries are at 12.8 float, still connected to shore power.

Tried boost, no help. Not skilled with voltmeter but checking each stud on isolator connected to good ground, get either 1 volt or open line. Same results with boost switch, whether switch is on or off.

Open line somewhere between batteries and isolator?
Mike & Molly Patronick
2001 U320 40'
2011 Forester

Re: No start

Reply #1 –
Mike:

I suggest you call either Mike Rodgers at MOT or James Triana at FOT. 

Might be something at the isolator, but I am not electric savvy enough to suggest options for you.

Best of luck.

Say hi to Molly and the dogs (after you get this issue solved, of course)

Ted & Karen
Ted & Karen
2001 U270 36' - sold after 12 years full timing

Re: No start

Reply #2 –
First, pull the terminals off the start batteries and clean both the cable connectors as well as the battery post side on both positive and negative posts. Using a voltmeter while someone tries to crank it, check voltage on the start battery cables, not on the post but the cable leading away from the battery. The engine should turn over and start without the boost switch being on. If you have a bad start battery connection, the boost solenoid cannot possibly pass enough amps to start the engine and you will get slow cranking as you describe while overheating and very possibly damaging the boost solenoid.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: No start

Reply #3 –
I agree with Pierce battery terminals on the starting batteries always seem to crop up. Negative connection very important. You can get good voltage readings and still have poor connections
1995 U320 40', 2013 chevy sonic toad, my real love are corvettes have owned 30

Re: No start

Reply #4 –
It was me (I think). Just before we started this trip I installed a new secondary transfer switch. Had to move the EMS and primary transfer switch and disconnect the battery maitntainer to get down to the new switch. When I put everything back together, got the battery maintainer connected to the chassis batteries but not plugged in to the engine preheat outlet.

Cleaned and tightened battery connections, decided to use my portable charger to add juice to the batteries. Got a call later from Mike Rogers, suggested percussive adjustment to the boost switch. Said I could run jumper cables from boost switch to batteries to recharge but that my charger would handle it. After about an hour of charging, cranked just fine.

If I don't need the charger tomorrow will assume problem solved.

Thanks all.
Mike & Molly Patronick
2001 U320 40'
2011 Forester

Re: No start

Reply #5 –
It wasn't me. Was in MOT a couple weeks after the problem came up. Talked to Mike Rogers and Keith Risch. They thought the batteries could be week. Load test showed two were shot, one was fair. Coach only started because the battery maintainer kept some charge in the bank. Now have three new group 31 agm start batteries. They spin the engine faster than any time since we got the coach.

One lesson learned, just because I have good voltage doesn't mean I have enough amps to get anything done.
Mike & Molly Patronick
2001 U320 40'
2011 Forester

Re: No start

Reply #6 –
That would be correct--- old batteries will often accept a "surface" charge and show good voltage even after the charger is disconnected.  When they are put under load, the surface charge vanishes and the batteries collapse.  They can't supply high current due to plate degradation.
Hope that helps.  Bad news is, new batteries is the fix.
Current coach 1996 U320 40'
Previous coach, 1990 36' U280