Engine stalls intermittently at stoplights

BG6 · July 08, 2009, 08:25:52 PM

I've been doing some running around with the coach, getting the final stuff done in the conversion, and the engine has started dying at stoplights. Not every time, but every 10 times or so, it just stops running for no obvious reason.

Anyone have this happen, and what was it?

I don't have time right now to check everything that it might be (I need to move into it next week, so final prep has priority).

WEC4104 · July 08, 2009, 08:44:30 PM

Two quick questions:

1) Does it die only as you roll to the final stop, or can you be sitting there idling at a stop for a few seconds and then it just dies?

2) Manual or Automatic transmission?

NJT 5573 · July 08, 2009, 08:45:09 PM

Just a guess, electrical, maybe a lose wire around the ignition switch or the stop run switch. What kind of bus you working on? What engine and transmission? I'd make sure the water and oil were topped off, not knowing what shut down features you may have. Is it hard to restart? Does it take right off? Is it missing and running rough and vibrating?

ol713 · July 08, 2009, 08:52:11 PM

When were your fuel filters changed last?
Was it hot when you were driving around?
That might be margional thermostats. Let us
know what you find.
Merle.

RickB · July 09, 2009, 01:56:31 AM

I had a similar issue not too long ago. It turned out to be rain water in my tailights shorting out a breaker in the front junction box.

Good luck,

Rick

JackConrad · July 09, 2009, 04:35:57 AM

Low oil pressure? or faulty low oil sender? You have been given many possibilities, they all need to be checked when you get time. Please let us know what the culprit was once you find it. Jack

dolson · July 09, 2009, 08:04:11 AM

Had the same issue and it was the oil pressure sending unit

BG6 · July 09, 2009, 08:47:01 PM

Quote from: WEC4104 on July 08, 2009, 08:44:30 PM
Two quick questions:

1) Does it die only as you roll to the final stop, or can you be sitting there idling at a stop for a few seconds and then it just dies?

2) Manual or Automatic transmission?

Manual trans. It dies as the coach comes to a stop. And just to make sure it wasn't me, I tried hitting the clutch before the brake, and same thing. Not every time, just once every few times.

BG6 · July 09, 2009, 08:49:52 PM

Quote from: dolson on July 09, 2009, 08:04:11 AM
Had the same issue and it was the oil pressure sending unit

This is possible, I noticed the oil pressure light came on as the engine died, but thought it might have just been because the engine wasn't running.

I will have to check the other things suggested here, too.

Coach is a 1990 MCI 96A3 with 6V92 turbo. It lights off instantly when I hit the start switch after it has stalled.

Runcutter · July 10, 2009, 06:39:07 AM

My 4107 (8V71) does something similar. If I stop a little quickly, I get a low oil buzzer/light. It's momentary, the engine doesn't die (isn't killed by the shutdown systems).

I suspect it's because the previous owner used 30 weight instead of 40 weight. The coach went into the shop yesterday (another towing adventure), because someone whacked the front end.

While she's in, she'll get her first oil change, to the correct 40-weight. Hopefully, that'll correct the problem.

Arthur

luvrbus · July 10, 2009, 09:24:37 AM

BG6, check your idle speed if you have a automatic it should be 650 rpm or 550 rpm for a manual.
idle speed will give you a low oil reading causing the engine to shut down. good luck

JackConrad · July 10, 2009, 10:06:51 AM

Disconnect the low oil sensor. If that solves the proble, it is either a bad sender or actual low oil pressure (oil level, idle RPM, etc.) Jack