Throttle control failure (split from Re: Break down on I-10 )

Topic: Throttle control failure (split from Re: Break down on I-10 ) (Read 3125 times) previous topic - next topic

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #75 – February 02, 2015, 09:26:24 pm

Please post the list John! That is, unless JT requested that you don't...

though I can't imagine why he would object to sharing information that has a direct effect on the safety of FOT motorcoach owners...
Don

Quote from: John Haygarth – February 02, 2015, 06:35:06 pm

Just had a reply from JT and he has sent me trouble shooting checklist so sent it to shop and hope it helps.
JohnH

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #76 – February 02, 2015, 11:32:40 pm

Don I did try to post them but it did not work. They are PDF files that are in "my Documents" now so if Michelle will explain how to add them I will do it. These are actually the fault code steps to check the wiring etc etc when this particular thing happens.
I will do it once I get them to work
JohnH

edit, see if they open

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #77 – February 03, 2015, 12:14:23 am

Thanks John! That worked...

Don

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #78 – February 03, 2015, 10:30:50 am

For those interested, you can get that information for free from Cummins QuickServe (for your engine) Cummins QuickServe Online

You have to register for an account, which is free and provides access the Electronic Service Manuals, Parts Catalogs, Wiring Diagrams, etc for up to 5 engine seriarl numbers.

After I logged in to the site, select Service, then Fault code search, then SPN/FMI To Fault Codes, enter 131 under fault code and get the following documents (these for my 03 so slightly different)

Anyway a great source of information!

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #79 – February 04, 2015, 10:36:04 pm

Good news to report. I just got a message from Cummins PHX and it goes like this."PERFORM WIRING CHECKS ON OEM SIDE OF HARNESSESS FOR THROTTLE PEDAL AND INSPECT HARNESS AND CONNECTORS. REMOVED PANELS AS NEEDED. R/I FUEL FILTER AND ECM. FOUND 5 VOLT SUPPLY AND RETURN TERMINALS DAMAGED AND WOULDN'T LOCK INTO THE CONNECTOR AT THE ECM. REPLACED WITH REPAIR CONNECTORS. ROAD TESTED, 2 HOUR ROUND TRIP, NO PROBLEMS. MONITORED ECM FUNCTIONS WHILE DRIVING."
So this repair is in the exact location behind fuel filter that I figured it would be and now tonight I think I can sleep finally.
We will be seeing it again in 5 weeks but am sure it now is working as should. The intermittant problems to me fit this finding.
You will all be glad not to be hearing any more on this issue I am sure, but thank you so much for all the input you had.
John H

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #80 – February 05, 2015, 12:22:13 am

John, bet you are glad THAT saga is over!

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #81 – February 05, 2015, 08:15:21 am

John, Fantastic, glad its resolved.
Gary B

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #82 – February 05, 2015, 09:52:50 am

I felt all along after the throttle sensor was changed that the location of all the connectors right tight behind the fuel filter was a bad place for them and in previous changes of this filter it was most probably comprimised by someone when changing as they maybe had not been aware of how sensitive those wires (and important) are, but are bundled up very close to filter. I could see that from below when I changed it last, but did not think to check them at that time as all was well.
So, anyone with same setup should make the service dept that is changing your filter VERY aware of them and to be careful or the same fate will happen to you too.
JohnH

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #83 – February 05, 2015, 09:55:54 am

John, ask Cummins if they can move the engine filter to the frame rail next to the other filter.

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #84 – February 05, 2015, 10:00:29 am

Bill, if that can be done I will do it once home. Seem to remember it being a cast unit bolted to block but will look in 5 weeks. I do not want any more time spent on it there when I can do it at home, thanks for idea.
JohnH

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #85 – February 05, 2015, 01:28:22 pm

John

Glad the problem has been found and repaired. It is amazing how big problems can come out of small wiring issues put in obscure places. Guess the designers never figured anyone would have to work on them. That filter on the engine is in a place made for someone with stretch arms to get to. Is it easier from your pit??

Enjoy the rest of your vacation now.

Ted

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #86 – February 05, 2015, 01:53:04 pm

If the filter & mount can't be moved, what about making some kind of sheet metal guard to protect the wiring from inadvertent contacts that could damage the wiring?

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #87 – February 05, 2015, 02:09:07 pm

the filter is easier from pit but still tough and any guard I think should be made out of insulating materials. I am sure I can place closer to rear end and run hosing to and from it. We will see. My first job once home is to repair the rear door and mountings that got broken and bent on first tow.
JohnH

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #88 – February 05, 2015, 09:49:12 pm

Certainly turned out to be a very educational saga. Would be nice if connections that lost integrity would glow in the dark or some such thing. Happy all is well and continuing your trip. The village here as referred to instead of trailer park has been busy. Juan has been busy since October with one paint job after another. Bus mechanics have rebuilt an alternator including bearings and are rebuilding a turbo charger. Between the isles, they have also installed a drive axle gasket. Last week was air conditioner repair days with many having the dash air brought up to speed and systems recharged. All done without moving the motor homes. Just does not get any better.

On a side note, Carnival is Sunday the 15th (the parade) Monday I'm going to try and get some plastic lawn chair seats on the Vista del Mar balcony. If you thought you might be here in Mazatlan and wanted to see the parade, I'll purchase extra seats. (it's nothing fancy, but a good vantage point.

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #89 – February 05, 2015, 10:09:20 pm

Just today I had a throttle problem with my 1996 U270 with a Cummins engine. I had just left my house and was doing about 25 mph on a residential street when the engine starts accelerating. A lot. I am braking hard against a racing coach and pull over. I can tell the coach is wound up tight as I put it in neutral and my heavy tool box gets thrown about a foot forward. The RPMs are over 2500 and the gas pedal does nothing. I turn off the engine. After a short meditation I start it up and all is OK. I take it to the storage lot without further incident.

This could have gone bad in so many ways. What do I do next? Is this related to Johns problem? Wear those seat belts please.

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #90 – February 05, 2015, 10:49:18 pm

Quote from: dkoeberle – February 05, 2015, 10:09:20 pm

.........Is this related to Johns problem? ........

Not related to John's Electronic Control Module (ECM) plug/contacts problem.
John's is a computer controlled engine while yours is a mechanically controlled engine. I believe that your 1996 Cummins 8.3 has a King Controls throttle and speed control (servo motor driven) unit. If I am correct, it (the King Controls unit) sits on the frame rail on the curbside of the engine compartment and has a cable attached to the mechanical throttle linkage on the engine.
There should be one or two large throttle return springs attached to that same linkage. Standard is two. It is, in a way, installed that way for backup protection. OEM, the springs are notorious for wearing a groove deep enough to fail, leaving one with no assurance that the throttle will return to the minimum setting (if both springs have failed).
If that has occurred, it must be corrected before operating the coach as another run away condition may be anticipated.
If the springs are OK, then there are King Controls trouble shooting charts available on the Barry Beam site and through Internet search. Here's a link: NOTE: Symptom -- Throttle Sticks Off Idle
NO THROTTLE, NO CRUISE, NO FAST IDLE
Let us know,
Neal

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #91 – February 05, 2015, 11:11:44 pm

Croos country, we will be going thru Maz' on the night of 8th and leave next morning as Ruth has dental work to get done on 10th but thanks for offer. If we get into town early enough we will pop over the san Ffernando to meet.
There are total of 4 FT coaches here in san carlos right now.
johnh

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #92 – February 22, 2015, 11:39:24 am

Ny First guess was the throttle position sensor. We were all in the right area anyway.

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #93 – February 22, 2015, 02:58:29 pm

John S, just wondering if you knew what the problem turned out to be? 3 bad connectors at the ECM for throttle control, not sensor just make and breaking at that point, exactly what I was experiencing and hope it never happens to anyone else as can be very dangerous outcome.
JohnH

Re: Throttle control failure (split from Re: Break down on I-10 )

Reply #94 – February 23, 2015, 02:04:46 pm

I have a new throttle position sensor in the spare parts bin. I think we had the same issue. Mine was wiring too but not at the ECM connector but at the sensor.

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