heip 8v92 ddec2

niles500 · November 15, 2011, 06:04:21 PM

Could be as simple as bad batteries - FWIW

Ace · November 15, 2011, 06:22:22 PM

Niles that was where I left it. I advised Jim to get 2 NEW batteries and start there and work back to the ecm!

hargreaves · November 15, 2011, 08:28:42 PM

Check and make sure the ground wires from the ecm have a good ground. If it is a DDEC 11 they should be the centre black wires between the red ones. If the grounds are bad and you have high resistance it will eventually fry the injector drivers. Good luck , Gerry

prevosman · November 16, 2011, 05:27:50 AM

I'm far from an expert, but one thing is critical on DDEC engines and that is good voltage. A while back I chased erratic voltages and while I will never know exactly what I did to correct the problem I did make it go away. I started with the batteries, verified they all were good (one bad battery drives you nuts) and then cleaned and reconnected every single terminal connection and ground. Using the voltmeter I was reading good continuity and voltage everywhere, but obviously somewhere in the bus load of connections and terminals there was one that tested good but wasn't carrying a load until I disturbed it, cleaned it and or retightened it.

I don't know about all coaches but on mine I had some power directly from the batteries to some DDEC circuit breakers so it takes a bit of detective work to find all the terminals. I think Ed has a good idea, but on those terminals I did not think of that. I just kept exercising the plugs to "wipe" the corrosion if any.

robertglines1 · November 16, 2011, 05:31:21 AM

Is this a new install? Bob PS have batt load tested. will show true condition/indivually

jimsflx · November 16, 2011, 01:40:09 PM

well worked on it today,took the plug from gauge on overflow tank like bk said bus ran for about 45 minits then shut down the 2 temp gauges by the motor where both at 180 degrees. the motor will start right back up. but over nite it takes a sma ll shot of either? started to cleen plugs have new batterys coming tomarrow. anyone know where to get the manuals? i want paper not cd. really need a least the eletric part thanks jim

jimsflx · November 16, 2011, 02:44:09 PM

we have a ecm that came off a 6v92 can we use this on the 8v92 to test? what does one cost if we need one, where to get rebuild one. thanks jim

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Ace · November 16, 2011, 03:33:26 PM

Jim I will see my buddy John tonight and see if he had one I can borrow! They ain't cheap if you have to buy one!
The first thing I'd do though is start With new batteries, then do voltage checks at all connections then start replacing sensors. I would not bother cleaning them! That's just me! I like to know that what I'm starting with is good!

kevink1955 · November 16, 2011, 03:56:34 PM

Sounds like you are chasing other issues when the tests already performed say the voltage to the ECM is droping while it is runing. I would be looking carefully at the fuses/circuit breakers that power the ECM. If they are located near the batterys as most are the batterys gassing off may have caused high restance.

The starting problem could also be voltage related, to low and the ECM will not turn on and fire the injectors. We have had fuse problems on fire trucks, they mount the batterys behind the front tires and expose the ECM fuses to road spray.

jimsflx · November 16, 2011, 05:20:32 PM

ace. earl has a ecm off of a 6v92 we just do not know if it will fit the 8v92. thanks kevin i still checking fuses thanks jim

Busted Knuckle · November 16, 2011, 06:53:18 PM

Quote from: jimsflx on November 16, 2011, 05:20:32 PM
ace. earl has a ecm off of a 6v92 we just do not know if it will fit the 8v92. thanks kevin i still checking fuses thanks jim

Jim DO NOT try a 6V92 DDEC on an 8V92 unless you want more problems than you already have!

They are different animals. The 8V DDEC is configured for 8 cylinders & the 6V DDEC is only configured for 6. (have a friend that tried that, didn't work out and caused many head aches.

I have a 8V DDEC unit on the shelf.

BK

buswarrior · November 16, 2011, 08:04:48 PM

Good grief.

Get two new batteries, check all the connections/wires/fuses for the ECM ruthlessly for corrosion.

And watch your problems go away?

Leave the ECM alone, nothing in this thread even comes close to touching it.

happy coaching!
buswarrior

hargreaves · November 16, 2011, 11:01:29 PM

The best way to to test an ECM is to purchase a plug that fits the power connector on the ECM, run some 14ga wires to it. one for power one for ground. put some aligator clips on the ends use a separate car battery and start it up. if it continues to run without problems, you have wiring issues on the bus side of the wiring harness.If you still have issues it is on the engine side of the wiring harness. This is one of the troubleshooting steps in the troubleshooting manual.

luvrbus · November 17, 2011, 04:07:09 AM

Jim,I forgot where you ask about the OBD2 reader but you buy one even at Wal/Mart for 50 bucks they will read the codes from the J 1587 link only problem they read in the SAE example 45 (oil pressure) will read P1001 then some will with the S like to many SRS will read s210 instead of 41 DD has a table to convert the reading and you can erase some codes with one also and it will not read any sub codes.
Not a Pro/Link or DDDL but they are better than trying to read the flashing lights lol

good luck

jimsflx · November 17, 2011, 05:02:32 AM

thanks bk,hargraves,buswarriow,luvrbus, jim