[AL]

With everything that has been done on this bus / engine, has it evrr been on a chassis dyno? Or has the engine been on a dyno stand, that would remove any items from the chassis that could effect the egine performance. The idea of going to an all mechincal engine may have some merit based on all your past issues.

[Peter]

I think you got good advise, take it back to mechanical…

[Peter]

Bi

FWIW….ECM’s do not self ground being bolted to a fire wall or the engine.

Suggest you locate the ground circuit coming out of DDEC, replace the pins and run a wire to a ground source.

Confirming ground is basic trouble shooting in most electrical repairs.

AL

[Archived]

[Peter]

Bill,I cannot help with the wiring on a Prevost but have it for a Eagle with a DDEC I you need to break in down into 2 parts on the wiring from the engine to the plug is a DD responsibility from the plug on is the OEM responsibility I can help with the DD responsibilty no problem.

Have you checked the 2 fuses that supply the power to the heads ? the Jakes shouldn’t come into play they don’t go through the ECM on a DDEC I.

I maybe wrong but I am leaning towards the boost sensor has been replaced over the years with the wrong sensor get the number from it and call Bill in the parts dept at WW Williams in Phoenix he is from the old school and knows those engines

I have a friend in NM that has a couple of spares of the EProm for the old DDEC I he will probaly lend you one to check yours, send me some type contact info and I will put you in touch with him he is good with the old DDEC I the one in his Eagle will get down the road

good luck

[jack]

[needtocamp]

I gave the guy your contact he is on the road and will contact you when he gets home

good luck

[Rodger]

I appreciate that. Thanks.

[Bill]

Bill,

I read your other posts and see that you still have had no success.
Here is a link to my DDEC I trouble shooting manual if you don’t already have
it. I thought I had 2 92 series DDEC I ECM’s but all I have is one 92 series
EDC. If you haven’t tried that yet I’ll get a part number from it tonight and
maybe we can determine which engine it works with. I’ll be happy to sent it to you. There are some Nexiq DDEC I cartridges
on Ebay.

https://drive.google.com/file/d/0B9Xv0QOH_HT4SkdqX29KbVBVSkk/edit?usp=sharing

I don’t mind trying to help. I have been working on
electronic controlled engines since 1977, but I have zero experience with DDEC
I. 615 210 4963

Ken

[Ken]

OMG! What a gem that trouble-shooting guide appears to be. I can’t wait to start digging into that. No one anywhere that I have had work on the coach had anything even similar.

Thank you a million times.

[Archived]

The one I have is the EDU it mounts on the engine. I quickly looked though
the trouble shooting manual. I’m pretty sure it’s the injector driver (big
switching transistors) if that’s correct the chassis mount box sends a signal
to it that requests the injectors to open at certain point in the crankshaft
rotation and remain open for a certain time or number of rotational degrees.
The chassis mount box determines the opening point (injection timing) and the
duration of the open time (pulse width) based on inputs from the engine related
sensors like throttle position, engine speed boost pressure and many other
possible inputs. All electronic fuel injection works on the same principal.
What makes this repair difficult is the limited information displayed by the
diagnostic tool and the limited information in the trouble shooting manual,
although that’s about normal for a manual. For me to be reasonably
confident I could find the problem I would a need another vehicle with the same
engine configuration that performed correctly. Then it would a matter of using
my data acquisition software and comparing the pulse widths and boost pressure
of both under similar loads. Maybe the Nexiq tool with monitor this, I don’t
know. If the pulse widths and boost pressure are the same under similar loads
that’s suggests a mechanical fuel delivery problem or other mechaical problem.
If not it would require monitoring the sensor outputs of both and determine
which sensor is sending the incorrect signal. Of course all the sensors could
be OK and there may be a wiring issue resulting in an incorrect sensor reading
to the ECM. Once the faulty input or output is found it’s not too difficult to determine
if it’s the sensor or harness . I have a tendency to overthink things, it maybe
something simple. There is an answer, no magic or voodoo with this system. I’m
not saying I could fix it, I know a lot of experienced folks have tried.

Ken

[Clifford]

I would look into your fuel delivery(lines,fuel tank restrictions,etc.).Sometimes there could be something floating in your tank and when fuel is drawing,it would partially block your lines. You did not mention fuel mileage.

[Archived]

I sent you a pm with a guys # he has 1 of the few Kent/Moore readers for a DDEC 1 and I am trying to get you some help from the 2 stroke rebuilding plant in Emporia Ks the military had 1000’s of the DDEC 1 with the 53 and 92 series engine till they were phased out to the DDEC 4

good luck

[Bryan]

I would check the fuel pressure and the return flow as mention the DDEC do not use the same fuel pump as the mechanical engine fwiw

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