T444E Help! Hard Starting, Power Loss, Getting Worse with Time

[RebelWithoutACausey]

Ok, I thought we were in the clear. This bus is all over the place, and cannot make its mind up whether it wants to run perfect or not at all. Here are the codes I have.



This suggests an ECM issue to my mechanic, and considering the welding I have done to the bus during the first stages of the build (before it starting running odd), im inclined to agree. I didn’t disconnect anything before welding, and I did quite a lot of it. Perhaps I cooked the ECM? Id like to have some second opinions before I throw a few hundred more dollars at it. Thoughts?

 

[ewo1]

I'm assuming your tranny is an Allison 2000 ???

No info in your user profile so I am gonna guess....

Check the fuse for your TCM, and also your ground connections too!
When you are trouble shooting any electrical circuit you must first verify power and grounds are in good shape.

Is your bus shifting all it's gears when you drive it?

Your not clearly telling us how it running poorly other than to say it is running poorly....

DETAILS !


SID 254 - That code usually means there is a problem with the power connections to your ECM which could be anything from loose battery connections to bad ECM power relay. That code translates to 626 which is an unexpected reset DTC. ..... could be problems at the small power and ground connecters at the battery which go up to the ECM power relay.

Also, have you done an injector test, verify coils are not going bad?

For the PID 164, is there an actual flash code that goes with it?

In my motivational post to you I put the link for the T444e diagnostic manual, are you using it at all ?

What does your injector pressure look like?


SID 254 - yes at first glance could be fatal, need new IDM.


Some past troubleshooting/repair efforts....

As per cadillackid - post #7 -> https://www.skoolie.net/forums/f37/t444e-stalling-dash-light-32200.html

Code 525 - Injector driver fault (IDM) the IDM is internal to the ECM.. setting this code would cause the engine to peter out and die.. as there are 2 IDM circuits.. shorting one out due to a bad valve cover wiring harness would knock put 4 of the 8 injectors and shut you down.. this code can also set if the ECM battery voltage is low...

post # 13

Update:
Shop showed me the pigtail for the IPR. Bare wiring at the very end, which was shorting out causing problems. Also, the ICP sensor's values were all over the place even when the engine was off.

Now I am NOT a mechanic but I am learning as I go so remember, the search button here is your friend and so is GOOGLE!

 

[RebelWithoutACausey]

By running poorly, I mean sometimes it runs perfect, sometime it stalls, sometimes the check engine light is on and there is no throttle response. There does not appear to be any reason whatsoever as to why sometimes it will not start, then ill come back to it later and it will fire right up with no hesitation having done nothing to it. It literally behaves differently every time I stick the key in the ignition.

****, after it ran slow for 15 mins and then shut off on me and would absolutely not restart the other day, when I finally got it to start the check engine light was off and I had all my power back. I have no idea what to think of that.

As far as shifting, yes it shifts through all the gears. High gear started having a rough feeling to it, but last time I drove it that had gone.

Now that I have a second to actually sit and not work I’ll crack into that diagnostic manual, hopefully theres a section in there about frying electronics with a MIG welder, but without a consistency in symptoms im not sure how well the manual will diagnose this.

 

[ewo1]

I don't know if you are in a major city or not but one thing that would be super easy and very helpful is if you can get a "loaned/borrowed" IDM and see if things clear up on your bus.

If they do then you know what you got.
If things stay the same then you might have poor wiring/connection issues which would be my guess.

Here in South Florida there are many "Private" school transportation companies. I made friends with two of them and when in need we help each other with parts and tech tips.