Have a u280 Cummings 8.3 1995
Coach will not start power going thru starter selenide but no signal to ecu
Battery is fully charged
Wait delay light comes on but nothing when I turn the key
Any ideas
Donnie
What does the Allison shift pad show/do?
What does the dash HVAC fan do with key on?
Don't think that engine has a ecu if you mean computer control,try gently tapping on the starter and check connections to starter.
Are batteries fully charged?
Allison pad shows like lightning bolts checking with Allison it means signal not getting from transmission to ecu
Am presently checking connections at transmission as well as the 2 solenoids under coach
How old is the ignition solenoid. This happened to me it was my warning sign. I managed to get home by cycling the key and watching for the time the pad came on. You could take just one part of the booster cables and connect each side of the solenoid to test or verify
Check connections at back of shift pad and at ECU. More likely a problem than at the transmission.
But, still need an answer to the "does the dash HVAC fan work with ignition on"-- that will tell us if the IGNITION SOLENOID is working properly.
If you are getting power to the starter solenoid but the engine will not turn over the problem is between the start solenoid and the starter itself,check the start battery voltage again and answer Brett's questions and go from there,the engine should start no matter
what the trans ecu says or does.
John44: I will have to disagree with you on that statement. When I had my "Snake Eyes" incident, my engine would not even
try to crank as long as the transmission shift pad was showing the error indication. I believe the OP's coach will act the same...
Donnie: Where are you located? If it was cold inside your coach last night, then you might be able to clear the "Snake Eyes" by warming the transmission ECU with a hair dryer or a heat gun (on LOW). I know it sounds funny, but this has worked for more than one member experiencing exactly the same symptoms. You don't need to get the ECU HOT - just warm it up so it feels warm to your touch.
Try it, and see what happens. Below is a link to my no-start incident, with the full story of how to deal with it:
No start, with Allison "snake eyes" (Problem Solved) (http://www.foreforums.com/index.php?topic=25783.0)
Chuck is correct. Snake eyes= no start. Transmission does not "understand" that it is in Neutral.
I understand,but for my info what is actually stopping the starter from engaging,maybe I intrepeted the starter solenoid as clicking
instead of just getting power,guess I thought if the start solenoid is clicking engine should try and turn over.Think we need more
info from the traveler.
Here is the update
First of all to Chuck I had that happen the morning we left Nova Scotia very cool night tried Starting and snake eyes appeared was able to warm up and coach started been driving 8 days nearly 4 thousand miles and suddenly the speedometer stopped. Working and a beep in the dash
Luckily we were in benson as 3 miles from a campground
Once stopped coach would not start and snake eyes showed on pad
Changed starter solenoid still no go
Batteries full
Jumped solenoid under coach and engine started but still snake eyes
Time for a diesel tech
He showed up and tested everything even talked to the Allison tech
Power going everywhere but not powering the ecu
Looks like replacing ecu but need to get the Allison tech to do it
Need to call tomorrow to schedule appointment he has to come from Tucson hopefully it will be tomorrow
Thanks to all for your help and suggestions
Donnie
If you are in cold weather, take you wife's hair dryer and warm the Transmission ECM and see if the snake eyes go away, if so you need to have the EMC repaired. Bret Wolfe has the listing that repairs them.
Donnie,
Not telling you what to do, and don't know your travel schedule, BUT...
If you can allow enough time parked where you are, I am guessing it would be much less expensive to pull your ECU and send it to John Kopalek for repair. He can tell you on the phone what his (shop) turn-around time would be. If you overnight it both ways, it might not take long to get it repaired (to good-as-new condition). Getting a brand new ECU installed by a Allison tech is gonna be pricey.
Transmission Instruments (http://www.transmissioninstruments.com)
Yes, IF you need shift pad or ECU repair, John is THE MAN.
But, you still have not ruled out the IGNITION SOLENOID. If it is going out, it will not power the Allison ECU.
3rd time: When this happens, do other things that should work only with ignition on work (i.e. dash HVAC fan)??
Brett,
When Donnie says (in his update, above) that he "Changed starter solenoid still no go" I'm guessing he might actually be referring to changing out his ignition solenoid. I'm just going by the context of everything else he has reported. But I could be wrong...
When I heard starter solenoid I took it for the one on the starter.
I just figure it's more likely he would be carrying a spare ignition solenoid so he could do a quick roadside swap. You don't hardly ever hear of people replacing the actual "starter" solenoid that is physically mounted on the starter.
Of course, he could also have been referring to the "AUX" start solenoid, mounted on the isolator panel. Guess we'll have to wait for clarification...
Too many darn solenoids involved in the engine starting process! :help:
The OP made the statement
Power going everywhere but not powering the ecu
Not sure what that means.......... he should answer Brett's question about the dash air blower -- does it run ?
All of our dash instruments went dead on I81 in WV and the coach would still run, it wouldn't start up again and won't start if the ignition solenoid is defective. Drove to a NAPA and replaced it in their parking lot, on the road again in 30 minutes.
........... we have the same year and model as the OP.
You had me dizzy for a while,thought you were the same traveler,think I would follow your advice.
Sorry guys it was the ignition solenoid that I changed
The Allison dealer in Tucson has taken the tcm out and back to their shop tested it and it failed
Apparently this model is no longer available so they have to send my core to have rebuilt
2-3 days and $3500
Wow
Have you talked with John K???? Post #12.
I sure would before committing to $3500!
We tried to help... (Shrug)
You can lead a horse to water, but you can't make him drink.
Nothing lasts, period. Brett replaced ours in 2010 with the two window display. He also moved the keypad and the Pac Brake switch to a MUCH MORE ergonomic position!
From what I read your going to have a better repair for less money going with John K.
A fraction of the price from John
Ok drove to Tucson got my tcm back from w w williams and have forwarded it to transmission instruments in Texas ( that's the name of the company given to me by Chuck ) hopefully will have it back by Friday maybe Saturday
Cost from them is $600 plus freight
Hopefully dodged a bullet with the help from you people on the forum
Ok drove to Tucson got my tcm back from w w williams and have forwarded it to transmission instruments in Texas ( that's the name of the company given to me by Chuck ) hopefully will have it back by Friday maybe Saturday
Cost from them is $600 plus freight
Hopefully dodged a bullet with the help from you people on the forum
Donnie,
When you get the TCM back, and get it reinstalled, please let us know how it works and if it has solved your starting problem. We always like to hear "the rest of the story" to tie up threads like this. The feedback, positive OR negative, will benefit all our members.
I believe you will be very satisfied with the work done by Transmission Instruments. They have a excellent reputation on this Forum.
And "No", we don't get a cash kickback under the table for sending work their way. 8)
Will do hope this solves the issue I may have to install myself but I will cross that bridge later
Thanks again for your help
Pretty easy "plug and play".
Is it possible to mix up the two plugs or are they different
I didn't take the unit out but have found where it goes looks easy
Again Brett thanks for all your help and especially the tip as to where to send for rebuild
I always labeled the two, so can't answer your specific question.
But from Allison's website and/or a call to them, they can tell you the wire numbers that correspond to gang plug positions.
Donnie,
As I recall, on my coach, the two plugs that inserted in the ECU (TCM) were
very similar...probably identical. So I suppose it would be
possible to mix them up (reverse their positions). However, on my coach, they were bundled together with electrical tape and nylon ties in such a way that they could only be easily inserted in one way (the correct way). If the Allison tech that removed your TCM did not disturb the wire harness bundle (by cutting all the tape and/or ties), then you will probably find that there is only one logical way for them to plug in. See the posts linked below for photos from my coach - your coach might be slightly different.
No start, with Allison "snake eyes" (Problem Solved) (http://www.foreforums.com/index.php?topic=25783.msg205110#msg205110)
No start, with Allison "snake eyes" (Problem Solved) (http://www.foreforums.com/index.php?topic=25783.msg205167#msg205167)
Think I found a more definitive answer to your question.
If you look at the photos in the second link (above) you will see 2 shots of the TCM plugs. Looking closely, you will notice that one plug has a black plastic piece where the wires enter the plug. The other plug has a white plastic piece in the same place.
On my coach, the TCM is mounted to the firewall in a horizontal position, so one wiring socket is on top, and the other is on the bottom. On my coach, the black/white plug goes into the right (top) socket. The all-black plug goes into the left (bottom) socket. If the plugs on your coach also have the two different colored plastic pieces, then they very likely fit the same way.
Additional evidence: I found a service manual online for the Allison transmissions. It has a LOT of good info. If you scroll down to page 6-23, you will see a diagram of the TCM and the two plugs. The black/white plug is identified as plug A, and goes into socket A, which is the "right" socket. The all-black plug is plug B, which goes into socket B (the "left" one).
https://f01.justanswer.com/JACUSTOMER-qz77bbnq-/5b6c3d57-2211-420a-bc75-c1cb6cf1b81d_wtec+2+troubleshootin.pdf
Hope this is helpful information.
Thanks a lot when I get my Tcm back l will check and see
I have time tomorrow so I will check out the wire bundles
My unit also stews to the firewall on the driver side
I'll let you know how it works out
Mu unit won't get to John until early tomorrow
Hoping for quick turn around
Chuck
I have had time to go thru the info you sent thanks it was a great help
My unit also screws to the firewall but vertically ( go figure)
My plugs are like yours ( white and black ) so by looking in the Allison manual l was able to figure which was A and which was B
Looks like John shud receive my unit by 10:30
Can't wait to get going
Ok final update ( I hope ) on the faulty ecu
John and Vojta at transmission instruments were fantastic they received my ecu at 10:30 in the morning were able to rebuild and ship out that nite
I received the next evening ( Friday )
Got up this morning and followed john's instructions exactly
Disconnect battery
Clean pins with electronic cleaner
Insert the plugs at least 10 times to insure contact
When I first did it the coach started but would not go into gear and the 6 left cell on the pad was flashing John said this may happen and said to run the coach for 10 minutes then repeat the process
I did that and everything worked fine
Packed up and drove to our destination in Yuma
Thanks again to all on the forum it is a remarkable resource that we are fortunate to have
Thanks especially to chuck and Brett saved me some big $
Happy to be of some assistance. Hope the rest of your trip is enjoyable and trouble free.
Congrats to all. Great thread. ^.^d