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Topic: Engine Will Not Turnover (Read 994 times) previous topic - next topic

Engine Will Not Turnover

Coach is in storage.  Parked it Thursday would not start today. All warning lights come on with 'wait to start' light and then go out but engine will not turnover.

2000 34' U270 build #5659, 8.3 ISC Cummins, Allison MD-3066R.

Battery voltage 13.6. Using boost switch does not help. HVAC fan and other ignition on, accessories work but Allison pad does not illuminate with N.

I have read several posts on the subject (solenoids, battery cables cleaned, starter voltage, etc.) and will use that data when I go back to work on the coach this week.

I did not see any discussion of the significance of the Allison not illuminating N while other ignition on, accessories work. Should the Allison circuitry be my starting point?
Bob and Phyllis
2000 U-270 WTFE
34' Build 5659

Re: Engine Will Not Turnover

Reply #1 –
Yes, the Allison pad must show a "N" before the engine will start.  Do you get any indication at all on the Allison shift pad?

If you get the indication shown below on your shift pad, search the term "snake eyes" on the Forum for guidence.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Engine Will Not Turnover

Reply #2 –
The mode light is the only thing on.
Bob and Phyllis
2000 U-270 WTFE
34' Build 5659

Re: Engine Will Not Turnover

Reply #3 –
You might try unplugging and then plug back in the wiring connector on the back of the shift pad.  Sounds like a partial lack of power or disruption of signal getting to the shift pad.  Make sure ignition is off before unplugging any connectors.

Unless you can restore power to the shift pad so it shows something in the gear windows, you are pretty much in the dark.  You obviously cannot access any stored diagnostic codes with a dead shift pad, and that severely limits your trouble shooting options.

Link below to Allison Trouble Shooting manual.  See Section 8, Table 8-1, second "complaint" for some ideas.

http://ww2.justanswer.com/uploads/HE/HeavyEquipmentTech/2013-09-22_223029_allison_transmission_md3060_trouble-shooting.pdf
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Engine Will Not Turnover

Reply #4 –
Quote from: Bob and Phyllis –
Coach is in storage.  Parked it Thursday would not start today. All warning lights come on with 'wait to start' light and then go out but engine will not turnover.

Well, you need a neutral safety switch before you can engage the starter. 

In my ignorance and purely for my own edification,

Is this an air shifter?  When you push the button, what moves the valves on the transmission?
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Engine Will Not Turnover

Reply #5 –
Old Toolmaker,

Please refer to the manual I linked above.  It tells you everything you could possibly want to know about the Allison tranny components.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Engine Will Not Turnover

Reply #6 –
Thanks for the manual. Still working full time but will use it when I can get back to the coach.

As to the question of the transmission operating by air, with the exception of the retarder, it is, as far as I know, electronically operated.
Bob and Phyllis
2000 U-270 WTFE
34' Build 5659

Re: Engine Will Not Turnover

Reply #7 –
Bob,

Found a recent thread describing a similar problem, and the way it was eventually fixed in two different Forum member incidents.

Shift Pad Blank

By the way, if you decide to check the connector on the back of the touch pad, do not be concerned if you discover a orange wire that appears to be cut in half.  This is a standard wire harness modification when the shift pad is "remotely" installed.  See thread linked below:

Allison Touch Pad connector
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Engine Will Not Turnover

Reply #8 –
Quote from: Bob and Phyllis –
Thanks for the manual. Still working full time but will use it when I can get back to the coach.

As to the question of the transmission operating by air, with the exception of the retarder, it is, as far as I know, electronically operated.


I skimmed the diagnostic manual.  Yup!  The computer controls all of the operations in the transmission.  I guess it's told you "Sorry Bob, but I can't do that."

Heed the anti static warning.  Once you start unplugging things an errant spark has the potential to cause you much heart ache.

FWIW I cleaned the centrifugal oil filter in my 1968 SIATA this morning.  I am ready for the robot apocalypse.

Something useful?  This is the stuff for cleaning electronic connections:

DeoxIT D-Series page with shop - CAIG

I used to have a friend who was in love with 60s Lincoln convertibles. . . .
1992 Foretravel Grand Villa
U225 SBID Build No. 4134
1986 Rockwood Driftwood
1968 S.I.A.T.A. Spring
1962 Studebaker Lark
1986 Honda VF700C
1983 Honda VF750C
Charlie, the Dog was broken out of jail 24 Oct 2023
N1RPN
AA1OH (H)e who must be obeyed.

Re: Engine Will Not Turnover

Reply #9 –
When I had my blank transmission pad problem earlier this year, the engine would start, but of course I could not shift the transmission.  Problem was a bad ground for the Transmission ECU.  No one seems to know where the ground is, so the mechanic spliced in a second ground and that solved the problem.  Since your engine does not start, have you checked the cables to the starter, maybe remove clean and reconnect, as well as give the solenoid on the starter a rap with a hammer.  Worth a try maybe.
Jerry Whiteaker former owner 96 U270  36' #4831 Austin,TX-Owner Mods LCD TV w/front cabinet rebuild - LCD TV bedroom - Dual Central AC, either can cool coach w 30 amp - Skylights at roof AC openings - Drop ceiling for ducting of AC - Shower skylight white gelcoat/wood/epoxy frame - Air Springs/Shocks replaced - 2014 CRV - 8K Home Solar - Chevy Volt

Re: Engine Will Not Turnover

Reply #10 –
Just as a test, unplug the neutral safety switch relay and use a piece of wire to connect the 2 wires together.  On my the relay is the third one from the bottom on the panel in front of the passenger.  On my you connect the large yellow wire to a smaller purple one.  I have a problem with mine and have jumped it out for good.  The engine should start.  The allison will be in neutral when key is first turned on.  If no engine crank, you got other problems also.
Pat/Blue Angel
1995 U240 36ft
MC# 16511
Build# 4653

Re: Engine Will Not Turnover

Reply #11 –
Back up and running. Thanks to all for the help.

Had shift pad replaced by Steward & Stevenson, 214.631.5370, 1631 Chalk Hill Rd, Dallas, TX 75212 . Road service tech Patrick Gentry brought a new shift pad with him. He was great and took time to explain what the Allison software was telling him.

Before calling in road service talked to James at FOT, Used attached diagram A-7212: tried unplugging shift pad and then ECU, confirmed there was power and ground to ECU unit (gray cable pin 1 and 16 had power, pins 17 and 32 had good ground),  also jumped neutral relay R-6 (pins 85 and 86), engine would not start.

ECU unit is in the pass-through bay on driver's side on the back wall. Unit is labelled ECU but Allison now calls them TCU.

There is no VIM box for the transmission because Foretravel wired the ECU and shift pad direct. The relays including the R-6 neutral relay along with the power breakers are on the panel in front of passenger seat. The ground and power both come directly from the battery terminals in the engine battery bay on rear passenger side.

Bob and Phyllis
2000 U-270 WTFE
34' Build 5659

Re: Engine Will Not Turnover

Reply #12 –
Bob,
Are you going to have the old shift pad repaired and have a spare? 
John does first class work.  Several here have used his service
Transmission Instruments

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."
 

Re: Engine Will Not Turnover

Reply #13 –
Yes, we plan on having it rebuilt. Thanks for the link.
Bob and Phyllis
2000 U-270 WTFE
34' Build 5659