Author Topic: MCI-9 Transmission won't engage  (Read 80378 times)

Offline NJT5047

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Re: MCI-9 Transmission won't engage
« Reply #90 on: December 16, 2007, 10:35:33 AM »
That will help resolve the problem one way or another...rule out or prove the ECU.  Are we placing bets?  ;)
I hope that solves your problem...but, if it does, that opens another can of worms.
Hope the weather isn't killing you! 
Post the outcome!
JR
JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

Ayn Rand

Offline Stan

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Re: MCI-9 Transmission won't engage
« Reply #91 on: December 16, 2007, 12:06:15 PM »
There are pros and cons to troubleshooting with a spare unit. The pros are obvious bur the cons are that if the original unit was damaged by an external fault, the spare unit will also get damaged. Probably the most likely causes of this scenario would be getting 24 volts into a 12 volt device or a short to ground on an output.

Offline Kwajdiver

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Re: MCI-9 Transmission won't engage
« Reply #92 on: December 16, 2007, 06:22:47 PM »
Being that I have checked and doubled check the grounds and voltages, I believe it is safe to hookup the spare.
It is well known that electronic devices fail mostly on shut down or start up.

One,,,,The problem developed either, when it was shut down last time I moved it, or during startup. 

Two,,,,We know there is a ground missing that the ECU sends through the shifter pad, for the FAST Idle.  If I replace this ground with a jumper, the fast idle works fine.

I'm putting my money on the ECU.  If I'm correct, I roll out of Gulfport, Ms Wednesday.  If wrong, I fly to Tampa.

Bill
Auburndale, Florida
MCI-9
V-6-92 Detroit, Allison 5 spd auto
Kwajalein Atoll, RMI

Offline Kwajdiver

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Re: MCI-9 Transmission won't engage
« Reply #93 on: December 18, 2007, 01:20:39 PM »
 :( :( :( :( :( :( :(

Installed the loaner ECU, after changing the PROM,  no fast idle, no lights on shifter pad, and NO engaging transmission.  Really now believe it has to be in the ground circuit with the fast idle.   BUT HEY,,,,,,,,,,,,

I'm driving  (instead of flying) to TAMPA,via car, for Christmas, then will four wheel it to Arcaida for the day.   With luck I can find a MCI-9 that I can look over.

Everyone thank you for the help.   :)      I will take this back up, NEXT YEAR.

Bill   ;D
Auburndale, Florida
MCI-9
V-6-92 Detroit, Allison 5 spd auto
Kwajalein Atoll, RMI

Offline Kwajdiver

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Re: MCI-9 Transmission won't engage
« Reply #94 on: January 03, 2008, 07:00:58 PM »
Okay, here's an update.

It's cold here.... :o in Gulfport, Ms.

Dallas is spenting a few days here, to help me trace out wiring.  We found a ground wire from the shift pad that didn't seem to be grounded.  That was part of the problem with the ground to the Neutral Relay.

What I have now, is a loaner shift pad from Tom at Heartland Coach in Arcadia.  It's lights up, and I have still have "Do Not Shift".  We now think that something is telling the ECU that there is a problem.

With a loaner ECU from Ted Keating, the ECU is once again flashing codes.  Something my ECU wouldn't do.  We are getting a 21 code, which is the Throttle Sensor.

Sammy has been a HUGE help.  I've lost count how many phone calls have been made and how many pages of information Sammy has scanned and e-mail to me.  The last set along is 21 pages. 

With our new data on the Throttle Sensor Trouble shooting, supplied by Sammy,,,,,, Dallas and I, tomorrow will be looking for a Throttle Sensor problem as soon as we double check the ECU is not carrying over codes from it's last home.

Wow,,,, have I learned a lot.  Not sure how many buses I checked in Arcadia.  Sure people were wondering why I was asking everyone "What Transmission Do You Have?"  Almost everyone has a Allison 740.  I am the only one with the 741.   ??? >:(      Just my luck.  (note to self, next bus, too have 740 tranny).

Anyway,,,,,That's what happening.   

Bill

Auburndale, Florida
MCI-9
V-6-92 Detroit, Allison 5 spd auto
Kwajalein Atoll, RMI

Offline NJT5047

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Re: MCI-9 Transmission won't engage
« Reply #95 on: January 03, 2008, 08:05:34 PM »
Hi Bill, it's cold up here too!  Real cold!   :o
Is your TPS mounted on the engine?  Your code is a good start for resolving the problem.
TPS might be the whole issue. 
Once you get the transmissin working correctly, it'll probably never give any more trouble.
ATEC transmissions shift smoother than HT740s...still, as you have found, diagnosing wiring faults can be a nightmare. 
Sammy, Bill's transmission issue have scared the poop out of me.  Do you have a part number for an Allison HT748R diagnostic manual?   I have a wiring diagram, but nothing with the codes and such.  I  have a DDEC dx manual.  It's worth its weight in gold!
I believe Allison still offers the HT ATEC manuals.  However, their website only lists one "Electronic" diagnostic manual...that sounds like it would have to cover a lot of territory?
Dallas, you did move a right good bit!?  Where ya'll headed?  Tell Cat HAPPY BIRTHDAY!  ;D
Reckon this is her 29th?   
Bill, Dallas and Cat, and Sammy, stop by if ya'll ever get up this way.   JR

 
JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

Ayn Rand

Offline NJT 5573

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Re: MCI-9 Transmission won't engage
« Reply #96 on: January 03, 2008, 09:14:49 PM »
Darn, 21 code huh. Throttle sensor huh! Well if I were a fancy "computer" transmission, there is no way I would let my transmission engage until that code was cleared. How did you read that code anyway? When my atec codes out it won't shift either. I think if you go into read code mode, (how ever you did it), and then simutaniously push r/n/r/n/r/n on the pad, ( new pad $200, don't spill pop on it), that old 21 code will go away and off you will go.

You better find out how to clear these codes. Some of the electronics pulse thousands of times a minute and 21 codes are not abnormal. Changing the ECM should get you one that has no codes but the real problem here is that you don't know or have not cleared the codes and you will go broke buying parts you don't need.

 Seasonal changes cause my atec to run false codes at random and this transmission is determined to protect its self until all codes are cleared.

 If you clear the codes and go a few miles and they reset repeatedly then I would replace the throttle sensor if its always a 21 code. If all else fails, call Randy, he's an expert and has every part ever made for DDEC/ATEC on his shelf, cheap, its all he does.

I have an atec manual, but I don't think you need one.

My atec is very sensitive to any input by me. If I try to select gears it will often code out. You have to just put this trans in D and let it do its thing.

You have been down quite a while and still have a code, you must start by clearing the code.

Codes don't really mean anything is wrong in my experience. The guys in the shop call these codes hickups. Clear the code, check the fluid and keep on trucking.
« Last Edit: January 03, 2008, 09:25:26 PM by NJT 5573 »
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makemineatwostroke

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Re: MCI-9 Transmission won't engage
« Reply #97 on: January 04, 2008, 12:18:40 PM »
isn't the 21 code a high voltage problem at the throttle sensor
« Last Edit: January 04, 2008, 12:35:07 PM by makemineatwostroke »

Offline Sammy

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Re: MCI-9 Transmission won't engage
« Reply #98 on: January 04, 2008, 12:50:07 PM »
It's an ATEC code, not WTEC.
There is no sub code like WTEC has, only complains that TPS signal is out of range.
Sammy  8)

makemineatwostroke

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Re: MCI-9 Transmission won't engage
« Reply #99 on: January 04, 2008, 01:22:17 PM »
Sammy,sorry i should remember that its a 741 Bill has been working on for 2 mos and I my condolence goes out to him
« Last Edit: January 04, 2008, 01:24:47 PM by makemineatwostroke »

Offline Sammy

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Re: MCI-9 Transmission won't engage
« Reply #100 on: January 04, 2008, 01:36:13 PM »
 :), lol
Yes, it has been a struggle.
He finally has a hard code (with the loaner ECU), now almost finished troubleshooting it.
Regards,
Sammy
« Last Edit: January 04, 2008, 01:38:55 PM by Sammy »

Offline Kwajdiver

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Re: MCI-9 Transmission won't engage
« Reply #101 on: January 04, 2008, 03:18:38 PM »
Guys,

I've cleared the codes.  The ECU kept flashing the 21 code

Dallas and I ran through all the Throttle Position Sensor Trouble Shooting Guide. The item that looks to be a problem is the TPS (Throttle Position Sensor) itself.

Being as it was almost 4pm CT, I started calling parts places out west.  I had hope to get one out to me,  TODAY...

John Allen of Bus Service, Inc, in Kansas, had a TPS ($155.00) on the shelf and was trying to get it out today.  If not, he will be able to ship it tomorrow.

IF the new TPS corrects the problem, I will install my ECU and see if it works.

That's all the news that is the news from Gulfport, MS.

Bill
Auburndale, Florida
MCI-9
V-6-92 Detroit, Allison 5 spd auto
Kwajalein Atoll, RMI

Offline Kwajdiver

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Re: MCI-9 Transmission won't engage
« Reply #102 on: January 10, 2008, 06:22:23 PM »
Update,,,,

Have the new TPS (Throttle Position Sensor).  A little trouble removing the old one, due to rusted bolts in the block that holds the TPS cable.  Have it soaking, hope to get back to it tomorrow, weather permitting.  If not, will be Saturday.

Hope this fixes the problem, will have to roll out of Gulfport soon.  I have accepted a new job with Raytheon in St. Petersburg, that I start Feb 4th.

Bill
Auburndale, Florida
MCI-9
V-6-92 Detroit, Allison 5 spd auto
Kwajalein Atoll, RMI

Offline NJT5047

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Re: MCI-9 Transmission won't engage
« Reply #103 on: January 10, 2008, 06:39:59 PM »
PB Blaster is good stuff.  So's a heat wrench if you can use it without burning the coach.   Even heating the bolt heads and letting them cool will often cause them to loosen.  Definitely help wick up chemicals. 
Is Dallas and Cat still down there? 
Waiting for outcome!   JR    8)
JR Lynch , Charlotte, NC
87 MC9, 6V92TA DDEC, HT748R ATEC

"Every government interference in the economy consists of giving an unearned benefit, extorted by force, to some men at the expense of others.”

Ayn Rand

Offline Kwajdiver

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Re: MCI-9 Transmission won't engage
« Reply #104 on: January 10, 2008, 06:43:52 PM »
Thanks JR,

Dallas and Cat, moved East to Florida, I think.  Dallas help me, go through the wiring.  Would have taken me forever, by myself.

Bill
Auburndale, Florida
MCI-9
V-6-92 Detroit, Allison 5 spd auto
Kwajalein Atoll, RMI