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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: gyoder on March 02, 2013, 11:00:08 AM



Title: 92 Prevost DDEC 2
Post by: gyoder on March 02, 2013, 11:00:08 AM
can a bad ECU in a ATEC Allison transmission keep a 8V92 DDEC II in a 1992 Prevost from starting,
   I am working on a coach for a friend, he put batteries on it and crossed the terminals, it has not started since, it will turn over but not start, someone told me the transmission will keep it from starting,, we pulled the codes from the ECM and it is not setting any codes, it is communicating good, I don't have a card to read the ECU of the transmission,,,,,,,, i am at my end with this thing


Title: Re: 92 Prevost DDEC 2
Post by: luvrbus on March 02, 2013, 11:22:45 AM
2 fuses 1 from each head check those


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 02, 2013, 12:18:42 PM
I have looked for those 2 fuses and looked in the book, can you give me a clue to where they may be?


Title: Re: 92 Prevost DDEC 2
Post by: dickegler on March 02, 2013, 12:42:02 PM
I have a 92 prevost and the ddec fuses are located in the rear electrical junction box above the engine.  They are resettable circuit breakers.



Title: Re: 92 Prevost DDEC 2
Post by: Ace on March 02, 2013, 03:55:27 PM
Mine are located right on top of the start batteries. One for each head of injectors.
Problem is, I had one blown and mine still started! Didn't run for crap but it still started! Doubt those two fuses are your problem. There are other circuit breakers but each coach location is different such as XL,  le mirage, and H


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Title: Re: 92 Prevost DDEC 2
Post by: robertglines1 on March 02, 2013, 04:32:36 PM
See you are new to board. The more you share the more people will answer. general location and first name would be start. prevostcar web site:  go to wiring diagrams: from your serial number use last letter and last 4 digits =will give you diagram specific to your coach.  More info better from you the better.   Bob


Title: Re: 92 Prevost DDEC 2
Post by: luvrbus on March 02, 2013, 05:14:34 PM
If it is turning over as you say the transmission has nothing to do with it, you have no power to the injectors is the problem could be a bad sensor by pass each sensor and see if it fires are you sure the guy hooked the leads up after changing batteries ? 
Those are 12v only if he gave it a 24v jolt then it will be the fuses


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 02, 2013, 07:35:02 PM
I finally found the in-line fuses above the batteries, they are good, there is good voltage coming to the ECM, we pulled the codes out of it and all is good, its not setting a code.
 this coach has 82,000 on it and it hasn't cranked since 08, the gentleman that owns it isn't able to drive anymore, he had a guy put batteries on it and he put one battery on backwards causing a reverse voltage spike and it hasn't hit a lick since. I called a ECM place and he told me that an ECM can communicate but still not send power to the injectors.

 I am an eagle owner, i built mine from scratch in the late 90s and have put 300,000 miles on it, it is a model 05 1969, this is my first experience working with a DDEC


Title: Re: 92 Prevost DDEC 2
Post by: robertglines1 on March 02, 2013, 07:45:14 PM
ck this: curb side rear bay, see if there is a separate switch on the ceiling that needs to be turned on also. Also a reset button on it.  Also ck fuel pressure switch left rear side of engine for loose wire.  Also low coolant will let it crank but not start. Level must be above level of sensor located thru and above left rear engine door-look up.  ???orignal seated coach?? converter??  xl??   ck fuse holders for corrosion.   Bob


Title: Re: 92 Prevost DDEC 2
Post by: PCC on March 02, 2013, 10:35:50 PM
It is possible that the ECM can fail, preventing the engine from starting.

It happened to me, so, after checking fuses, and power to the ECM was able to rule out everything else, and it was the ECM.


Title: Re: 92 Prevost DDEC 2
Post by: stevet903 on March 03, 2013, 06:28:40 AM
Turn the key on, do the Check Engine and Stop engine lights come on for about 10 seconds and then go off?  When it stops, is the stop engine light on?  If they come on and go out, it means that you have power to the DDEC system, and there are no codes.  If the lights stay on for 20 or 30 sec and then go out, you have a historical code.   If the stop engine light is on when it stops (or it doesn't start and the light is on), the DDEC system has shut it down.  There are three things that will shut you down -
Code 43, Low Coolant, Code 44, Oil or coolant high temperature,  or code 45, Low oil pressure.
The transmission ECU should not affect the ability of the engine to start.

Do you get any smoke while cranking?  If it hasn't run since 2008, I'd put new filters on and be sure they are full of fuel and the engine is primed. 




Title: Re: 92 Prevost DDEC 2
Post by: expressbus on March 03, 2013, 08:47:13 AM
Going to the bus barn this afternoon. I'll take a picture of a relay that kept mine from starting spring a year ago. The engine would turn over and produce whitish smoke but would not fire. The relay (mechanical) is inside the large electrical box attached at the rear of the engine bay. It is on the left hand side of the box in a row of relays. On mine it was the center relay that a friend tapped while I was turning the engine over and it fired right up.

I'm hoping that is the problem with the coach you are looking at but I can't say a gentle persuasion tap will free your stuck relay. You might have to get a new one from NAPA.



Title: Re: 92 Prevost DDEC 2
Post by: Ace on March 03, 2013, 03:00:28 PM
Ok great, you found the two fuses laying on top if the batteries and you say they are good! How did you check them? If you made the mistake I made by merely looking at them, then please take a volt meter and on top of each fuse there are test holes where you can check to see if  voltage is in fact crossing the fuse. Mine looked good but one fuse was blown and looking at it I couldn't tell because the break was way down below the bottom and very very hard to see! Check them with a volt meter to absolutely sure!


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Title: Re: 92 Prevost DDEC 2
Post by: expressbus on March 03, 2013, 03:48:32 PM
gyoder,

Here are two pictures taken this afternoon at the bus barn. One shows two relays, the other the location of the relays. The relay in the black plastic case is the one that was keeping my 8V92 from starting spring one year ago. The relay in the metal case is an original relay since they supposedly do not come with a metal case anymore. The relays are inexpensive and available from NAPA and most likely other parts houses. Having experienced the condition you speak about when the coach sat for 4-6 weeks I'm thinking that the coach you are looking at could easily have a hung relay. I was told they control something to do with the setting of the fuel racks timing but don't hold me to that.

Just sayin' ...



Title: Re: 92 Prevost DDEC 2
Post by: wg4t50 on March 03, 2013, 04:02:35 PM
In our experience, not DDEC, but Cummins electronic engine and control systems, when someone connects the DC reversed, you will have at least blown fuse, smoked diodes, and from there is get real costly.  As said, don't know the DDEC, but other computers do not like reversed DC, also most likely took out the battery belt driven alternator too.
ALways fun and expensive games when you see things arcing :o
Dave M


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 03, 2013, 04:25:07 PM
ck this: curb side rear bay, see if there is a separate switch on the ceiling that needs to be turned on also. Also a reset button on it.  Also ck fuel pressure switch left rear side of engine for loose wire.  Also low coolant will let it crank but not start. Level must be above level of sensor located thru and above left rear engine door-look up.  ???orignal seated coach?? converter??  xl??   ck fuse holders for corrosion.   Bob

didn't find a switch, checked the fuel pressure wire,, the coolant sensor was setting a code so I replaced it but still will not start,, it is a converted coach,, [country coach] check all the fuse holders and no corrosion, I pulled the ECM to send it off to get it checked

thanks,,


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 03, 2013, 04:31:01 PM
If it is turning over as you say the transmission has nothing to do with it, you have no power to the injectors is the problem could be a bad sensor by pass each sensor and see if it fires are you sure the guy hooked the leads up after changing batteries ? 
Those are 12v only if he gave it a 24v jolt then it will be the fuses
I have a friend that has scanner and he bi passed  all the sensors and still no go, yes I re-hooked the batteries and they are correct now,,


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 03, 2013, 04:35:32 PM
Turn the key on, do the Check Engine and Stop engine lights come on for about 10 seconds and then go off?  When it stops, is the stop engine light on?  If they come on and go out, it means that you have power to the DDEC system, and there are no codes.  If the lights stay on for 20 or 30 sec and then go out, you have a historical code.   If the stop engine light is on when it stops (or it doesn't start and the light is on), the DDEC system has shut it down.  There are three things that will shut you down -
Code 43, Low Coolant, Code 44, Oil or coolant high temperature,  or code 45, Low oil pressure.
The transmission ECU should not affect the ability of the engine to start.

Do you get any smoke while cranking?  If it hasn't run since 2008, I'd put new filters on and be sure they are full of fuel and the engine is primed. 

we have full power to the ECM system and no codes,, no smoke when cranking,, we put all new filters and I have an electric pump hooked to the fuel feed and took the return line back into the container and let it pump and circulate new diesel for 30 minutes



Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 03, 2013, 04:37:25 PM
Going to the bus barn this afternoon. I'll take a picture of a relay that kept mine from starting spring a year ago. The engine would turn over and produce whitish smoke but would not fire. The relay (mechanical) is inside the large electrical box attached at the rear of the engine bay. It is on the left hand side of the box in a row of relays. On mine it was the center relay that a friend tapped while I was turning the engine over and it fired right up.

I'm hoping that is the problem with the coach you are looking at but I can't say a gentle persuasion tap will free your stuck relay. You might have to get a new one from NAPA.



thanks


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 03, 2013, 04:39:08 PM
Ok great, you found the two fuses laying on top if the batteries and you say they are good! How did you check them? If you made the mistake I made by merely looking at them, then please take a volt meter and on top of each fuse there are test holes where you can check to see if  voltage is in fact crossing the fuse. Mine looked good but one fuse was blown and looking at it I couldn't tell because the break was way down below the bottom and very very hard to see! Check them with a volt meter to absolutely sure!


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I took the the holder apart and just looked at them,,i will go back and check them with a volt meter
 Thanks,,


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 03, 2013, 04:44:35 PM
gyoder,

Here are two pictures taken this afternoon at the bus barn. One shows two relays, the other the location of the relays. The relay in the black plastic case is the one that was keeping my 8V92 from starting spring one year ago. The relay in the metal case is an original relay since they supposedly do not come with a metal case anymore. The relays are inexpensive and available from NAPA and most likely other parts houses. Having experienced the condition you speak about when the coach sat for 4-6 weeks I'm thinking that the coach you are looking at could easily have a hung relay. I was told they control something to do with the setting of the fuel racks timing but don't hold me to that.




Just sayin' ...




Is there some tester I can buy to check these relays? Or do I just go and start replacing them?


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 03, 2013, 04:46:24 PM
In our experience, not DDEC, but Cummins electronic engine and control systems, when someone connects the DC reversed, you will have at least blown fuse, smoked diodes, and from there is get real costly.  As said, don't know the DDEC, but other computers do not like reversed DC, also most likely took out the battery belt driven alternator too.
ALways fun and expensive games when you see things arcing :o
Dave M

Thanks Dave,, I have checked everything I can visually without replacing all the relays, yesterday i pulled the ECM and I am sending it off to get it checked


Title: Re: 92 Prevost DDEC 2
Post by: robertglines1 on March 03, 2013, 04:54:55 PM
We are just passing on problems members or ourselves have had. One member had new fuses there and the problem was in fuse holder. New fuses are cheap. If you want to try the prevostcar web site  use K-747 # that is a universal # that should get you to 8-v92 wiring of that vintage. I think I might have a book at shop if I get up that way I'll check Look for a vanner and see if your ddec feed is fed off it. Sometimes if polarity is reversed the breaker on vanner is tripped.   No reason for that but it has  happened . Do wish you luck with your venture.   Bob


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 03, 2013, 05:10:49 PM
We are just passing on problems members or ourselves have had. One member had new fuses there and the problem was in fuse holder. New fuses are cheap. If you want to try the prevostcar web site  use K-747 # that is a universal # that should get you to 8-v92 wiring of that vintage. I think I might have a book at shop if I get up that way I'll check Look for a vanner and see if your ddec feed is fed off it. Sometimes if polarity is reversed the breaker on vanner is tripped.   No reason for that but it has  happened . Do wish you luck with your venture.   Bob

Thanks


Title: Re: 92 Prevost DDEC 2
Post by: robertglines1 on March 03, 2013, 05:40:36 PM
wiring diagram   prevostcar site    wiring diagram  use unit # L-1685  was delivered to converter's  Should be close to yours.  Bob


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 03, 2013, 06:48:48 PM
I have just found a relay tester, I have wanted one for a long time and this is a good time to get one

 ESI 190 Electronic Specialties 190


Title: Re: 92 Prevost DDEC 2
Post by: robertglines1 on March 03, 2013, 08:35:50 PM
Basic ck: switch position   front key on    rear engine compartment  panel  toggle switch  has three settings   rear  off   front   if starting from rear front must also be on. center position on rear toggle kills system all together.  Not trying to insult your knowledge just sometimes we miss the simple.   Bob


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 04, 2013, 07:14:30 AM
Basic ck: switch position   front key on    rear engine compartment  panel  toggle switch  has three settings   rear  off   front   if starting from rear front must also be on. center position on rear toggle kills system all together.  Not trying to insult your knowledge just sometimes we miss the simple.   Bob

 you never insult my knowledge by trying to help

Thanks,,,,


Title: Re: 92 Prevost DDEC 2
Post by: Gerry H on March 05, 2013, 07:33:15 AM
Hello: Just a thought, but seems everyone is committed to an electrical problem due to various things happened or happening.
Diodes are typically engineered into the systems to prevent reverse voltage damage. Is it possible that it's a lack of fuel issue? Just following along. Good Luck Gerry H


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 05, 2013, 10:10:01 AM
Hello: Just a thought, but seems everyone is committed to an electrical problem due to various things happened or happening.
Diodes are typically engineered into the systems to prevent reverse voltage damage. Is it possible that it's a lack of fuel issue? Just following along. Good Luck Gerry H

I changed all the filters then hooked an electric fuel pump to the system, I disposed of the original fuel then I connected the return back into the container of new fuel and let it circulate for 30 minutes until I were sure that all of the air was out of the system.
  The mechanic that was working on this project before me cranked it on starting fluid. This tells me we have a fuel/injector problem. I pulled the computer and its getting checked out. Thanks 


Title: Re: 92 Prevost DDEC 2
Post by: B_K on March 05, 2013, 11:10:15 AM
OK 2 things here.

I had one once that had some old inline fuse holders and once in a while they'd lose connection if I hit a bump just right or something.
I'd just be going down the road and it'd either start running bad or just die.
Get out pull fuses out stick 'm back in and it'd run fine for who knows.

Also once in a great while I'd to to start it and it's just crank and crank. Again play with fuses and it'd fire right up!

Got tired of fooling with it and replaced both fuse holders and never had another problem with it!

Also I have reconditioned DDEC II ECM (new never used after being rebuilt by DD) available if you are interested. (it was a spare and we don't run the 8V92's anymore!)
;D  BK  ;D


Title: Re: 92 Prevost DDEC 2
Post by: tomhamrick on March 05, 2013, 12:44:50 PM
What do you have to have for that?


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 05, 2013, 06:36:14 PM
OK 2 things here.

I had one once that had some old inline fuse holders and once in a while they'd lose connection if I hit a bump just right or something.
I'd just be going down the road and it'd either start running bad or just die.
Get out pull fuses out stick 'm back in and it'd run fine for who knows.

Also once in a great while I'd to to start it and it's just crank and crank. Again play with fuses and it'd fire right up!

Got tired of fooling with it and replaced both fuse holders and never had another problem with it!

Also I have reconditioned DDEC II ECM (new never used after being rebuilt by DD) available if you are interested. (it was a spare and we don't run the 8V92's anymore!)
;D  BK  ;D

What year model prevost do you have? I found 1 in-line fuse holder and its coming off of the 24v battery disconnect, it has voltage going through it and I cant find any other in-line fuse,, several people have mentioned fuses between the ECM and the heads but I can't locate them.
  How risky is it changing ECMs from vehicle to vehicle without getting them re programed?
  What did that rebuild cost you from DD?


Title: Re: 92 Prevost DDEC 2
Post by: expressbus on March 07, 2013, 04:32:16 PM
Bob,

My coach is about the same vintage as gyoder's. I can start from the rear without having the front key in the on position. I did it a couple of times just this week when the rear radiator hose blew off the piping. What I can't do is start it from the front if I leave the switch on the side of my 24 volt electrical panel in the rear position. Also, the toggle switch does not get used very often. I tried to rear start 4-5 years ago, successfully, then restored the toggle to the front position. Darn think would not start. I called a friend in Chicago and was advised to flip that flipping toggle from top to bottom and back again "vigorously." I did and she started right up.

Just sayin' ...


Title: Re: 92 Prevost DDEC 2
Post by: robertglines1 on March 07, 2013, 04:49:39 PM
Hopefully we will hear back to his successful outcome. A electrical ghost is the most difficult to find. I can understand the working of the switch --sort of cleans contacts off.  Have a friend fighting a lightning strike now.  Every-time he gets it running something else come up.  2004 MCI.  I can't even suggest to him where to start. He has had it to the pro's and they keep changing parts.  Best of luck and please do post outcome so we all may learn.   Bob


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 09, 2013, 04:50:01 PM
Hopefully we will hear back to his successful outcome. A electrical ghost is the most difficult to find. I can understand the working of the switch --sort of cleans contacts off.  Have a friend fighting a lightning strike now.  Every-time he gets it running something else come up.  2004 MCI.  I can't even suggest to him where to start. He has had it to the pro's and they keep changing parts.  Best of luck and please do post outcome so we all may learn.   Bob
This prevost will turn over but not fire the injectors,

I pulled the DDEC ii ECM and sent it off to have it checked and the circuit board is toasted in it, so I feel really confident I have found the problem.
 Thanks,,


Title: Re: 92 Prevost DDEC 2
Post by: luvrbus on March 09, 2013, 04:59:30 PM
Just remember the DDEC11 is 12v make sure it is a 12 v supply they do not like living in a 24v world what are you calling toasted most the time it is the clock or battery


Title: Re: 92 Prevost DDEC 2
Post by: robertglines1 on March 09, 2013, 05:27:08 PM
Triple ck battery install and feed.  12 volt is very important!! If someone has them out of order your still in trouble.  Do you have the 4 group 31 install?(My 89 did)  Is your wiring diagram still on back of door? Triple ck since you didn't do it yourself. Now you will be the go to Batt hook up guy.   Bob


Title: Re: 92 Prevost DDEC 2
Post by: rv_safetyman on March 09, 2013, 05:38:47 PM
Detroit has an upgrade kit for conversion from DDEC II to DDEC IV.  The kit is detailed here:

http://www.ddcsn.com/cps/rde/xbcr/ddcsn/18SP546Rev.pdf (http://www.ddcsn.com/cps/rde/xbcr/ddcsn/18SP546Rev.pdf)

The bulletin says that it is for Series 60.  My thought is that it would also be valid for any DDEC II.  Mark Renner checked and was told that it was only for Series 60.

Maybe someone who has direct knowledge can chime in.

If the conversion would work for your engine, it would probably be worth it since you have to buy an ECM anyway.

Jim


Title: Re: 92 Prevost DDEC 2
Post by: luvrbus on March 09, 2013, 05:57:35 PM
Should be easy to upgrade a 11 to a IV for the 92 series, some 92 series were the DDEC IV up grading from the I requires different cams, 2 cylinders short on that one Jim and the way the DDEC reads the firing order on a 8v92 is crazy it confuses me big time after all the years fooling with the mechanical 8v92  

You probably know a DDEC ECM is good up to 8 cylinders then like on a V12 it takes 2 ECM's to make that puppy run double the trouble


Title: Re: 92 Prevost DDEC 2
Post by: Sam 4106 on March 09, 2013, 06:30:43 PM
When I had to replace my ECM last sumer on my DDEC II 8V92 I asked about upgrading and was told that it would work for a series 60 but not an 8V92. For whatever thats worth. Interstate Detroit Diesel in Sioux Falls, SD had an ECM for a 6 cylinder that they tried on my engine and my engine would barely move the bus. They had to order the correct ECM for my engine. So, I would be very skeptical that a DDEC II ECM could be upgraded to a DDEC IV for an 8V92. But, I've been wrong many times, just today, ask my wife. LOL

Good luck, Sam


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 09, 2013, 09:57:17 PM
Triple ck battery install and feed.  12 volt is very important!! If someone has them out of order your still in trouble.  Do you have the 4 group 31 install?(My 89 did)  Is your wiring diagram still on back of door? Triple ck since you didn't do it yourself. Now you will be the go to Batt hook up guy.   Bob

I have a wire diagram from prevost and I have them correct now


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 09, 2013, 10:00:53 PM
When I had to replace my ECM last sumer on my DDEC II 8V92 I asked about upgrading and was told that it would work for a series 60 but not an 8V92. For whatever thats worth. Interstate Detroit Diesel in Sioux Falls, SD had an ECM for a 6 cylinder that they tried on my engine and my engine would barely move the bus. They had to order the correct ECM for my engine. So, I would be very skeptical that a DDEC II ECM could be upgraded to a DDEC IV for an 8V92. But, I've been wrong many times, just today, ask my wife. LOL

Good luck, Sam
What is the gain by upgrading to a IV? is it better milage, power, performance?


Title: Re: 92 Prevost DDEC 2
Post by: robertglines1 on March 10, 2013, 07:15:39 AM
B_K  Offer up one for your engine. good trusted member here. Might ck it out.  Bob


Title: Re: 92 Prevost DDEC 2
Post by: PCC on March 15, 2013, 04:56:37 AM
Voltage sensitive - that is the killer of DDEC ECMs.

Make sure you have enough voltage, and not too much.

That is what I have learned, from experience.

I now start my genset (wired to charge my main batteries), if I have left the vehicle alone for any length of time, to be sure that the ECM gets full 12V.

It is worth the cost of fuel to make sure the volts are all there.


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 15, 2013, 08:51:35 PM
Voltage sensitive - that is the killer of DDEC ECMs.

Make sure you have enough voltage, and not too much.

That is what I have learned, from experience.

I now start my genset (wired to charge my main batteries), if I have left the vehicle alone for any length of time, to be sure that the ECM gets full 12V.

It is worth the cost of fuel to make sure the volts are all there.

thanks, I had Diesel ECM in Dallas rebuild my ECM and I am going o install it tomorrow and start this beast tomorrow


Title: Re: 92 Prevost DDEC 2
Post by: luvrbus on March 16, 2013, 06:14:47 AM
So can we presume the DDEC II got a taste of 24v ? or did the clock battery go dead from setting so long without power


Title: Re: 92 Prevost DDEC 2
Post by: gyoder on March 18, 2013, 04:44:25 PM
So can we presume the DDEC II got a taste of 24v ? or did the clock battery go dead from setting so long without power

It never set a code and it was still readable but when the guy put the battery on backwards he spiked the ECM , I had it rebuilt and she fired up, but I have a world of illness with this one, the spike also get the alternator, I am replacing it and going one step at a time in replacing stuff the spike got.


Title: Re: 92 Prevost DDEC 2
Post by: Electman on April 11, 2013, 02:45:15 PM
DDEC II can be upgraded to DDEC III, no DDECIV available for a coach 8V92. The down side is DDECIII inability to comunicate with the ATEC1 (CEC) transmission controls.
The right way to upgrade is to upgrade the transmssion to a WTECIII controlled HD 6 speed and the engine to a DDECIII, which will comunicate and give you optimum performance.
Just completed one, results where awesome!


Title: Re: 92 Prevost DDEC 2
Post by: Sam 4106 on April 11, 2013, 04:57:04 PM
Electman,

What does it take to upgrade an 8V92TA DDEC II to a DDEC III? When I had to replace my DDEC II ECM last summer I asked about an upgrade and was told by Interstate Detroit Diesel in Sioux Falls, SD that it couldn't be done. Then again at Interstate Detroit Diesel in Fargo, ND I was told the same thing. How did you do it? I have an Allison 740 transmission so no electronics there.

Thanks, Sam


Title: Re: 92 Prevost DDEC 2
Post by: luvrbus on April 12, 2013, 05:32:16 AM
There is no need to upgrade Sam unless you are going to one of the newer electronic transmission but you can upgrade your 8v92 to a DDEC lV if that is what you want it will cost you a new ECM


Title: Re: 92 Prevost DDEC 2
Post by: Sam 4106 on April 12, 2013, 06:12:21 AM
Clifford,

I don't want to upgrade now, but as long as I had to replace my ECM last summer anyway, that is when it would have been practical to upgrade. But, I was told twice that I couldn't. That is why I asked how Electman did it. From reading another post of his, I think he upgraded by changing both the engine and transmission as a package. I hope he responds to my question so I can know for sure.

Thanks, Sam


Title: Re: 92 Prevost DDEC 2
Post by: muldoonman on April 12, 2013, 06:33:28 AM
What would be the advantage of upgrading the ecm's on an older (91/92) 8v92 with the 755cr?


Title: Re: 92 Prevost DDEC 2
Post by: rv_safetyman on April 12, 2013, 12:41:05 PM
Detroit sells a kit to convert a Series 60 DDECII to a DDECIV:

http://www.ddcsn.com/cps/rde/xbcr/ddcsn/18SP546Rev.pdf (http://www.ddcsn.com/cps/rde/xbcr/ddcsn/18SP546Rev.pdf)

I thought that the kit would also work for other DDEC engines, but apparently not.  Boomer did quite a bit of checking on his 6-71T DDEC engine and they said it would not work for his engine.

As you will see in the bulletin, you add a couple sensors and that would be of benefit. 

Kind of strange that they say it is for a manual transmission.  The DDECIV has J1922 communication that can talk to a lot of automated transmissions like my Autoshift.

If you get the latest DDECII you get most of the output data that talks to things like the SilverLeaf products.  Older DDECII units are not good about reporting speed related data.

I think that the conversion to DDECIV (if there is a way to do it) would be well worth it (assuming you had to buy an ECM anyway.  The software that controls the engine is much more sophisticated.

Jim


Title: Re: 92 Prevost DDEC 2
Post by: luvrbus on April 12, 2013, 04:02:27 PM
Sam,,unless you have a real early version of the DDEC 11 they are not that hard to upgrade to a 111 or IV, early versions of the 11 require a cam change because unlike a 60 series there is no bull gear you can change like on the early 60 series then it gets costly.

All I have been around just takes the new harness's,programing,a couple extra sensors and a new crankshaft positioning sensor ,  is yours a  Motorola ECM ? The 111 is faster and has more memory than a 11 but that is no asset for you using a 740


Title: Re: 92 Prevost DDEC 2
Post by: muldoonman on April 12, 2013, 05:35:39 PM
My 1991 8V92TA, 62,000 mile coach is running like a top. I think I'll stay with what I got till she blows.


Title: Re: 92 Prevost DDEC 2
Post by: Sam 4106 on April 12, 2013, 07:23:01 PM
Clifford,

I am not interested in changing from DDEC II to anything else at this time. My original 1990 ECM was a version 111 my current ECM is version 154. My fuel milage dropped dramatically after the ECM change, but that is also when my engine started smoking badly. The smoking problem was from a blown exhaust manifold gasket, that has been fixed. I also cut a hole in the side of the bus above the air cleaner intake to allow the engine to breath better. It will be interesting to see if the fuel mileage goes back to the previous level after I drive the bus enough to use a few tanks of fuel. 

Thanks, Sam