Silverleaf and DDEC 2

[Ace]

Okay after multiple test on the road, not to mention phone calls to Silverleaf, shipping the unit back to Silverleaf, emails to and from and more phone calls than I can count, it has been determined that my Sliverleaf VMS 120 is not and was not manufactured to work with MY ECM due to it being a 1992 model. Apparently, there are or were 2 versions of DDEC 2, one old and one newer version. Guess which one I have! Right the older version but, it CAN be updated to the newer version at the cost of 100 bucks and a 50 buck core charge for a small chip and the clip that actually holds it in the ECM. Now granted this MIGHT be a fix for allowing my VMS 120 to work but again, it puts the added cost even higher! NOT what I wanted hence the lesser expensive model.

My question is, IF I were to happen across a known DDEC 2 ecm that HAS been upgraded is this a simple R&R and what if the ecm I presently have is rated at 450hp and the older (upgraded) one at 500 hp what should I expect in different performance such as, will my engine (8v92) run hotter? Will it have better acceleration and or cruising speed? What about fuel mileage, more, less or about the same? My coach weighs approx., 40k lbs where as the one the upgraded ecm came from that used the same 8v92 weighed in at a whopping 53k lbs. and he was getting close to what I am presently getting.

As for upgrading my VMS 120 to a VMS 240 (better model) they tell me that would make NO difference since the 240 uses the same software as the 120. It all has to do with working with or not working in my case with the ecm I have which has NOT been upgraded!

I only wish I would have known about having to have my ecm upgraded to make this monitoring tool work before I purchased it but I guess out of the 3-400 users of these units that are running Detroits, only a few of them have complained! 

Thanks...

[stevet903]

There's not a lot of info out there, or people who know much about the inner workings.  DD seems to keep the info pretty close to their chest....   So here's my two cents from what I've been able to find out, guess, and learn from experience.  You need an 8v92 ECM that is either part number 7570050-154, R7570050-154 (rebuilt) or a DDEC II ECM that has the prom upgrade to 154 to get the Silverleaf products to work correctly.   (6v92 ECM is part number 7570049-xxx) In addition, the Silverleaf product has to be programmed specifically to work with a DDEC II ECM to get the MPG and trip miles (It has to look at PID 244 to get the odometer reading from the ECM).

In your case, you can replace the PROM in your ECM to get the 154 version and get your Silverleaf working.  It involves taking the ECM off of the engine, removing the bottom cover, replacing the PROM and the installation is the reverse of the removal....  The hard thing is removing the tiny bolts holding the cover on without breaking them after corroding for the last 18 or so years.

As for a replacement ECM, it may or may not work in your application.  It will definitely run the engine, but each ECM is specifically programmed from the factory with vehicle specific HP/torque settings, and more importantly, the vehicle specific wiring mapping to the pins on the ECM.  This could include cruise control, coolant level sensors, fire truck pump pressure sensor, PTO controls, etc.  If you got a 500 hp ECM, your local friendly DD dealer could reprogram it to your engine serial number which would restore the correct wiring mapping, but it would also restore your current HP setting.  They usually charge about $100 to do this.  They can up the HP as well, but I have heard that due to the EPA and smog laws, it's difficult to find a dealer to up the HP.  Telling them that it is a motor home instead of a commercial bus may help.

As for the 50 hp difference, I've never done the change so I don't know, but I'd expect that you probably wouldn't see much of a difference in performance or economy. (The change from a 27 sec 0-60 time to a 25 sec time isn't really noticeable, where and extra 50 hp in a car that changes it from 7 sec to 6 is very noticeable.)
Steve

[luvrbus]

Ace, 50 hp is not going to cause you any heating problems you will go from 1425 ft lbs torque on the 450 hp to a little over 1500 lbs on the 500 hp.
Be sure if you do the hp upgrade your engine has the 4775 injectors and the TV 8513 turbo with a A/R of 1.39 if you have the TV 8513 with a A/R of 1.23 it will be good on the low end torque but it will lose it on the top end torque and that is where you need it most for cruising


good luck

[Ed Hackenbruch]

It sounds to me like the simplest thing to do is spend the $150 and hope that puts an end to your problems. Reading about all of the crap you guys go thru with all of this electronic junk makes me sooooo glad that my bus is mechanical   Good luck with this.