heip 8v92 ddec2

[rv_safetyman]

Just a bit of clarification on DDEC II.  The data port is an OBD2 configuration.  However, as Clifford points out, OBD2 is a different computer protocol.  DDEC uses SAE J1708 protocol.

The OBD2 reader should not be able to read the codes since it is looking for a different data stream.  That said, Clifford has made it work, but I can't figure out how. 

I am pretty sure that the OBD2 reader will not give you information on what the sensors are reporting.

Bottom line, don't rush out and buy an OBD2 reader thinking it will replace a ProLink or DDDL software.  Clifford says that, but I wanted to make sure that there is no confusion.

Jim

[luvrbus]

My OBD2 reads J1708,1587,1922,1939 and others BMW is J1708 and I think M/B is also ?

good luck

[bevans6]

Just because I'm interested, I looked up this:  It says that J1708 is a physical interface only.  So I wondered what data protocol DDEC uses?

OBDII Bus Description

OBD2 [On-Board Diagnostics II] defines a communications protocol and a standard connector to acquire data from passenger cars. It was required by U.S. EPA on all gasoline powered cars and light duty trucks manufactured for the U.S. after 1996 to help monitor/inspect vehicle emissions.
OBDII will light a lamp called a MIL (malfunction indicator lamp), also known as the "check engine" light on the dash.
The OBD-II standard allows for multiple electrical interfaces, which complicates the hardware used to interface with the vehicle. OBDII data as defined by the SAE J1979 standard
For a detailed description, Engineering Data, and circuit Interface implementation; see the OBDII Bus page.
   
OBDII to 15-pin Dsub Cable
OBDII Cable

{Automotive Buses Index}
SAE J1708 Bus Description

Serial Data Communications Between Microcomputer Systems in Heavy-Duty Vehicle Applications. J1708 defines the physical layer only. J1708 uses the RS485 bus as the electrical layer.
The cable is a 2-wire 18 AWG wire with a maximum distance of 40 meters. Class A operating to 9600bps. A message starts with a Message Identification Character [MID], followed by Data characters and then a checksum.
The total message length is 21 or less characters. Each character is 10 bits, each character begins with a Start bit [logic low].

[jimsflx]

wow,you are losing me know. put new batteries in 8d it cured the starting problem started instantly then shut off 2 minutes we unplugged the sensors and by passed them,we found a wire in the engine bay leftside that was loose .it controled the alternater. fixid that so calling mci tomorrow to get electric schematic. really a pane in the a&&. thanks jim

[Rick 74 MC-8]

Maybe too simple. Does his coach have a rear set of switches for start and run. I know nothing how about electronics engines mine is mechanical


    Rick 74 m c 8

[luvrbus]

Voltage is not the problem Jim if it was Ace would have got the 46 code with his pro/link if your fix doesn't work pull the ECM and have a DD dealer check it they can tell you in a minute if the ECM is bad and it is not going to cost that much.  

You haven't used a welding machine or plasma torch on the engine or bus ? maybe the shut down idle is set to turn it off the DDEC 11 will drive you nuts on a 60 series or a 92 series  

good luck

[Flatspot]

Being the cheap ... frugal person I am and not wanting to pay the pro link price I remembered that Kent Moore provided the first readers for Detroit. I worked for a fleet that beta tested the 60 series for Detroit and we were provided with the J 36500 Kent Moore readers.
I have found several readers in the past. I currently have serial number 777 so I'm going to stick with it.
Usually they can be had for under a hundred bucks.
They read DDECI and II. It even has some test and reset features for them. It also reads the ATEC transmission ECU.
Just a thought if you don't want to pay the pro link price.
Good luck with your troubleshooting and I am in the 'find what ever is making your voltage drop' camp, not discounting grounds.
Good luck trouble shooting it and I bet you find it.

Happy Trails
Larry

[luvrbus]

Jones did you say "frugal" that is not what I heard it called Lol his voltage falls in stages just like the ECM tells one to do maybe one of the Prevost guys could tell us if that model of Prevost was a 12 volt or 24 volt programed ECM  

good luck

[rv_safetyman]

Every day I learn something new.  I had no idea that an OBD2 reader would communicate with J1708.

Clifford, will it only read fault codes, or does it have the same features that ProLink and DDDL have (read output of all of the sensors)?  If it can read all the sensors, that is a cheap way to get around the ProLink cost.

DDEC protocol is J1708.  The later DDEC versions have the ability to "talk" to J1939 "accessories" like my AutoShift, but the engine controls are J1708.

DDEC II uses the same data port as is found on OBD2 vehicles but it does use the J1708 protocol.  DDEC III and later use the "modern" round 6 or 9 pin Duetsch connector.

My understanding is that OBD2 is the protocol for gasoline and light diesel engines.  All HD diesel engines use J1708 protocol, although I am hearing that some of the recent HD diesels are using J1939 to some degree.  The J1939 protocol facilitates much higher date rate and modern diesel technology will demand that capacity. 

SilverLeaf converts J1708 data for their engine display data.  As far as I know the VMS products will "talk" to all HD diesel engines.

Jim

[jimsflx]

up date this morning, moved the bus out of the barn while setting their waiting on air to build watching volt gauge,at 28 volts then it started to go down fast to 10 volts shut down lite came on and motor stop.the motor started right back up , have not done any welding or torch.it is like something large kick on.still on it will get it. waiting on call from mci about a electric schmatic  thanks jim

[Flatspot]

I guess I missed where you are reading the voltage?
What does come back to and how fast does it come back after a shut down?

Larry

[jimsflx]

larry reading from dash guage. when it is started back up starts charging within seconds rev it up goes to 28 then a few minutes starts falling to 10 then shut down lite comes on and engine shuts down thanks jim

[robertglines1]

run separate feed  12 volt to your DDEC. independent batt.

[luvrbus]

Not clear to me either if he is reading from the dash could be the override engaging the starter that big of drop he would be smelling smoke for anything else you would think.

The problems he is having the guy will hate a DDEC if it wasn't in a MCI I would already had changed that one over to MUI engine lol  

good luck Jim

[jimsflx]

bob we did that so we think the ecm is ok,clifford send me a mechincal engine and i will change it.just kidding i have a 69flx with 350hp 6v92mechical ,i bought this 88mci102c because of the height and the width and the extra 5 ft. norust,smooth sides,the nice bay doors that goe out&up and new all white paint plus newgoodyear front tires (1,000)bucks. paid 5,ooo for it so i thought it was a good deal.i just don't have any experance with dang ddec stuff.thanks jim