DDEC comes on unreliably

[luvrbus]

DDEC are simple it is best to have a scanner owning one they pay for self,-one trip to a DD dealer to scan and replace a 50 buck sensor will cost you from $1200.00 up scanners have their limit they are not a cure all though

[chessie4905]

yes, you still need to measure voltages and resistances with a good vom, wire tracer, test light. most sensors vary voltages by engine temp, rpm, throttle angle, neutral- drive position, engine on stopped or running.

[windtrader]

Agree witth you both but just having tools and a diagnostic manual does not make an experienced bus electrical diagnostic tech. I read these posts and shutter at the thought of having to do much in depth diagnosis on this stuff. Particularly, since you clear one fault and another or several new ones pops up. And given the mass of the bus, wires go a long way and there are so much to deal with. Hats off and good luck. I got my popcorn and easy chair all set. lol
I do agree that spending the money on the DDEC diag tools are a cost but essential. Seems like there should be if not already some tool sharing group going on amongst the busnuts. Must have come up in past times.

[buswarrior]

Tool sharing?

Does that not fly in the face of 'merican individualism and independance?

Survival of the fittest, pay to play, dare we even suggest socialism?

This Board and the internet already sails mighty close to those winds...

If John Wayne was still alive...

Comedy in truth?

Happy coaching!
Buswarrior

[Bill Gerrie]

Don
Very rare to have multiple codes that are not indicated by the sel and cel lights
They read out any codes active or stored. It is almost a necessity to have a tool like a Prolink.

[chessie4905]

like GM products, many times a fault will trigger multible codes because the ground or voltage feed is interconnected. wires going from front to back can be checked by disconnecting plugs or connectors at both ends and using a wire tracer to verify correct wire. then wire checked for resistance. Most computer circuits are fed 5 volts and the return wire voltage or resistance is read by computer to be in a specified range. Each component in a Computer system is expected to be in a certain range when engine is operating. Find a GM computer command control diagnostic manual from Oldsmobile, for example. It explains how computer command control (ccc) works for each component. Basically what they used in DDA engines till they started using frequencies on the same wire in the latest computer systems. This is a manual everyone should obtain to make your life easier if your coach has a computer.
https://www.ebay.com/itm/403802509970?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=4TOpVwFhTEa&sssrc=2349624&ssuid=QbPh_E0WTG6&var=&widget_ver=artemis&media=MORE

[luvrbus]

People need the scanner for the World Transmissions to like the B500 the Allison World can trigger a engine code to.the World Transmission are a electronic marvel their self ,the newer generation of the World controls the engine it tells the engine what it wants and needs.With a 500 page trouble shooting manual for the DDEC life is not all that easy sometimes 

[windtrader]

So, it seems something like a Prolink or other expensive, low use tool could be shared amongst those needing one from time to time. Pool some funds, buy one, pass around as needed (yes, shipping costs). It's just that I have no recollection of recent times where that practice is done here.

[Sebulba]

Once you get the hang of how the DDEC system works it is a nice feature to have. I know a lot of guys on here don't like an electronic engine but it is the fear of the unknown. I carry one of each sensor and a spare computer so I could fix almost any electronic issue at the side of the road. Very seldom does anything go wrong.

That sounds like a good plan.  How much $$ do you think would cost to have those sensors and a spare computer?

Seb

[Sebulba]

I was introduced to them in 1980 when GM went to Computer Command control. Mileage on all models picked up 3 mpg right off the batt. Some teething issues early on but by 83 they were reliable.
Lucky they went with them on the Detroits. Better fuel economy and less annoying smoke, unless jacked up a lot. You definitely need the scan tool and good manuals. A better one that describes how each sensor works, normal running and stopped voltages, whet episodes can trigger a fault.
GM manuals were great back then in all the help to understand them and properly diagnose problems. Biggest problem was that many mechanics refuse or can't or can't comprehend it. Seems little has changed.
GM needs proprietary scan tool to work on them, or an really expensive aftermarket one now.

I guess I can see the benefits....until something goes wrong.  Then it's nice know that all you need is fuel air and compression to run a diesel engine.

I have a lot to learn.

Seb

[Sebulba]

DDEC are simple it is best to have a scanner owning one they pay for self,-one trip to a DD dealer to scan and replace a 50 buck sensor will cost you from $1200.00 up scanners have their limit they are not a cure all though

That sounds like a plan.  Where would you suggest looking for a scanner and which one do you advise looking at?

Thanks

Seb

[Sebulba]

Don
Very rare to have multiple codes that are not indicated by the sel and cel lights
They read out any codes active or stored. It is almost a necessity to have a tool like a Prolink.

Hello,

Here Prolink is mentioned again.  I would like to learn more about this tool.  Do you have a link?

Thanks

[Sebulba]

like GM products, many times a fault will trigger multible codes because the ground or voltage feed is interconnected. wires going from front to back can be checked by disconnecting plugs or connectors at both ends and using a wire tracer to verify correct wire. then wire checked for resistance. Most computer circuits are fed 5 volts and the return wire voltage or resistance is read by computer to be in a specified range. Each component in a Computer system is expected to be in a certain range when engine is operating. Find a GM computer command control diagnostic manual from Oldsmobile, for example. It explains how computer command control (ccc) works for each component. Basically what they used in DDA engines till they started using frequencies on the same wire in the latest computer systems. This is a manual everyone should obtain to make your life easier if your coach has a computer.
https://www.ebay.com/itm/403802509970?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=4TOpVwFhTEa&sssrc=2349624&ssuid=QbPh_E0WTG6&var=&widget_ver=artemis&media=MORE

OK, so I see that Ebay auction.  It is for GM.  Is this manual transferable to MCI?

Thanks

Seb

[Bill Gerrie]

I think I have a Prolink at home but need to check on the DDEC II III card. I am on vacation till Oct 10 in MI. Call me at 416 580 3048 and I will check later.

[buswarrior]

So, it seems something like a Prolink or other expensive, low use tool could be shared amongst those needing one from time to time. Pool some funds, buy one, pass around as needed (yes, shipping costs). It's just that I have no recollection of recent times where that practice is done here.

A more serious responce...

Sensitive electronics will not survive in a shared tool environment.

Who is paying to repair it when someone burns its brains out doing something foolish?

Who is being blamed for burning it out?

Way too easy for friendships to be destroyed.

Measure the value a different way, how many tires worth of electronics to prevent being taken to the cleaners when trapped out in the world with a problem?

Scan tool is one of the best value to potential disaster expences one can make.

Happy coaching!
Buswarrior