My VMSPC is seeing a lot of bad data coming from the ECM. There are no engine performance symptoms but certain VMSPC gauges, like odometers & tank minders, are not working. Others, like RMPS & temps are working fine. I spoke with Art at Silverleaf and he says that less than 1% bad data, as reported under the VMSPC Advanced tab, is normal. He says they can deal with up to about 20%. Mine is running at 30%. He suggests checking all connections at the ECM.
I plan to check the ground wire at the ECM and disconnect, clean & grease both plugs at the ECM. Is there anywhere else in the system, other than the plug under the dash, that should also be checked?
Good idea, but go carefully on 21 year old connectors and wire.
Our Allison ECM has several long plugs. And each of these plugs have dozens of small wires, each with a single metal termination connection that also pulls out of the back of the big plug. All places for problems which need to be checked.
Good advice from Bruce, wires and connectors can be brittle. Use a electrical contact spray cleaner. It is just as often the connection between the wires and the connectors as the connectors or a bad or frayed wire so look carefully. You can use a dielectric grease to waterproof the plug.
Bad data especially for miles that are used in the trip odometers and the tank minder seem to be pretty common for our older coaches. VMSpc is just seeing what is reported and trying to use that. There is almost no error checking at the source and the reporting rates on the older data bus protocols are slower. This makes trying to read many data points, smooth out the curve and throw away the outliers pretty hard especially if you see lots of bad reports in a row.
The newer coaches have a much faster reporting speed and the latest hardware from Silverleaf is able to read the faster rates. It is not retroactive.
Let us know how this goes and if it helps.
Roger
Anyone know how to remove these ECM connectors? I was expecting to see a bolt through the middle but there's nothing obvious holding it. It feels very solid. Does it snap in place?
Bumping this back up in case someone today might know the answer. From everything I've found online, the entire yellow connector should pull straight away from the ECM, towards the side of the coach. But, all of the ones I've found have a bolt through the center that I don't have. It seems like it has to be simple but I stopped pulling & very light prying for fear of breaking something.
Have you asked Dave Atherton? I would shoot him a picture and ask him.
Is there a bolt on the other end of the connector?
Contacted Dave Atherton as Brett suggested. He was going to diagnose the problem a few days ago when we were coincidentally in Custer, SD. Unfortunately he had to cancel due to an emergency of some kind. He did tell me that there is an Allen screw holding the plug in place bit didn't recommend removing it. I'm not going to risk it while on the road.