ECM problem

I am going to see a specialist in ECU problems, I am starting to run out of ideas, with out having it in front of me, this is becoming very frustrating, I hope to be able to post something soon, trouble is, these people will want the car to test, but I may get something of help with a call.

Mark

The tech said that with this type of problem, it should be looked at by a tech with a very good understanding of engine management problems, it is important to eliminate all probable causes one by one, he also said that in all his years he had never come across such as problem, one suggestion was to do a continuity test through each ECU wire to test for a high resistance or a earth leak, if a new ECU has been fitted we can eliminate this a problem, so logic says that the issue is loom related or a sensor or driver that is back feed a current that is shutting down the ECU, now this is a time consuming thing to take on, he suggests that testing the fault gathering capability of the ECU first is where to start, that is disconnect a sensor and try and start, then do a scan to determine that the ecu is reading faults correctly, also he said that if you can get a scanner with live data read out a tech can check many systems are incorrect value without actually doing a hands on bench test of each item, a fer things to get on with.

Mark (mhpautos)

With out having this in front of me to check first hand is really difficult, especially a problem that is not able to be resolved by conventional wisdom, as for why the engine will run with the OBD11 tester connected only, that I just don't know, I have no idea as to the workings of the tester that will over ride what every is causing this problem, maybe if you contact the manufacturer of the tester and ask there tech department they may have a better idea as to why it is so, this post is now on our moderators board for all the techs to see, I can only hope that one of them can shed some new light onto this, often fresh eyes can see what we are now blind to.

Mark (mhpautos)

I have gone back over all the posts, and this stands out.

I pulled the scan tool itself and left the cord on and the van continued to run with just the cord plugged in. Cord gets warm a little. Once I pull the cord it dies out.

What type off scanner are you using? With the cord still attached is it still able to run) which wires to which pins feel warm? What is the connection like to look at? Is it just a loon with a plug to fit both ends? Is there a interface that you also have plugged in? There must be some sort of circuit associated with this "cord" as if it is, it will just be individual wires between to plugs and this will do nothing,

sorry about all the weird questions but I am really grasping at straws just now to come up with some form of attack to sort this out.

Mark (mhpautos)

With your back ground, then I am sure that you can understand my own frustration with this, have you considered the last set of questions I sent?

Mark

A continuity test of the adaptor loom would show up, if you get 0 ohms resistance down each wire, that should tell you, would you agree?

Mark (mhpautos)

The OBD scanner cable, I cant see how that is creating a circuit.

Yes, so I would be checking that cable independently first,

also just to let you know, in a few days I will be away for about 1 week, so I may not be able to reply as I wont have any access to a network where I am going.

Mark

This is the schematic of the data link connector, what is the colour of the 2 wires you have bridged out?

mark