Hi guys I hope someone can help me with a big problem I have with vems. In not sure this is the best sub forum but here goes. I am building a audi urquattro with a 5 cylinder 20 vt engine and as I have used vems before on my audi urs4 I desired to use it again. I bought a used vems ecu and sent it to be tested at vems. I have had many problems some are my own fault and others are not. The ecu came back with no cam hall inverter so I had to add a circuit to the cam sensor to make the car run. This is an external circuit. I then had no wideband sensor working and I found that I had only have 12v to the sensor and not the ecu. After I connected the 12v to the lambda probe AND the ecu lambda probe pin wideband is working but I have other issues now.
What is happening is that the ecu is randomly crashing when I try and start the car. When it crashes vems tune cannot connect to the ecu and I have to jumper pins 2 and 3 on the the rs232 connector to force the ecu to go to boot loader mode. I then can upload firmware and config and restart the car ok.
The ecu crashes when I turn on the ignition. It sometimes runs the fuel pump constantly and other times not at all. Vems tune cannot connect and the car won't start. When the ecu is correct the fuel pumps should only run for about 2 seconds and stop and start again while cranking.
The ecu seems to get confused somehow. Why would this be? It happens at random and I can't force vems to do it. I could start the car 10 times no problem and then the next time the ecu won't do what it should somehow. This issue only started after I connected the 12v to the ecu wideband connection. Could this be related. I seem to have good ground and 12 v supplies but is there anything else I should check? This is a Motronic style vems ecu.
Also I have no internet connection in my garage so I'm uploading firmware 1.9x boot loader. Is there a way of downloading firmware 1.2.3x into my laptop do I can load the latest firmware when not online?
Thanks des.
