Poor car running

[sie1970]

I wonder if you can help me, one of our club members is having trouble with their car. They recently changed their ECU for a second hand one to cure a poor cold starting problem. This was fine for about 6 months, now another problem has appeared. He took it to his local VW garage who in the past have managed to help him out, they found the ECU fault last time, but now they seem to be stuck.

This is what the have found and done so far:-

Engine RPM fluctuating from 800rpm to in excess of 2500rpm, idle stabilization valve opening too much allowing excessive air flow scoped digital signal to valve and when RPM changes scope pattern doesnt.

Swapped valve and fault still apparant. If you block inlet to valve RPM slows down as it does when valve is disconnected electronically.

Possible ECU issue but strange why signal does not alter.

Any idea,

Simon.

[Red1600i]

It's the power supply, not the ecu.

It's relais J176 in the middle of the trunk, next to the radio...

Broken soldering inside the relais. It's the 5-pin relais, not the 4-pin next to it.

Had the same problem years ago.

Martin

http://www.1600i.de/1600i-elektronik/relais-steuergeraet/CheckingandrepairingtheECUrelay.htm

[sie1970]

Thank you very much, I'll get him to change it and I'll let you all know how he gets on.

Many thanks again,

Simon.