Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Should I change ecu?

I had a similar problem and it took me ages to resolve. In the end it was to do with the stepper motor mechanism, the motor turns a cam which acts on a brass pin which acts on the throttle. The brass pin was sticking and once cleaned everything was fine.

Before this I had spent ages changing sensors, and the ecu ( which has to be registered with the imoboliser by a dealer) .

Hi Tony,
Did you solve the problem with fast idling? I have recent the same problem on my +4 1991 M16 engine. Checked all sensors and vacuum hoses, stepper motor cleaned etc...
but till now no positive result.
What did you do to solve this?

Best regards,
Bart
Belgium

I would vote for the potentiometer too.

This is a common problem and if it is not set correctly can lead to strange problems with idle. The potentiometer lets the ECUknow what the throttle position is and if it is not set correctly the idle running may be effected by the ECU trying to adjust other parameters, fueling and spark advance, to cope with what it sees as the throttle position.

Fortunately with my setup I can make the adjustments myself but for original systems it tends to require specialised equipment and therefore a workshop visit.