Engine wont rev after starting

Just recently I have been having problems when starting my S1 Exige (with Emerald ECU). When I start it and press the throttle on idle the engine revs rapidly drop until I lift off. Doesn’t matter how slight the throttle press is. After idling like this for up to 5 minutes the problem goes away and it revs enough to be able to drive off under load.

The car is kept out and its been quite damp recently if you hadn’t noticed

So is it damp getting into it somewhere ? (I’m sure I’ve had the same symptoms even on the odd morning when it hasn’t rained overnight!)

Could it be a dodgy TPS ?

I presume I really need to hook up the ecu up to my laptop and see what the emerald software says though I haven’t done this yet. (Has anyone got the software they could send as I don’t have a floppy drive!)

Could it be anything else ?


Sounds plausible and I think you have the method of testing it.

Have you tried their website for a download?


I had the exact problem on a mates Emerald run Exige, it was a dodgy TPS connection. In my case it was at the Emerald unit itself but in you case I would look to the sensor.

Cheers guys - Sounds like I have another job for the weekend - weather permitting

Update - I seem to have sorted it now - I disconnected the connector to the TPS, lengthened the lead coming from the loom (it was under a tie wrap) and reconnected it.

Not had problems since It seems that either the loom to the TPS was probably slightly too tight or it just needed re-seating.