1996 Escort 1.6 'surging'?

When / how does it surge? During a constant speed with a very light throttle (lazy o2 sensor usually) or at or around idle speed no load (sticking ISCV usually) ??

Tim..

At any point. It can be idling at 1000rpm, when it'll kick up to 2-2500 for a while, then back down. Or, I can be going along at 60, and I'll feel a kick as it accelerates. It's usually accompanied by a ticking coming from just above the radio, if that makes any sense.

pete

does this occur only when the aircon is on?

if so then it is quite normal

mrcheerful

I've never noticed any link between the aircon and the surging.

I'm curious, why is it normal? I'd have thought that having your engine potentially accelerate as you slow down to approach a junction could be dangerous, no?

pete

As the aircon cycles in and out the load on the engine changes dramatically, particularly on a small high revving engine.

When the aircon cycles in it makes a dramatic difference to acceleration.

The control systems have to work out the load and compensate for it or the engine would stall, so sometimes the idle speed will increase or decrease without any driver input.

Turn the air con off and see if the problem goes away. Don't have the heating system on full demist or the aircon comes on anyway (without being switched on manually)

mrcheerful

From the radio? Then your car does it's own thing?

Are you Mike Corley?

(for newbies:

I had no idea it could make such a big difference - I'll try that, cheers.

pete

Heh, no... but I think I know how he feels...

pete