2001 Citroen Saxo 1.1 Ticking Over Badly

tm2204

Problem with the son's Citroen Saxo 1.1 petrol. When the engines cold it ticks over really badly; the revs dropping back then recovering. It sometimes cuts out.

Also when you slow down & pop into neutral the revs dive before recovering.

Changed the plugs but this didn't sort it.

Any ideas?
Cheers

Mr Benevolent

Could be the mass air flow sensor. Have you tried unplugging it to see if it's any better without it?

stevenmu

Sounds very much like a dirty/clogged throttle body. Happened to my old Seat Ibiza a few times.

You can get a spray can of throttle body cleaner in any motor factors/halfords. In the Ibiza I would just take off the air filter box, the throttle body is the metal intake with a valve below it. With the engine running and warmed up I would spray the cleaner on and around the valve and it's pivot. Spray in short 1 or 2 second bursts, as it gets sucked in the engine will have to gulp for more air. If you can, have someone in the driver's seat as well to rev the car every now and then which will open the valve wider and let you spray around it better. I've also seen people suggest to use a small brush (toothbrush etc) to scrub it and around it, I tried that and it seemed to help but I was terrified of dropping it in . I'd also stop the engine to give it a good long spray (it might be a little hard to start after if you spray too much). After 10 or 15 minutes of spraying in bursts and half a can or so it should be back to running much smoother.

Ideally you should take the throttle body out and give it a full cleaning, but the above is quick and simple and should be enough to resolve the issue in the short term, and if it works then you can take it out and do it fully again some time.

Ferror

tm2204 wrote: »

Problem with the son's Citroen Saxo 1.1 petrol. When the engines cold it ticks over really badly; the revs dropping back then recovering. It sometimes cuts out.

Also when you slow down & pop into neutral the revs dive before recovering.

Changed the plugs but this didn't sort it.

Any ideas?
Cheers

This problem sounds like a faulty idle control valve (mounted on the back of the throttle body), It's seems to be a common fault on these engines in their later years, they can sometimes be cleaned and will come back to life for a while, but ultimately it's better to replace it.

To Test: (works if it's electrically dead)
You can take it out and manually adjust it by screwing in the 'servo actuated' plastic post (note original position), refit to see what the engine idles at. Screwing it in increases the rpm, out lowers rpm.

(adjust it a couple of turns at a time, then refit - all the way in and the engine will idle at about 3000rpm, all the way out and it'll fall apart )

You can set it to have a high idle, irrespective of engine load/temp, to get you by for a while and make the car drivable but you'll be wasting petrol. (ECU cannot regulate idle rpm)

It's a good test to do before throwing new parts at it anyway or disassembling anything else, as it's easily accessed and held in with only two torx (t20) bolts.

Hope that helps...