214 si 16v

This seems to be a common problem on these cars, I have had it happen to me (exactly as you describe.) I recall a variety of causes being traced and reported in this NG, in my case it was an alternator starting to fail causing a drop in charge voltage, which the ECU responds to by raising the revs. However, others have reported similar symptoms caused by incorrect or faulty thermostat, faulty temperature sender, blocked vacuum pipe to the ECU, faulty throttle potentiometer - maybe others which I don't remember, but that's a few things to check out for starters. All these will cause the ECU to deliberately change the idle speed. Of course a fouling throttle cable or broken stepper motor will also cause the idle to be out - may be easiest to eliminate these first. Hope this helps - Bob

Bet it's a sticking throttle cable, very common on that engine. The throttle body is plastic and it warps over time which means the butterfly gets stuck sometimes when returning to the closed position casuing the hesitancy in the revs dropping. Eventually the spring manages to snap it shut and you get normal idle speed again.

It's worth taking it off first and giving it a clean incase it is just gunged up. Otherwise it isn't too expensive to replace (around 100 quid I should think from a dealer - dead easy to fit yourself), and later models were fitted with a revised alloy throttle body which cures the problem (and some say gives a better response too)

Have a look over at the mgrover forums

Oops, my bad! That should be

If the vacuum pipe to the ecu is loose, damaged, split etc. the car will have these symptoms. The hard plastic pipe connection on the ecu can get split too.

MrCheerful

Hi Group, The fact that you have changed the spark plugs worries me. The ECUs on these cars are very prone to damage caused by stray HT radiation. Some spark plugs generate far more HT radiation than the Rover specified plugs.If you have not fitted genuine Rover specified parts (which are often cheaper than the ones from your local shop) then this may be interfering with the ECU or may permenantly damage it. This is the most common failure pattern for Rover ECUs and the first components to fail are often the idle stepper-motor components. If you fear this is the case , getting the ECU tested off the car may be worthwhile. Regards Mike

You've just succesfully linked 3 completely seperate issues. For starters the amount of EM you need to fry even a stepper motor driver never mind a stepper motor would have melted your radio

Hi, SO what do we actually think is causing the problem then? I replaced the sparks in my wife's 214 last January (2003) and she has been using it in town for the past year with no problems. However we did a 60 mile (high-ish speed) Motorway trip in it on wednesday and every since it has been doing this strange rev pattern at idle.

Also does any one know where the water is likely to be coming in from for the boot leak????

Cheers

Some people have had a problem with a badly sealed light cluster but having doused those with plenty of water I decided that wasn't the cause in my case.

I removed and put back with plenty of sealant, the two outlets from the sunroof which are pressed into the inner wing, and then sealed the downpipes into them. It's a bit of a fiddle, but I've had no further problem since.

Andy Pandy To e-mail, address hopefully, self-explanatory !

That could be something even simpler like an air leak in the inlet system.

I am sorry but you are completely wrong !. Firstly I said nothing about damage to the stepper motor itself only to the components within the ECU. The effect of high dV/dT waveforms on semiconductors is poorly documented but a major cause of semicinductor failure. There are several papers published on this subject mostly by the semiconductor manufacturers - it seems a pity that more vehicle system designers have not read them. The radiated signals from an ignition system certainly can and do cause this type of damage. This effect does not require direct coupling of the stored energy in the system to cause damage , however , a modern HT system normally stores in excess of 0.5 Joule which is quite sufficient to cause considerable damage. Regards Mike

That seems a little harsh in the case of Rover, who you admit have specified suitable plugs !

It seems though that the producers of maintenance manuals should take more care in explaining the need for OEM parts in this application.

The

Andy Pandy To e-mail, address hopefully, self-explanatory !

Yep but you'd have to fit non resistive spark plugs which would take a real effort to purchase nowadays. It's not the most common cause of failure.

Hi again group

I posted the original fault and now the car is in the local independent rover workshop I will keep you posted.

Thanks

stepper-motor