I reset my ECU over the weekend and now the car idles irratically dropping to a couple hundred revs then shooting up to 1-1.5K revs. It has stalled a couple of times too. Will this be resolved over time when the ECU sorts itself out, or do I have a problem?

 

A problem - ECU resets are a good way of showing them!
What MY?
Particularly if it's a MY99/00, it's likely to be your MAF, which you will want to change ASAP! If it's any other MY, there's a couple of other things it could be as well.

 

Yes its a MY99. No error codes though. Have just been looking through some of the old threads on this topic. Can you recommend anywhere to get a new one?

Cheers

Andy

 

AFAIK, the best place is your local Dealer. Should be around £70 for a new one.

A faulty O2 sensor can also cause erratic idle.

Stefan

 

anaconda, looks like we have the same problem then. i have a maf sensor with my name on it at my not so local dealer. will get it tomorrow mornin hopefully (diy job).

part number is 22794AA010, cost £73.50 inc vat.

outta curiosity, how did you do the reset ? battery off job or the routine mentioned here ? http://www.mudd90.freeserve.co.uk/te...stuff_diy1.htm

lemme know how you get on....

 

I followed the procedure here

http://www.mrtrally.com.au/

 

andy/anaconda, is it normal for the fan to do strange things and an odd clicking noise to come from around the alarm when you connect the black plugs together and the green together ?

(did both before in error when trying to get the ecu code which wasnt there)

 

Yeah mine did that too. I am no expert so can't confirm that its normal, but I guess that as you have put it into a diagnostic mode various things are being powered on and off to check their health.

Andy

 

andy, maf replaced. seems to have done the trick. dont be fooled by the new maf having only 4 pins rather than 5 - it works a treat.

when drivin along yesterday, was dippin the clutch and watchin the revs drop quite quickly to around 200 then jump back up to 800. with the new maf, the same test shows it dropping to around 1k then very slowly settling back to 800rpm.

 

Got MAF in post today, will fit tonight.

 

cool. lemme know if yer want any instructions/tips in advance. wasnt the 10 minute job i was led to believe....

 

Replaced sensor over weekend. Sorted idling problems. but now get error code 12. Acceleration is also a bit lumpy and hesitant! Any ideas?

 

anaconda, u get that 12 sorted ?

i too am gettint intermittent hesitation (but no error codes). when it happens its normally in 4th/5th doin 30-40 tryin to accelerate up an incline. changin gear normally sorts it. suspect its unrelated and its plugs (cleaned boost control solenoid at the weekend)...

service due soon....

 

error code 12, is that crank position sensor

 

12 should be starter solenoid, and thus shouldn't cause odd running once the engine has fired. Are you sure you counted right?

While I'm here... Yes. This is the ECU in test mode. It cycles all the solenoids, fans etc. in sequence so service engineers can check they're working right.