I posted a thread last week about my car failing the MOT and it being mainly down to emissions. That cost me £80 for a new lambda sensor (fitted) as the CO2 and HC readings were fine. Guessed as mine was about 6 years old it could do with a change. (They have a life of around 100000km according o one wibesite I visited).
Took it back yesterday .....
Now I knew the idle was high but the examiner last week only mentioned it ("You've got a problem with a high idle speed". "I know, can you still test it?". "Yes").
So yesterday, different examiner same comment. Put it on machine ... same high lambda readings ... and as Victor Meldrew would say "I don't believe it!". But then he said,, the problem wasn't just a high idle but the erratic idle when he tried to hold it at 2500-3000rpm. "Weren't you making it do that?". "No, the car is doing it by itself!".
Sure enough you hold the accelerator steady at around 2500 and it would hop up and down to between 2000 and 3000rpm. But what really annoyed me was it must have done that last week but the other prat didn't say anything!!!
Anyway, next door but one is my local specialist ... L&M .... so we tried a new (known to work) MAF. Same. They put it on examiner ... two fault codes, both down to broken lambda ... faults cleared. Still same. Idle 1420rpm!!!!
I borrowed a throttle body and idle actuator. Put body on today after giving it a good clean. Revs went through roof!! Looked again ... oops. Throttle cable cam is different size.
Swapped idle actuators very carefully. Success!! Rock steady idle ... but still at around 1100-1200rpm. Tried reset. No change. So idle actuator must be busted ... now did I do that cleaning the throttle about four months ago???
Oops!! Guys ... don't!! Even with a throttle cable .... probably will cure the "Hiccup" on throttling back too.
Now what the guys at L&M also said was that it seemed to them the car was getting too much air but after the MAF. That was behaving just right according to software - no errors, apart from the idle setting was 1 not 0.
It might be an air leak and the culprit could be a valve behind the throttle body and on the plenum chamber. This connects to the camcover. Now know this is the "oil vapour separator". Take it off and clean it was the suggestion , as "there is a small plastic bit which gets dirty and sticks". But when I did take it off ... there's actually nothing in it!
Should there be? Well he gave the impression that there should be "plastic bit"
So I squeezed the pipe and lo and behold ....
Idle dropped to a healthy 700-800 rpm!! Yes!!!! ......
So it looks like it could be this and the only explanation I have for the missing internals ... they fell out when I had the plenum chamber replaced (it split) and no-one noticed. We expected the idle to drop on its on as it learnt. That was about 2 years ago!!!
So it's off to the dealers on Monday for a new idle actuator (currently borrowing L&M spare) and "oil vapour separator" ...
Ordered "oil vapour separator" from Alfa dealer today, due in Wednesday ... cost £2.58 plus VAT!!!! Negotiating with L&M to buy their actuator.
then negotiations with the MOT guys about a free retest as they didn't tell me the whole story!!! Will do one more retest for free!!
I'll keep you posted.
PS anyone got a spare idle actuator they want to sell Bosch part no 0 132 008 650!!!!!