Car refusing to accelerate beyond 5000rpm

[DavidR]

Further to what Golich said about Audi dealers inability to diagnose serious faults, I was told on 3 occasions that my car was fine, whereas the following graph would disagree.

[img]images/rsul/24703-SickS4.JPG[/img]

A change of MAF sensor provided me with 50bhp more and a car that felt transformed.

Thanks to Jim at Star Performance, and Camerons Audi Perth for taking my call at 3pm today and fitting a new MAF by 4:30 under warranty...

[DavidR]

Worth also noting that Camerons had not seen the car before (another dealers ineptitude), and the ECU had 5 error codes logged on it.

[Nige_RS4]

Sounds like the 155mph limiter kicking in. I measured 80mph at 3000rpm this morning, so 160 would be 6000rpm, therefore 5000rpm wold be around the 150-155 region ?

[DJG]

Nige,

Don't think much of your maths mate. [img]images/graemlins/confused.gif[/img]

From your measurements gearing is 26.7 mph per 1K rpm.

So 5K would give approx 133 mph
[img]images/graemlins/beerchug.gif[/img]
David

[DJG]

Hi David,

Any symptoms other than your car being a bit sluggish?

David

[DavidR]

Hi David,

Any symptoms other than your car being a bit sluggish?

David

I assume you mean me! The car was pinking at 3000rpm due to both banks running lean, and in the last few weeks it has had a lumpy idle and occasional spluttering on acceleration. However, the performance has been off par for at least 3 months now.

[DJG]

Yes you. [img]images/graemlins/thumbs.gif[/img]

Thanks for the update.

David

[Golich]

I should add to my post above. That in the case of my power loss. The car appeared to be running ok. By that I mean it didn't miss-fire or slutter, fuel was ok and plugs looked ok. But it wasa just plain flat and would hardly accelerate in 6th at speed which is what I've picked up from your post. In my case the car was simply being robbed of boost pressure.

Have you amanged to get it checked out?

[Dippy]

It's handy to have a boost gauge...

[Golich]

Defintely

[peterskellen]

Finally got the car to my local dealer last night for them to check it out quickly.

Both banks are running lean. He suggested 3 possible causes: the MAF, the injectors or the lambda sensor. The problem is, Audi can't replicate the conditions under which I was experiencing the flat spot (ie under heavy load), for obvious reasons, and the MAF is working fine for idle (which according to him is the only state they can get readings for?) Because both banks were running low, he has initially ruled out the lambda sensor and the injectors, though he said the injectors are a pain in the arse to check. After checking with the "master technician" they concluded that a new MAF should do the trick.

Seems to me that a trip up to AMD for them to test it on a rolling road would be a safer first port of call before shelling out for the MAF.

Any thoughts guys? (bearing in mind some of his explanations may have been misunderstood by me of low technical knowledge!!)

[DavidR]

pete, see my posts above, but my car had the same error codes with the faulty MAF. AmD in all liklihood will have a spare MAF kicking about (its a 30s job to swap the sensor element out) and if you reset the errors, run the car you'll be able to tell my performance and (hopefully) lack of error codes after the new run.

[Golich]

Get it down to AMD or someone with a rolling road and a MAF. Like David said 30s.