Third Time Lucky

[Joshie]

I just collected my car on Monday after the KO4’s had been replaced for the third time.

They were analysed and excessive heat as a result of the engine running lean (faulty MAF) meant that they were burned out. Turbo Dynamics analysed them and as a result of the report, AmD could have refused the warranty altogether and charged me a fortune for their replacement but I only paid a small contribution and thanks to AmD for that.

AmD remapped the car last week when I was away and it is running very well. I had to get AmD’s reassurance that the very slight, almost inaudible whistle, when cold on spool up and the very slight whine under full boost was normal. Scott’s S4 saloon with 400 BHP had exactly the same turbo sound and in performance terms there was very little in it.

AmD are reluctant though to map it for all out power – it is developing about 400 BHP and 450lb/ft. They are concerned about over-stressing the turbos. To get another 30 or so BHP will require fitting of the RS4 MAF, airbox, fuel pump and injectors and I’ll consider that if the car fails to sell when it goes into the next addition of Top Marques.

Call me a sad b*stard but I spent some time with the car on jacks last night seeing if it was possible to identify the serial number of the turbos. I can advise that with a small mirror attached to a straightened out coat hanger and a digital camera it is possible to photograph the ID plate on the offside turbo. The ID plate is located on the other side of the turbo, the image in the mirror needs to be reversed using Paint Shop Pro or similar. Now why would anyone want to do that, I hear you say, – well the number can be entered on the Borg Warner website. to get verification of the type of turbo, development date etc. I remember reading on another site that someone wanted to know if KO3’s or KO4’s were fitted to his S4. Well it is possible look.

[Prawn]

OK Mate,

You are a S*d B*****D

[img]images/graemlins/thumb.gif[/img]

[Prawn]

Seriousley though Mate,

What are you going to get to replace it if it sells, RS4 ?

I have to say the degree of failure you saw for a MAF fault is pretty concerning

[Mik]

Very concerning re the potential results of MAF failure. I had my Air Mass Meter changed recently too, and it removed what I thought was serious spool from the turbos (I have stock K03s). Your experience leads me to believe that my turbos may have suffered significant strain due to the bad MAF and it makes me wonder how long they will last.

However, this is also interesting, because I (my S4 Avant 98) currently suffers from the now so famous exhaust manifold rattle (for which Audi have advised complete turbo and manifold change to cure btw), and I am wondering if the failed MAF may have caused the turbos to overheat (due to overwork) and thus resulting in the heatshield "unwelding" itself off the manifold ('unwelded heatshield' is what Audi diagnosed).....just a thought

/Mik [img]images/graemlins/s4anogaro.gif[/img]

[jeffw]

The Unwelded Heatshield is a known problem with the earlier cars....

I had also had a duff MAF and suffered a turbo failure because ot it.....Me thinks that we need to find a test or warning system for the MAF failure.....Exhaust Temperature Guage maybe ?

[Joshie]

I think the solution is to pay attention to what the ECU does. In my case the malfunctioning MAF was causing the engine to run lean. The ECU responded by putting the car into limp mode and at this stage I should have gone directly to Audi to have the fault diagnosed and the MAF replaced.

Lessons learned.

[Mik]

Does it help to have VAG.COM to diagnose? AMD told me there was an errorcode for the MAF?

[Joshie]

Seriousley though Mate,

What are you going to get to replace it if it sells, RS4 ?

I have to say the degree of failure you saw for a MAF fault is pretty concerning

Either
RS4 - but I'd better count on a further £7000 for Milltek, Brakes, Suspension and Remap

M3 - no temptation to mod, three years warranty and from what I've read lots of fun

New S4 - with 400 BHP potential this has appeal

Porsche 996

Of course half of me doesn't want to let go of "The Bitch"!! [img]images/graemlins/jump.gif[/img]

[Joshie]

Does it help to have VAG.COM to diagnose? AMD told me there was an errorcode for the MAF?

Well as I said the MAF caused other problems, in my case - fuel mixture lean on bank 2.

Not sure if there is a code for faulty MAF - I'll have to have a look.

Incidentally, AmD stated that to clear fault codes with the engine running can damage the ECU. Anyone have a view on this? I wasn't aware that the fault codes could be erased without the engine running. Anyone know?

[Nige_RS4]

Jeff, et al...

I had also had a duff MAF and suffered a turbo failure because ot it.....Me thinks that we need to find a test or warning system for the MAF failure.....Exhaust Temperature Guage maybe ?

An easy solution to this would be to use VAG-COM regularly to measure the g/s airflow through the MAF [engine, block 002] You should be seeing around 235-240 on an un-chipped car and 265-270 on a stage 2 car - on WOT. Anything less than this and your MAF may needed cleaning or replacing. This is a common problem, so check it - it may also manifest itself as an increase in engine oil temp (if the the mixture is lean and increasing engine temp, so keep an eye on this too).

Not related, but whilst your VAG-COM is connected, it's worthwhile doing a TBA at the same time.

Have a good weekend folks !

[Dippy]

Well done Nige [img]images/graemlins/thumbs.gif[/img] - just the info I wanted. Now I just have to wait to get my laptop back from repair before I can check it!

Ian,
I don't think you're sad - I would do the same! Interesting comments from AmD - I remember discussing it with you when the K04 mod was on the table. IMO this is proof that the fuel and air system of the S4 gets maxxed out with K04s. I think it is only not recommended due to cost, and that in reality if you have the work done you might as well go the whole way.

As you know, your mistake was in IGNORING the DTCs. IIRC you not only reset them on the fly, but you did so several times? I.e. the ECU was going into limp mode to protect the engine and you kept overriding it!

Having thought about it now, I could believe that there is a small risk of problems resetting the DTCs when the engine is in anything other than idle - as if the ECU doesn't get time to respond to the DTC properly, maybe it would apply the wrong combination of settings to some controllers???

[Joshie]

As you know, your mistake was in IGNORING the DTCs. IIRC you not only reset them on the fly, but you did so several times? I.e. the ECU was going into limp mode to protect the engine and you kept overriding it!

Sounds a bit silly in retrospect Dave doesn't it but hindsight is great isn't it. The fact is that I genuinely thought that it was an intermittent fault with the lambda probe which was provoked by the hot weather and therefore resetting the ECU wouldn't do any damage. And 'on the fly' means dipping the clutch BTW - my VAG Com software stalls if there are any revs on board when connected.

But like I said you live and learn [img]images/graemlins/blush.gif[/img]

[Dippy]

An easy solution to this would be to use VAG-COM regularly to measure the g/s airflow through the MAF [engine, block 002] You should be seeing around 235-240 on an un-chipped car and 265-270 on a stage 2 car - on WOT. Anything less than this and your MAF may needed cleaning or replacing.

I tested mine today and was getting around 240 g/s at about 5000 rpm, rising to a peak of 280 g/s at the redline. Does this suggest that my MAF is OK?

I also did some runs logging block 120 and found that the torque measurement seems wrong. The best was about 450 Nm, but AmD measured my peak torque at 560 Nm. Then I read on some VAG-COM sites that block 120 reads wrong on chipped cars. Any comment?

I also monitored block 005 and am going to have a go with the 'butt dyno' spreadsheet. But that'll have to be later - I'm off on holiday now [img]images/graemlins/grin.gif[/img]