Ran VAG COM on S4 - some faults on engine module?

[Stevo]

I did replace the TBB for the samco one even though the stock TBB looked fine, i'll keep it for a spare although im seriously considering the APR bipipe.
I've been searching this forum and im getting conflicting reports about optimal mass air flow figures for stock and chipped cars.
I read somewhere about a 0.8 figure * bhp, if so then my max 256 maf reading isnt far off 330bhp * 0.8 = 264 (Confused?????)

David, did you have VAGCOM and did you do any runs for the MAF readings when you had the car?
If it is the MAF at fault, thats £200+
I think i'll take your advice David and take it to Jim at Star Performance as i dont want to replace the MAF if its not that at fault.

[DavidR]

I didn't take MAF readings (or at least if I did I cannot remember them or how to interpret them). The car had a MAF sensor last year, and the symptoms of its failure were quite dramatic - 0.4bar boost max and noticeable power drop.

Does the car drive poorly at the moment with the EGT sensor playing up? I guess if it did, then a replacement EGT is the first point to resolve. Knowing how the fuelling works, I would imagine that a rogue EGT reading could cause an ECU adaptation along the fuelling / boost / timing lines and cause issues.

When the MAF was faulty I had 5 error codes including lean running of both banks and a lambda probe reading out of normal - but definately not an EGT DTC...

[Nige_RS4]

I took some VAG-COM readings to identify my failing MAF - I am stage 2 (chip + exhaust) and was reading a max of 220g/s. With the new MAF I am getting around 260g/s.

Hope that helps.

[Stevo]

That certainly helps Nige and puts my mind at rest a little.

I've just got the APR chip and stock exhaust.
I'm off to pick up some new DV's and vacuum hose this afternoon.
I have noticed that the car is getting a bit jerky when lifting of the gas and i read somewhere that this was solved with new DV's although the APR optimax program makes the car abit more jerky at lower speeds.
Think im getting abit fussy, paranoid or getting used to the power and need an upgrade.

Steve

[Stevo]

Well back to this again

The codes have re-appeared for the EGT side of things.

I think i'll have to book it in.

Steve.

[Stevo]

Got it booked in for thursday.
Any one know if i took out a warranty with some one, would i be able to get these replaced and fitted under warranty or is there an initial period where you cannot claim.

Its going to sting me £600+

Steve.

[Stevo]

Anyone know if the APR chip could cause these error codes and should i revert the car to the stock program before putting it into the audi garage for diagnosis?

[DavidR]

Revert to OEM code and lock it out on the cruise control before an Audi garage sees it.

I had EGT codes prior to chipping, resolved with new EGT. I wouldn't have thought that the chip, as such, would cause codes, but perhaps the additional airflow sent another EGT west.

[Stevo]

David,

I have not read up on the lock out procedure, guess its time too eh

Thanks for replying.

I wonder if the RS4 EGT's would be better suited or are these not compatible?

Steve.

[UKS4APR1]

MAF =£200+........That's a Brand new one from Audi steeler.
"Reconditioned" MAF's are readily available at German & Swedish for £65
Even the steelers are doing a "Reconditioned" MAF for £75.
They are VERY VERY common failures on ALL AUDIS.

[Mik]

But apparently the Hitachi MAF is less prone to failure. I have just changed my 3rd MAF in 4 years as S4 owner and I briefly investigated the Hitachi option which was used on later S4 cars. I asked a couple of tuners in the US who seemed to readily supply this either as part of their tuning kits or just as parts on their Web Sites. Unfortunately, both ECS and AWE recommended against trying this on my S4 ( I suspect because they only have experience with US ECU's ) although it does require a fair bit of modification from what I can understand.
However, I have decided to change to an RS4 MAF longer term as I will be upgrading the fuel system, intake etc. soon anyway - but got a reconditioned S4 MAF the other day from the stealers for the time being, to avoid risking any damage to the turbos.

Mik

[DavidR]

Steve, chose program 1, then hold the cruise to resume for about 5 seconds, the EPC light will flash a lot, then its locked out.

Haven't a clue about the RS4 EGTs TBH. Intrinsic Audi (un)reliability, I guess...

[KayGee]

Mik,

Check out Verrukt and Mike S4 postings (AW) before going RS4 fueling route. They are getting some excellent results with home brew kits at a fraction of the cost.

[Dippy]

I read somewhere about a 0.8 figure * bhp, if so then my max 256 maf reading isnt far off 330bhp * 0.8 = 264 (Confused?????)

Yes, that's why I thought your figures looked OK. It is actually quite hard to get a good peak MAF reading unless you are on a test track or have a clear, open road.

However all the responses here are correct - the MAF tends to get contaminated or otherwise go faulty.

[Stevo]

I ran a check on the MAF at idle running speed with AC off with VAGCOM and my values were all within spec:

01 Engine
Basic settings
group 002

Specification is:

idle speed: 750-850 rpm
load: 15-25 %
average injection period: 2.0 - 4.0 ms
air mass: 3.0 - 4.5 gs


Is this all the checks the audi dealer would do to check the MAF?

My main concern is that if my ECU requires replacement and i have the APR chip in there, what do i do? get it replaced and ask for the old one back?????

Thanks for all the replies folks.

Steve.