Project: RS2 ABY

[Jamo]

Do you have a lot of friends with RS4's?

yep

Andy you can get an Rs4 maf from GSF for around 60-70 as an exchange item.

Shame i'm not local at the mo

[rynaqui]

Do you have a lot of friends with RS4's?

Just the one

[prj]

No chance of getting lent one from a friend just in case it's not the MAF?

Do you have a lot of friends with RS4's?

[rynaqui]

No chance of getting lent one from a friend just in case it's not the MAF?

[Sonic]

Cheers Dmitri - I think given the number of times I'm diagnosing issues it's worth getting a spare maf blade regardless lol.

It's the one from a b5 rs4 right? Just so I know which part to ask for. Hopefully I can get the blade not the complete unit.

[rynaqui]

It's beyond just a lumpy idle - it is misfiring big time even being held at 2-3krpm and wont idle at all - it just stalls over the duration of a few seconds.

I can get another RS4 MAF blade from a dealership to test.

Would a bad MAF cause the issue? The car runs the same whether the MAF is connected or not.

True, I don't know if it would cause such issues as I hadn't driven it when it had the MAF issue, just started and ran horribly which was rectified by properly plugging it in. Not sure how it would have driven but am confident it would not have been pretty.

Hope you sort it out very soon!

[prj]

It goes rich because it sees a really high signal from the MAF and then my failsafe logic turns the MAF off until you restart the engine.
That said, you do have a used MAF fitted.

To answer your question, yes it can be very much the MAF, but I'd pressure test before throwing money at parts. I have not really had issues with these MAF's failing.

Long time ago i had some off your symptoms to. Turn'd out the maf wire was broken.

His MAF does not have a wire.

[V6quattro]

Long time ago i had some off your symptoms to. Turn'd out the maf wire was broken.

[Sonic]

Go to the passenger side of the engine. There is two sensors in an alloy bracket. Tighten the two 5mm allen keys up. If these are loose your car will behave as described. Likewise try unplugging the lambda probe. A faulty one will cause it aswell.

Just rushed outside to check for this one before Top Gear starts, however i can't find anything that matches... can you be more specific on location? I could see a couple of 5mm allen bolts under the inlet manifold but they look to be knock sensors.

I'll need to try the lambda also.

Do you know anyone that can lend you a working MAF to test? Worth a try!

I once experienced a very lumpy idle which was caused by the conncetor to the MAF being loose.

Good luck

It's beyond just a lumpy idle - it is misfiring big time even being held at 2-3krpm and wont idle at all - it just stalls over the duration of a few seconds.

I can get another RS4 MAF blade from a dealership to test.

513 is always present when the engine is not started. This is a well known fact.
Does the car start? If it starts, this sensor is not the problem.

From the log it looks like you have a big leak in the intake.

Yeah i remember this also, although i thought it might be the G68 not G28 but that makes sense.

I've triple checked every inlet hose, i've even loosened, re-seated and tightened every jubilee clip. My inlet is very simple... turbo -> IC -> IM, so only 2 hoses that can go wrong (3 if you could the ISV, which i've also checked).

When i had the IC -> IM hose split side-to-side it didn't do anything like it is now, it just wouldn't hold any boost.

Would a bad MAF cause the issue? The car runs the same whether the MAF is connected or not.

Everything seems to stem back to the car running ultra rich - this explains the clouds of blue smoke coming from the exhaust on start-up and the misfiring... i just cant seem to find why its running so rich

[prj]

513 is always present when the engine is not started. This is a well known fact.
Does the car start? If it starts, this sensor is not the problem.

From the log it looks like you have a big leak in the intake.

Go to the passenger side of the engine. There is two sensors in an alloy bracket. Tighten the two 5mm allen keys up.

Let's hope that is it. If it is, this guy deserves a beer

[JP]

Go to the passenger side of the engine. There is two sensors in an alloy bracket. Tighten the two 5mm allen keys up. If these are loose your car will behave as described. Likewise try unplugging the lambda probe. A faulty one will cause it aswell.

[rynaqui]

Do you know anyone that can lend you a working MAF to test? Worth a try!

I once experienced a very lumpy idle which was caused by the conncetor to the MAF being loose.

Good luck

[Sonic]

Fault codes -

00553 - Mass Air Flow Sensor (G70)

07-00 - Signal too Low

00281 - Vehicle Speed Sensor, G68
- No Signal

00513 - Engine Speed Sensor, G28
- No change in signal


00513 looks to be a good match on s2central for symptoms - http://www.s2central.net/aby_ecu_codes.html

Engine does not start
Engine misfires
Engine stalls

All of which seems to occur in my case!

So, possible faults being:

Foreign material on G28
G28 loosely mounted
Distance from G28 to ring gear on flywheel exceeds 1.2mm
Broken teeth on flywheel ring gear
Open circuit between 3-pin connector in engine bay and G28
Open circuit between J220 and G28
Short circuit between terminal 47 and 3-pin connector and J220 shielding or ground
Open circuit in G28 shielding

[Cottis]

Yep, you can rely on beer. It never breaks down, is always available and the prices never seem too steep. Good luck with the motor.