Help - not running right! Won't rev

[Key Walshe]

I received an RS2 MAF the other week to replace my S2 ABY item which appeared past its best. The car was stuttering badly at 3.5k rpm and would only pass this mark forcibly by being knocked down a gear which is far from ideal. After checking for boost leaks anywhere, none that I could find, the plugs seem good, the air filters quite new, the oil & fuel filters have been changed since the problem arose, and the MAF connector plug has been cleaned though not tested, I can't think of anything else to check bar from the turbo boost (no gauge fitted yet).

So, we unplugged the MAF and the car ran much better and would rev to just over 5k round town in the lower gears, though still way down on the redline surpassing shove it used to have! Yet at speed it won't go past 4k and was flat back the other day at 1am when coming home from Birmingham at a measly 135mph (private road ofcourse!).

Fitted the RS2 item and the original problem arose of not going past 3.5k rpm. The car just bangs and pops and refuses to give up any sort of power and still, will not go past 3.5k rpm. I've disconnected the battery for a few hours to see if that reset the ecu but to no avail, so have reverted to running with no MAF!

I did have the head gasket done last year, could that have altered the compression at all? Although it ran great after that was done. And the problem was progressive, it started to stop revving past 4.5k, adn gradually moved down the revs until it now hits a brick wall.

It's very frustrating, any ideas anyone? Going to try and hook it up to an Audi diagnostic machine if my Dad can get his mits on one, but they aint being too forthcoming at giving him one as of yet. But, I doubt that will highlight anything.

Oh yes, and the car's an original Nothelle spec motor if that changes anything?

[S2central.net]

You replaced the MAF with a brand new RS2 MAF or 2nd hand one ?

Measure the MAF output voltage at pin 3 on idle and under load if possible.

[Key Walshe]

Brand new item!

Will try and measure that this week, hows the best way?

[S2central.net]

Good old voltmeter at pin 3 on the MAF connector is good enough... Expect about 2.5V at idle - need to look it up.

If the MAF is healthy (and a fresh one should be) then check to see that you have a good fuel supply. You'll need to borrow a fuel pressure guage to be sure on that and probably need to remove the fuel feed pipe and measure the amount of fuel delivered in 10 seconds or so.

Another way to fail to get correct fuel pressure is a leak in the hose that links from inlet manifold to the FPR is OK - if you have a boost leak in this control hose then you can run too lean.

[s2_bo]

Have you tried pulling any foult codes? You can reset the ecu by disconnecting the two motor fuses in the fuse box for about 3 minutes. Althought disconnecting the battery should do the same I guess.

Sounds to me though like the dead maf foult has not clearerd it's self yet. So the car is still running safe even though you fitted a new one.

[vcosmin]

I received an RS2 MAF the other week to replace my S2 ABY item which appeared past its best. The car was stuttering badly at 3.5k rpm and would only pass this mark forcibly by being knocked down a gear which is far from ideal. After checking for boost leaks anywhere, none that I could find, the plugs seem good, the air filters quite new, the oil & fuel filters have been changed since the problem arose, and the MAF connector plug has been cleaned though not tested, I can't think of anything else to check bar from the turbo boost (no gauge fitted yet).

So, we unplugged the MAF and the car ran much better and would rev to just over 5k round town in the lower gears, though still way down on the redline surpassing shove it used to have! Yet at speed it won't go past 4k and was flat back the other day at 1am when coming home from Birmingham at a measly 135mph (private road ofcourse!).

Fitted the RS2 item and the original problem arose of not going past 3.5k rpm. The car just bangs and pops and refuses to give up any sort of power and still, will not go past 3.5k rpm. I've disconnected the battery for a few hours to see if that reset the ecu but to no avail, so have reverted to running with no MAF!

I did have the head gasket done last year, could that have altered the compression at all? Although it ran great after that was done. And the problem was progressive, it started to stop revving past 4.5k, adn gradually moved down the revs until it now hits a brick wall.

It's very frustrating, any ideas anyone? Going to try and hook it up to an Audi diagnostic machine if my Dad can get his mits on one, but they aint being too forthcoming at giving him one as of yet. But, I doubt that will highlight anything.

Oh yes, and the car's an original Nothelle spec motor if that changes anything?

My car with MAF disconected worked almost ok, expcept for idle, and revved to redline no pb, you might want to check fault codes, fuel line, ignition.

[S2central.net]

Have you tried pulling any foult codes? You can reset the ecu by disconnecting the two motor fuses in the fuse box for about 3 minutes. Althought disconnecting the battery should do the same I guess.

Sounds to me though like the dead maf foult has not clearerd it's self yet. So the car is still running safe even though you fitted a new one.

Actually a good point Bo... the old fault may well still be stored in the ECU.

I often forget that a lot of people can't see when they have active alarms - wiring up the MIL bulb is a great mod for that. Its nice to see it come on with the key, but go out when the engine fires up.

Paul

[Key Walshe]

Just to double check, which fuses do you suggest to remove? Will that reset the ecu more so than disconnecting the battery (for around 10 hours it was left unhooked)?

How can I check the fault codes? Is it a plug and play job or one of those where you turn the steering wheel each way, pump the pedals, rub your head and stomach at the same time, and then switch the ignition on?

[s2_bo]

If you open the fuse box there should be a secondary cover that covers two fuses labeled "Motor" it sits horizontally in the center underneath the line of vertical fuses.


Have a look on www.s2central.net to see about fault code checking. Its quite easy really

[stevieyid]

When i had the same symptons the coils had gone. New coils and the car was running sweet again. I would try what bo has suggested first though

[S2central.net]

Is it like a hard fuel cut at specific rpm or just general misfiring & splutters ?

Running normal plugs (Bosch F5DP0R) ?

[shark_90]

Possibly coils IMHO too.

[Key Walshe]

Thanks for the replies, thought I'd added my own yesterday but mustn't have worked.

Would removing the said fuses clear the ecu more than disconnecting the battery? If not, is there any way to completely reset it? Would that affect the running of it with it being a Nothelle, not sure if there's been any re-mapping, will have to check the history?

Will try and check the fuel pressure this weekend, and the pins.

[S2central.net]

Battery disconnection or fuses out is all the same as far as ECU concerned...

I don't expect this one has anything to do with the ECU itself or any chip contents - assuming it ran nicely for you at some time... You haven't bought it in this odd running condition have you ?

[Key Walshe]

No, bought it nearly two and a half years ago and it ran great - had a few issues but nothing engine wise. I'll remove the fuses, but as I've already done the battery it's really just a case of double checking.

I'll make the coils and fuel lines my next lines of enquiry.

Sorry for not replying to your previous question Paul, my phone wasn't showing an upto date page, it was only when I added my last post did I see all the other replies about coils etc. The rev's rise steadily to about 3.5k rpm then it would cough and splutter with no rise. A slight lift and more steady, progressive input of the throttle it would then rev upto about 4.2k rpm, but only just. And without the MAF it will rev to around 5k but it feels flat all the way there with no rush of power, either on or off boost.

Thanks for the replies, certainly giving me some things to think of