A3 1.8T Power loss at 5500 RPM?

[Tricky20vt]

Looking for a bit of advice or help with a slight issue I'm having. Car in question is a 2002 A3 1.8T sport 82k on the clock with the AUM engine fitted. I first noticed the problem a few weeks back when I was running an S2000 air filter and creations motorsport silicone TIP. So I put the mods back to standard and also fitted a brand new genuine MAF sensor. Took the car for a run and all seemed well until last night when I was giving an Accord type R a run for its money and at the top end of 3rd gear just as it hits 5500 RPM it just seems to hit a flat spot almost like a rev limiter but obviously a good way short of the actual rev limiter. The only mods on the car now are a R Tech stage 1 map and a deeper alloy side mount intercooler. No fault codes are stored and in 1st and 2nd gear it will rev past 6k it just seems to be 3rd gear thats the problem and I haven't tried 4th gear as its up into 3 figures by that point!

There's no boost leaks that I can see, all the vac pipes look in good order, pretty much all the breather pipes were replaced by the previous owner and it's also got a brand new genuine recirc valve fitted.

Seems a bit odd how it went back to working ok but now has faulted again.

Any help or advice greatly appreciated

 

[robin_bga]

Hi Tricky,
Try doing a fuel pump pressure test to see if there is no issue with the pump.
Otherwise you might want to check the Airflow meter.
Hope that helps.
Cheers.

 

[16Klappe]

MAF is faulty.

Unplug it and try again.

 

[Tricky20vt]

How is the maf faulty? It's about 3 weeks old and a genuine Audi part.

I was thinking something along the lines of fuel pressure problems. I'll change the filter first and give it a whirl again. Just need to find some time to spend looking into it a bit more. Hopefully have a go this weekend.

 

[16Klappe]

Yeaaaah, ok then.

I have had as many faulty genuine MAF's from Audi as you have posts on this forum.

But ok, don't even try unplugging it. I hope for your sake it is the easily fixable MAF, but I guess without data logs it will be hard to tell what it is past that. I certainly hope you don't end up on a wild goose chase like I have many time, at great expense.

 

[Tricky20vt]

I'm not disputing the fact it could be the MAF just trying to understand why its doing exactly the same as the non genuine MAF was before it and why it only happens in 3rd and 4th gear?

 

[Tricky20vt]

Quick update, just unplugged the MAF and been for a run down the A59 as its a good 2 mile open stretch of road, and the car is exactly the same, struggled just past 5500 in third but wouldn't go over 5200 in 4th gear. Looks like that wild goose is gonna take some catching I think.

 

[Greg-S3]

Diverter valve letting go higher up the rev range?

 

[Tricky20vt]

Thats crossed my mind, Its got a new genuine Audi DV fitted so could be what controls the valve I guess? Unless Audi are in the habit of selling faulty DV's along with all those faulty MAFS?

 

[rajazed]

I have a s3.

Changed it to the s2000 air filter as well. Soon after developed the same problems as yourself. spoke to a good friend who advised me take the maf off and put it back on. Done that and now i am fine.

I know you have said that you took yours off.

Maybe i am no help but thought id let you know.

 

[Greg-S3]

Doubt it's a faulty dv mate if it's new! Have you checked you've not got a collapsing boost pipe/tip?