My B5 A4 breaks up at high acceleration

[01UA]

Ok I have a 2001 a4 1.8t with a k04 turbo, 5 bar fuel regulator apr chipped computer, 3 inch maf, and a front mount intercooler... So since I got all this installed I have experienced what seems to be the plugs like breaking up at high rpms and what feels like miniature back fires.. I also get a back fire every shift when accelerating hard.. I have check vacuum check my plugs and my coils no issues like that. Also checked for an exhaust leak I don't have one.. Maf is good and injectors are good.. I had the TT injectors on there and it was worse so I put the stock back on there... Just trying to see if anyone has run into anything like this before???

[adam044]

Yes, change the plugs and decrease the gap of them. I had the same issue.

[demonmk2]

does your tune call for a 3" maf?

[01UA]

I did that still same issue..

[01UA]

I called apr and it says that should be fine inside the parameters but I will switch it out and check and see

[demonmk2]

check your crankcase ventilation/pcv area for cracks/rips in the plastics or rubber hoses.

same thing for the inlet pipe

[Avant Nate]

When did APR start making a 5 bar, 3inch maf, tt injector K04 tune?

[01UA]

They don't but I have done my research and all this stuff stays inside the parameters of the tune .

[demonmk2]

just a suggestion but I would put the stock maf housing back in, stock fpr back in, and the stock injectors back in. if the tune does not call for it wether or not it may work or not I doubt your gaining much or any advantage by using that setup.

[RallyeBourne]

'Within parameters' doesn't always mean 'ideal.' Without having the tune optimized for those components, you won't see a gain, and as you are experiencing, you could run into issues. Your tune thinks it's pushing 4bar of fuel for xx milliseconds. You're actually pushing 5 bar of fuel for xx milliseconds. Too much fuel in the system could be your backfire issue. You could also be flooding your plugs, causing those little misfires. Trust me, I WISH it was that easy to gain a few ponies. But it's not. So stahp.

[01UA]

Alright well I have already put the stock injectors in with the 5 bar and that seemed to help a ton, but it still happens so I will put the stock regulator back in.. I noticed an issue with the inlet as well has anyone used this one from racewerks http://www.evolutionracewerks.com/node/64 if so is it worth it

[adam044]

I did that still same issue..

What are your plugs gapped to?

[01UA]

I have them gapped at .28 and I fixed the inlet tube and it is gone now.. I just can't believe that I just got that and it had a cut on the back side.. I also put the stock maf housing back on and I believe that did the trick..

[Avant Nate]

A 3 inch maf is going to give the computer numbers low by 20% over stock, a 5 bar is going to give 25% extra fuel, tt injectors, even more so. On a narrowband, I'd doubt that it'd even run. That's a lot of compensation for the ecu to even handle.
You're not going to outflow the stock MAF with a K04. Stick injectors, maybe