Hey guys I'm running into some boost issues on my 2001 AWM Audi A4.

Heres the story so far, The car (stock) was running at a low 5-6 psi (no cel), and hesitated at high rpms. I changed the spark plugs,MAF, fuel filter, and vacuum lines still no change. I installed a GIAC Chip (from a private seller) and test pipe, and changed the spark plugs (new gap .028), now I'm boosting around 9-10 psi without the hesitation. Im pretty sure Im supposed to be boosting at around 16psi, either I got scammed with the ecu or I still am missing something. In some gears when the throttle is fully open the boost slowly goes down from 10 to 5 psi, its strange. Anyone have any ideas? I was thinking maybe its the diverter valve (thats basically the only thing i didnt change), but why is it all of a sudden able to handle 9 psi, but only 5-6 with the stock ecu.

Thanks for the input.

 

I'm not sure what the issue was, but it definitely sounds like the DV is leaking now. You need to change it anyhow now that you have the chip (stock 1.8T DVs can't take chipped boost). Somewhere along the way it sounds like you fixed it though - I'm thinking the stronger replacement DV will bring you back up to the right boost.

Even though you didn't have a CEL did you scan for codes anyhow? It's possible that you have one or more latent codes that'll point in the direction of the part that originally failed.

 

9-10psi is limp mode on a GIAC chipped ECU.

You really need to scan both ecu's for codes.

 

See I'm having the same problem, but mine will clear out at around 5k. My car feels like it hits a wall around 3-4k rpm and it sounds like its studdering and all it throws is a misfire which I change the coil and plug and it runs good for a month then back to the same problem.. any thoughts?

 

Thanks for the advice guys, Ill get the ecu's scanned and order a new DV. Hopefully thats it.

AudiTurbo, it could be the gap of your sparkplugs possibly, maybe a coil pack is going bad.