Pc007

Hi guys, have a MY01 turbo with repo from RStuning, to 508hp. Amazing car!!! Car had recently a gas pump replacement, and now the boost won't go over 0.7/ 0.9 bar, when usually it would go 1,2 bar...any suggestions on what could be the problem...?

Thanks

911mhawk

If boost level didn't change at exactly the same time it is possibly unrelated and start with a pressure test. I finally started using the Durmetric that came with my car to pull info previously not needed. My tuner helps tremendously by analyzing log files and picked up a slight boost leak indication that I found with a compressor, regulator and home made tester.

Pc007

Thanks 911mhawk....do you think it's a leak?

911mhawk

Only way to know if you have a leak is to check. There are several posts where people make their own tester and discuss how to.

I chose to go with my tuner's (UMW) version of testing that is published in the manual too. Made one of these for a couple bucks, serrated the edge that the hose clamps to with a file so it didn't blow out, and put a packing blanket over the rear inside of engine compartment in case it did.

Then put a regaled 10 psi to and found a leak at the diverter hose to the intake Y-pipe. Tightened that clamp and upped pressure to 15 psi and started spraying watered down hand soap (coconut smells good) on the right side of vacuum fitting/hose area and got some bubbles on the vacuum pump. Adjusted/tightened that hose and still had a hisss sound that ended up being the oil filler cap. Backed it off/loosened slightly and all good for now.

Pc007

Thanks 911mhawk, will check it neext week and will give some feedback, really an easy way to check for leaks

Third-Reef

Something you can check without geting dirty. The F hose where it meets the Y pipe hose clamp. I left mine loose after adjusting my wastegates and it did the same thing. It also made sort of a swoosh sound when backing off the throttle. 30 sec with a flat blade screwdriver and I was back it 1.1 and not swooshy. The way everything is stuffed in there it realy can't blow off, just leaks like mad under boost.

Pc007

Thanks guys, today when I was going to the mechanic, car did around 0.8 bar...so I think I have 2 problems...sometimes something makes the car go limp mode, and other times he just boost a little bit more but not reaching 1.2 as usual. For what I've been reading:

1- air leaks
2- check for gasoline filter ( car had a new gas pump, but dealer didn't change the filter!!!)
3- turn off battery and reset ecu
4- diverter valves
5- waste gate ( is there a difference to the diverter valves?)
6- maf
7- knock sensor ?? (What's this?)
8- broken muffler/ catalyst j
9-N75 sensor

...

Any other ideas??

Thanks

Pc007

so after taking it to the mechanic, told me it was the MAF sensor, replaced it, car is now making 1,2 boost and doesn't go to limp mode, but acting strangely, it seems the power is not linear, it seems to "stall" or hesitate during the boost increase, making the car not linear....like there's hiccups on the acceleration....

The car had a 100 cel europipe exhaust now is on 300 cel stock exhaust...

Could this be the problem? Or the wastegate?

Thanks

wross996tt

So your flash may have been set with the higher flow exhaust...putting the stock exhaust back on changes the back pressure...so you likely need a reflash. Those Europipes are one of the best exhaust systems for our cars...why did you remove it?

Olemiss540

The ECU "should" be able to adjust for the decreased exhaust flow. I would lean towards a boost leak, they can cause drivability issues. Pressure test....

wross996tt

Not if the flash has been designed for high flow...the ECU can't adjust for this. Now it is also quite credible:
1. there is a leak,
2. the waste gates need adjustment,
etc. can you flash it back to stock?...Do you know who did the flash? Perhaps contact them...

Olemiss540

The MAF measures FLOW. The tune does not dictate flow. That's like saying you can't run a high flow exhaust on a stock tune since it was designed for lower flow. It may not be providing optimal HP, but shouldnt result in differential driving charicteristics, but I am no problem, so if you are a tuner, guess I will take your word for it!

Pc007

Thanks guys, Car waste flashed with RSTuning, for 508hp, i contacted them and they said it's probably not the exhaust...the mechanic said no leaks, but I really doubt it, now he is saying it's probably the wastegate's, I just don't want to keep changing parts, without a good diagnostics....I bought the car with the stock exhaust, the 2nd owner didn't liked the noise, (too loud), so he changed it...ill put it back in the car by next week.

Thanks

Pc007

One more thing guys, if I change the wastegate's should I go stock? Car has an RS ecu for 508 hp, it goes like a bullet!!!

Pc007

One more thing guys, if I change the wastegate's should I go stock? Car has an RS ecu for 508 hp, it goes like a bullet!!!