1.1 bar boost all of sudden.......
Discussion
Had my 996TT for around 2 months and have been generally happy with everything. Was seeing 0.7 bar boost under hard acceleration which I thought was normal.
Last week I had a problem where acceleration was down and boost wouldn't go over 0.4 bar on the gauge. Had this diagnosed as a failed diverter valve which was replaced today.
Just got the car back and it's now reading 1.0 or sometimes 1.1 bar boost under heavy acceleration and seems a LOT quicker :-)
Should I be worried about this, or has the previous owner flashed the car ?
Last week I had a problem where acceleration was down and boost wouldn't go over 0.4 bar on the gauge. Had this diagnosed as a failed diverter valve which was replaced today.
Just got the car back and it's now reading 1.0 or sometimes 1.1 bar boost under heavy acceleration and seems a LOT quicker :-)
Should I be worried about this, or has the previous owner flashed the car ?
Thanks Mousem....presume the faulty diverter valve must have been causing the reduced boost level when I bought the car.
I have just been out in the car again though and the PSM / ABS warning lights came on under hard acceleration. Stopped the car and restarted and the lights haven't come on since. Have read this could be a MAF fault ? Do I need to hook up to a Durametric cable to read the code or can this be tested by disconnecting the MAF for a short period if it happens again ?
I have just been out in the car again though and the PSM / ABS warning lights came on under hard acceleration. Stopped the car and restarted and the lights haven't come on since. Have read this could be a MAF fault ? Do I need to hook up to a Durametric cable to read the code or can this be tested by disconnecting the MAF for a short period if it happens again ?
If you disconnect the MAF, you will get ABS / PSM fault lights anyway. Durametric would give you the code though.
I thought that a boost leak could cause higher indicated boost than normal? And I also thought a boost leak could cause false MAF failures?
I think I'd wonder if something isn't tight after the DV replacement.
I thought that a boost leak could cause higher indicated boost than normal? And I also thought a boost leak could cause false MAF failures?
I think I'd wonder if something isn't tight after the DV replacement.
hacka1979 said:
When I had the problem last week, I could actually hear the boost leak when accelerating with the window down. You could also hear something blowing at idle too.
That's all now gone away since replacing the DV but I'm not sure whether they did a full boost leak check.
You need a boost leak check - it is the only way that you are going to know for sure. It is very easy when fitting DVs to cause a leak as well. There are a lot of small pipe connections. I am not saying it is impossible that the car was tuned before and now you are getting the benefit - it is if one DV was not functioning correctly. But the fact is that the car was running 0.7, then has an issue (drop in boost is generally DV related) and now is imo overboosting. In these temps you should definitely be seeing 0.8 as the car in warmer temps needs to boost higher to hit the load targets.That's all now gone away since replacing the DV but I'm not sure whether they did a full boost leak check.
This problem turned out to be a failed N75 boost control valve.....part only costs around £20! Now boosting to 0.8 bar with smooth power delivery. The car was also found to have a number of minor boost leaks which are now all sorted too.
Difference in the drive is amazing, the car feels much more responsive at lower RPM and acceleration above 4K rpm is amazing :-)
Difference in the drive is amazing, the car feels much more responsive at lower RPM and acceleration above 4K rpm is amazing :-)
hacka1979 said:
Had my 996TT for around 2 months and have been generally happy with everything. Was seeing 0.7 bar boost under hard acceleration which I thought was normal.
Last week I had a problem where acceleration was down and boost wouldn't go over 0.4 bar on the gauge. Had this diagnosed as a failed diverter valve which was replaced today.
Just got the car back and it's now reading 1.0 or sometimes 1.1 bar boost under heavy acceleration and seems a LOT quicker :-)
Should I be worried about this, or has the previous owner flashed the car ?
It's not 1.1, it's 11.Last week I had a problem where acceleration was down and boost wouldn't go over 0.4 bar on the gauge. Had this diagnosed as a failed diverter valve which was replaced today.
Just got the car back and it's now reading 1.0 or sometimes 1.1 bar boost under heavy acceleration and seems a LOT quicker :-)
Should I be worried about this, or has the previous owner flashed the car ?
[pedantic]
"Chipped" referred to the original process of removing the original computer 'chip' which controlled the fuel/boost map with a reprogrammed one. Sometime this involved de-soldering the original component from the circuit board. Typically the original chip would not be re-programmable so would be copied to a PC and then amended and written out to a new chip (e.g. EEPROM) and this reinserted in its place.
"Flashed" referred to the method of re-programming a memory chip (so called Flash memory). These days cars can be 'flashed' using their diagnostic ports. A USB memory stick typically uses flash memory.
[/pedantic]
I had some superchips for both our 944 Turbo and an early ZX Volcane. Seemed mystical back in the 90s that such small devices could change a car so much..
"Chipped" referred to the original process of removing the original computer 'chip' which controlled the fuel/boost map with a reprogrammed one. Sometime this involved de-soldering the original component from the circuit board. Typically the original chip would not be re-programmable so would be copied to a PC and then amended and written out to a new chip (e.g. EEPROM) and this reinserted in its place.
"Flashed" referred to the method of re-programming a memory chip (so called Flash memory). These days cars can be 'flashed' using their diagnostic ports. A USB memory stick typically uses flash memory.
[/pedantic]
I had some superchips for both our 944 Turbo and an early ZX Volcane. Seemed mystical back in the 90s that such small devices could change a car so much..
Gassing Station | Porsche General | Top of Page | What's New | My Stuff