Boost pressure problems

[Tuffty]

Hello all,
Wondered if anyone out their can reasure me?
I have a LCR, had it re-mapped by jabba sport back in Jan, they did a very impressive job, dead chuffed with the results, i have always run the car on shell v-power, to cut a story short i have been in Thailand for 6 weeks,i loaned the car to my brother and he has been putting tesco super unleaded in it and the boost pressure has dropped to what is was before the remap, obviously its the fuel, im wondering if once i finish off the tank of tesco fuel and start using shell v-power will the boost pressure automaticly come back?
Thanks in advance for any advice.

Matt.

 

[dj_hektik]

usually takes a few tanks if it is caused by the petrol.

 

[Mitchy]

Hello all,
Wondered if anyone out their can reasure me?
I have a LCR, had it re-mapped by jabba sport back in Jan, they did a very impressive job, dead chuffed with the results, i have always run the car on shell v-power, to cut a story short i have been in Thailand for 6 weeks,i loaned the car to my brother and he has been putting tesco super unleaded in it and the boost pressure has dropped to what is was before the remap, obviously its the fuel, im wondering if once i finish off the tank of tesco fuel and start using shell v-power will the boost pressure automaticly come back?
Thanks in advance for any advice.

Matt.

It certainly wont be down to the fuel thats caused your boost issues mate. I can guarantee that 110%

I have used V-Power and Tescos 99 in mine and no difference at all

You have a problem elsewhere. How do you know your back at standard boost pressure? Have you got a gauge?

When you hit standard boost pressure, with a remapped car its known as limp mode. However it should reset itself when you stop and then restart the car.

Try an ecu reset and throttle body allignment.......

Undo negative end of battery, leave for 20 mins, and then re-connect. Put keys in ignition, feet off pedals, click round once but do not turn engine over, leave for 1 minute, and then start engine.

This should hopefully work

 

[dj_hektik]

When you hit standard boost pressure, with a remapped car its known as limp mode. However it should reset itself when you stop and then restart the car.

Try an ecu reset and throttle body allignment.......
This should hopefully work

Limp mode will not reduce boost to normal if the car is remapped, Limp mode will hold boost at 5 psi or so, whether the car is remapped or not.

If you are seeing 5 psi, then it is definitely not caused by petrol.

As mentioned above, try resetting ECU or TB alignment. If not, try the usual suspects - faulty Air Mass Meter, faulty DV, faulty N75, leaking charge hose...

 

[Mitchy]

Limp mode will not reduce boost to normal if the car is remapped, Limp mode will hold boost at 5 psi or so, whether the car is remapped or not.

If you are seeing 5 psi, then it is definitely not caused by petrol.

I went through about a weeks period of on/off limp mode mate

Boosting fine at 21-22psi, come off accelerator, back on accelerator to find i could not boost more than 9-10 psi. (I have boost gauge)

Stop car, restart and then my normal boost pressure was back. This happened for about a week on and off. It never dropped as low as 5psi though

Very annoying

 

[RobM]

I went through a months worth of boost problems, where the boost would drop from normal right down to 5-6PSI for no apparent reason. Recycling the ignition would often cure it, but it always came back. Sometimes it would come back within minutes, other times nothing for days.

After going through 101 possible causes it turned out to be the MAF. I'd wager this was the case here too. My MAF didn't die outright, but it got gradually worse as time went on. The moment it was replaced it was fine again and has been ever since

 

[dj_hektik]

AFAIK there's limp mode and soft limp, 0.5 and 0.8 bar respectively. Rest the ECU first, then find someone with vag-com. Oh, and don't lend it him again!

you may be right. whatever the boost point is on limp mode, the point is its fixed whether the car is remapped or not ...

 

[Mitchy]

you may be right. whatever the boost point is on limp mode, the point is its fixed whether the car is remapped or not ...

Yes true mate and i never said otherwise

All i informed the original poster of, is that he was hitting limp mode and its nothing to do with him putting in tescos fuel.

The only limp mode i have experienced is dropping to 10psi from 21psi but i do know that full limp mode like Phil has correctly said is around 5-6psi

 

[dj_hektik]

no worries

 

[Tuffty]

Hi guys,
Thankyou all for your help here.
I just been out and tried the car and its working perfectly normal now,about 22psi. Very strange! lol.
After reading all your posts i have strange feeling this might be a short time regular problem for me. I hope not! lol
Oh and yep i do have a gauge, it's a defi one, fantasic bit of kit-reccomend it anyone