Limited Boost

[Martin62]

If its not one thing then it's another, these cars are really trying my patience !!

Having had the knock sensor issue with my CQ20V last week I have been driving my S2 around and noticed today that the boost doesn't go any higher than 0.5 bar (or slightly below), normally it's above 1 bar on the gauge.

Everything else feels normal, just limited boost.

I pulled the codes and found a mixture adaption, limit not reached error.

I ran the car after clearing it but it made no difference and I have since checked the codes again and all clear.

I've looked in previous posts and all the ones I saw related to boost leak but I did read something about 'Limp Mode'

Does anyone have any ideas before I go down the Boost Leak route.

Thanks in anticipation !

Martin

[Error404]

Remove MFTS plug and see if that solves your problem

[Rusty]

What he said.

[UrS4boy]

S2 3B and ABY and RS2 ADU Boost Leak Testing

Everything else feels normal, just limited boost.I pulled the codes and found a mixture adaption, limit not reached error.

Almost always that means a boost leak. Check the MAF as others suggest but prepare for a boost leak test:

S2 3B and ABY and RS2 ADU Boost Leak Testing:

http://www.s2forum.com/forum/showthread.php?t=63974&highlight=boost+leak+testing

[Martin62]

Great, thanks for the pointers.

Will try the MFTS plug first and then boost leak test.

Cheers,

Martin

[newsh]

Could also be the N75 has packed up. If unplugging MFTS doesn't change anything and clearing codes doesn't give you back your boost then I would check that. Boost leak test is always a good idea though.

[Rikki Kitto]

With N75 valve disconnected they run at 0.4 bar so might be that

[Martin62]

The boost is back !!!!

Disconnected the MFTS and boost is back to normal so it looks like an easy fix.

I bought a new MFTS for my 7a a couple of weeks back, it was a Meyle one and like a few people have mentioned it makes the gauge read a bit high.

I have also now seen that some other members have had bad experiences with the Meyle MFTS.

Is Behr the one to go for then ?

If so, does anyone know the best place to get one from ?

Many thanks for the advice so far, this is the second time in a couple of weeks I've benefited from the massive amount of experience on this forum and it really is very much appreciated.

Cheers,

Martin

[Rikki Kitto]

A great Forum indeed