Boost Loss On 1991 S2

[audimaniac]

Hi all S2 Members

Help needed here, i am still having a few problems with my S2, replaced WGFV Valve, Replaced all vac pipes with Silicone, Replaced Main Turbo Inlet Hose, due to split around neck which connects to the end of the Turbo, Checked Wastegate Diapragm with no preblems there, Temperature perfect, Idling Perfect, but Boost is sometimes at 5 PSI and other times no more than 9 PSI, hence replacing WGFV Valve etc, done David H Mod aswell.

Set off in 1st gear and the car rips through that gear, put the car into 2nd and then the acceleration is like someones holding the front of the car back, put into 3rd, 4th and 5th, same thing with only 9 PSI Maximum and no overboost.

Is it worth checking the MFTS Sensor???? i know the procedure for testing but couldnt get at it earlier today, what else could it be ???

I will say this though, Dizzy sounds slightly noisy??? could this be causing hassle at high revs, although this wouldnt be causing boost pressure loss would it??

Any help would be appreciated folks

Regards Audimaniac

[martinjs]

Have you checked the other boost hoses?, especially the short large diameter hose that connects to the throttle body, this is prone to splitting underneath.

[audimaniac]

Boost Loss On 1991 S2 3b Engine

Hi all on S2 Forum
After Re-checking all pipework i still cannot understand why the Boost is lower than it should be, WGFV Replaced, TPS Sensor Changed, aLL Vac pipes replaced with Silicone ones, Replaced Front Turbo Hose which WGFV Plugs into, H Mod done on Intercooler etc etc etc, but still only got 9 PSI Boost at the most??? and as low as 5 PSI.

What i have noticed though is, my Dizzy is slightly noisy and my Power Steering Pump has developed a nice nocking noise all the time which is getting replaced in the next few days.

Is it at all possible the Knock Sensors could be picked this knocking up and lowering Boost???? Or is it more likely to be the multifunction Temp Sensor??

Regards Audimaniac

[Greg_S]

i would check the MFTS first, alot cheaper to replace

[AndyP]

Where abouts in South Yorkshire are you?

[ian_jemo]

Where is the MFTS

Thanks

Ian

[terrybullwon]

Where is the MFTS

Thanks

Ian

Under the water rail next to the smaller 2pin sensor

[ian_jemo]

Under the water rail I'm still not sure where it is, sorry probably being stupid??

Didn't know there was a water rail

Cheers James for the response looks like something I should probably check as my car has similar issues.

[terrybullwon]

Under the water rail I'm still not sure where it is, sorry probably being stupid??

Didn't know there was a water rail

Cheers James for the response looks like something I should probably check as my car has similar issues.

Bad teminolgy, water manifold / water rail.

Its under you inlet manilfold just look for the oil temp sensors on the side of the block and then go up