Boost Loss But No Leaking???

[audimaniac]

Hi Guys, just recently I kept loosing boost down to 5psi waste gate only pressure, looked into it and found no power to wgfv plug, (wires corroded) Got that sorted, then ok couple of weeks and boost went again, looked again and socket behind off side headlamp had positive corroded, so bypassed it, chopped wires and soldered ( sorted )
Ok until this week and boost went again, fine until warmed up, but it doesn't do it every time?? it seems temperature related but not all the time??? Any ideas?? No Boost leaks anywhere, wgfv seems ok?? What can I check next??
Thankyou in advance for any help

[UrS4boy]

Thankyou in advance for any help

I would still question the wiring to the WGFV as being suspect.

http://forums.quattroworld.com/s4s6/msgs/20987.phtml

I also would have to wonder how you are sure that there are not boost leaks.

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

I would also check the connection between the intake manifold and the MAP sensor in the ECU.

http://forums.quattroworld.com/s4s6/msgs/20401.phtml

[Rikki Kitto]

I've been chasing similar issues for over a year since an engine transplant here is some of the things I found and changed, hope they may help.

ISV pipe
WGFV
Bypass valve
All boost hoses for silicon, including the small diametre ones round the back of the engine
MAF connectors cleaned up, then changed MAF
Airfilter
Mark H mod on intercooler connection to crossmember
Think that's it from memory been running nice now for a month but it has done this before then suddenly started playing up sometimes feels never ending
Good luck let us know what you find

[andy10v]

3B? ABY?

Any codes?

[chris]

boost

Funny symptoms , i am chasing similar,[ 200q with 3b engine], no boost leaks, no codes ,checked all electrical connections, but i get max 1 bar on a mechanical gauge, connected to the ecu end, oddly though my temp gauge is reading very high but no over heating, so am chasing a link to the multi switch on the water rail?
will be interested in any progress you have

[UrS4boy]

MFTS info

...oddly though my temp gauge is reading very high but no over heating, so am chasing a link to the multi switch on the water rail?
will be interested in any progress you have

MFTS info: http://forums.quattroworld.com/s4s6/msgs/22584.phtml

[chris]

boost

thanks Dave , that looks like the trouble..

[andy10v]

Funny symptoms , i am chasing similar,[ 200q with 3b engine], no boost leaks, no codes ,checked all electrical connections, but i get max 1 bar on a mechanical gauge, connected to the ecu end, oddly though my temp gauge is reading very high but no over heating, so am chasing a link to the multi switch on the water rail?
will be interested in any progress you have

MFTS will limit boost on a 3B.

Quick check, unplug the MFTS, and see if that cures it.

You might need a new MFTS and/or MFTS plug and/or MFTS plug pins.

I would imagine Dave has the info and part no.s covered nicely.

[220bhp]

Faulty knock sensor will also do this, and may not log a fault.

[Tonks4x4]

Check if you have power to the idle valve and also the blue evaporative loss valve at the back if the head as they all share the same power supply fuse 24 I think


Tonks4x4 - The Land Rover Specialist

[chris]

boost

sorry to be so slow, where is fuse 24, not in the fuse box, bearing in mind this is a 20v transplant,,

[UrS4boy]

sorry to be so slow, where is fuse 24, not in the fuse box, bearing in mind this is a 20v transplant,,

If you don't know how are we supposed to know? Maybe the person who did the conversion knows?

This is where 24 is in an S2 or RS2:

[chris]

boost

oh i see, i have 12v to aux air valve and blue vap solenoid, when i disconnected the multi switch the temp gauge returned to a 'normal' gauge position but no change in driving performance, will check the fuses
thanks

[newsh]

Assuming you know where the WGFV is, behind and below the driver's side headlight

Start the engine and pop the bonnet, wriggle your hand down so you're touching the WGFV. Blip the throttle, you should feel the valve click.

[newsh]

Any progress??