Boost gauge bother

[simonf]

Went out for a hoon over the weekend and my boost guage suddenly stopped working.

Would i right in assuming that this would opperate via a vacuum pipe?

Would it feed off the waste gate or the turbo itsself?

Has anybody else had a similar problem and if so how was it rectified?

Your help, as always, would be greatly appreciated!

Many thanks

Simes

Edited November 5, 2007 by simonf

[Glyn Harper]

If yours is the same as mine was when I first got it (an 88 Turbo) then there is a boost gauge transducer in the buttress area near the right hand filler cap area. Put your hand up the inside and you'll feel it in there. But of a s0d to get to.

there is a pipe that goes from the plenum somewhere to it, it then turns that pressure into an electrical signal to your boost gauge in the instrument cluster.

therefore, there are a few things that could have failed. Wiring, transducer itself, the wiring to the gauge, the gauge, or the pressure pipe going to the transducer.

this unit also limits boost as well. If you get too much boost, it will cut the ignition briefly.

For this reason, I chose to change to a racetech mechanical gauge. You just need to run a piece of vacuum tube into the front of the car and plum it into the back of the gauge. I think it's a common mod, especially if you want more than the 0.7 bar of boost you get stock.

[simonf]

If yours is the same as mine was when I first got it (an 88 Turbo) then there is a boost gauge transducer in the buttress area near the right hand filler cap area. Put your hand up the inside and you'll feel it in there. But of a s0d to get to.

there is a pipe that goes from the plenum somewhere to it, it then turns that pressure into an electrical signal to your boost gauge in the instrument cluster.

therefore, there are a few things that could have failed. Wiring, transducer itself, the wiring to the gauge, the gauge, or the pressure pipe going to the transducer.

this unit also limits boost as well. If you get too much boost, it will cut the ignition briefly.

For this reason, I chose to change to a racetech mechanical gauge. You just need to run a piece of vacuum tube into the front of the car and plum it into the back of the gauge. I think it's a common mod, especially if you want more than the 0.7 bar of boost you get stock.

Cheers Glyn

It is entirely possible i have disturb the pipe to the tranducer when i was fitting my new HT leads as i have had the plenum off more times than i care to mention recently, i will check it out when i get home but somes likely!

Cheers fella

Simes

[dazmans3]

Hi

The S3 Turbo's ,UK spec, have a narrow hardened plastic black pipe that goes from the front of the Plemun Chamber(by the Alternator) straight to the boost gauge. You should see a metal elbow peace that is screwed into the side.

As far as I am aware the transdures were only fitted to the HC turbo's on.

Have you got boost, ie v good excelleration, or is that not very good? More than likely the pipe has come off or if has been routed incorrectly, might have caught on one of the belts & worn through.

Daz

Edited November 6, 2007 by dazmans3

[Simon350S]

As Daz said......

Simon

[simonf]

Hi

The S3 Turbo's ,UK spec, have a narrow hardened plastic black pipe that goes from the from of the Plemun Chamber(by the Alternator) straight to the boost gauge. You should see a metal elbow peace that is screwed into the side.

As far as I am aware the transdures were only fitted to the HC turbo's on.

Have you got boost, ie v good excelleration, or is that not very good? More than likely the pipe has come off or if has been routed incorrectly, might have caught on one of the belts & worn through.

Daz

Yes Daz i have boost! It accellarates like a mother! Thanks for the heads up on the pipe, i will check it out tonight!

SiF

[simonf]

Well done Daz. the pipe had snapped at the elbow peice! Not sure how i am gonna get it back on as it looks like a very tight fit! Maybe get the hair dryer out and heat it up!

Thanks for your help

[dazmans3]

You should be able to heat it to expand it enough to get it back on,

However, on my HC conversion, the boost is taken from the vacuum loop that also feeds the Vac assisted Distributer(Not on the LC engines), the Fuel regulater, via the carbs & engine breather, over boost switch(LC has an mechanical one loctaed under the Fuel Regulater) & looped in to an electronic boost sensor. But as I don't have the electrics to cover this, I simply connected this direct to the boost pipe. All these pipes are standard Vacuum hoses of about 5mm ID. So if you are having trouble getting this back on, try bridging it with vacuum hose.

Daz

Edited November 7, 2007 by dazmans3