Dancing boost gauge

[Richard123 11]

My boost gauge never did zero, it always read a needles width up, but going down freeway yesterday it really started to act up.  It would jump up to 0.5bar for no reason, then drop back.  When I did dig in for some boost, it would over-read substantially.  All the while the car ran fine and seemed unbothered by its antics.

Am I right to assume the gauge gets it's signal from the sensor behind the carpeted right hand engine bay side cover?  And that is also the sensor that gives the ECU it's information?  So a quick Freescan should tell me if the sensor is failing?

Since the car ran fine, is it safe to assume it's a gauge problem?  If so, any ideas?  The other gauges were fine.  You think the gauge itself?  Grounds?  Anybody else have this issue?    

[Chillidoggy 4,341]

The ECU gets info from the MAP sensor, not the gauge transducer, and yes, it’s on top of the RH fuel tank, at least on an RH drive car. Sounds like a gauge problem  to me. I’d be tempted to look at the transducer first, if only to delay the  fight to remove Rubik’s binnacle cover.

[Richard123 11]

17 minutes ago, Chillidoggy said:

The ECU gets info from the MAP sensor, not the gauge transducer, and yes, it’s on top of the RH fuel tank, at least on an RH drive car. Sounds like a gauge problem  to me. I’d be tempted to look at the transducer first, if only to delay the  fight to remove Rubik’s binnacle cover.

Ah, so they are separate, which explains why the car seemed unaffected.

 

So the device I found (above RH fuel tank) is the MAP sensor.  Where might one find this gauge transducer?  Clearly somewhere with ease of access and likely a commonly available and inexpensive part I assume?   

 

 

 

 

[Chillidoggy 4,341]

The gauge transducer occupies the same space, it looks like a small round metal thing.

[Richard123 11]

So it's the thing with the hose and two red tagged wires running to it?

 

I didn't see it when I was there, but once I saw the MAP sensor and the plastic hose running to it, I stopped looking!  

 

Thanks so much Ian, I really appreciate it.  (Crossed fingers for a loose wire!)

[Chillidoggy 4,341]

Yes, that’s it! Good luck!

The baron sensor is the black thing behind it.

[Richard123 11]

Found it.  Mine was fastened down under a couple of hoses, not easy to see.  The +tive looked good, but the ground that went to the far side of bracket seemed loose.  Fished for it with a screwdriver and snugged it up.

 

Boost gauge back to normal, owner back to happy.

 

(It's all this good living I've been doing.  Give a few bucks to a homeless guy, and see how it pays out?!?!?)