Need a little help with boost gauge

[kevin.bodman1]

On start up my gauge reads .4 of boost,than on throttle it reads 0,has anybody had this problem and if so what to do??thanks.Kevin

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[kenikh]

First you need to confirm what your boost actually is. If you are only getting .4 BAR, them that is a different problem. Can you borrow a known good sender or aftermarket boosr gauge?

[kevin.bodman1]

i have this gauge,not sure how reliable it is,but i can disconect the one in the car and hook this one up,thanks

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[kenikh]

Nice gauge. Valuable, too. If you get the same reading, your sensor may be kaput.

[Mike80911]

Is it reading 0 when the car is under boost or just during acceleration? Does the gauge read correctly as boost is coming on? If so I believe that is normal on a vacuum type gauge.

[kevin.bodman1]

Now is the sencor in the gauge itself,and thanks for the compliment on the gauge..Kevin

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[kevin.bodman1]

The gauge reads .4 at idle,then when u are on a load it reads 0

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[mark houghton]

Your aftermarket gauge is probably vacuum operated via a T connection to the brake vacuum boost line behind the dash. Probably.....unless it has it's own sending unit located somewhere on the engine.

The stock gauge in the tachometer is connected to a sending unit that's mounted directly beneath the intercooler....it's about 1.75" in diameter and covered with orange silicon rubber with a single wire leading to it. You can't miss it if it's still there. If you pull off the single wire, the gauge should peg all the way to the right. If you then ground said wire, the gauge should peg to zero. That will help to narrow down whether it's a gauge issue or a sender issue. All this assumes your aftermarket gauge is using the stock sending unit.

[JFairman]

Your boost gauge looks to be tweaked and needs help. Maybe send it to north hollywoood speedometer.

I bought new outer rings and glass from them and they're good.
Took a few unimpressive pics of the innards of mine while making it look better.
The boost telltale needle always worked perfect on this one.



You'll get it fixed.

[kevin.bodman1]

Mark i am sure this is what u r talking about,i should of metioned that i recently had droped the motor and trans,maybe i mis wired it,although i dont remember removing the wires.

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[kevin.bodman1]

I also have this comming off the oposite side of the intercooler,and had always thought it was for thr andial fuel enrichment,

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[Norm K]

Irrespective of the two posts on the sender, my car ( a 1980) has but a single lead connected to the sending unit. There should be a brown/white wire leading to the spade connector (right above the "V" in VDO) while the other post remains open.

Now I could, of course, be mistaken but that's how my car is wired and my factory boost gauge has always worked as well as one can reasonably expect from a stock unit.

[Ronnie's.930]

Kevin, yep, Norm is correct, and based upon you HUGE picture above (the opposite of Paul's you know whatsit) you've got the sender wired incorrectly . . . there should not be a wire on the right post (the one with the larger sized nut - ha ha ha - looks like you have a ground wire there?) and on the left post, the original wire is light brown with a white stripe.

[JFairman]

The above posts are correct. One female spade terminal wire goes to the sending unit and it grounds through it's threads into the end tank.
Make sure the intercooler has a good ground or make one for it if in doubt.

edit: Thats an after market hobbs switch in the other post. There is no picture showing an Andial device I can see so there's no way to know why it's there unless you follow the wires and figure it out. It could be someones replacement for an overboost sensor because they are half the price of the low quality overpriced original over boost sensor and hobbs switches are usually adjustable.

[kevin.bodman1]

so i removed the wire from the right terminal,and on start up it read 0,but as it started to warm up it bounced to .3 and on a load it went back to 0

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[kevin.bodman1]

Right??

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[kevin.bodman1]

Thanks guys for all the input,no punt intended ronnie..Is there a way to test if the sencor is bad..Thanks. kevin

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[Norm K]

You can remove it, apply some pressurized air and check the resistance with a multimeter, watching the change in resistance as pressure is increased and decreased (somebody here probably has the values). Or, assuming your car is driveable, you could simply wire it as advised and see if things work again.

_

[Ronnie's.930]

Originally Posted by kevin.bodman1

Thanks guys for all the input,no punt intended ronnie..Is there a way to test if the sencor is bad..Thanks. kevin

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Kevin, since Norm's errrrrrr, "input" is only partial , I will complete the procedure!


Mark H. provides the sender test data in the following linked thread -

Boost Gauge Pressure Sending Unit Problem

[kevin.bodman1]

Thanks Ronnie,it looks like i have afew more issues,looking at my wiring some wires seem to be burnt also bad connections,so when i get back down to my shop tommarow i am going to spend some quality time on the old girl.Kevin

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