Boost Guage

[EagleClawz]

I just bought myself a '90 Eagle Talon TSI, and my boost guage is way too low. It is an autometer guage, and when I start up the car the boost only goes up to around 7. The guage should be up way over 10 for sure. As far as I can tell there are no vacuum leaks, and I have no idea where he wired the guage into. Please help.

 

[LiquidX]

If you question your boost then you should do a boost leak test and it's something anyone with a DSM should do as part of their maintenance. Just follow the nylon or vacuum tubing to the tap source.

What do you mean "when I start the car up it only goes up to 7". Are you referring to when you go WOT?

 

[Friend-O]

If your car starts in boost theres a major issue or your idle is over 3500rpm. your reading should be 18 inches of mercury or 18Hg. if its 7Hg you have a vacuum leak somewhere.

 

[EagleClawz]

Is it possible that it is just wired wrong?

 

[Friend-O]

if the boost gauge is the more expensive electrical model then the sensor could be bad, but if its the old school mechanical style with a hose running from it, there could be a leak. If the car runs good then its possible the gauge is bad, You can pick up a vacuum tester at any parts store if you wanted to verify the actual vacuum. a healthy idling engine running at 800-1000rpms should sit at 18Hg.

 

[turbo_lag92]

the only wiring that should be involved is for the bulb. otherwise its all vaccum lines. trace the lines to see where the running to. otherwise get a t and take the vaccum line from the front of the intake manifold and also the one from the fuel reg. and than run your line from your boost gauge to the t also

 

[EagleClawz]

I'm just scared to up my boost to 15 psi, without the guage actually reading properly.

 

[LiquidX]

I'm just scared to up my boost to 15 psi, without the guage actually reading properly.

#1 rule

Maintence and repairs before modding


That being said, do the boost leak test to rule out a faulty gauge and verify the tap location. Make sure everything is working properly before you even consider upping the boost.

 

[Friend-O]

If you have a vacuum leak I would get that fixed before you do a lot of driving. If you up the boost before you fix a leak you wont get an accurate boost level to run at since your air may bleed off. Alternatively if the gauge is bad your back to square one and need a gauge before a boost change.

 

[EagleClawz]

guage shouldn't be bad, auto meter is respectable. only way to find out is to swap the guage into something else i guess.

 

[EagleClawz]

found the boost leak, its up to 15 Hg

 

[Friend-O]

I believe 18.7-18.9 is stock on a warmed up engine under no load and no accessories on. Sounds like there may be another. Granted thats perfect world so 17-19 is healthy

 

[nick97gst]

any ideas on why mine would run at 26hg at idle

 

[EagleClawz]

any ideas on why mine would run at 26hg at idle

Busted guage?