Hey guys and gals,

I just recently noticed this on my VDO boost gauge, but at idle the needle on the gauge would oscillate. This mainly happens upon start up, idle, and a little bit after being driven. After driving the car for a while, the problem would go away. I never noticed this with my Autometer boost gauge.

Anything similar happen to you guys and gals?

Thanks for looking.

-K-

you may need a restrictor on the vacuum line running to your boost gauge, on some gauges you'll get a shaky needle if you dont have a restrictor.

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99 GS-Turbo 3.55 MTX
S16G @ ~15psi - FMIC - Forged Internals
Clinton Township, MI

Status: Parting Out...

my boost gauge kept getting stuck at diff spots. i found it was cause i didnt have a catch can and oil must have been blowing through all my vac/boost lines. i put a catch can on the pcv and it cleared out after a few days. its fine now.

91 civic hatch, homemade turbo+ LS motor = 12 sec street car.

could be the gauge itself, so maybe try a spare vac gauge if you can...

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

Hmmm, lately I;ve been driving the car more, and it stops oscillating around at 16-17 vac.

-K-

Ok I've been holding off posting cause this is really just a limited experience, but my VDO mechanical gauge needle was much "faster" compared to an Autometer. I'm not really suprised you're seeing vacuum fluctuate at idle though, theres probably some EGR solenoid or something that pulses and the VDO just happens to be sensitive enough for you to see it.

(Ironically, my VDO EGT was MUCH slower than the autometer, even using the same probe on each gauge.)

Finally, my mechanical fuel gauge fluttered a LOT at idle... I put in a vacuum restrictor to the SFMU and it caused the fuel to smooth out a lot... so I think it's fairly normal, and if it bothers you maybe use a restrictor.

what vac numbers is it reading? normal vac numbers should be 17-22Hg steady needle. if the needle fluctuates, that leads to diffent engine problems. could be many possiblities why that occures, you can't assume is the boost gauge. if you have doubts,buy a real vacuum gauge and check if you get the same numbers. the gauge should be hooked up or tee'd to the intake manifold.

My boost gauge bounces a little at idle sometimes. I took will's advice and put my SFMU restrictor in the vac line and haven't had a problem since. Thanks will. U be da man. ;P