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I have the same problem usually only when my A/C is on or the car isnt fully warmed up, its just the timing being pulled from knock, doubt its a leak, i've checked for boost leaks on my car and there were none. Al also mentioned to me about when the car pulls timing the boost gauge will flutter. I have a Defi-D gauge, which is more sensitive then my old Autometer, that gauge didnt flutter at idle or under boost, the Defi flutters at idle cause of my cams with the A/C on, I never really worried about it and it hasnt affected performance, only notice it when the car isnt warmed up or the AC is on.

Tek3Evo

iTrader: (11)

I do seem to notice it more when I am accelerating hard. However, to make it complicated, I do get a steady needle from time to time while accelerating hard. It's very frustating that it is not a consistent issue to work on.

Tek3Evo

iTrader: (11)

bump

plokivos

iTrader: (3)

I read your post again.

Yes, mine does the samething with mechanical Autometer ultra lite boost gauge.

It does that when my MBC is bleeding when the boost hits.


I remembered just looking at my boost gauge thinking it was pretty accurate for it to flutter like that instead of staying constant, because how the throttle was and such.

I don't think you have to worry about anything.

Although, I don't know how good the stewart warner gauges are...

Tek3Evo

iTrader: (11)

That sounds like a logical explaination. Thanks for info.

I tried turning down the boost tonight to see it I was boosting too much and the ecu was pulling timing. That didn't help. even down to 16 psi and it still flutters.

ct9a gsr

iTrader: (7)

I have an AutoMeter Sport-Comp boost gauge... my gauge stays constant and doesn't flutter at all for the first 4 gears, but in 5th gear, 80% of the time, it will flutter at anything past 26~27psi. I boost 29psi in 3rd and 4th just fine, but 5th will always flutter up at that high boost. I still have yet to figure out what causes this on my car.

By the way, misfires and your bov can cause flutters in the boost gauge as well.

Tek3Evo

iTrader: (11)

ok, so I've still been working on this. I built a boost leak tester and found a very tiny leak by the T where I tap for the boost gauge by the fuel regulator. (fixed) I found that when I took the pressure up to 15 PSI the Hallman MBC started bleeding the excess, could this be the issue? I'm not sure what to expect for the leak test, I couldn't hear any other leaks or see anything bubbling that I sprayed with soapy water but the pressure didn't stay, it slowly diminished until finally nothing. Is that normal for the leak test? I continued looking but couldn't locate anything.

Lately when I've been driving I still get the flutter but it finally stops and settles on 19-20psi when I hit about 6K or more. Am I pulling timing causing it to flutter? I put some octane boost in to see if I can calm any knocking if any to see it that is causing the issue, but haven't driven enough yet to see if that helped.

Tek3Evo

iTrader: (11)

bump

Thegame

iTrader: (26)

I have a defi d boost gauge and I see a little bit of what you're describing sometimes. Al aslo told me that it was probably the ECU pulling timing. It could also be your gauge. Defi just recently pulled these from production so I'm assuming the gauges can't be that great. I'm sure your car is fine and I wouldn't worry about it.

Emo-Evo

iTrader: (4)

it could be the bov, in fift grar you have the highes load and the stock bov is known to leak after 15 psi. Not all of them but some. In my case I gained 1.5-2 lbs of boost when i got my greddy installed.

USP45

iTrader: (13)

There is a pretty good thread on NASIOC about this, the guy even called VDO about it (his was of course a VDO gauge). Read post #16 for an explanation, granted it is an old post, but it offers an explanation....

http://forums.nasioc.com/forums/showthread.php?t=40361

Tek3Evo

iTrader: (11)

That looks like a good explanation. I'll try to see if I can make a restrictor for the gauge and see if that helps. Thanks joeycoates