Subaru Forester Owners Forum banner
1 - 11 of 11 Posts

·
Registered
2002 ES300
Joined
·
4,412 Posts
Discussion Starter · #1 ·
My car is randomly boosting now. Sometimes 6psi. Sometimes 12psi. Also, the vac/boost gauge flutters really bad at: idle and full boost. Not so much when coasting. Ideas? And thorough instructions on how to remedy it.

I took videos and may not be able to post em. If a kindly member wants to post em for me, PM me and I'll send you the vids.
 

·
Registered
2002 ES300
Joined
·
4,412 Posts
Discussion Starter · #4 ·
Boost gauge vids. In 2nd vid, I kept thte throttle pegged. It seems to fluctuate boost pressure randomly. Click to watch.



 

·
Registered
2012 XT Touring 4EAT
Joined
·
3,751 Posts
My car is randomly boosting now. Sometimes 6psi. Sometimes 12psi. Also, the vac/boost gauge flutters really bad at: idle and full boost. Not so much when coasting. Ideas? And thorough instructions on how to remedy it.
I'm puzzled by what you say (and I doubt that a video would make it any more clear).

When your warm engine is idling, your gauge should show a constant vacuum - maybe 15-20 in-Hg (the higher, the better). If there is a significant fluctuation, or periodic fluctuation in this reading it could indicate a variety of things - bad valve(s), vacuum leak, other issues. An irregular idle will also cause the gauge to fluctuate (but, why do you have an irregular idle?)

When you are on the road and put the hammer down, you should go into boost - maybe up to 10-12 psi for a few seconds or more. But, as you start to run out of road, you will have to ease off the throttle and the boost will drop to 0 or maybe back into vacuum. There shouldn't be a lot of 'shaking' in the needle, except in response to your foot on the gas.

I'm not that familiar with your Auto-meter gauge model. But it is generally good practice to put a restrictor in the line for vacuum and vacuum-boost gauges. Although this is a closed system, there are serious pulses that pass up and down this line. A restrictor tends to minimize these, smooth out the readings and stop the gauge from chattering. The restrictor can be a solid piece of plastic or aluminum rod used as a plug with a tiny hole drilled in it (tiny, as in 1/64" or smaller, or maybe use number-sized bits like a #75).
 

·
Registered
2002 ES300
Joined
·
4,412 Posts
Discussion Starter · #6 ·
Went to SubiWorx in Tempe. Was diagnosed as a faulty EBCS. So a new one is on order. Hopefully that'll take car of the flutter. If not, I may need to put in a restrict or pill for the gauge.
 

·
Registered
2012 XT Touring 4EAT
Joined
·
3,751 Posts
Went to SubiWorx in Tempe. Was diagnosed as a faulty EBCS. So a new one is on order. Hopefully that'll take car of the flutter. If not, I may need to put in a restrict or pill for the gauge.
I hope that solves your problem. But put in a restrictor anyway. It really doesn't impair the accuracy or responsiveness of the boost/vacuum gauge.
 

·
Registered
2002 ES300
Joined
·
4,412 Posts
Discussion Starter · #8 ·
I hope that solves your problem. But put in a restrictor anyway. It really doesn't impair the accuracy or responsiveness of the boost/vacuum gauge.
How and where would it go on my setup? Or would I have to change it?

 

·
Registered
2012 XT Touring 4EAT
Joined
·
3,751 Posts
How and where would it go on my setup? Or would I have to change it?
You have to disconnect the vacuum line, fabricate a small plastic or aluminum plug that will fit snugly in the line, then drill a small hole in the plug. and then insert it in the line. If you are clever, you will design the plug so that it can be removed easily (if, for example, you want to bigger-up the hole). But, you really don't need much 'hole' to make a vacuum/boost gauge work - a small number sized bit put will make a small hole that works just fine.

Another way to do this is as follows. In your setup, notice the small, white plastic tee, onto which is threaded a brass reducer cap? Suppose you took an appropriately sized Allen screw which would thread down inside this plastic tee. If it was a short Allen screw, you should be able to drill your hole through the Allen screw, screw it in the plastic tee, and you would be good to go.
 

·
Registered
2002 ES300
Joined
·
4,412 Posts
Discussion Starter · #10 ·
I also believe that my faulty EBCS is causing my transmission to shift at random points because of not achieving proper boost. It seems that it expects it to be in a certain gear, at a certain speed, AND be at a certain PSI. It's acting as if it is underpowered and shifting up prematurely, like an NA going up a steep hill. When it realizes it can't maintain/accelerate it's normal parameters, it downshifts to a lower gear shortly after an up shift. Thus, the ride can be a bit jerky and make you believe the tranny is going bad. ... This which I have noticed over the last couple weeks, and yet thought it to be odd being a strong transmission and just having done a tranny fluid swap. I will keep you posted if this theory holds true, because it did not do it when I had the other EBCS in.
 

·
Registered
2012 XT Touring 4EAT
Joined
·
3,751 Posts
I also believe that my faulty EBCS is causing my transmission to shift at random points because of not achieving proper boost. It seems that it expects it to be in a certain gear, at a certain speed, AND be at a certain PSI. It's acting as if it is underpowered and shifting up prematurely, like an NA going up a steep hill. When it realizes it can't maintain/accelerate it's normal parameters, it downshifts to a lower gear shortly after an up shift. Thus, the ride can be a bit jerky and make you believe the tranny is going bad. ... This which I have noticed over the last couple weeks, and yet thought it to be odd being a strong transmission and just having done a tranny fluid swap. I will keep you posted if this theory holds true, because it did not do it when I had the other EBCS in.
Maybe, but I would focus on one problem at a time.
 
1 - 11 of 11 Posts
Top