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95 Impreza L AWD
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Discussion Starter #1
I got my car back last Wednesday from getting the turbo installation finished up. The car has not idled quite the same since the turbo went on, which I think is normal, but it wants to and a lot of times does stall out when I push the clutch to put it in neutral. It doesn't happen all the time, but often enough that I really want to fix it! Only problem is I'm not sure where to begin fixing it. I have had to modify my driving style-when decelerating, I have to keep the clutch engaged until about 1500rpm, then push in the clutch-I can't push it in at 2500 rpm and coast without stalling or coming really close to it! Sometimes it takes a long time to get it started again after stalling. The things that have changed since the turbo went on that I can think of right now are:
-vaccuum line right by the throttle body spliced into and ran to blow off valve
-all hoses formerly attatched to intake hose now have breathers on them
-spark plugs one range colder

I'm not sure my vaccuum hoses are hooked up properly, so I'm going to take a look at my friend's RS-T and see how his are set up, since his seems to run a lot better than mine. However, he has an Apexi SAFC, while I have a shitty Field SFC Hyper R and no instructions for how to work it! I have noticed that the car seems to be running rich almost all of the time, at least when my Autometer A/F gauge decides to settle on one spot! I did install the Field before the turbo went in, and had no problems then. Any ideas? Thanks.
:(
 

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overdeveloped beater
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I'd think it was the vacuum lines. Double, triple check them.

Take the tee out of the BOV line and keep that vacuum line seperate. It's the idle line for the idle control motor. Get the BOV line from somewhere else, or tee it from the boost gauge.

Not sure about the Field SFC though.
 

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I could be wrong, but you might have a blown MAF, not sure though. It could be possible that your MAF is trying to compensate fuel for the extra air from the turbo and something is getting messed up. I doubt its your vaccum lines, unless one of them is seriously out of place. Is your friends RS-T a 2000+?

Honestly, to find out your answer, you may want to post over on i-club.com, there are a lot more tech savvy guys over there for this type of problem. I have a 2001 RS (MAP) so I am unfamiliar with MAF based cars.

Graham
 

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95 Impreza L AWD
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Discussion Starter #4
I am going to start with the vacuum lines, since that will be easiest. I have the label on the underside of the hood with the vacuum diagram, so I will look for something else to hook to. The Field sucks, but it may not be so bad if I can get some instructions for it.
I think I would get a CEL if my MAF sensor was blown, so I'm ruling that out for right now. My friend's car is a '98, so his has a MAF sensor, too. Hopefully I can check his car out tonight!

This is a newbie question, but I need the answer anyways. What purpose does it serve to have the BOV hooked up to anything? Does it need to read the vacuum in the manifold, or something like that, or does it even need to be hooked up? Once I see my friend's car, I should have a better idea about it, but I may not get to see it for a few days. Thanks! :)
 

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well, it sounds like your ECU is having a hard time maintaining idle. so it could be your fuel computer is giving too much or too little fuel to keep combustion going (or there is too much/little air coming through. make sure no wires were snipped accidentally. check your TPS and MAF. if you can get an OBD II scan tool, that would be helpful.
 

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95 Impreza L AWD
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Discussion Starter #6
I have tried adjusting the fuel computer, but to no avail. It seems to run rich regardless of how I set it. I even tried disconnecting it, but it made no difference; the car still stalls! I think Storm was right about the vacuum line that my BOV line is teed into, so I'm going to try that first. I have a homemade MAF adapter on the car right now which gets the job done, but the inside is a little bit smaller than the opening on the MAF. My guess is that it's not getting enough air, as far as that's concerned. Since the filter sits behind the headlight on the passenger side, I'm probably going to take it out and drive it around a little bit to see if that helps. If the TPS or MAF were having problems, I'd most likely get a CEL, but I'm not. I even checked it although the light has not come on aside from when the ignition is turned on. My car is a '95, so I don't have OBD-II; I have the connectors under the dash. OBD-II wasn't required until '96, and although a lot of things I've read say that my car should have OBD-II, it doesn't. :)
 

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95 Impreza L AWD
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Discussion Starter #7
I went out to the car and put a piece of hose in where the BOV was teed from-the car ran much better; I revved it up and it came down smoothly! However, I discovered that the BOV needs a strong vacuum source in order to work at all. I tried teeing the BOV line into every vacuum hose I could see, and it wouldn't work. Then I saw the line that goes straight into the intake manifold on the passenger side-I teed into that, but I'm basically back to where I started. I revved the engine up for and let it come down repeatedly for about 15 minutes and it didn't stall, but it got damn close! I'm sure it will stall once I go out and drive it! I'm beginning to wonder if the boost in power is worth the trouble! :(
 

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could it be your BOV is venting too much, causing the ECU to think that there is plenty of air coming in when really its all getting vented?
 

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Good thought. BOV's do vent under vaccum, so you might want to make sure that it is being run back into the intake tract, not venting to atmosphere. This is one of the problems with MAF based cars, if you vent to atmosphere, they get a fouled reading of the amount of air coming into the engine.

Graham
 

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95 Impreza L AWD
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Discussion Starter #10
Actually it's not, but it will be in a few minutes. A friend of mine brought that up yesterday, and I went and got the parts for it last night. I had it welded together today, and it's going on in a few minutes. I'm thinking that will take care of it. Hoping, too! It sounds really cool, though! :)
 

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I'm having the same problem the BOV is creating havoc on the fueling. Any kind of off throttle situation where the BOV is recirc back into the intakes causes a rich condition and the car stalls out.

There's gotta be a way to tell the ECU to lean out the mixture when the BOV goes off.

I'm using a HKS EIDS which fixed this problem like 98% of the time. I'm still working on getting rid of the last 2% of my problems which is think is probably solved by raising the idle speed.
 
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