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Old 06-15-2004, 11:52 PM   #1
lotusTT
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Default Stalling while in neutral?

So after running rich for months do to a faulty O2 sensor, my car has been running much better. I have noticed a few little wierd problems popping up though.

1) Sometimes while driving slowly through a parking lot, with steady light pressure on the gas, the RPM's will just start falling. Then all of a sudden it wakes back up and speeds back up to where it was before. Doesn't happen all the time though.

2) Sometimes when starting from a stop, the car will stutter before the RPM's start to climp. Kinda like the previous problem, but the car isn't moving. It will pop and stutter for a second, then just start going fine.

3) This one has me worried the most. I got in my car today, put it in neutral and started it up, no problems. While I was situating myself before going anywhere, the RPM's just dropped and the car stalled. The clutch was not depressed and the car definetly remained in neutral the entire time. I started it again, and it fired right up with no problems and kept running fine. Any ideas how this could happen?
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Old 06-16-2004, 02:25 AM   #2
akcel
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on occasion my link plus causes my car to die
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Old 06-16-2004, 04:36 AM   #3
White 2.5rs
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Sometimes while driving slowly through a parking lot, with steady light pressure on the gas, the RPM's will just start falling. Then all of a sudden it wakes back up and speeds back up to where it was before. Doesn't happen all the time though.

only when the engines cold? or all the time
i know its a long shot but my gl always does that when its cold
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Old 06-16-2004, 09:23 AM   #4
Elliot
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It has happend to me in my RS. I am using a SAFC. I think it is realted to the piggy backs!!

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Old 06-16-2004, 09:56 AM   #5
akcel
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my linkplus is not a piggy back though doh
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Old 06-16-2004, 04:27 PM   #6
lotusTT
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now that you mention it, it might only be when the engine's cold. I'll see if I can replicate it after it warms up.

I am using an e-manage, but I'm not sure how just having a piggyback can cause a problem. If it was one specific piggyback causing problems, maybe, but piggybacks in general just doesn't seem logical to me.
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Old 06-16-2004, 05:03 PM   #7
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have you changed out your IAC solenoid? Just curious
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Old 06-16-2004, 06:18 PM   #8
lotusTT
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haven't touched it. (don't even know where I would find it either)
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Old 06-16-2004, 07:32 PM   #9
benjaminetanyahoo
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Just asking, but it's on your intake manifold, on the right side of the throttle body. It's the Idle Air Control solenoid, find somebody with an RS and swap them to see if it changes anything, if so, walla you have your answer. just a shot I guess
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Old 06-16-2004, 07:50 PM   #10
no-coast-punk
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This is "normal" if you are using larger injectors with a piggyback. The stock ECU has all sorts of strange little parameters for throttle changes under light loads that no piggyback can deal with and no standalone will deal with either. Basically when you let off the throttle the ECU wants to add a little bit of fuel for various reasons that I won't get into... well it does this by saying "add X ammount to injector pulsewidth". Well with larger injectors it adds WAY more fuel than it thinks it is and the car runs hideously rich momentarily and completely chokes out the motor. It gets worse the larger your injectors are. The only way to really deal with this is to always keep the throttle cracked slightly when transitioning to a neutral/no load condition. Mine is so bad (555cc injectors) that in certain conditions the car will completely die when coming into stop lights if I let off the gas in neutral... scared the bejezus out of me the first time it happened. I was coming towards this stop light that was about 1/4 mile off and at the end of this long lazy downhill turn... instead of doing my usual downshift/double clutch thing when approaching lights, I just dropped it into neutral to coast in... only the motor died... and I was without power steering.... and lost most of my brakes.
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Old 06-17-2004, 02:52 AM   #11
lotusTT
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I didn't let off the throttle at all when any of the problems are occuring though. When it stalled, I didn't even touch the throttle, put the clutch in to start, then let it out in nuetral with no gas pedal movement at all.

I tried it with the engine warm, and it won't let the rpms drop while cruising slowly, but when starting from a stop, the rpm's go from 700 to about 1000, then pause for a split second, then climb again. After driving for a minute or two, then coming to a stop and idling the narrowband O2 sensors will go full green and stay there regardless of the throttle position or rpm. Its not just the "normal inaccurate guage" because its never done this before, something is definetly not right.

These problems haven't existed for the past 10 months, so I don't think any of its "normal". Like I said these problems have all just popped up after an ECU reflash and O2 sensor replacement. Not sure if they're related or not though.
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Old 06-17-2004, 08:31 AM   #12
Mariano
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Quote:
Originally posted by no-coast-punk
This is "normal" if you are using larger injectors with a piggyback. The stock ECU has all sorts of strange little parameters for throttle changes under light loads that no piggyback can deal with and no standalone will deal with either. Basically when you let off the throttle the ECU wants to add a little bit of fuel for various reasons that I won't get into... well it does this by saying "add X ammount to injector pulsewidth". Well with larger injectors it adds WAY more fuel than it thinks it is and the car runs hideously rich momentarily and completely chokes out the motor. It gets worse the larger your injectors are. The only way to really deal with this is to always keep the throttle cracked slightly when transitioning to a neutral/no load condition........
This makes a lot of sense....I have WRX 420s installed on my 99RS-T, and although the car doesn't stalls, I see the revs sometimes going up and down while on neutral. It's more of a hesitation than a stall but only momentarily; I guess I have "mastered" my S-AFC...
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Old 06-17-2004, 10:27 AM   #13
maxiav
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Just experienced the same thing last week. I thought it was my link plus. I was driving on the highway for about 20 mins ~85mph, then came to a construction zone, and went into neutral... and the car almost stalled. Revs dropped. I turned off the car, and started it up again, and perfect. It has done it 3 times so far, and I can't replicate the problem. It does it whenever she feels like doing it.
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Old 06-18-2004, 03:03 PM   #14
incognito351
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I too am having a similar problem. I live up in Massachusetts and during the month of January we had a really nasty cold spell which had me ending up with a cracked fuel line. It spent about 2 months in the shop while I waited on a back ordered fuel hose from Japan. Finally got my car back and CEL was popping up EVERY time i drove for over 5 mins. Called up dealership and they told me everything was ok. Then i had my first stall at a light in downtown Hartford, CT around 6pm during a weekday. That was a nightmare because my car wouldn’t start. Sat around for 30 mins, fired up like there was no problem and drove 40 miles home. Finally get my car into the dealership and they say the O2 sensor needs replaced, free under cali emission standards. That is replaced, still CEL. They say I need a new Temp sensor for exhaust that was coupled to o2 sensor and signals were mixed up with the O2 sensor ones. Get that replaced for free under cali emissions. CEL still persists. (Mind you I have NO major modifications) The dealership says they will call me when they figure out what to do since its like 430 on Friday and the main office is closed. They did however tell me I was safe to drive. They didn’t call me for 2 months...amongst my 3-4 calls i made to them. So i figure they said its ok to drive....so i drive. Then I have the stall happen to me again about a block from my house at a red light. Sits for an hour. Starts up like nothing was wrong and go about my business. Then last night I am FAR away from home getting 18's put on with some Falken Ziex 512s and it does it again..... wouldn’t start for the life of me. Had it towed. I definitely get the impression that its something with the fuel and I want to get a Cobb ecu flash for it but what the #*$*, if the car doesn’t work stock.... dare I get a Cobb Flash???
Well, lets see what the great and wise Subaru of America tells me today i need to get replaced.

BTW, I do realize this is aftermarket but I was hoping to get insight from you guys with similar problems.
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