This a weird problem and I searched the posts for it and couldn't find anything so here goes.
The engine will sputter/quit when the A/C is turned off. At idle she'll quit or almost quit. When driving, she'll sputter for a fraction of a second and then keep on going as if nothing happened.
Could this be a IAC thing?
The car has 198K and it (up until last week) has run like a top.
Yes, it does sound like an IAC thing. The ECU compensates the increased load of the A/C with a higher idle. This includes the IAC as well. Sounds to me like the IAC is dirty and the ECU is getting bad readings off of it.
Manarius wrote:The Neo-Cons would call me a defeatist. I'd call me a realist. I'm realistically saying that a snowball has better chances in the blazes of hell than democracy has in Iraq.
1995 Polo Green Subaru SVX (189k miles - 08/2007-Present)
The engine will sputter/quit when the A/C is turned off. At idle she'll quit or almost quit. When driving, she'll sputter for a fraction of a second and then keep on going as if nothing happened.
Could this be a IAC thing?
Chris
Is it an actual sputter or more of a hard cut of the ignition for a split second?
My 92L does something similar but it isn't what I would call a sputter, it's more like if you just turned the key off and back on really quick (1/10th sec.).
Manarius wrote:Yes, it does sound like an IAC thing. The ECU compensates the increased load of the A/C with a higher idle. This includes the IAC as well. Sounds to me like the IAC is dirty and the ECU is getting bad readings off of it.
IF the IAC was dirty wouldn't the engine rev up and be slow to come down when the AC shuts off, not just die?
Edit: And I should mention that with my 14# flywheel it flat kills it. It doesn't even try to stay running.
92 Legacy L
EJ25
GC Coilovers
KYB AGX
Whiteline Swaybars
Well, if the IAC reads the idle being higher than it is and then the ECU thinks it's idling higher but isn't and then doesn't compensate....
Manarius wrote:The Neo-Cons would call me a defeatist. I'd call me a realist. I'm realistically saying that a snowball has better chances in the blazes of hell than democracy has in Iraq.
1995 Polo Green Subaru SVX (189k miles - 08/2007-Present)
Manarius wrote:Well, if the IAC reads the idle being higher than it is and then the ECU thinks it's idling higher but isn't and then doesn't compensate....
Is the IAC capable of responding fast enough to send a serious jolt through the car? If you give it a little gas (enough to bring the engine speed up but not enough for the TPS to read) and bring the engine up to about 1000 it will very slowly bring it back down the the set idle speed (over quite a few seconds). I just don't see the IAC doing anything fast enough to send a substantial jolt through the car. But I could be wrong and Chris' problem could be completely unrelated to mine. Mine is absolutely instantaneous the engine cuts at the exact moment you hear the AC relay click off. I don't think the ECU even has time to figure out there needs to be an adjustment before it dies.
My neighbor has another 92 L that does the exact same thing as mine.
92 Legacy L
EJ25
GC Coilovers
KYB AGX
Whiteline Swaybars
Another thing, mine still does it while at half throttle and 3500+ RPM climbing a hill. I'm pretty sure that the IAC isn't doing anything in that situation. Just a thought.
Also just to clarify I am saying that while cruising and the AC cycles off you get a serious jolt through the drive train. At idle when the AC cycles off it just kills the engine (does the same thing when you manually shut the AC off). The catch is that it doesn't always do it (I'd say about 50% of the time).
Is this similar to your problem Chris?
92 Legacy L
EJ25
GC Coilovers
KYB AGX
Whiteline Swaybars
Have you been riding in my car?! Seriously, that is exactly what is happening. I here a relay click behind the instrument cluster and the ignitiion is cut for a micro second. It will do it in P and D and at all rpms. I am now convinced that it is an electronic problem.
Some more info too. My CEL has been off and on. On mostly with a 35 code. I replaced the SPV with one from a salvage yard (freebie) and it went out but it comes on periodically. Since it's been acting up the CEL will go out when I turn off the A/C but then come back on a few seconds later and sometimes no at all until I restart the car. I need to pull the codes and see if it is throwing another code other than 35.
I sure hope someone has an answer, otherwise it's going to the dealer (McRee Subaru).
I think the code 35 is probably unrelated to the AC issue. Mine has had the issue since i got the car with 250,000 miles on it. It now has 297,000 and a different engine and the problem is still there and it has never had a CEL to go along with it. It's really annoying when you are sitting at a stop light and your engine just dies . You're lucky you have a torque converter to cushion the shock when you are driving. I have a manual and a lightweight flywheel. It makes for a pretty hard hit when it cycles. It's gotten to the point that I just don't turn it on unless it's above 90 degrees.
Maybe some of the electronic geniuses on this board can pitch in with some ideas.
92 Legacy L
EJ25
GC Coilovers
KYB AGX
Whiteline Swaybars
I got it!!! I think. I called a call in radio show (The Car Dr.) that is on on Saturdays here in Houston. I described the problem and they said it is probably bad diodes which were causing back feed on the electrical system when the a/c was turned off. I checked the diodes that are a part of the a/c system. They are both bad. Looks like a trip to the dealer.
The diodes are small, two pronged black gizmos that are kind of like a fuse. They go into the end of a 4 wire brown connector. It comes off of the main wire bundle that comes through the firewall on the driver's side. It's kind of hard to get to, but if I can do it anyone can. Use a small flat screw driver to pop them out.
Bad news for me though is my a/c has developed a major leak (the evaporator I think) this happens right as I find out (hopefully) the answer to the engine cut out problem.
I'll have to dig into that and try it sometime. Right now i'm too pissed off at the car to care about the AC. I just found that both steering rack boots are torn and one of the control arm bushings has an 1/8" of slop. Oh the fun of a 300K mile car.
92 Legacy L
EJ25
GC Coilovers
KYB AGX
Whiteline Swaybars
I live in Pearland. I plan on going to BAP/GEON and picking up a/c parts on Friday and then swinging by McRee in Dickinson to pick up the diodes at $21 a piece But they are the only game in town that I can find.
Two new diodes and she's working like she used to. It's funny how two little (tiny) parts can make such a difference.
I went ahead and replaced the compressor (rebuilt), condenser, exp va and dryer. Flush the evap and hoses. She's making ice cold air now, but for how long, that's the question.
This is for posterity and whoever else has this problem. What I thought was fixed with the diodes wasn't.
The whole time it was my A/C Condenser fan that was bad. What caused me to figure it out was when the engine fan quit. After I replaced that then I noticed the A/C Condenser fan wouldn't come on at all.
Replaced it too and now the problem is really gone. No more ignition cut out.
What's funny about these Subaru's (I've owned 3) is they start "talking" to you when something is wrong. My problem is I don't speak Japanese.
Thanks for the update Chris....and the quote-worthy laugh
C. Scott wrote:What's funny about these Subaru's (I've owned 3) is they start "talking" to you when something is wrong. My problem is I don't speak Japanese.
Seriously, that is exactly what is happening. I here a relay click behind the instrument cluster and the ignitiion is cut for a micro second. It will do it in P and D and at all rpms. I am now convinced that it is an electronic problem. 
But they are the only game in town that I can find.