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Showing results for tags 'idle switch'.
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NopeNope posted a topic in 1990 to Present Legacy, Impreza, Outback, Forester, Baja, WRX&WrxSTI, SVXHey Y'All, My '91 Subaru Legacy seems to have a flat spot (I believe that's the correct term, but I'm still not fully versed on some of this stuff). Generally occurs when accelerating (usually somewhere between 2k and 3k RPMS) or climbing a hill: I'll depress the accelerator but nothing happens (RPMS don't climb, no speed increase). If I keep giving it gas it'll eventually surge and begin accelerating relatively rapidly (except when climbing hills, usually I just have to limp to the top); sometimes it'll surge then return to lagging, then surge again. Doesn't seem to demonstrate this problem above 3k RPMS, though every once in a while it does below 2k. What I've done since the problem appeared. I've changed or had changed: spark plugs and wires, intake manifold gasket, O2 Sensor, & Throttle Position Sensor. Originally it had the flat spot intermittently and would occasionally lurch or misfire on the freeway (and I'd get an occasional ECU Code, though at the time I hadn't pulled the codes), so I took it to a mechanic for diagnosis (this is about a month ago at this point). They told me the sparks and wires needed replacing and I had them replace them. The problem persisted, so I took it back to the mechanic; they diagnosed a bad O2 sensor, bad intake manifold gasket, and bad fuel injector seals. I replaced the O2 sensor and intake manifold gasket. Car was 10x worse (had no power at all, couldn't maintain speeds above 30 or 40, etc.), so I took it to another mechanic who pulled codes for a bad O2 sensor and replaced that (the O2 sensor I'd used was cheap and the mechanic said it likely was poor quality). Now it's back to the condition I originally described (flat spot under load). After doing some research, I replaced the TPS (twice, using TPS's pulled from junk yard subarus), and it's appeared to fix the problem very briefly, but within a few hours the problems return. It has been giving occasional ECU Codes, specifically for the O2 sensor (which I have trouble believing is bad since it's been replaced twice), and just yesterday it threw codes for the TPS and Idle Switch. I'm at a loss. Still need to replace the Fuel Injector Seals, but haven't been able to get them out and scared of breaking them. Wondering about the possibility of a wiring issue since the O2 Sensor and TPS have both been replaced multiple times and continue to throw codes. Saw one post suggesting a knock sensor might cause such a problem, but not stoked to pull out the intake manifold again unless there's more indication that is a problem. Anyone have any thoughts? Thanks.
So I inherited a 85 brat with a ej 22 conversion. After many hours and several small repairs including a idle air control cleaning I am having a problem with the tps. I started tracing wires back to the ecu and found a problem with the tps power and signal wires. The information I have found on the internet claims pin 58-2 to be the signal wire. white wire at the tps sensor however it is black at the ecu and was clearly grounded in a harness which appeared to be factoryish. The opposite was true for the ground wire, black at the tps and the b58-1 pin has a white wire. My next step was to make a bypass harness for the tps/idle four wire set up. I grounded pin 58.1 and ran a wire back to the tps black wire (position 4). The red wire voltage seems good at 4.7 volts (position 3) I left it alone. I connected a wire to pin 58-2 and ran it back to the white wire (position 2) on the tps. Which leads me to the problem I am having now. Set up like this it seems to run well with the exception of a high idle. Good throttle response anyhow. So I turned my attention to the idle switch wire, brown and on pin 56-6 (position 1) on the tps. I reads a constant 4.7 volts. The voltage originates from the ecu and not the tps. Removing the plug from the computer and testing pin 56-6 I get 4.7 volts. So my question is. should there be voltage at the idle switch and the tps works by grounding it out when the throttle is closed? Or am I getting some kind of feedback through the ecm because of the shotty harness install? Is there something else hooked to the idle circuit that might be causing this? Is the info I have on the ecu pinout incorrect? Just chasing my tail at this point. Please help.