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Showing results for tags 'Power Indicator'.
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Hey 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.
- 12 replies
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- Flat Spot
- Power Indicator
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Hello. Thanks in advance for reading. A bit of a long post, I'm trying to provide as many details as possible. History I recently swapped a '95 4EAT (90k) and rear differential into my '92 Legacy L AWD Sedan. The original final drive ratio was 3.90, and is now 4.11. However, the winter tires I am using are significantly larger than the factory tires (I do not have tire clearance issues, BTW). The factory calls for 185/70 14s with a circumference of 76.017 inches, and I'm running 195/75 14s with a circumference of 80.161 inches. At the advice of the local Subaru guru, I did NOT swap the TCU. The steeper gears combined with the taller tires is a near-perfect match IF there were to be a TCU issue: 3.90/4.11 = 0.949 76.017/80.161 = 0.948 I've also verified this by calculating my speed through several mile markers. Symptoms 1) Intermittent, totally random failsafe mode (stuck in 3rd gear). This can happen at any speed, at any time, and for any duration. It can be downshifting normally as I slow to a stop, only to go into failsafe as I accelerate. I can drive it for 30 minutes on the highway with no problems when it suddenly drops to 3rd and revs. It can happen first thing in the morning when cold, or not. It can be in failsafe for two seconds or fifteen minutes. Totally random. Overall, it seems to fault approximately 25% of the time, and is not getting better or worse. 2) When it exits of failsafe mode, I receive one and only one power light indicator flash. I receive no indications when the 4EAT enters failsafe mode, and I am even sometimes unaware the the transmission has faulted until I observe the one flash. Occasionally, I also get one extremely fast AT temp indicator flash. This happens very quickly. So quickly, in fact, that I can barely even tell which indicator came on. The AT temp indicator may be flashing every time the power indicator flashes, but I don't think this is the case. I cannot tell because when I am able to visualize the indicator, it stays lit for just a split second. 3) Occasionally, but much more infrequently then the symptoms above, I receive the 16 power indicator flashes, indicating a stored TCU code. When I am able to retrieve the codes, I always receive a 32 and a 33 for vehicle speed sensors 1 and 2. 4) As to 3) above, I cannot always retrieve codes. When I follow Josh's code retrieval steps, the power indicator lamp does not always come on in step 3. Actions I've changed the fluid twice. It is always bright red with no burnt odor. I've used 1/2 bottle of red LubeGuard each time. I always keep the fluid right on the full mark. Next I do not think that I have a mechanical issue with the transmission. The intermittent but binary nature of the symptoms, combined with occasional lack of power indicator at startup point me to an electrical issue. I could try a '95 TCU, speed sensors, cleaning the transmission connectors, or cleaning and adjusting the throttle position sensor. Any other ideas? Thanks for the forum, the great write-ups, and the good community attitude. This is my first Subaru and I've had fun learning not only about my car, but what everyone else is doing. Dana
- 12 replies
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- 4EAT
- power light
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