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| surging idle goes away when i unplug TPS sensor; 94 with the newer emissions | |
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| Tweet Topic Started: Sep 11 2017, 04:45 AM (164 Views) | |
| saladaddy | Sep 11 2017, 04:45 AM Post #1 |
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New Member
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idle surges once engines up to temperature, i disconnected the TPS sensor and it goes away. It's a '94 4 door hatchback, 1.0 base model with the new emissions setup that has the ISC instead of the IAC. a couple weeks ago i had the hood open and it rained. water got into the manifold so i took the throttle body off to suck the water out. the gasket between the upper portion of the TB and the lower portion was pretty degraded, so i'm sure that when i separated them it ruined whatever seal was left (don't think that's the problem though). after i put it back together it had a crazy high idle. since then i've burped the coolant, disconnected the PCV valve because it was bad, and just poked around cleaned stuff and the idle has gone down, however just as soon as the idle goes down i get this surging idle. that's where i am now. after the engine warms up, the idle jumps between a regular idle speed and maybe 2000 RPM (don't have a tach). it comes in intervals of maybe 2-5 seconds and is most noticeable standing still in neutral. it does it while accelerating in gear though and it jerks the car, really unpleasant in 1st gear. i unscrewed the TPS sensor and took it off the second time i took the TB off to try and find a vacuum or coolant leak, so it could be out of adjustment. but the idle surging started before i took the TPS sensor off, so i'm not too inclined to think its an adjustment issue. I currently have the PCV valve detached from the hose that runs from the valve cover to the air cleaner box, and the TPS sensor unplugged at the connector. the car runs okay but i don't like driving around with the TPS unconnected. on another note is there a general description/thread of all of the sensors/air fuel mix/computer operation? i don't have a manual so i'm not sure what all is going on at the throttle body/intake/EGR. If I had a better understanding of the whole system i reckon i could diagnose better. thanks |
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| geogonfa | Sep 11 2017, 09:24 AM Post #2 |
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Just my .02ยข...would look for a vacuum leak...there is still a vacuum leak and the map sensor is trying to compensate for it... when you disconnect the TPS the computer can no longer tell your at idle and is not trying to compensate for it....
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| 91 ragtop | Sep 11 2017, 09:23 PM Post #3 |
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Try taking off the tps plug and blow dry the insides of each side of the plug in.It does that when they get wet. I won't even pressure wash an engine unless it is out of the car. Ken.......... |
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| suzukitom | Sep 11 2017, 09:39 PM Post #4 |
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Tom
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Running the car with the TPS disconnected will make the ECU parameters for FI on the rich side. It will idle better but waste gas and is hard on the cat. |
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3:49 AM Jul 11