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TPS reading is backwards

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Old 02-11-2019, 02:07 PM
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Default TPS reading is backwards

Ok so long story short my tps sensor is reading backwards. 4.5 volts closed .5 open. I read that this means that the green and yellow wires are backwards, so I switched them around and it’s still doing the same exact thing? How is this even possible? I replaced the tps sensor and it’s doing the same thing. I did l take out the engine harness and removed unnecessary wiring/ covered everything in expandable sleeving but I don’t see how that could be related.
Old 02-11-2019, 02:57 PM
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Default Re: TPS reading is backwards

When you did the expandable sleeving did you de-pin any connectors?
Old 02-12-2019, 10:36 AM
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Default Re: TPS reading is backwards

Originally Posted by stampern22
When you did the expandable sleeving did you de-pin any connectors?
I did, and I took pictures of every connector before hand. I could really use a good pin out diagram for the 90 civic ex engine harness if you could point me in the right direction
Old 02-12-2019, 12:27 PM
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Default Re: TPS reading is backwards

You depinnned both the yellow/white and green/white and switched their physical location in the plug, and nothing changed? Because that makes, well, absolutely no sense. Reversing the wires should reverse the behavior, and if there's a short somewhere then you shouldn't see the appropriate range at all.

If you're asking for a pin-for-pin trace of every wire in the harness, there isn't one. The are diagrams to be found in about 30 seconds on google, but you're going to have to match wire colors and probably think in 3 dimensions.

And just for giggles, it would be good to know what chassis, engine, and modifications are in play here- is it actually a stock 1990 EX or something else?
Old 02-12-2019, 01:09 PM
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Default Re: TPS reading is backwards

do the wire colors match on both sides of the connection? sounds to me like you may have the MAP sensor connector plugged into the TPS

TPS colors - Yellow/White stripe, Green/White stripe, Red/Blue stripe
MAP colors - Yellow/Red stripe, Green/White stripe, White/No Stripe

TPS wires at ECU - Yellow/White - C13, Green/White - C12, Red/Blue - C7

Are you checking voltage between Red/Blue and Green/White?
Old 02-12-2019, 02:23 PM
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Default Re: TPS reading is backwards

Originally Posted by scelestus
You depinnned both the yellow/white and green/white and switched their physical location in the plug, and nothing changed? Because that makes, well, absolutely no sense. Reversing the wires should reverse the behavior, and if there's a short somewhere then you shouldn't see the appropriate range at all.

If you're asking for a pin-for-pin trace of every wire in the harness, there isn't one. The are diagrams to be found in about 30 seconds on google, but you're going to have to match wire colors and probably think in 3 dimensions.

And just for giggles, it would be good to know what chassis, engine, and modifications are in play here- is it actually a stock 1990 EX or something else?
Alright so I guess I’m just crazy but I checked it again today and everything is fine? The sensor read exactly as it should. Now there’s a new problem though. It’s running in limp mode I’m assuming, won’t rev past 3,500rpm and has a cel. When I jumped the connector to check codes the cel stayed solid. I’ve read from some people that means a bad ecu? And the civic is the stock engine with a z6 head and converted to obd1
Old 02-13-2019, 01:30 PM
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Default Re: TPS reading is backwards

Sounds like your TPS plug is not connected. If there is no signal from your TPS your car will not rev over 3500 rpm.
Old 02-13-2019, 02:43 PM
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Default Re: TPS reading is backwards

Originally Posted by ~sp33~
Sounds like your TPS plug is not connected. If there is no signal from your TPS your car will not rev over 3500 rpm.
The tps is definitely connected, like I mentioned it’s getting all the right voltages from every wire. I just don’t know if I’m checking the codes correctly. The original ecu has a light on it for checking codes, but with the mini me swap and a p28 ecu shouldn’t the cel flash? Or am I missing something?
Old 02-13-2019, 03:54 PM
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Default Re: TPS reading is backwards

If you are jumping the service connector and get a solid CEL, then there is an issue with the ROM. So if your P28 is chipped, there could be an issue with the chip, the file on the chip, or some issue with the chip kit install. If its a stock ECU, then it's probably bad.
Old 02-13-2019, 04:29 PM
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Default Re: TPS reading is backwards

Originally Posted by CasperBones
If you are jumping the service connector and get a solid CEL, then there is an issue with the ROM. So if your P28 is chipped, there could be an issue with the chip, the file on the chip, or some issue with the chip kit install. If its a stock ECU, then it's probably bad.
i have a feeling it might be bad too, im jut worried theres a wiring issue that fried something on the ecu, and if i put in a new ecu it will just fry that one too.
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