TPS values only change in key on engine off

s300 and SManager software questions & answers
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skaterguy1986
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Joined: Mon Jan 01, 2018 7:31 pm

TPS values only change in key on engine off

Post by skaterguy1986 » Fri May 10, 2019 4:17 pm

I have an odd problem on a friends car I'm trying to figure out. If you datalog with the key on, engine off you can move the throttle through the full range and it see's every percentage change properly from 0% to 100% but if you run the engine there is no change in TPS when actuating the throttle.

Car is a 99 Civic EX coupe using a P72 S300 V1, B18C engine swap, TPS is calibrated, it's a new sensor, wiring is good, using the ITR basemap with an AEM wideband. We haven't had it on a dyno, just loaded the map after the swap, set the ignition timing, adjusted the idle and really only altered the timing advance in the idle area and the fuel in the 2nd and 3rd columns to get it to idle cleaner.
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Spunkster
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Re: TPS values only change in key on engine off

Post by Spunkster » Fri May 10, 2019 4:57 pm

If it is not reading with the engine running then it sounds like there might be a vibration issue and the TPS is not reading properly, there could be a wiring related issue that the TPS is not being properly powered when running, or you have non-resister spark plugs and they are interfering with the datalogging.

You should try the ECU in a known working vehicle to see what it does.

skaterguy1986
Posts: 39
Joined: Mon Jan 01, 2018 7:31 pm

Re: TPS values only change in key on engine off

Post by skaterguy1986 » Fri May 10, 2019 7:03 pm

Yeah, we'll try swapping ECU's tomorrow to see what happens. Also gonna check the signal wire at the ECU while the engine is running to see if the signal is even making it that far.

skaterguy1986
Posts: 39
Joined: Mon Jan 01, 2018 7:31 pm

Re: TPS values only change in key on engine off

Post by skaterguy1986 » Mon May 13, 2019 9:31 am

Forgot to post but we took his ECU, loaded my map to it and ran my car and the ECU seemed to run normally. none of the odd problems were present.

We're starting to think that his cheap OB2/OBD1 adapter harness may be to blame since it's using the original harness that the car had with the single cam VTEC engine (sorry, don't know all the D series off the top of my head) ran normally. The spark plugs while not the NGK laser platinums that Honda recommends are a resistor type plug so we don't think that is the source of electrical noise.

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