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TPS question


TPS question

Old 07-06-2019, 12:16 PM
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I have a whipple 540 EFI with mefi 4 ecm. Suddenly the engine starts to stall when shifting in and out of gear. I took a diacom scan and read a fault that the TPS voltage was low. I adjusted it and can only get 0,5v on idle with 0% throttle postion and 3,9v on full throttle and max 99,6% throttle. Can not reach 100% without that the idle position starts to go above 0%. Is the volt value to low and need to change the sensor? I lost also 600rpm on top.

Dan / Norway
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Old 10-03-2019, 09:16 PM
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Can't answer the volt range question. But I can help with the potentiometer test. Disconnect and do a sweep test on the 10000 ohms scale. This needs to be done with an analog meter. Watch the needle as you sweep the potentiometer from stop to stop. It should be completely smooth with no judder from stop to stop. If it passes The sweep test then you just need to dial in The volt range.
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Old 10-04-2019, 07:36 AM
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I had a similar issue on 1 engine and it was the IAC, 3.3 Whipple mefi 4B.........0.5 v or less is what Whipple recommends if I recall ?
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Old 10-04-2019, 07:36 AM
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Make sure your 5 Volt Sensor Supply is at or Very close to 5 Volts . If your Sensor voltage is low ( Supplied by the ECM ) you will get erratic sensor feedback values.
It will cause you Lots of Issues! . Most times when 5 Volt is low , there is an intermittent short to ground in the harness.
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