Advice on waveform Harley TPS

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Advice on waveform Harley TPS

Postby baging » Tue Jul 02, 2013 9:07 am

Hi all,

Working with a Harley Davidson at the moment which can't produce a stable TPS signal
Replace the TPS sensor, but it's still all over signal wise...
Connected my Pico yesterday and from what i can see it got some interference? Or what am i looking at?

Attaching 2 images. The stable one is with engine off and the interfered one is with engine running...

/Stefan
Attachments
20130702-0001.gif
20130702-0005.gif
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Re: Advice on waveform Harley TPS

Postby KimAndersen » Tue Jul 02, 2013 10:50 am

Hi

Which Harley Davidson model are we talking about ?

Are there any faults with the bike right now or are you just curious to know how the TPS sensor are operating ?

I would look after those wires that runs along throttle position sensor and specially the ignition wire that goes to the ECU. :wink:

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Re: Advice on waveform Harley TPS

Postby baging » Tue Jul 02, 2013 11:21 am

Thank you for yor quick reply!! :)

This is an 2004 Ultra CVO 103" which has a history of missing/stutter at times, but not always.
Problem emerged when i was trying to map the ECU and discovered that the TPS was all over the place.
Done all the tests suggested by the Harley service manual, but can't find any faults there.
All relevant wiring to/from TPS is checked and can't find anything there.

Never had the need to check a Harley TPS with my Pico before, so in a way i'm curious to know if i'm looking at an ok waveform? Used the scope on several other TPS'es, but none of those have shown this kind of interference....

Rgds /Stefan
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Re: Advice on waveform Harley TPS

Postby KimAndersen » Tue Jul 02, 2013 1:40 pm

Hi stefan

Despite your hard effort to solve this running issue i would still be looking at the wiring net and how the sensor gets power and ground.

I don´t have a wiring digram over that particular model but can see on other harley models that the ground connection from TPS sensor are connected to the oxygen sensor and the coolant temp. sensor and so maybe it could influcence the TPS sensor, if you have a bad oxygen senor or a bad coolant sensor.

You could try to temporary disconnect these sensors.

Regards
Kim
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Re: Advice on waveform Harley TPS

Postby Chris_W » Tue Jul 02, 2013 8:29 pm

I know nothing about Harleys but have an observation.

That interference is very regular. Count it up, 12 times per second. 4 stroke twin? So 1 fire per rpm...

What's the idle speed....
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Re: Advice on waveform Harley TPS

Postby SamP » Tue Jul 02, 2013 9:32 pm

Hello buddy, it seems like some other circuit component is pulling TPS to ground so 1+ with wiring tests.
Just unplug other sensors in line and see whet happens.
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Re: Advice on waveform Harley TPS

Postby baging » Wed Jul 03, 2013 8:21 am

Thank you all for your input!

I'll definitely check the other sensors and their wiring and get back to you with the result! :)
Great forum! Quick, relevant answers!!

Chris W: Yes, 4-stroke twin and idle is 1000 rpm
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Re: Advice on waveform Harley TPS

Postby Fat Freddy » Wed Jul 03, 2013 10:00 am

Can you post the data files.

FF
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Re: Advice on waveform Harley TPS

Postby arjen » Wed Jul 03, 2013 5:05 pm

You can scope power and ground to see if they are stable.
If they are, then place breakout leads between tps and the connector. Connect power and ground but leave the signal wire disconnected to see if the signal is good then.
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Re: Advice on waveform Harley TPS

Postby baging » Wed Jul 03, 2013 8:52 pm

Thanks again!

I had to put the bike away for a few days (overswamped with other bike related work right now), but will continue next week.... I'll get back to you with my findings! Thanks all!! :)
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