Please find attached an oscilloscope screen shot of what should be a stable TPS voltage. Is this amount of noise on the TPS signal normal or is there something that may be not right in the megasquirt. I am not very electronics literate so please keep it simple. It has the same noise both at the 5v output from the megasquirt and after the TPS.
Thank you in advance.
TPS eratic 5volt
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jsmcortina
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Re: TPS eratic 5volt
It is difficult to tell what precision your scope has, but that looks to be at the minimum level it can detect. I think that's likely an acceptable level of noise.
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slow_hemi6
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Re: TPS eratic 5volt
If it is 200mV/div then that would be around 40mV, which is just under 1% in a 0 to 5v resolution.
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nzgrub
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Re: TPS eratic 5volt
Ok good to know it's normal, So i have to have the TPS averaging Lag factor set to 10 and the TPSdot Threshold set to 35% otherwise I get TP Accel Enrich happening at random times. Those settings mean I have to stomp the accelerator otherwise I get lean stumble. Is there any way to smooth it out?
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nzgrub
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Re: TPS eratic 5volt
Another bit of info, my TPS (from a Suzuki gs1000) only changes voltage from 3.5 to 4.2 so those spikes are a lot more than 1% in that range.
Re: TPS eratic 5volt
A different TPS may be in order, especially if you are using Alpha-N or Hybrid which is heavily dependent on TPS.
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nzgrub
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Re: TPS eratic 5volt
Hi all,
Still working on this, have been mucking around with potentometers to see if I can get a more stable tpsDot.
I have noticed that the lower the ADC count the better the tpsDot, even only getting 10% with a lag of 80 at ADC count around 20.
At 3/4 throttle ADC count of about 300 I get big tpsDot movements, as per picture.
I notice I have a lot of mapDot movement as well.
These are all without car running.
Still working on this, have been mucking around with potentometers to see if I can get a more stable tpsDot.
I have noticed that the lower the ADC count the better the tpsDot, even only getting 10% with a lag of 80 at ADC count around 20.
At 3/4 throttle ADC count of about 300 I get big tpsDot movements, as per picture.
I notice I have a lot of mapDot movement as well.
These are all without car running.