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Discussion Starter #1
Hello everyone! I'm new to the forum here. I just bought an RC 51 (2000) a few months back and have a problem. The FI light is blinking 8 times which tells me I'm having a problem with my TP sensor, connectors or related wiring. Problem is all my connections look fine and now I'm scared that I have to replace the TP sensor which looks to be part of the throttle body that it is connected to. Does anyone have any suggestions or has anyone had this trouble code and found a solution other than a bad TP sensor? Is there a method anyone is aware of to test the TP sensor?

Thanks,
 

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So far I've had no problem you are experiencing.
But the TPS only comes as a part of the throttle bodies.
So if you are certain the TPS is bad, you may be able to find a throttle body assembly by someone parting out his SP1.
Would be a lot cheaper than new.
 

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Discussion Starter #3
Well I'd really like to verify that the TP sensor is actually bad before digging in to replace it. There must be some way to test the resistance through it's full open to close stroke.
I figure I'll try clearing this code from the ECM's memory and seeing if it returns.
 

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Have you tried the test procedure in the service manual to check whether it's the TPS, connectors/wiring, or ECM?
 

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Discussion Starter #5
I've downloaded the service manual you posted (thanks) it is lengthy. I didn't realize that there is a test procedure for this. This is what I am looking for. Can you tell me what chapter and page it is on?

Thanks!
 

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Look under the section "Fuel System (Programmed Fuel Injection)" and around 5-18 (for the combined SP1/SP2 UK service manual).
They essentially want you to check voltage readings at full closed and full open throttle settings.
 

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Discussion Starter #7
I found it, DUH. Thanks for your help. Hopefully I can get this problem resolved soon. I don't trust it to ride on the streets with so it's been a while since I have ridden..(jonsin)
 

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As an unrelated side note. I noticed the UK SP1/SP2 does not show the license plate light as the US/Canada manual does. They do show the eyebrow lights though.
So if you're doing wiring work, use the US/CAN version.
It's just the scan of the US/CAN version is poor quality while the UK version is really nice.
 

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Discussion Starter #9
Thanks for the advice. Say, I've done all the wiring tests as outlined in the manual and everything tests normal. It looks as if I need a test harness to perform the test on the TP sensor itself though. Do you or does anyone else who may be reading this have one for sale?

Thanks,
 

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You might be able to slide a thin test probe or straightened paper clip past the rubber seal on the ECM test points.
Also have you tried reconnecting the ECU connectors as well?
The contacts on these bikes can get oxidized from weather.
That's why I coat all connectors with dielectric grease. Great stuff.

Here's ECU pin layout:
 

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Discussion Starter #11
Thanks for the pin layout. I'm guessing that these must be connected to the ecm in order to get voltage at these connectors and thats why you are telling me I should use a paper clip or thin test probe. I tried a paper clip and looked like it was going to damage the rubber seal. I think I'll try using a bobby pin. I tried connecting to the specified points with the connectors disconnected and got no voltage whatsoever so I'm guessing in order to read voltage at these points the connectors must be plugged in to the ecu. I wonder why I cant read ohms at the TPS?
 

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To measure the indicated voltages, the ECU connectors do need to be connected.
Just to ensure the pin layout is correct, pin B5 (gray ECU connector) is color R/Y and A22 (black ECU connector) is color G/O.
I would think that if you disconnected and measured at any of the three TPS connector pins you'd get some ohmic reading. R/Y is the wiper, and Y/R and G/O are the ends of the pot.
 
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