17 replies to this topic

[al_roethlisberger]

OK, we'll see what happens here.... the forum blew up when I first posted this topic, but it posted without the first.... well, POST. Very weird.

Anyway, basically, here's the jist of what I wrote:


This last weekend I decided to check my TPS voltage, while balancing the TBs, etc.... just on a lark.

The bike ran fine, but since I had never performed this check before myself, I thought it would be good to give it a try.

Well, after several tries/methods of probing the purple/black wire on the TPS connnector with the positive lead of my DMM, and grounding the negative lead.... I got nuthin'

Now, it could be that my cheapo DMM doesn't read milliVolts too well, but it does have a 2V range that is supposed to .... but I read nothing, and no change when the throttle was moved(with the ignition on, as per Guzziology).

So, I would like to ask if someone can take that time to fully explain the procedure for testing the TPS voltage, just to make certain I(or others) don't overlook something in the process.

Thanks!
al

[Mr. Bean]

Thanks for posting this question Al.

I had the same question myself. My bike is running very well, but I wanted to try and see what the setting was anyway. I never was able to get any response on the multi-meter either.

The instructions I was using from Guzziology said to pull back the rubber boot and connect to the purple/black (positive) and blk (negative). My bike does not have a rubber boot that I can see when it is plugged in to the sensor. I tried using a couple very small paperclips to push down along the wire holes but still got no response.

Can someone maybe post a picture of what it looks like to hook up a MM to do this test?

Thanks,

Randy

[callison]

http://home.pacbell....07/tps/TPS.html

[Bruce]

You can also check it where it goes into the 'computer' under the seat. I carefully shaved off a bit of insulation on each wire. There are in-line test ports which are suppose to be easy to install which would be an improvement. IMHO this is a critical reference point for your system.

A bit off topic, replacing those star drive screws on the TPS with good old allens will make the adjustment task much easier.

[Mr. Bean]

Thanks all

Now if I can get a spare few minutes I'll try these ideas.

Randy

[big J]

Readings should be taken from the top and bottom pins on the TPS and should be read with the ignition switched on and the kill switch in the "run" position. With the cold start mechanism disconnected from the right hand throttle body, and the connecting bar removed it should read 140mV. Reconnect cold start and bar, it should read 375mV for a stock set up or 525mV if you've got a Power Commander, adjusted by the 2.5mm grub screw on the left throttle body. This is a highly truncated version, check the "setting TPS, synchronising, etc" info in the forum. These settings are of course optimum factory type settings, in realitythey can be all over the place. Is the bike running ok? If it is,dont mess with it, get down on your knees and thank the Luigi that built it that you got a good one.

[dlaing]

I traced the two required wires back towards the ECU and spliced and soldered in a pair of wires with female spade connectors:

I keep them wrapped with electrical tape(not shown) to reduce the chance of them shorting or drowning in water.

[tomsp]

Al, I did this and it seemed easy enough -- disconnect the TPS connector plug thingy, right at the TPS. Insert tiny wire leads into the two holes in question and re-connect. Run the two tiny leads newly coming out of the re-connected TPS connector, to your mv reader and you got a good read. The tiny leads yo insert must be small enough to ensure that the connector can indeed by re-connected with positive effect!

[quazi-moto]

I used a pair of pins that I took from a new shirt that I had received as a gift. Some call me thrifty. That's polite talk which really means that I'm just plain cheap. Anyway I was able to get my voltage readings this way when I replaced the stock TPS sensor with the Harley version. I set it for 150mv with the throttle plate closed and then adjusted the throttle stop screw until I was reading around 510mv. Hopefully this is the correct procedure because these values (I believe) are for a stock TPS sensor. After I obtained the 510mv reading I balanced the TB's with a Twinmax unit (nice) by adjusting the left hand stop screw. Then I cracked open the airbleeds (1/2 turn) and doublechecked for balance. A minor tweak on the left hand air bleed had the Twinmax right on zero. I had to adjust the linkage bar before re-connecting it or it would have pulled the right throttle plate off the stop screw. After doublechecking for cylinder balance I also checked the TPS sensor voltage to make sure nothing had moved. All was well so I embarked upon a little shakedown run. The bike felt smoother and seemed to be running a tad richer off idle, but it still leans out and surges a little in the midrange. This is now confined to around 3500-4000 RPM so overall running has been improved, but not quite perfecto! I have the PCIII mounted on this '02 LeMans along with FBF intake, Stucci X-over and Staintunes. I had read that the 1.5M ECU has a fuel trim screw under the little bung plug thing, but I didn't notice it when I removed the plug so I just popped the plug back in and let it be. There's an approved tuning center not far from where I live so my next stop is the dyno shop to get the injection map sorted out.