TPS for Dummies

[swooshdave]

[from the thread Decent Tune-up]:

 

2) Using a Casper's TPS Breakout Harness (or equivalent), disconnect the right throttle linkage, release the upward facing slotted screw for the high idle cam, back out the difficult to reach 2.5mm idle stop set screw, and clean the throttle butterfly (if necessary). Loosen the TPS fasteners only enough to tap it or budge it slightly, it is very sensitive. Changing the TPS fasteners to standard hex drives simplifies the process (4mm/0.7 thread pitch x 17mm long). With a good voltmeter, adjust the TPS to 150-157 mV. Realize the TPS value changes when it is tightened down, so just repeat until you're in range. Reconnect the throttle linkage and set the high idle cam so it just nudges the throttle when engaged. Leave the right side idle stop backed out.

 

While this is a good start I can see why it would be intimidating for a beginner or someone who just wasn't familiar with a V11. So I'm going to try to break it down even more. The first attempt will be without the Breakout Harness. Apparently it can be done, just not as elegant. I'll update the first post as I learn more. And there will be pictures, a LOT of pictures. You cannot have too many pictures.

 

I not only welcome feedback it's going to be required. Please respond and respond frequently. Questions will be in italics. I'l add pictures as I go along.

 

So let's start with what Docc has provided and expand some more.

 

1) Using a Casper's TPS Breakout Harness (or equivalent)

 

This was $30 with shipping and got to Oregon from Colorado in two days.

 

 

Breakout installed. You need to strip the purple (pos) and purple/black (neg) wires so you can measure them. Leave the yellow alone.

 

 

2) Disconnect the right throttle linkage

 

 

Prior to disconnecting the throttle linkage I took a measurement of the TPS. Not sure it shows anything useful.

 

 

I had to use a screwdriver to pry the throttle linkage off. But it just pops off.

 

3) Release the upward facing slotted screw for the high idle cam

 

 

4) Back out the difficult to reach 2.5mm idle stop set screw

 

 

To get mine back out completely took a long time. 

 

5) Clean the throttle butterfly (if necessary)

 

 

I was happily surprised that once you loosen the hose clamp the intake hose slides back. Very nice!

 

As a side note I measured the TPS voltage before and after cleaning, this should give you an idea that you should at least consider cleaning it.

 

 

Before cleaning

 

After cleaning

 

6) Loosen the TPS fasteners only enough to tap it or budge it slightly, it is very sensitive.

7) Changing the TPS fasteners to standard hex drives simplifies the process (4mm/0.7 thread pitch x 17mm long).

 

 

I had some screws that were the perfect size, except they are countersunk heads. Because someone jammed an Allen wrench into the Torx screws I had to use these until I can get the right head on the screws. But the countersunk ones hold just fine.

 

8) With a good voltmeter, adjust the TPS to 150-157 mV. Realize the TPS value changes when it is tightened down, so just repeat until you're in range.

 

9) Reconnect the throttle linkage

 

 

I needed to use pliers. I also put a smudge of silicone grease on the ball before re-assembly.

 

10) Set the high idle cam so it just nudges the throttle when engaged.

11) Leave the right side idle stop backed out.

 

 

Buttoned up!

 

Like I said info will be added to this until anyone can walk through the steps. Especially me!

[docc]

Where you stick the multimeter leads?   Positive in the black/purple (nero/viola) and negative in the purple (viola). Since your ECU faces the connector nefariously upward under the seat, you can "back probe" the computer.  The TPS connector is a real hassle to get to. You'll see why the Caspers Breakout Harness is such an elegant, and cost effective, solution. Have a look at the photo I posted of the Breakout Harness and you can see the pins I used for too many years.

 

Is the bike on or off? Make your connections key off. The ignition is on to see the TPS voltage. I think you can pull Fuse#2 and Fuse#5 so the fuel pump and headlamps are not on while you fiddle with the TPS. 

 

What settings do you use on the multimeter? DC volts, 2 volt range is good.

 

Pull off the boot before or after the throttle body? I assume between the throttle body and air box. Yep.

 

Do you test the voltage before you loosen the TPS incase it doesn't need adjusting? Oh, for sure. Get a "starting point" so you know how much you are changing it. This will make you feel even better about getting it set right!

[Chuck]

Docc replied as I was going to. Looks like he has it covered. 

[swooshdave]

Just to be clear I'm not adding anything to the great instructions that have already been provided except to see if I can illustrate them a little better. I'm a very visual person and need to see things for them to sometimes make sense. I appreciate your patience with me!

 

 

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[swooshdave]

 

The only way, or at least easiest, is to probe the wires going to the ECU? I don't see any other way. Am I right?

 

 

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[Chuck]

You can do it right there at the TPS or back at the ECU.

[docc]

What Chuck said. I always had trouble stabbing the connectors there, so went to back-probing the ECU connector since my connector is on the top side and easy to get to.  Not sure when the ECU was turned connector down (perhaps as early as late 2001?) We all did it one way or the other until member danl had Caspers make up the breakout harness back in June 2013:

 

http://www.v11lemans.com/forums/index.php?showtopic=18052

 

In that same thread, member JBBenson has a concise post why the pins are so fiddly and frustrating:

 

http://www.v11lemans.com/forums/index.php?showtopic=18052&p=196877

 

Probably even more fiddly are the Torx fasteners that hold down the TPS. Replacing those with hex drive fasteners (4mm/0.7 thread pitch x 17mm long) allows the use of a common L-angled hex wrench. ((That space above the throttle body and behind the cylinder gets really small once you start trying to put your hands in it and also see what you're doing). 

 

No doubt, getting the TPS set exactly right is one of the four critical tuning parameters that will make the V11's song a joy and a delight.

[swooshdave]

You can do it right there at the TPS or back at the ECU.

 

For my curiosity, doesn't the TPS need to be connected to work and measure? How can you probe it at the TPS if it's connected?

[68C]

Some stick pins through the insulation and into the wire core then attach a multimeter to the pins. I do not like that, seems a good way to get water into the wire and future corrosion. I stripped a part of the wire back and soldered on two permanent test leads then sealed with paint and overlayed with self almalgamating tape. A more expensive way is to buy the special lead however it is difficult to unplug and replug the TPS connecter as it is behind the RH throttle body, I was scared of damaging the plug or the TPS. I supposed most folk leave the lead attached.

 

The ignition must be turned on so 5v is applied across the TPS by the ECU. There are three wires to the TPS, ground/neutral, positive and the lead from the TPS wiper arm. As the TPS rotates from zero to full the voltage on the wiper arm raises from zero to 5 volts theoretically. In fact it rarely goes as high as a true 5 volts.

 

We will adjust the TPS to approximately 0.15 volts (150mv) with the throttle cable and the link rod disconnected. Once reconnected expect about 0.45 volts (450mv).

[swooshdave]

Poking the wires seems barbaric.

[swooshdave]

Breakout cable ordered. It was $30 with shipping. We need to get one of those Chinese places to knock it off for $5. 

[Chuck]

Poking the wires seems barbaric.

Agreed. I stick a length of .020 safety wire in the female side of the two wires, push the connector together, attach a couple of alligator clips, and Robert's your Mother's brother.  Saves 30 dollars. (Guzzi content)

[swooshdave]

 

Poking the wires seems barbaric.

Agreed. I stick a length of .020 safety wire in the female side of the two wires, push the connector together, attach a couple of alligator clips, and Robert's your Mother's brother.  Saves 30 dollars. (Guzzi content)

 

 

Now you tell me. 

[docc]

It occurs to me to say that the motor does not have to be hot. Lots more comfortable poking around the cylinder fins when they are not sixty or eighty degrees Celcius.

[Chuck]

 

 

Poking the wires seems barbaric.

Agreed. I stick a length of .020 safety wire in the female side of the two wires, push the connector together, attach a couple of alligator clips, and Robert's your Mother's brother.  Saves 30 dollars. (Guzzi content)

 

 

Now you tell me. 

 

Looks like I was a half hour too late.  well, really.. the breakout harness is much more elegant. I wish I had one.. but 30 dollars? I could buy a used tire for that. (snapping suspenders)