03 Titanium throttle dead spot

[masdbo]

Greetings, I am wondering if anyone has seen this problem.  I have an 03 Titanium with about 100k miles.  The problem is it has a dead spot in throttle position just off of idle, runs fine any other position, idles fine, WOT and all points between all good.   It's just the one exact spot that if I roll the throttle slowly and get to that spot, (although a very small spot), it completely looses power until you advance the throttle a little more.   If I am riding hard, you would hardly notice it.  It was suggested TPS?

[Chuck in Indiana]

Yep.

[Kiwi_Roy]

Yep.

Plus 1
If you have a multimeter set to 20 Volt range, clip the black lead to chassis or battery Negative, poke a sewing pin into the three wires leading to the TPS and measure the Voltage with red lead
One will read just over zero and go up to about 4.5 Volts at full throttle in a smooth ramp. You can set the meter range on 2 Volts for better resolution at the low third of throttle.
You need the key On to take this reading.

The wire you need either goes to pin 1 or pin 11 of the 15M ECU, the drawings are a bit confused.

[antmanbee]

It is pin 11. they are marked if you look very closely.

[masdbo]

Thanks, I will check it out.

[masdbo]

If any voltage,it does not change with the throttle advancement.   Never goes up to 5v.   There are black, yellow and violet wires.   The are lettered ABC.

[BrotherJim]

Make sure kill switch is on as well.

[Wayne Orwig]

No need to test it.
TPS is bad.

[masdbo]

Ok, thanks for the kill switch tip.   I have 5v "feed" on the yellow wire, on the black it seems to be working as described.   At idle it's about .2 v  and steadily goes up to 5v as I roll the throttle.  Not saying it's still not faulty but that's what I am getting.

[Wayne Orwig]

Ok, thanks for the kill switch tip.   I have 5v "feed" on the yellow wire, on the black it seems to be working as described.   At idle it's about .2 v  and steadily goes up to 5v as I roll the throttle.  Not saying it's still not faulty but that's what I am getting.

Another test is if there is a dead spot on the throttle. Then the TPS is bad.

OR, someone put a really bogus map in your ECU. Has anyone remapped the ECU or installed a power commander type device?

[masdbo]

No, it has never been mapped, no power commander.   It started out of the blue a while back, just getting around to messing with it.   Where can you get the TSP?  Someone told me you had to get them from Guzzi, I read somewhere else there was also a cross number off a Harley?

[Kiwi_Roy]

You will need to measure the TPS because when you put the new one in it needs to be set

To
150 mV with the throttle body fully closed
Or
About 450 mV with the throttle at the idle position
Or
Same as it is now with the old one.

At some point you will want to do a full alignment but for now quick & dirty method will suffice.

[John Croucher]

Take the oem tps off, pop the cover off and inspect the inside.  My be dirty.  Most likely has a bad contact finger or bent.  Easy to replace the tps.  470-500 mv @ idle. 

[fotoguzzi]

No, it has never been mapped, no power commander.   It started out of the blue a while back, just getting around to messing with it.   Where can you get the TSP?  Someone told me you had to get them from Guzzi, I read somewhere else there was also a cross number off a Harley?

yes there is an alternative to the very expensive tps from Guzzi. One is from Harley Davidson sorry I don't have the part number anymore... someone here will.

[Kiwi_Roy]

Ok, thanks for the kill switch tip.   I have 5v "feed" on the yellow wire, on the black it seems to be working as described.   At idle it's about .2 v  and steadily goes up to 5v as I roll the throttle.  Not saying it's still not faulty but that's what I am getting.

That seems a bit low, John says 470-500 mV - Sometimes they move for no apparent reason.

Take the oem tps off, pop the cover off and inspect the inside.  My be dirty.  Most likely has a bad contact finger or bent.  Easy to replace the tps.  470-500 mv @ idle.

I would try starting from scratch by backing off the throttle body idle so the butterfly is completely closed where it should be 150 mV
Then take it to the correct idle speed 1100 revs where it should be 470 - 500 as John says

Another test is if there is a dead spot on the throttle. Then the TPS is bad.

OR, someone put a really bogus map in your ECU. Has anyone remapped the ECU or installed a power commander type device?

Your 0.2 (200 mV) may be pointing to a dead spot on the throttle map

Either way I would get the TPS setting procedure for your bike and verify its at 150 mV with the throttle plate fully closed, that's the only defined point
At idle speed it could be a few mV either way because its effected by how much air is getting through the Air Bypass Screws

If your TPS is ramping correctly there is no need to change it out.

Tips
Don't use Guzzidiag to read millivolts, I quote Chuck in Indiana , "Just a heads up. If you are trying to set the 150 mv with Guzzi Diag, it won't work. It *has* to be set with a digital voltmeter.")
Make sure the fast idle lever is not holding the butterfly open when setting 150 mV
The mV can vary at idle because idle speed is effected by the air bypass screws hence John's 470 - 500 mV
I believe 150 mV was chosen as the start point with throttle plate fully closed so there is no way the TPS can bang into the end stop - Roy
 

[Chuck in Indiana]

No, it has never been mapped, no power commander.   It started out of the blue a while back, just getting around to messing with it.   Where can you get the TSP?  Someone told me you had to get them from Guzzi, I read somewhere else there was also a cross number off a Harley?

I've used the Harley one.. but the bike kept trying to turn into a bar every time I passed one..   other than that, it worked fine.
The "correct" one is available for around $90 I think, but don't remember where. <shrug>

[Bill Owens]

Harpers has them on their website for 94.00

[Wayne Orwig]

I've used the Harley one.. but the bike kept trying to turn into a bar every time I passed one..   other than that, it worked fine.

It will also make the exhaust sound more flatulent. 

[Guzzidad]

   The Harley TPS is 27271-95. And it works fine. I have one on my 01 EV. But you can get the correct PF3C from California Cycle Works for about the same price. Also fits Ducati 2000-2003.

[Ncdan]

I've used the Harley one.. but the bike kept trying to turn into a bar every time I passed one..   other than that, it worked fine.
The "correct" one is available for around $90 I think, but don't remember where. <shrug>

Just be glad a bunch of tattooed  floozys didn’t attempt to climb on the back😂

[masdbo]

Thanks all for the help, I will get back on it as soon as possible.

[masdbo]

I finally got around to ordering and installing a new TPS...(I have a lot of projects).   Just wanted to confirm that it was the TPS, I installed it and it works great, no more dead spot, idles fine etc.  However, I went through no procedure to set it up.  If it runs fine, is there any reason to?

Thanks

[Wayne Orwig]

I finally got around to ordering and installing a new TPS...(I have a lot of projects).   Just wanted to confirm that it was the TPS, I installed it and it works great, no more dead spot, idles fine etc.  However, I went through no procedure to set it up.  If it runs fine, is there any reason to?

Thanks

It you don't set the TPS, you usually are too rich or lean. You will carbon up the plugs pretty quick, or be unhappy with the idle.

If you adjusted it for a nice idle speed, you may be close enough. Hard to imagine that you just screwed it on, and it was good enough. It is a pretty touchy setting.

[Chuck in Indiana]

Thanks for the update on this thread.  As Wayne says, though, it's a *really* touchy thing to get right with a digital voltmeter. Just the slightest movement will change it many millivolts.

[Vagrant]

Just be glad a bunch of tattooed  floozys didn’t attempt to climb on the back😂

So what is so wrong with that?

[John Croucher]

It you don't set the TPS, you usually are too rich or lean. You will carbon up the plugs pretty quick, or be unhappy with the idle.

If you adjusted it for a nice idle speed, you may be close enough. Hard to imagine that you just screwed it on, and it was good enough. It is a pretty touchy setting.

From my observation when working with a tps, the ignition timing will change with the movement of the tps.  Advancing or retarding the firing of the plugs. 

My method, set your idle speed, set the tps to the specification .5 mv.  fast and easy.  Balance/sync the right butterfly to the left.  Go ride.

[Kiwi_Roy]

I finally got around to ordering and installing a new TPS...(I have a lot of projects).   Just wanted to confirm that it was the TPS, I installed it and it works great, no more dead spot, idles fine etc.  However, I went through no procedure to set it up.  If it runs fine, is there any reason to?

Thanks

You may be running rich or lean the mV at any throttle position determines how much fuel is added among other things,
Setting the TPS is normally done with the throttle plate fully closed, not held off by the idle stop or throttle linkage.
With it fully closed set the mV to 150, this is the reference point, it never runs in this position because as soon as you set the idle speed with the idle stop screw the TPS is much higher about 450 from memory.
Why fully closed @ 150, this value ensures that the TPS is not banged up against the end of its travel, it's a fixed reference point that never moves.
Some procedures tell you to now adjust the idle screw to give you a certain mV, in reality you are adjusting the idle stop to 1100 RPM the new mV value 450+/- is what it is.

Now all you need to do is balance the throttle bodies to make sure both cylinders are sharing the load somewhat equally


Oops John just posted something different I think he meant 500 mV (0.5V) I think that would end up so close to my method.
I also agree that the TPS has more effect on ignition timing than fuel mixture.

[s1120]

You may be running rich or lean the mV at any throttle position determines how much fuel is added among other things,
Setting the TPS is normally done with the throttle plate fully closed, not held off by the idle stop or throttle linkage.
With it fully closed set the mV to 150, this is the reference point, it never runs in this position because as soon as you set the idle speed with the idle stop screw the TPS is much higher about 450 from memory.
Why fully closed @ 150, this value ensures that the TPS is not banged up against the end of its travel, it's a fixed reference point that never moves.
Some procedures tell you to now adjust the idle screw to give you a certain mV, in reality you are adjusting the idle stop to 1100 RPM the new mV value 450+/- is what it is.

Now all you need to do is balance the throttle bodies to make sure both cylinders are sharing the load somewhat equally

I always thought that made sense..  Everything I read when I did mine said to set the idle with a VOM, and I always fought too high idle RPM...  It made sense to set it to RPM as long as the baseline setting was right,  but I was fighting so many engine control issues I didnt want to start causing more issues.  I already had so many red Herrings to chase after.

[Kiwi_Roy]

I always thought that made sense..  Everything I read when I did mine said to set the idle with a VOM, and I always fought too high idle RPM...  It made sense to set it to RPM as long as the baseline setting was right,  but I was fighting so many engine control issues I didnt want to start causing more issues.  I already had so many red Herrings to chase after.

I'm an industrial instrument technician, when I started my trade many of the instruments were based on slide wire feedback, very similar to your TPS with an up scale reference point.
The Guzzi procedure for setting idle confused me at first.
I even tried not setting the revs at all, just using the fast idle lever, that worked fine also.

[John A]

When you get the TPS close, it is very touchy as pointed out.  A trick to get it spot on is to set it at WOT, or wide open throttle. The reason is repeatability.  At WOT it is against a hard stop, at the idle it depends on how you push it.  at WOT you want at least 80% of the reference voltage, about 4.72 by memory.  You can easily  tweak it up or down from there,  .001 volts will make a difference and that's hard to set at idle, especially with the idle stop unscrewed.  Then check as per regular instructions.  This method didnt work on a Harley TPS but I don't remember why, I think the voltage was too different and I couldn't get my WOT and idle to be in spec. I care not what it is at idle.  If the TPS is set too high the bike will accelerate slightly on closing throttle.