High Idle Speed - SOLVED AT LAST

My 2007 has always idled a bit fast, 1500 revs.
It has the stock exhaust and as far as I know stock map.
It used to idle sometimes at 1500, sometimes 2000
Lately though it seems to mostly idle at 2,000 sometimes 2100 which is a bit annoying.

It has another stepper motor thanks to Pete so that's ruled out
I'm certain that the sacred screws haven't been messed with.

It's 12,000 km since I balanced the throttle and set the TPS, a couple of long trips ago

Any thoughts why it should idle so fast.

Is there anything to be learned from Guzzidiag?

Thanks in advance
Roy

When were the TB's last removed and cleaned thoroughly?

Roy, a few of the now older ones do this. Mine included, and others on this forum, and still others I know. Damned if I know why. A simple solution is to remove the stepper hose from the airbox and plug it with a short bolt. It will idle steadily after that.

I have a suspicion (though not in any way confirmed) that it has something to do with the mapping somehow. I have spent much time, with Beetle's assistance, in getting it just right. Sometimes it's good, other times it gives me the shits.

I recently unblocked my stepper as I was doing more mapping adjustments. System worked well until the last week when again I get high idle and today, she was a bitch of a thing to start - actually had to give it throttle to start.

I was giving it some thought, and the only thing that comes readily to mind is that the TPS has "shifted". It may simply be the TPS (which is a potentiometer) may be wearing (as pots do) and might need a refresh - read replace. From time to time here at work, we need to replace pots as they wear a spot in them at certain settings. I made a mental note to purchase one and fit it and see if the problem goes away. Your TPS, like mine, is now 11 years old.

Previous comments around this seemed to point to the stepper motor. Sometime some cleanser or lubricant helps, sometimes not. As you say, you have replaced the stepper, and set things up correct. In the quest for flawless running, I am now leaning to a TPS. Wonder how much they are worth new?

Pete Roper wrote:

When were the TB's last removed and cleaned thoroughly?

Never been done Pete to the best of my knowledge, just under 50 k
Is that what it takes?
By cleaning do you mean an Ultrasonic bath or a good soak in some solvent?

Tony, it seems Pete thinks we should do some housework

I hear you about pots wearing out but I would have thought these are still too new for that.
I sourced a Hall Effect TPS with a plan to try it on my VII Sport. in theory they should last forever with no sliding parts.
For all I know the GRiSO might have one already.
Looking at the stepper motor it's pretty hard to visualize it gumming open, I will try to take a look this weekend, its been 12k since I put it on.

Try squeezing the hose from the airbox with a pair of pliers. If the idle changes, which I suspect will, then the stepper motor is the issue.

On my 1200 Sports (x3), I have installed pneumatic switches. As soon as the motor has warmed up, I switch the air supply off. An added bonus is the increased engine braking.

Price of said potentiometer (apart from being a special order) approaches 300 euro or pounds. GU05112830

price of the bolt I placed in stepper hose = $free.

(I stole it from Tony )

Tony, I have a list alternative TPS to the Magneti Marelli PF1C00 from another 6 manufacturers & the models of Fiats, Lancias, Alfas, Renaults & Dacias they were used in. The earlier V7s had a different Guzzi part number (32530508) but the 2011 number is the same as yours. Also heard a rumour that some Harley's had the same TPS. A note in one of my sources says the car ones may be the same, but some may have different adjustable mounting holes. I'll juggle the USB sticks & see if I can't get it to you.

Wonderful Mal, love your work.

If you think the TPS may be the issue, and you want to go full nerd, it may be possible to tweak the lookup table in the map to compensate. First thing to check is that there no undue noise on the output of the TPS. If there is, you're stuffed and only a new TPS will fix. You'll need a scope for that.

If it's good, note the voltage at closed, WOT, and several TPS breakpoints. If the readings differ greatly from the lookup table, adjust the lookup table to compensate.

Simples!

Beetle,
         I come from VIIs where the TPS pots were set for 150 millivolts with the throttle bodies fully closed, I gather the GRiSO is not done that way, can you explain the difference.
Are there any mechanical adjustments to make or is it strictly up to the ECU?

Thanks

The TPS value is interpretative. You balance the TB's and then recalibrate the TPS electronically. The actual throttle plate angle is set by WM on a flow bench and should never be adjusted with the throttle stop screw. The only physical adjustments are with the bell crank screw and the air bleeds.

Pete

My 2006 G1100 had a bit fast iddle sometime ago, it was the stepper valve that was dirty.

I unpluged from the airbox the hose that feeds air to the stepper valve, and whille the engine was running, i sprayed some bursts of carburator cleaner in the hose.

At each burst, the motor coughed, stumbled, stalled, had to use the throttle to keep it going, some smoke came out from the exhaust... Finished spraying when no more smoke was comming out.

Normal iddle since that.

Kiwi_Roy wrote:

Beetle,
         I come from VIIs where the TPS pots were set for 150 millivolts with the throttle bodies fully closed, I gather the GRiSO is not done that way, can you explain the difference.
Are there any mechanical adjustments to make or is it strictly up to the ECU?

Thanks

Completely different. As Pete says, it's interpretive. After the TB's are balanced, the TPS absolute position may have changed. When you reset the TPS, the ECU reads the voltage and saves this as the closed position. Throttle values are then based on voltage versus lookup table. Variations in the ECU ADC, wiring, connector resistance, and TPS can affect the value that the ECU uses in its number crunching.

Thanks for the explanation.
I once had the crazy idea of adjusting the mixture on the fly based on the readout from a wide band fuel mixture meter, I thought by adding a zero offset to the TPS signal +/- 50 mV it would slide the mixture up or down the map, I was surprised how little the mixture changed.
MyECU kitset, VII Sport

beetle wrote:

Kiwi_Roy wrote:

Beetle,
         I come from VIIs where the TPS pots were set for 150 millivolts with the throttle bodies fully closed, I gather the GRiSO is not done that way, can you explain the difference.
Are there any mechanical adjustments to make or is it strictly up to the ECU?

Thanks

Completely different. As Pete says, it's interpretive. After the TB's are balanced, the TPS absolute position may have changed. When you reset the TPS, the ECU reads the voltage and saves this as the closed position. Throttle values are then based on voltage versus lookup table. Variations in the ECU ADC, wiring, connector resistance, and TPS can affect the value that the ECU uses in its number crunching.

Is the TPS value linear?
If you plug in with the diagnostic software you get 4.8 at closed throttle.
Just thinking you could check the values at full throttle and work back slowly to see if the TPS throws up any random values until you get back to 4.8.

eeyore wrote:

Is the TPS value linear?
If you plug in with the diagnostic software you get 4.8 at closed throttle.
Just thinking you could check the values at full throttle and work back slowly to see if the TPS throws up any random values until you get back to 4.8.

The TPS is not linear throughout its range.  But watching for hiccups in resistance as the throttle is slowly wound open, is a good means of determining any dead spots.

The GRiSO tps are linear, that's why they can be set to reference with reset tps. The tps (pf3c) on a v11 is logarithmic. The thing with harley tps, is something people do when they don't want to pay the guzzi price for the PF3c. But then they get the pf4c that has another curve. Out of the question for a GRiSO 1100.

The 8v tps is physical completly different, so no exchange for that one.

The high idle thing, there is a table in the map for idle fuel. I did adjust mine, and since then I didn't get the high idle anymore, but can be coincidence. In my case I took fuel out because it was to rich when idle.

When at idle the ecu tries to goto the requested rpm(1200 when hot), it does that with the valve and ignition time. WHen it cant do it with these things it will be to high or to low.

Kiwi_Roy wrote:

Is there anything to be learned from Guzzidiag?
Roy

Look the TPS reading, should be 4.7 +- 0.2.

Also, look at the engine and air temperatures, they should be realistic. ECU reading lets say 30C while the engine is boling hot, is not realistic, you may have to put some thermal conductive stuf in the sensor well (I've used a bit of copper antiseize paste at the tip of the sensor)
Not very surre, I suppose wrong temperature reading has some efect on iddle speed...

If you are going to go to the trouble of finding an alternate TPS why not go all the way and find a Hall Effect one, with no rubbing parts they should last forever, several manufacturers make them for the auto industry.
They are about $75 but you have to be really careful to match up the specs, same rotation direction etc
You need one with 90° rotation. typically they are sprung loaded.
Look at the attached brochure

[You must be registered and logged in to see this link.]

I have a Honeywell I was looking at for a VII Sport.

When I pull the throttle bodies for cleaning I will look to see what would be applicable

My Guess would be
RTY-090-LV-E- ? - X Substitute A or B for ? depending on rotation

A few of us working on this is good, we all have our various expertise, so should get to the bottom of this quickly.

I will check my TPS response tomorrow, to see if there are issues or funny numbers.

I too, have sprayed carb cleaner (well tipped it actually) into the stepper - mostly it improves things for a while. However, at the back of my mind is the nagging possibility that there could be something else.

Bring on the collective wisdom.

"Bring on the collective wisdom", Tony says ,,,,,,
This is how things really advance .....
I think there is more collective wisdom around here than at Mandello ...
Awaiting the thoughts

Tony,
        I will see if I can bring out the end of the stepper hose
It has got worse since I changed out the stepper and I ran some serious dusty road up the Dempster Highway, maybe it's just crud.

wardentm wrote:

"Bring on the collective wisdom", Tony says ,,,,,,
This is how things really advance .....
I think there is more collective wisdom around here than at Mandello ...
Awaiting the thoughts

Nah, got nothing...