Idle rpm to high when warm

[john zibell]

From the updated picture the seal has been broken. Since you are having an issue, I'd look at e-bay or similar for an unmolested TB setup. I was able to score a set a couple years ago for about $100.00 USD. When you replace the TBs, go ahead and replace the manifold rubbers at the same time. I've got a set that has been altered (the stop screw) but the bike didn't have the high idle issue. If you want them you can have them. They are just taking up space on my parts shelf.

 

[sign216]

Changing throttle bodies (TBs) because the "sacred screw" has been turned is overkill. First, try to fix it with what you have. On this site there used to be instructions for adjusting the system in the event The Screw has been played with. A search should bring it up.

If you think the screw is the problem (and I'm not sure it is) you could always try adjusting it yourself. Record the orig position, and as a fail-safe you could return it to that, should nothing work.

My suggestion is to have one or more buddies/Guzzi riders/etc take a look at things. When I get stuck another guy's point of view, from someone actually right there looking at the bike, is a huge help and sees things that I didn't think of.

Joe

 

[poon]

Since it was raining the whole day yesterday I had to find something to do, so I decided to check the OBD equpment.
When I took it apart I found some really bad solderings in the Autodia K409, so I decided to put everything in a little box so I could get rid of those bad connections. When I tested it on the bike it was working again
I filled the box with epoxi so it will be water-proof as well. The old parts are the black ones over the little white box, the label is from the old parts just to remember what it was originally.

 

[poon]

Here are som pics of the Guzzidiag windows, first we have the window when the throttles has been balanced,
'

And then the picture of the window after balancing at idle speed and TPS reset, the TPS is the one called Throttle, and it's going from 3.10 3.51, after a reset it is 3.10

The air bypass screws are fully closed at all time.

 

[poon]

From the updated picture the seal has been broken. Since you are having an issue, I'd look at e-bay or similar for an unmolested TB setup. I was able to score a set a couple years ago for about $100.00 USD. When you replace the TBs, go ahead and replace the manifold rubbers at the same time. I've got a set that has been altered (the stop screw) but the bike didn't have the high idle issue. If you want them you can have them. They are just taking up space on my parts shelf.

I've found two TB at ebay,
http://www.ebay.co.uk/itm/190685928640?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
and
http://www.ebay.co.uk/itm/350287211855?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Breva and Nevada should have the same TB, so both would work and $99.95 is a good price if they are working.
I have asked for a price of the shipping cost to Sweden, but haven't got any answer yet.

I have tried to find any leak with the help of CRC Quickleen, but there were no change in the rpm when I sprayed it.
But the TB are at least clean now

 

[sign216]

Ok, so it's not a leak.

I'm trying to think outside the box. With Guzzidiag (GD) can you shut off the lambda sensor, and just go open loop?

 

[john zibell]

Your screen shots don't show sensors being out of range except for the TPS being at 3.1 degrees at 1,900 RPM. So, since the throttle stop has been moved, there is nothing to loose in moving it again. Somehow reference where it is now so you can return if necessary. Open each air bypass screw 1/2 turn. On a hot engine, back off the throttle stop screw until your idle is about 1,200 RPM then to a TPS reset. You may have to do this a few times as each reset may impact the idle RPM. See how she behaves after that. If all else fails, you can always try replacing the TBs and hopefully a TPS will come with them.

 

[poon]

Ok, so it's not a leak.

I'm trying to think outside the box. With Guzzidiag (GD) can you shut off the lambda sensor, and just go open loop?

Yes, it's possible to do that and save it as a new map and upload it, but then the CO level has to be set manually I guess, it's a choice there to do that.

I just removed the lambda sensor to measure it, accordinf to the number on the sensor it's an OZA334-BB1, but it should be an OZA341-BB1 from what I've seen in the recommendations. Also the resistance are wrong, the one I measured at 20 degrees celsius was 4.4 Ohm and it should be 12.8 Ohm.
Here's a picture of it,

I also just saw something strange when I watched my pictures here from Guzzidiag, the voltage at 1970 rpm are higher than at 3913 rpm. So I checked with my multimeter at the battery, at 4000 rpm I get 13.46V and at 2000 rpm 13.67V, also if I go over 4000 rpm the voltage will be a bit lower than at 4000 rpm, the voltage should be between 13.5 and 14 V at 4000 rpm according to specs.

 

[poon]

Your screen shots don't show sensors being out of range except for the TPS being at 3.1 degrees at 1,900 RPM. So, since the throttle stop has been moved, there is nothing to loose in moving it again. Somehow reference where it is now so you can return if necessary. Open each air bypass screw 1/2 turn. On a hot engine, back off the throttle stop screw until your idle is about 1,200 RPM then to a TPS reset. You may have to do this a few times as each reset may impact the idle RPM. See how she behaves after that. If all else fails, you can always try replacing the TBs and hopefully a TPS will come with them.

The TPS was reset after balancing and 1900 rpm is the idle speed after that, so that's why it's reading 3.1 or 3.51 degrees.
Don't think it has anything to do with the rpm being 1900.

I'm not sure that the throttle stop screw has been changed even though the paint is cracked, I have had it for 5 years and I have only had it in a workshop once, 3 years ago and this is a recent problem.
But who knows, there might be some guy thinking it would be cool to fiddle with that scew after learning that it should be left alone, stranger things has happened

I also found some other issues you can read on here.
But if I can't get it running as it should, then I will try to tweak the throttle stop screw

 

[john zibell]

Can you have one of the channels read lambda voltage? If it isn't changing then that is a problem. Also the Lambda shouldn't be covered in carbon. This indicates she is running rich which is uncommon on new Guzzis. While it is out you can clean it off with a propane torch. Re-install and see if the voltage output of the lambda is changing. Usually if it changes within 3 to 4 seconds the bike seems to run OK, if longer or not at all it would be a candidate for replacement. It uses the same sensor as one of the small Fiat cars a Brava or Bravo I think. Just about all the lambda sensors provide the same output, it is the connector that you need to interface with the bikes wiring.

Here are some references for you

http://auto.howstuffworks.com/question257.htm

http://www.lambdasensor.co.uk/main/mcolours.htm

I think this sensor may be a direct plug in. http://www.lambdasensor.co.uk/main/ntkp ... =OZA334-A1

 

[poon]

Can you have one of the channels read lambda voltage? If it isn't changing then that is a problem. Also the Lambda shouldn't be covered in carbon. This indicates she is running rich which is uncommon on new Guzzis. While it is out you can clean it off with a propane torch. Re-install and see if the voltage output of the lambda is changing. Usually if it changes within 3 to 4 seconds the bike seems to run OK, if longer or not at all it would be a candidate for replacement. It uses the same sensor as one of the small Fiat cars a Brava or Bravo I think. Just about all the lambda sensors provide the same output, it is the connector that you need to interface with the bikes wiring.

Here are some references for you

http://auto.howstuffworks.com/question257.htm

http://www.lambdasensor.co.uk/main/mcolours.htm

I think this sensor may be a direct plug in. http://www.lambdasensor.co.uk/main/ntkp ... =OZA334-A1

I was also a bit surprised by the carbon on the lambda, the sparkplugs looks nice and grey as they should.
The voltage of the lambda is changing after I start the engine, I attach a small video to look at,
https://dl.dropboxusercontent.com/u/5182885/MOV_0313.mp4
The idle speed is OK now when it's cold

I cleaned the lambda and removed all the carbon before I refitted it again, didn't know about the torchlight, but it might be a good idea to replace it since it seems to be the wrong one there, the resistance for it is not according to the specs. 4.4 Ohm when it should be 12.8 Ohm, and it should be an OZA341-BB1 not OZA334-BB1.


Just learnt from your links that the resistance is only for the heater in the lambda

 

[john zibell]

Based on the video there is nothing wrong with the Lambda sensor. I wish the one in my bike changed that rapidly. Don't waste any money changing it.

Have you checked that the high idle linkage isn't keeping the throttle slightly open?

 

[sign216]

Have you checked that the high idle linkage isn't keeping the throttle slightly open?

Happened to me. Some of the wires/tubing under the tank would occasionally hit the TB crossover mechanism, and keep the rpms quite high. Fortunately it happened in my garage. After shutting it off I was able to trace the problem.

Hope your solution is that simple.

 

[poon]

Based on the video there is nothing wrong with the Lambda sensor. I wish the one in my bike changed that rapidly. Don't waste any money changing it.

Have you checked that the high idle linkage isn't keeping the throttle slightly open?

Yup, that's the first thing I checked
There's always a gap there, and the high idle is only when it's hot.

 

[john zibell]

Based on the video there is nothing wrong with the Lambda sensor. I wish the one in my bike changed that rapidly. Don't waste any money changing it.

Have you checked that the high idle linkage isn't keeping the throttle slightly open?

Yup, that's the first thing I checked
There's always a gap there, and the high idle is only when it's hot.

This is turning into a real mystery. Sensors are all in range, Lambda is working properly.

Again, the vacuum leak may the the ticket. Since it is already idling at 1,900 rpm the test may not be valid or indicate a change. It is tempting to put new manifold gaskets and rubber collars on just to be sure. They aren't that expensive.

Also there is evidence of a rich condition which might point to injectors not closing properly and needing to be cleaned. I consider this a long shot though but possible.

 

[poon]

Based on the video there is nothing wrong with the Lambda sensor. I wish the one in my bike changed that rapidly. Don't waste any money changing it.

Have you checked that the high idle linkage isn't keeping the throttle slightly open?

Yup, that's the first thing I checked
There's always a gap there, and the high idle is only when it's hot.

This is turning into a real mystery. Sensors are all in range, Lambda is working properly.

Again, the vacuum leak may the the ticket. Since it is already idling at 1,900 rpm the test may not be valid or indicate a change. It is tempting to put new manifold gaskets and rubber collars on just to be sure. They aren't that expensive.

Also there is evidence of a rich condition which might point to injectors not closing properly and needing to be cleaned. I consider this a long shot though but possible.

I have just borrowed a lambda from a friend to test with during the weekend, just to see if there's any difference in behaviour. Also gonna remove the tank and then the TB and check everything there.

For the moment it's no problem with the idle during the morning ride to work, we have had 10 degrees here in the mornings for a couple of days, it's just in the evening when going home from work it's a problem when it's 20 - 23 degrees outside.
The weather should quite nice and warm in the weekend, so I'd better try to do as much as possible when I have the chance to test when it's hot. But I can always run it for full throttle for a while to get the problem I guess

 

[john zibell]

I just looked at the diagnostic software screen shots again. Yes the engine temperature is much higher than the air temperature, but the engine sensor should be reading well above the boiling point of water. Your engine sensor looks like it is reading low to me. With the reading of a cooler engine, it is dumping extra fuel into the system. That would account for the carbon buildup on the lambda sensor, and possibly the high idle when the air temperature is higher. Hook up the software with the the bike cold (hasn't run at all) and let's see what the engine temp sensor is doing. The solution may be to try another engine temperature sensor.

 

[poon]

I just looked at the diagnostic software screen shots again. Yes the engine temperature is much higher than the air temperature, but the engine sensor should be reading well above the boiling point of water. Your engine sensor looks like it is reading low to me. With the reading of a cooler engine, it is dumping extra fuel into the system. That would account for the carbon buildup on the lambda sensor, and possibly the high idle when the air temperature is higher. Hook up the software with the the bike cold (hasn't run at all) and let's see what the engine temp sensor is doing. The solution may be to try another engine temperature sensor.

Have been thinking about that too, so I have already ordered a new sensor, hopefully I'll get it to the weekend .
What's a normal temp. for that sensor when it's hot?

 

[john zibell]

Have been thinking about that too, so I have already ordered a new sensor, hopefully I'll get it to the weekend .
What's a normal temp. for that sensor when it's hot?

I usually see about 240 to 260 F, which would be 115 to 127 C

 

[poon]

I just looked at the diagnostic software screen shots again. Yes the engine temperature is much higher than the air temperature, but the engine sensor should be reading well above the boiling point of water. Your engine sensor looks like it is reading low to me. With the reading of a cooler engine, it is dumping extra fuel into the system. That would account for the carbon buildup on the lambda sensor, and possibly the high idle when the air temperature is higher. Hook up the software with the the bike cold (hasn't run at all) and let's see what the engine temp sensor is doing. The solution may be to try another engine temperature sensor.

Here is a screendump of the engine when it's cold,