Recommended CO settings on ECU screws
- Thread starter babutler
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- ecu recommended screws settings
There is no stock setting for the dials.
With some Eproms they don't even work.:confused
Fine tuning a Ape is a fine balance between the bypass screws and the trimpots.:devious
If you find your bike idling fine and co is around 4% Co you are ok.
For my Eproms I advise to start with the trimpots at 12 O clock.
The front bypas screw 2 -2.5 turns out from fully in, and the rear 1-1.5 turns out.
If you have a 2-1-2 exhaust this differs.
This is just a starting point!!.
From here you need a Co tester and a fine ear!!
I would call Griff and see if he can squeeze me in :devious
Here is wat KZmille wrote.
You want to check the TPS but they are usually okay if they have not been messed with. It should read 0 with the idle adjuster wound completely off. -1 or 1 indicate a need for adjustment though 0 or 1 are normal readings with the idle speed adjusted. You will see 1 especially if you have the idle speed set a little higher than standard.
This is how I go about adjusting the idle.
Since I don't have access to a CO meter, I must do without. I have used the mercury tube type of vacuum gauge for many years and find it the easiest to use. There are alternatives out there. I have not had as good a result with the Uni-Syn type flow meter that you place over the throttle opening. This is the same thing sold under the Evoluzione name. If it is all you have it works but you cannot monitor both cylinders at the same time, you have to have the air box open, and sometimes simply placing the device over the throttle changes the engine speed.
The first step is to fully warm the engine and hook up the gauges. You want to use the vacuum taps on the right side of the TB rather than the tiny ones on the left that are often mentioned. Using the taps on the left requires disconnecting the manifold pressure sensor which is active during idle. It makes no sense to me to try and tune the idle without the pressure sensor completely hooked up.
I first wind off the idle adjusting knob. I then balance the front and rear cylinders with the bypass screws and then go to a slight bias towards the rear cylinder. By rear cylinder bias I mean more vacuum on the front cylinder and less on the rear. This means more air is going to the rear cylinder giving it a bigger hit. I set the bypass screws for a very low idle and then keep playing with the trim for best idle. I keep going back and forth between bypass and trim till I have the best idle at quite low rpm. I like to do this when the bike is fully warmed up and the fans are running off and on. This ensures that the bike will idle well when hot in traffic and it still idles well at the normal cruising temperatures. After I am satisfied I have trim right I play with the bias till I have the smoothest idle still at a low rpm. When I feel it is the best I can get it I use the idle speed adjusting knob to raise the idle speed. I like it at 1250 to 1500 rpm for street use.
Using this method the bike always performs very well with good off idle response and I have never had any trouble with stalling.
related thread: http://www.apriliaforum.com/forums/s...d.php?t=151818
Another related:
The trim potentiometers alter injector open time so they directly adjust fuel delivered. They are not active on all chips. The brass screws adjust idle air bypass. These meter air that is allowed to bypass the throttle plates. The bypass screws mainly effect idle and small throttle openings but their effect diminishes quickly as the throttle opens. I think the trim mainly effects idle and small throttle openings as well but some have reported an effect at higher RPM's that can be measured on the dyno but I have no means of confirming this so I tune my bike based on my assumption that they mainly effect idle.
Ideally you use both the trim and bypass to tune the idle while measuring the CO levels with an exhaust gas analyzer and monitoring intake manifold pressure with vacuum gauges. Whether your local shop has the skill to do this carefully is another question.
There is a great deal of misinformation on this forum about the TPS and how to adjust it. The TPS is not generally something that needs to be fiddled with when tuning the bike. Adjusting the TPS is an initial set-up of the throttle body that, once done correctly, usually never needs to be adjusted again. The TPS on my 01 has never needed adjustment. For the fuel injection system to deliver the proper fuel it has to know the throttle position. Adjusting the TPS synchronizes the sensor with the throttle shaft so the sensor can accurately report the throttle position to the ECU. The only reference for this synchronization is with the throttle closed. This means that the idle adjusting knob is fully wound off so the throttle lever contacts the end of stroke adjustment screw which is locked with a lock-nut. At this point the TPS reading should be zero. It is often reported that the reading should be zero at idle but this is not necessarily true. It is also often reported that it should be adjusted to zero at idle and this is not correct. Zero or one are normal readings at idle but it will most likely be one unless your idle speed is low. A reading of -1 at any time indicates that the TPS is not adjusted properly.
Adjusting the TPS is not done with the lock-nutted end of stroke adjustment screw but by loosening the TPS mounting screws and moving the TPS. The end of stroke adjustment screw is there to keep the throttle plates from jamming in the throttle bores and generally does not need to be adjusted unless someone has tampered with it. Some chips like the FP with advanced ignition have a problem with high idle speed and adjusting the end of strike adjustment screw may be necessary to reduce the amount of air getting past the plates.
With some Eproms they don't even work.:confused
Fine tuning a Ape is a fine balance between the bypass screws and the trimpots.:devious
If you find your bike idling fine and co is around 4% Co you are ok.
For my Eproms I advise to start with the trimpots at 12 O clock.
The front bypas screw 2 -2.5 turns out from fully in, and the rear 1-1.5 turns out.
If you have a 2-1-2 exhaust this differs.
This is just a starting point!!.
From here you need a Co tester and a fine ear!!
I would call Griff and see if he can squeeze me in :devious
Here is wat KZmille wrote.
You want to check the TPS but they are usually okay if they have not been messed with. It should read 0 with the idle adjuster wound completely off. -1 or 1 indicate a need for adjustment though 0 or 1 are normal readings with the idle speed adjusted. You will see 1 especially if you have the idle speed set a little higher than standard.
This is how I go about adjusting the idle.
Since I don't have access to a CO meter, I must do without. I have used the mercury tube type of vacuum gauge for many years and find it the easiest to use. There are alternatives out there. I have not had as good a result with the Uni-Syn type flow meter that you place over the throttle opening. This is the same thing sold under the Evoluzione name. If it is all you have it works but you cannot monitor both cylinders at the same time, you have to have the air box open, and sometimes simply placing the device over the throttle changes the engine speed.
The first step is to fully warm the engine and hook up the gauges. You want to use the vacuum taps on the right side of the TB rather than the tiny ones on the left that are often mentioned. Using the taps on the left requires disconnecting the manifold pressure sensor which is active during idle. It makes no sense to me to try and tune the idle without the pressure sensor completely hooked up.
I first wind off the idle adjusting knob. I then balance the front and rear cylinders with the bypass screws and then go to a slight bias towards the rear cylinder. By rear cylinder bias I mean more vacuum on the front cylinder and less on the rear. This means more air is going to the rear cylinder giving it a bigger hit. I set the bypass screws for a very low idle and then keep playing with the trim for best idle. I keep going back and forth between bypass and trim till I have the best idle at quite low rpm. I like to do this when the bike is fully warmed up and the fans are running off and on. This ensures that the bike will idle well when hot in traffic and it still idles well at the normal cruising temperatures. After I am satisfied I have trim right I play with the bias till I have the smoothest idle still at a low rpm. When I feel it is the best I can get it I use the idle speed adjusting knob to raise the idle speed. I like it at 1250 to 1500 rpm for street use.
Using this method the bike always performs very well with good off idle response and I have never had any trouble with stalling.
related thread: http://www.apriliaforum.com/forums/s...d.php?t=151818
Another related:
The trim potentiometers alter injector open time so they directly adjust fuel delivered. They are not active on all chips. The brass screws adjust idle air bypass. These meter air that is allowed to bypass the throttle plates. The bypass screws mainly effect idle and small throttle openings but their effect diminishes quickly as the throttle opens. I think the trim mainly effects idle and small throttle openings as well but some have reported an effect at higher RPM's that can be measured on the dyno but I have no means of confirming this so I tune my bike based on my assumption that they mainly effect idle.
Ideally you use both the trim and bypass to tune the idle while measuring the CO levels with an exhaust gas analyzer and monitoring intake manifold pressure with vacuum gauges. Whether your local shop has the skill to do this carefully is another question.
There is a great deal of misinformation on this forum about the TPS and how to adjust it. The TPS is not generally something that needs to be fiddled with when tuning the bike. Adjusting the TPS is an initial set-up of the throttle body that, once done correctly, usually never needs to be adjusted again. The TPS on my 01 has never needed adjustment. For the fuel injection system to deliver the proper fuel it has to know the throttle position. Adjusting the TPS synchronizes the sensor with the throttle shaft so the sensor can accurately report the throttle position to the ECU. The only reference for this synchronization is with the throttle closed. This means that the idle adjusting knob is fully wound off so the throttle lever contacts the end of stroke adjustment screw which is locked with a lock-nut. At this point the TPS reading should be zero. It is often reported that the reading should be zero at idle but this is not necessarily true. It is also often reported that it should be adjusted to zero at idle and this is not correct. Zero or one are normal readings at idle but it will most likely be one unless your idle speed is low. A reading of -1 at any time indicates that the TPS is not adjusted properly.
Adjusting the TPS is not done with the lock-nutted end of stroke adjustment screw but by loosening the TPS mounting screws and moving the TPS. The end of stroke adjustment screw is there to keep the throttle plates from jamming in the throttle bores and generally does not need to be adjusted unless someone has tampered with it. Some chips like the FP with advanced ignition have a problem with high idle speed and adjusting the end of strike adjustment screw may be necessary to reduce the amount of air getting past the plates.
Joined Jul 2008
207 Posts | 0+
Awesome info thank you. For now I still have the factory Eprom on map 2 so I'm guessing if my son accidentally did turn the knobs on my ECU it doesn't matter? Also why do you run the rear cylinder a little bias? Is there something to be gained by this?
Last edited:
Why the bias. open to conjecture. Kz had a thoery as below
After the front cylinder fires, the crankshaft rotates 300 degrees before the rear cylinder fires. After the rear cylinder fires, the crankshaft must rotate 420 degrees before the front cylinder fires. Therefore rear cylinder needs a bigger hit to get the front up on compression after 120 degrees more rotation.
What kind of shoots holes in that is the post 04 bikes have a front bias on map 1 and a rear on map 2 (from memory) :dunno
Generally i think the bikes tend to be a little less sharp off/on throttle with a bit of a bias and a sweeter idle but many run them matched as well.
My front cylinder runs richer than the rear cylinder how can I run it a bit leaner. I checked all sparkplugs the front ones are carbon fouled and the rear ones are normal brown/tan colour
