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Discussion Starter #1
So I've been trying to troubleshoot the erratic idle on my Brutale 1078 when the fans turn on. Idle is steady with fans off. Already did the usual fixes,(tps reset, idle trim, new plugs, dyno tune, etc.) and it didn't solve the problem. So my mechanic and I were checking all the parameters on VDSTS to make sure everything was in spec and we noticed that when the fans turn on the idle gets erratic and the lambda sensor column shows anywhere from 4 to 8 mv and goes back to 0 when the fans turn off and idle stabilizes. We watched it for a few cycles to confirm and it did the same thing over and over. I have a race ECU and vdsts confirms open loop. So lambda should be disabled, and it is, only till fans kick on and registers a millivolt/s. Any ideas why? Right now I have the lambda sensor off the bike and taped off at the quick disconnect. No error codes either. Please help.
 

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So, if I am reading this right, you are saying the vdsts is showing a small voltage recorded at the ecu from a non existent lambda sensor?

Might pay to do a full check of the battery charging circuit. On my 1090 I notice a small change in idle speed as the motor is loaded up when the fans come on, but nothing dramatic.
 

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Discussion Starter #3
Yes, small amount of voltage noted when fans come on from non existent lambda. I'm assuming just disconnecting it was good enough with no special "plug" to cap off the connector.

For my next step I'm going to replace the battery cables/ground to a thicker gauge as I've read on the forum that they are quite thin and may not handle full loads well, as in fans or starter. Voltage looked good on best software when bike was running.

So, if I am reading this right, you are saying the vdsts is showing a small voltage recorded at the ecu from a non existent lambda sensor?

Might pay to do a full check of the battery charging circuit. On my 1090 I notice a small change in idle speed as the motor is loaded up when the fans come on, but nothing dramatic.
 

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Discussion Starter #5
Anyway to bypass this, or anything I can change to fix the bikes symptoms? It can become very annoying in stop n go stoplight traffic, sometimes idle dips to low and engine dies.

The fuel and ignition mapping changes when the bike get's hot enough to make the fans come on.
 

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Microtec is the best option, there's one for sale at the moment for a great price. But also, it does sound like your idling is a bit low, and yes, well worth doing those battery cables in something decent.
 

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Discussion Starter #7
Anything I can change on my power commander V? In the closed throttle position/column? More fuel? Less fuel? Can't afford Microtech right now.

Microtec is the best option, there's one for sale at the moment for a great price. But also, it does sound like your idling is a bit low, and yes, well worth doing those battery cables in something decent.
 

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do you live in Brisbane?

Mine used to do that also, but no longer, stays steady even when the fans come on.
number 1 change your battery leads and earth, should be 3 of them ,one to the starter motor one to the battery an earth by memory, anyway change them all they are crap.

and really you need to spend some time adjusting stuff, like air bleed valves ,fuel trim ,and then adjusting your pc5 etc. I have the equipment to help at home. Its just a matter of going back and forth until you get it stable, A real pain in the backside, but well worth it. No need to take of the tank always, just get yourself a long flat head screw driver and adjust those air blead valves to get a constant 1200 to 1250 rpm range guided by your software. with vdsts you can further adjust fuel trim and reset tps, then do not forget to reset your pc5 throttle position in the software.

cheers eddy
 

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Discussion Starter #9
Live in Milpitas, California..in San Francisco Bay Area. I'll start with the cables then try more fine tuning. We'll see how it goes..

do you live in Brisbane?

Mine used to do that also, but no longer, stays steady even when the fans come on.
number 1 change your battery leads and earth, should be 3 of them ,one to the starter motor one to the battery an earth by memory, anyway change them all they are crap.

and really you need to spend some time adjusting stuff, like air bleed valves ,fuel trim ,and then adjusting your pc5 etc. I have the equipment to help at home. Its just a matter of going back and forth until you get it stable, A real pain in the backside, but well worth it. No need to take of the tank always, just get yourself a long flat head screw driver and adjust those air blead valves to get a constant 1200 to 1250 rpm range guided by your software. with vdsts you can further adjust fuel trim and reset tps, then do not forget to reset your pc5 throttle position in the software.

cheers eddy
 

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ps:
also discovered that my cam chain tensioner was locked solid,and i am not an expert on the effect of this but when i installed the new one my idling was smoother again,like go figure. Maybe the guys with more exsperience on this have a view.

cheers eddy
 

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Discussion Starter #11
Battery cable overkill?!

Changed out my battery cables today. Stock ground/earth cable was 8 gauge. Earth/positive cables were thinner at what looked like 10 gauge. I changed the 3 cables to 4 gauge with gold plated lugs and I also soldered them. Pictures below 1-4 left to right. 1)Upper cables are stock, and lower are the new 4 gauge cables . 2)Ground/earth cable. 3)Battery to solenoid cable. 4)Solenoid to starter cable

Looked a bit like overkill after I installed them, but the starter motor does kick over much stronger and easily. Engine starts right up at the first hit of the starter. I will be taking it for a commute test ride tomorrow in stop and go traffic. We'll see if it helps with the idle issue.

do you live in Brisbane?

Mine used to do that also, but no longer, stays steady even when the fans come on.
number 1 change your battery leads and earth, should be 3 of them ,one to the starter motor one to the battery an earth by memory, anyway change them all they are crap.


cheers eddy
 

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Discussion Starter #13
Starting other adjustments starting with air bleed valves..where?

I'm going to start the adjustments starting with the air bleed valves. Idle hovers between 1100-1150 now. I posted some pictures below and just wanted to confirm that the brass screws are indeed the air bleed valves, and that bringing them out increases idle? Any specific order they should be brought out, or just all the same number of turns out after they are synchronized? Thanks in advance!

and really you need to spend some time adjusting stuff, like air bleed valves ,fuel trim ,and then adjusting your pc5 etc. I have the equipment to help at home. Its just a matter of going back and forth until you get it stable, A real pain in the backside, but well worth it. No need to take of the tank always, just get yourself a long flat head screw driver and adjust those air blead valves to get a constant 1200 to 1250 rpm range guided by your software. with vdsts you can further adjust fuel trim and reset tps, then do not forget to reset your pc5 throttle position in the software.

cheers eddy
 

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thats them,yes out increases the idle,I normally work of number 2 cylinder, then use a carbtune to adjust the others to sync to number 2.
 

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Discussion Starter #15
Finally..idle stablized!!

Finally got the idle stabilized and rock steady with and without the fans on :moped:. I do not have a carbtune, but decided to play with air bleed screws and bring them out 1/4 turn until idle stabilized. Ended up with a total of 1/2 out and motor idle at about 1225 with the fans on. What a difference, and a relief to not worry about holding the throttle open a bit so it would not die at stops. Next step is to dish out for a carbtune, but bike runs, and idles great now. Thanks for all the advice and help.

thats them,yes out increases the idle,I normally work of number 2 cylinder, then use a carbtune to adjust the others to sync to number 2.
 

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Discussion Starter #17
Erratic idle returned when stock exhaust cans put on

I put the stock exhaust cans on to accommodate the noise restriction imposed on the track I will be riding at next week. Took it for a test ride to work and the erratic idle returned when the fans came on. I assumed that idle fuel mixture became a bit richer from restriction of stock cans. I then backed out the mixture screws 1/8 turn to compensate. The idle then stabilized once again, I'll put more test miles in to confirm. Anyone else have this much sensitivity from changing out the exhaust cans:confused:
 
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