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Discussion Starter #1
Guys and gals ..... 馃憢

My year 2000 996 is generally running well apart from a peculiar stutter that only starts to happen when warm and then stays until it cools down again... When it's warm, low throttle application from about 2k to 4k rpm causes a sound like a relay is clicking somewhere under the dash and very briefly killing the ignition - every now and then it also jerks the throttle in my hand. I have read about the popular switch to a single injector solving a 3.5k stutter ... is this what I have or is there some relay that could be causing my issue?

It revs on out past 9k no problem and if you keep the revs up above 4.5k then it doesn't happen.

Many thanks for any help
:upyeah:
(y)
 

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Make sure the fuel lines in your gas tank are not cracked and leaking.
Does it happen on a full tank?
How is the charging system? Provide voltages at the battery at idle, 2k-4k rpm, and 5k rpm and up
There isn't anything under the dash to make a clicking sound. Intake under the gas tank could be popping
Post a video, it sounds like more than one issue but it is probably one problem.

Based on what you have said, it does not sound like the dual injector stutter
 

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Discussion Starter #3
Thanks for the reply Namor.

I wanted to video it before I got back to you. Have now managed to video it and upload to youtube. A few more things I've noticed - it only happens when it's hot, when it's warm it doesn't happen - I have to have been stuck in traffic for a while. It's almost as if the fan should be coming on but instead this click is happening and effecting the throttle. On the video you can hear the click but the sensation of the throttle moving (slightly) in my hand doesn't come across. (Also, my engine temp gauge only works intermittently, wonder could that be related...)

Really appreciate any help....

Video is here:
 

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Discussion Starter #5
Perhaps the bike is a little lean? Does sound like it.
Interesting ... I could try to twist the little screw a touch in beside the EPROM, I had a look at it already but couldn't find anything small enough to turn it - it's tiny!
 

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I agree with lean as it is intake backfires. And lean gets worse with heat. Mine did that when I upgrade the engine from 916 to 996. Maybe it's not an upgrade, but a change.

While idling turn the dash pot to full counter clockwise to make it richer. At some point you will notice the difference in idle. Tinker with it in either direction and you will understand.

Run it full rich and I bet the intake backfiring stops. Adjust as you desire.
 

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Discussion Starter #7
Is the "dash pot" the screw in the ECU? Or somewhere else you can adjust the mix?
 

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Yes, and be careful with it. It's plastic and doesn't need much force to move. It is easy to strip the slot where a small screw driver goes... not that I have done that... with the tip of a knife and 4 or 5 beers.
 

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Discussion Starter #9
Gave the screw a bit of a twist... increased it bit by bit, ended up back from 3 o'clock to about 10 o'clock -- I felt like by that point the sputter had reduced in both frequency and amplitude - but it was still there.
I have a very good Ducati tech not far from me so I'm going to bring it over to him on the weekend as I feel like I might screw it up if I keep messing and, apart from this sputter, it is running really really well. Thanks for all the tips I will update with the outcome!
 

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Mine did it years ago. 10+. I don't recall everything i did back then because the bike was in bad shape and i did a lot of work.

It may have been adjusting the throttle position sensor (TPS) or replacing the + and - wires for the battery and then some of the + leads elsewhere. Good luck
 

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That little screw is for adjusting the mixture at idle and very low revs for CO level. The higher the revs the less the effect on the mixture. So at 3k revs you can only do so much with that little screw. Eprom tuning is the way to go
 
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