Engine Surges
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Stage II
Joined: Dec 2010
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Engine Surges
Hi, I have a '97 Ultra EFI with 33K and have just come across a potentially dangerous problem. My engine light comes on in intervals and with it comes steady RPM surges to 3000 or so - even when idling - it eventually returns to normal but continues this pattern. I can turn it off to reset but it does the same thing and I have been riding when it does this which is not fun but no longer do as it has become worse. I was hoping someone can help pin-point this problem. I have read about a few similar problems but none I could find addressed this specific issue. Any help would be appreciated. Thanks in advance!
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Joined: Sep 2006
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You have the Marelli FI system....It sounds like your fast idle actuator is working when it shouldn't. It is basically a little electric plunger that has a piston that comes out and opens the throttle a little bit on cold starts....basically the same thing as turning the throttle by had a smidge. It is easy to see on the right side of the throttle body. When you turn on the ignition, you can see it move. There is a set screw on the throttle plate that adjusts cold idle speed. You can back the set screw out all the way and make the acutator not affect your cold idle speed....You don't need it...On cold starts, just crack the throttle a bit to start the bike.
My MM FI bike had the fast idle actuator go bad twice. It did the exact same things you are describing. The first time, it was replaced under warranty. The second time, I just turned the set screw out and took it out of the loop. Like I said before, just cracking the throttle is all that is needed to start the bike on a cold start. I've been riding it that way for 5+ years.
If you want to replace the part, they are about 85 bucks. It simply unplugs and is held on by 2 screws. Once you replace it, you will have to re-adjust your cold idle speed.
My MM FI bike had the fast idle actuator go bad twice. It did the exact same things you are describing. The first time, it was replaced under warranty. The second time, I just turned the set screw out and took it out of the loop. Like I said before, just cracking the throttle is all that is needed to start the bike on a cold start. I've been riding it that way for 5+ years.
If you want to replace the part, they are about 85 bucks. It simply unplugs and is held on by 2 screws. Once you replace it, you will have to re-adjust your cold idle speed.
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Stage II
Joined: Dec 2010
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Thanks!
Thank you for the quick response Triple X. I will have to look at this more closely tomorrow. If your problem was the same as mine and it was the actuator then I would think I would have the same solution. I have a 70-yr old experienced ex-technician who has done some minor work on my bike and he wants to run codes but I am afraid to drive it to him. It appears you and others on this site are quite knowlegeable and your sharing of your experience is really appreciated.
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