What causes the engine to "hunt" for idle?


Information and questions on GL1800 Goldwings (2001-Present)
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yechave
Posts: 131
Joined: Tue Sep 13, 2011 6:39 pm
Location: Lehighton, Pa
Motorcycle: 2006 Gl1800

What causes the engine to "hunt" for idle?

Postby yechave » Tue Sep 20, 2011 4:44 pm



Is this normal? The engine goes above and below idle speed at least twice before it settles in. I do use Sea Foam and Lucas Engine treatment. Bike (06) has less than 15k miles on it. Otherwise, the engine runs great.



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Steve F
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'03 GL1800

Re: What causes the engine to "hunt" for idle?

Postby Steve F » Tue Sep 20, 2011 10:08 pm

If it had a carburator, it would indicate a lean condition. Not sure that if the injectors are not spraying right you'd have the same problem. Try getting it out on the interstae for a few hours and see how it runs after that. Injector cleaning may be required, beyond the additives to the fuel.
"To ride is the reason, the destination the excuse."

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mcbrown
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Re: What causes the engine to "hunt" for idle?

Postby mcbrown » Wed Sep 21, 2011 12:31 pm

My new 2010 Gl1800 Luxury is just over a week old and the day I picked it up from the Honda dealer it was pulse idling as though someone was flicking the throttle every second or so. I took it back to the dealer 2 days ago and when I pulled into their driveway to get it fixed it wouldnt do it. It has done it several times since but I have noticed it seems to happen when the engine gets hot while sitting at traffic lights and in heavy traffic while crawiling along. I have decided to leave it until I take it in for its first service at 1000kms. I assume its one of the injector or choke settings which needs to be tweaked. I have been running it along our freeways up to about 100kms per hour so it should be still running clean.

yechave
Posts: 131
Joined: Tue Sep 13, 2011 6:39 pm
Location: Lehighton, Pa
Motorcycle: 2006 Gl1800

Re: What causes the engine to "hunt" for idle?

Postby yechave » Wed Sep 21, 2011 1:01 pm

Due to all the time in the shop (6 mos) and bad wx, I've only ridden ours 2500 miles the past year. While I don't ride often, it is ridden in a way there should be no grass growing anywhere on this bike. I just came from an LT, and that was ridden in the mid 7K range. When I got this back from the tranny rebuild, I was told the engine idle hunting was normal.

I just called Honda USA and was told by TYE, the hunting is normal as is the lights dimming. That was the end of the conversation.

Time to start looking outside the box for answers here. It took well over a year to find the dealer to rebuild the tranny under warranty.. Once you stop looking for answers, there aren't any!

yechave
Posts: 131
Joined: Tue Sep 13, 2011 6:39 pm
Location: Lehighton, Pa
Motorcycle: 2006 Gl1800

Re: What causes the engine to "hunt" for idle?

Postby yechave » Wed Sep 21, 2011 1:56 pm

I just called a guy with 50k on an 08. He said to reset the ECM via running in neutral until the fans come on. Just did that and may try to get the bike out for a ride before it rains. He also said he is on the original battery, and his lights do not dim under any circumstance. He does not use any fuel additives and runs the lowest octane gas available.

yechave
Posts: 131
Joined: Tue Sep 13, 2011 6:39 pm
Location: Lehighton, Pa
Motorcycle: 2006 Gl1800

Re: What causes the engine to "hunt" for idle?

Postby yechave » Wed Sep 21, 2011 6:17 pm

I did the ECW reset and managed a test ride before it rained. It did not solve my problem, the engine is idling between 550 and 800 RPM's, and the lights dim at all stops.

yechave
Posts: 131
Joined: Tue Sep 13, 2011 6:39 pm
Location: Lehighton, Pa
Motorcycle: 2006 Gl1800

Re: What causes the engine to "hunt" for idle?

Postby yechave » Wed Sep 21, 2011 6:57 pm

This is rather long and the info was obtained from a link on an old thread at Gl1800riders.

Causes of idle hunting:
Cruise control cable too short
throttle adjustment
air bleed screws may need adjusting
fouled 02 sensor
vacuum leak
alternator
change ECW

"This is correct what you say, the complete fuel injection systems is a new one, from model year 2006, that's where the problems begin, my dealer told me...
I have changed the complete throttle body, the same, changed all the sensors, the same, vacuum line's, the same, then changed the ECW computer, and the hunting idle is gone.....
Also when i stop at a traffic light, the rpm is normal, does not go down anymore..., funny not?? Cost only a lot of money..."

Factory spec 700 RPM +/- 70

The following was also listed as a fix for the GL1800 engine hunting problem:

"Pair Valve Blockoff Mod


A mod that is stated to improve throttle response as well as smooth out the Vtec transition.


Here is how to fix the running issues that VFR800 VTEC.

1 raise fuel tank

2 locate hose that runs from the air box to the PAIR valve

3 Insert a blockage into this pipe. (A large ball bearing is good)

4 Ride bike

What is happening is that when the bike is running the pair is opening to blast fresh air into the exhaust system. This was done to clean up the bikes emmisions. This systems worked fine on all models. Even carb models have this system fitted. When the VFR went to the first fuel injected model the PAIR valve was still used again to clean up emmisions without any problems. Then the VTEC model came along and it all went wrong. The reason for this is that the VTEC model had an O2 sensor fitted in the exhaust. What happens is that the PAIR valve is working pretty much from idle speed blasting fresh air into the exhaust system. The fresh air entering the exhaust is picked up by the O2 sensor which then thinks the bike is running lean (around 19:1) so sends a signal to the ECU to richen up the fuel mixture. The ECU is now pouring as much fuel into the engine as it can because the O2 sensor thinks its still running lean. The real fuel/air ratio being poured into the bike is now around 11:1 making the bike hard to ride and resulting in the snatchy throttle responce we have all been talking about in this thread. Trust me. Block off the PAIR pipe from the airbox to the PAIR valve and go for a ride."




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