HUNTING IDLE, DEAD SPOT OFF IDLE

[WALTSTAR]

I went through the '88 GL1500 and put in new ignition wires, E3 plugs, tightened all the carb connections, found no cracked hoses, cleaned the coils, rebuilt the cooling system after cleaning-flushing & painting (now the bike runs at 1/4 the temp gauge), resealed the cooling ducts and sprayed carb cleaner in the carb body orifices & slides. I noticed a pressure release when I took off the gas cap and dont know what else to check. The bike rides great above idle and at speed. Pulling off in first with very light throttle reveals the dead spot and then a surge. The bike idles evenly but hunts to about 1200 rpm every five seconds now and then.

HELP ME, please

[GlimWas]

You did synchronise the carbs, did you? I know that the earlier year models had an issue with the carbs regarding idle and surging, maybe make a search on the sit in that direction?

[WALTSTAR]

No, I actually didnt. The bike has 43000 miles and ran great before being un-ridden for two years in my heated garage. I thought it would have something to do with the vacuum lines, but they are all unbroken and flexible. There are times when there is no dead spot. I was thinking more along the lines of bad gas (I filled it with good gas in the fall) or gummed passages.

[Aussie81Interstate]

I had the same model, it had a near similar problem - found out that it is the accelerator pump.

There are a few videos on youtube about this problem- basically you twist the throttle and a fine squirt of fuel is misted into the tops of both carbs - smooth transition off idle really. The pump in mine was (stuffed) not working correctly and actually leaking a bit from having sat for a long time - I reckon the seals dried out. then also the fine jets the fuel comes out of were also clogged - once these items were cleared and new O rings in place- all was perfect...



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might help

[WALTSTAR]

Seems like the most likely cause. Thanks for the info, i will look up similar posts on youtube.

[Alan_Hepburn]

My '94 had the same issues: with a very light hand on the throttle I could turn it a few degrees with no response, then suddenly it would jump up to around 1200-1500 rpm. Had a slight surge at idle also idling from about 850 - 1000 rpm. Then it started really acting up: come off the freeway after a long run and come to a stop at the end of the off-ramp it would idle around 2500-3500 rpm!

Turned out to be the engine coolant temp sensor on the right-hand intake - Item #36151-MT8-003 is about $31 from Babbitt's...

[dingdong]

There is also a vacuum line under the rubber mat that causes a surge at idle and off idle hesitation. It is a 90 degree bend hose that breaks down at the bend. Carbs have to be pulled to get to it. Very common problem with the 1500.

[WALTSTAR]

GOOD INFO ON THE TEMP SENSOR. MY ENGINE TENDS TO RUN COOL NOW THAT i FLUSHED AND SERVICED THE COOLING SYSTEM. ALL DAY RIDING IN THE NEW YORK WEATHER YESTERDAY RESULTED IN THE TEMP STAYING AT 1/4 GAUGE OR LESS. FIRST I WANT TO
1) seafoam the carbs to try and clean the off idle squirters
2) check the pump diaphragm if the seafoam does nothing to help. I have about 1/4 tank so I figure to pour a bottle in and see what it does.
Sorry about the caps. The cap lock was on and i didnt know until I stopped typing the sentence. Im not yelling.
I checked the elbows and hoses which were still flexible and not cracked or loose.

[kane67]

Hi,

Please read these, my wing had not this recall done so I updated slow jets to #55 and rebuilted accelerator pump. Other recall, vent hose routing is done.
I keep pilot screws open 3 1/8 turns like -88 manual says.

The orange tube under heat mat is vacuum for ecu. Important that it is good, no leaking or collapsing.
http://www.goldwingworld.com/pages/sb2.pdf
http://www.goldwingworld.com/pages/recalls%20GL1500.htm

br, kane

[WALTSTAR]

I just let the bike idle for a while with some techtron and noticed that the temp went to high without my fans coming on like normal. Could this indicate the bad temp sender?

[kane67]

Fans have their own temp switch, in the bottom of left radiator.
Next to switch there’s ground wire for radiator. Check and clean both the ground wire
connection and the temp switch connector/wire.
If you remove and ground the Temp switch wire, fans should turn on (power on or bike running)

I just had same issue last week and reason was bad contact in the ground wire to radiator.

There’s another temp switch for ECU.

[WALTSTAR]

Back to the temp sensor. My wing does not seem t have one. I will remove the right fan and look som more. Could it be that a 1988 would be built without one? I think it wouldnt make sense.

[WALTSTAR]

This is what I found. I see one sensor in the right center of the picture that appears to have a different connector that the sensor I bought. Is this the correct sensor at the bottom of the thermostat between the radiators with the green connector? The sensor I bought is also shown.

[Erdeniz Umman]

I am not sure what you are looking for, but the sensor on the thermostat for the 88 model is shown below.

[WALTSTAR]

Thats the connector. Just like a fuel injector. Thank you, I have to exchange it.

[WALTSTAR]

After doing some more research, it seems as if the 88 has just the temp sensors on the thermostat housing while the 89 has the thermo sensor on the right intake manifold.

[Erdeniz Umman]

After doing some more research, it seems as if the 88 has just the temp sensors on the thermostat housing while the 89 has the thermo sensor on the right intake manifold.

No, the change starts at 1990 models.

[WALTSTAR]

Understood and thank you all for the help. Lets see if I can get the problem fixed.

[WALTSTAR]

Got the correct sensor, put it in last week, and started the bike for the first time today.....Voila! problem solved. Thank you all for the help!

[WALTSTAR]

OR SO I THOUGHT....
Took her out and the idle still hunts, although only 500 RPM top to bottom now (rather than the 2000 RPM as before). I get the smell of UN-burnt hydrocarbons as well and the bike has a staccato exhaust note when she idles down. I have E-3 spark plugs in her and at speed, she pulls fast, hard, and clean.
What now?

[ct1500]

How long have you owned this machine and when did the problem start?

[WALTSTAR]

I have owned the bike since 2001 and it started when I pulled it out this spring. I havent ridden it much so I did all the tightening and wire replacements. Its idling between 600 and surges to about 1100 right now. Now the smell is gone.

[terryt]

Hi I had the same or similar problem with my 1989. it turned out to be the carb a slide diaphragm was not sitting in the carb properly they weren't opening when it was reeved up. also the carb to head rubbers were sucking in air. removed the carb refitted them making sure they didn't slip and replaced the jubilee clips on the rubbers runs fine now
Check the diaphragms they may have slipped when refitting and spray carb cleaner around the rubbers to check for air being sucked in.
Hope this helps