Low RPM, Fuel Pump & Enrichment


Information and questions on GL1500 Goldwings (1988-2000)
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bbrackett
Posts: 134
Joined: Mon Oct 01, 2018 6:15 am
Location: Sedalia, MO
Motorcycle: 1988 GL1500

Low RPM, Fuel Pump & Enrichment

Post by bbrackett »



Hi, thank you for reading - Low RPM, Fuel Pump & Enrichment
1988 GL1500 - has the ECU and Fuel Shutoff etc.. fix.
does not have the Bank Angle Sensor Fix - hm..

I tossed $200 at the local Dealer found a couple of Vac leaks and said the only problem they found it was running great
and had the usual idle surge.

Hm

I've read about 47 posts about low rpm and off idle surge issues
Solutions from changing the ECU Temp sensor, to new carb boots 'n Vac lines, to #55 Jets, rebuilding the Fuel Shut off, replacing Ignition Timing Wheel(forget the name with 4 degree, new pump, coils, plugs, wires & changing the tires (haha)

I kinda thought I noticed the issue recently, but was like.. nah.. and finally confirmed I have the issue and adding about 1/4 to the Choke/Enrichment seem's to resolve.
when I do add about 1/4 choke, it helps.

tonight I confirmed also that my Fuel Pump runs all the time with the key on.

I LOVE my $250 Goldwing, I've put on 13K since 8/2020 and about 9k since 4/21, I have what looks like a good complete history of work done on her (Alice)
I don't have much money, but have to replace stuff to keep her on the road, I need her.

I dont want to run the choke all the time for low rpm usage and love driving her like a tractor :-)

1. Is the Fuel Pump supposed to be running all the time with the Key on ( with about 1/4 tank she sounds like it's sucking air and sick )
- I took the unit out a couple weeks ago, the big hose wasn't connected

2. If I'm adding a bit to the Enrichment, is it a Vac issue ? or does it need the jets ?

3. when I had about 3g left, I added a full can of Seafoam, seemed to help.. but..

- Found this - http://gwrra-wav.org/goldwingbulletins/1500SB2.pdf
- reading :-)

the pdf states to mark the frame with an X .. well.. I've got the X :-(
which is good, means I have the jets, upgraded ECUs..

then what the heck is the issue

Thanks.

34 yrs old, 110K
6/18/14 - 79,650 - Carbs Synch, Oil Changed, Replaced Vac Line to Manifold


Last edited by bbrackett on Mon Jul 11, 2022 6:49 pm, edited 1 time in total.
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Rambozo
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Motorcycle: 1992 GL1500 Aspencade
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Re: Low RPM, Fuel Pump & Enrichment

Post by Rambozo »

From your hints, I'm guessing the is a 1988 GL1500. Your side info shows an 86 GL1200.
The 88 89 had that problem and there was a Honda fix. You might see if you had that recall done. I seem to remember part of it was that 4 degree change, but that might have been something else. I'm sure you can search here and find all the info. The 88-89 also had a different fuel pump circuit with a relay. Should run a few seconds at key on then off until started. I don't have the wiring diagram for that model, so I'm not sure if the logic was in the relay like many cars of that era had, or if Honda did it differently. Running all the time the key is on is not right. It won't effect anything with how the engine runs, it's just a safety thing so if you crash the fuel pump doesn't continue to pump fuel all over the place when the carbs are no longer upright. A nice thing to have working IMHO.

Oh I see you have the service bulletin. Make sure all of it has been done on your bike. If not I think Honda will still do it, but many dealers won't touch older bikes anymore. So you might have to DIY. Still I would contact Honda and give them your VIN. I was very surprised that when I did they were happy to fix a few things that were still outstanding on my bike. They do the X mark for some things not for others so I don't always trust it. Trust but verify? :D
bbrackett
Posts: 134
Joined: Mon Oct 01, 2018 6:15 am
Location: Sedalia, MO
Motorcycle: 1988 GL1500

Re: Low RPM, Fuel Pump & Enrichment

Post by bbrackett »

soo.. I found this - http://gwrra-wav.org/goldwingbulletins/1500SB6.pdf
and.. I have no mark on the frame.. I guess I need the Bank Sensor

yes, updating profile, I sold my 1986 GL1200 :-(
bbrackett
Posts: 134
Joined: Mon Oct 01, 2018 6:15 am
Location: Sedalia, MO
Motorcycle: 1988 GL1500

Re: Low RPM, Fuel Pump & Enrichment

Post by bbrackett »

yea, I am extremely thankful to have a local Honda bike shop that has a guy that's been around a LONG time
I asked him in jest when he was going to retire so in case I needed to find someone else..
He said he wasn't, he's just going to turn to dust behind his tool box.. :-)

There is another Local Metric Expert, he taught the guy at the Honda shop, when he worked there the person I previously mentioned was a Kid :-)

lots of exp and I blabbered a couple times, that I was extremely thankful they even would look at my bike.

Tightened the head bearings, mounted my tires :-), and they inspected the bike the past two times

I need new rotors :-(
bbrackett
Posts: 134
Joined: Mon Oct 01, 2018 6:15 am
Location: Sedalia, MO
Motorcycle: 1988 GL1500

Re: Low RPM, Fuel Pump & Enrichment

Post by bbrackett »

I just pulled and checked the fuel shutoff, um, I think I have a problem.
I attached a tight hose and I can not establish a vacuum :-( just keeps allowing air, going to rebuild :-)
bbrackett
Posts: 134
Joined: Mon Oct 01, 2018 6:15 am
Location: Sedalia, MO
Motorcycle: 1988 GL1500

Re: Low RPM, Fuel Pump & Enrichment

Post by bbrackett »

update - removed the Fuel Shut Off, bypassed it, and the fuel pump turns on, then stopped, key off then on.. runs for a 30sec-min, shuts off
gonna run it without just for a short local errand.. see what it's like.

then later I'll dissemble the shut off..
bbrackett
Posts: 134
Joined: Mon Oct 01, 2018 6:15 am
Location: Sedalia, MO
Motorcycle: 1988 GL1500

Re: Low RPM, Fuel Pump & Enrichment

Post by bbrackett »

took apart the Shut off.. it has a big rip, like dry rotted ripped, inserted a golf tee in the vacuum line
took the bike for a short ride, no change

adding choke/enrichment helps <2k rpms
It sounds like a mis-fire hovering at 1500rpm in 1st/2nd
whats odd, in high gear @ 25mph 1500rpm it's not missing

plugs replaced 3000 miles 2 months ago, NGKs

found this elsewhere - vacuum lines used on the Honda are subject to becoming soft... soft enough they can actually collapse under high vacuum conditions, causing a loss of vacuum until the RPMs drop. He discovered a vacuum line that felt kinda smushy in one spot so he replaced them all and shazam, his bike roared back to life.

hm..


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