Hi Idle issues.

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Curlytops

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Well here's my first post... I have just acquired a 1986 GL1200 SEI which has a problem or 2. The guy i got it off says the PBR sensor is duff, which I believe to be true. There are no lights on once the ecu has booted up they all go out. Its also idling at around 2000rpm, would a PB sensor cause it to do this? Ive tracked down a set of used PB sensors so dont want to mess with the bike until these arrive, I just wanted to find out if they would cause the high idle issue if one was faulty?
 

Rednaxs60

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If a PBR sensor is faulty, you will get an error code and the FUEL SYSTEM light would come on. If one PB sensor is faulty the ECU defaults to the good one and all is good. If both PB sensors are faulty, the ECU defaults to a sort of get home mode. These should not cause a high idle.

I would recommend that you should adjust the idle down to 1000 RPM +/- 100 using the idle adjusting screw in the middle rear of the air chamber.

Do not adjust the screw that is behind the right side CFI cover. This is used to balance the left/right cylinder banks. Having mentioned this, this could also be the issue. To confirm that this may or may not be the issue is to connect a set of vacuum gauges to the engine. Use numbers 3 and 4 cylinders. You cannot balance the cylinders on the same side because of the fuel injection.

When you check the cylinder bank balance, and if the balance is off, adjust the screw behind the CFI cover to balance the cylinders. You will have to adjust the idle speed as well when doing this.

Check all the vacuum hoses and ensure these are in good shape, if not replace as required.

I would do this before replacing parts.

Good luck.
 

Curlytops

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Hi Thanks for the reply.. This is my first fuel injected 1200 and I did purchase it with a bit of trepidation as I know bits are hard to come by for the CFI system, But ive bought it as a project so will have a go at it. Bit of background...

The bike runs fine above 3k revs but a bit lumpy below that, previous owner researched it and concluded it to be the PB sensor. He told me he swapped the sensors over and the running fault moved over to the other bank with the sensor hence he concluded it was at fault.

All vacuum pipes were replaced so I know they are good.

No idea if anyone has messed with the setting screws for the idle or the other screws they shouldn't touch, but your info is very interesting and a good place for me to start my investigations.

I did order some used sensors from a place in the states, so at least I had something to start with if there was a fault, and I also have some suzuki sensors which the previous owner bought after researching other forums, as apparently these will work on this system if all else fails. Parts for the SEI are pretty non existent here n the UK.

Bike runs fine apart from a bit lumpy at low revs and starts on the button, its the high idle that concerned me so if its something as simple as the idle linkage screw then thats great...I will keep you in the loop thanks!
 

Curlytops

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Ok… have adjusted the idle screw as far as it will go but can still only get revs down to 1300rpm.. if i apply pressure with screw driver then it drops way dow…. So im thinking the other screw which I shouldn’t touch without vaccum gauges is holding it … bike runs but sounds like its running uneven… bit like a plug going off.. ill wait now until all my bits arrive then proceed in an orderly manner…
 

Rednaxs60

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Parts for these fuel injected models is a challenge, but there are options/alternatives.

An alternative for the PB sensors are MAP sensors from a late model Suzuki:
Brand: Denso.
Type number: 100798-5630. Suzuki ordering number: 15620-35F00.
Suzuki description: Sensor Boost, IAP (Inlet Air Pressure) sensor.


Have had theses Suzuki sensors installed on my '85 Limited Edition fuel injected model for 4 years and these work well.

Below the details of the two Toyota sensors.

Brand: Denso
Type number: 100798-4530 and 100798-5250 Toyota ordering number: 89420-16080 and 89420-02010

Lots of other options.
 

Curlytops

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Parts for these fuel injected models is a challenge, but there are options/alternatives.

An alternative for the PB sensors are MAP sensors from a late model Suzuki:
Brand: Denso.
Type number: 100798-5630. Suzuki ordering number: 15620-35F00.
Suzuki description: Sensor Boost, IAP (Inlet Air Pressure) sensor.


Have had theses Suzuki sensors installed on my '85 Limited Edition fuel injected model for 4 years and these work well.

Below the details of the two Toyota sensors.

Brand: Denso
Type number: 100798-4530 and 100798-5250 Toyota ordering number: 89420-16080 and 89420-02010

Lots of other options.
I have 2 suzuki sensors the previous owner bought i just to to make the wiring fit. Im hanging on though until a set of used PB sensors ive bought arrive from the states… hopefully these will be fine and cure that problem. Thanks for the other sensor info👍
 

Rednaxs60

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A quick check to determine if the cylinder bank balance is off is to use a small heat temp gun on the exhaust header. All cylinders should be close to the same temp. If one side is significantly cooler than the other, a good indication that a balance may be required.
 

Curlytops

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Okey dokey i think im made an error with the PB sensors which are on the way from the states… i was unaware there were 2 types of electrical connections, and looking at the pic they look different to my bike… even though i was assured they would fit… is it a case of changing the plugs over or are they not compatible… are the wires even the same configuration… bit of a pain but just asking in case i need them… schoolboy error i know … bugger ☹️
 

Rednaxs60

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In case you want to upgrade the PB sensors, attached a couple of pics for your maintenance library.
 

Attachments

  • New PB Sensor Pigtails.jpg
    New PB Sensor Pigtails.jpg
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  • pb sensor connector.JPG
    pb sensor connector.JPG
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  • PB Sensor Final Install.jpg
    PB Sensor Final Install.jpg
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  • PB Sensor Mod 1.jpg
    PB Sensor Mod 1.jpg
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  • pb sensor schematic.JPG
    pb sensor schematic.JPG
    67.4 KB · Views: 73

Curlytops

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Thanks for that at least I know I can use them if needed or modify my suzuki ones.
 

Curlytops

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HI.. Managed to get a bit of time working on the wing today... changed the vacuum lines and noticed the previous owner had the PB sensor wires in the wrong sockets. Started bike and it seems to run ok and the idle is down at 950rpm where it idles nicely with no pinking etc.. when i rev it it sounds clean and drops back to idle speed. I checked the vacuum on cylinder 3 & 4 and they were quite different. I tried to alter it using the right hand screw on the linkage but they didnt seem to come anywhere near each other so i set it back to what it was. If i disconnect each PB sensor it does bring up a fault light on the ecu, but when connected everything appears fine. Would a faulty PB sensor still cause vacuum issues without showing a fault light code? I dont want to change them if there is nothing wrong with them...Sorry for all the questions... I find carbs a whole lot easier on older bikes!

IMG_7189.jpg
IMG_7188.jpg
 

Curlytops

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Bit of an update... All balanced up and running fine.
 

Rednaxs60

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Good to read that you have balanced the right/left cylinder banks, and the engine is operating as it should. You'll really enjoy the bike now. As for carbs, no easy solution either way. The big difference is when you lay the bike up for a prolonged period of time, carbs can be an issue. My preference will always be FI over carbs; however, if you ride all year round, shouldn't have an issue with carbs.

Enjoy.
 

Curlytops

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Hi .. not posted for a while as not had a lot of time to work on the wing. i have a question about PB sensor connections... i managed to get a set from the states but they have the wrong connections on the end as i wasn’t aware at the time there were 2 types. the set that arrived have the round connectors where mine are the flat square type. Does anyone know if the wires are the same configuration on both, and its just a case of splicing them to my connectors? I looked in the clymer manual, and it only shows the sensors on the 85 model and not on the 86 sei diagram so assumed they are the same apart from the connectors… any ideas?
 
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