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Discussion Starter · #1 ·
Thought I would start a new thread since my miss has disappeared. If you like you can look at that thread here:
http://gl1800riders.com/forums/showthread.php?t=290819

First let me say that my bike is now running great – it hasn’t missed (literally) a beat since I added the new parts. It runs great while at cruise or while I’m on the throttle. It just doesn’t idle well and seems to still be running rich while at idle.

I did the PAIR solenoid test this morning and my results seem strange to me but might be correct – I just can’t verify them because (as techdude2000 said) Honda doesn’t specify when the valve should be open and when it should be closed. I removed the air filter this morning so I could tell when air was being drawn in through the solenoid. The cold engine started normally (about 2000 rpm) and looking at the tail pipes they turned from black to more of a grey color. As the engine warmed up the rpm dropped as normal to around 700-800 rpm. The PAIR solenoid was open the whole time – and I could tell when the ECM switched to “closed loop” mode because the idle started running rich (and a little rougher) and the tail pipes turned black – I’m assuming to a rich condition. If I raised the RPM to around 1200 to 1500, I could hear the solenoid close and all was normal – including the tail pipes turning to a more grey color. I’ve done several ECM resets. My test rides lately have shown a normal mpg above 40.

I did find this on an internet search but not for the GL1800 so could be totally different but I found it interesting:

PAIR System Operating Strategy

PAIR operating strategy varies between different engine applications; therefore, refer to the Repair Manual for exact system operating parameters. An example of a typical program strategy (Truck with 22R-E engine) allows secondary air flow during the following conditions:
· Cold engine operation; when coolant temperature is below 86 degrees F and engine speed is below 3600 rpm
· Deceleration; when either of the following conditions are met:
o Coolant temperature above 140 degree F, IDL on, and vehicle speed above 2 mph
o Coolant temperature above 140 degree F, IDL on, vehicle speed below 2 mph, and engine speed above 2,500 rpm
Has anyone done the PAIR test like I did and did you see similar results? Should I quit worrying and just ride? I am planning to ride up to “Wings over the Smokies” in a couple of weeks and want things right. Thanks all…
 

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GL1800 Doctor
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The engine temp probably does have something to do with it. During the service manual test of the control valve, you are supposed to warm the engine up to normal operating temp and then check the valve for air movement. It says to slightly turn the throttle and you should get air flow. Using logic, this means there should be no air flow without turning the throttle slightly. I think you still have a problem, it may be the wiring coming from the ECM that provides the voltage to keep it closed at idle.
 

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Discussion Starter · #3 ·
Thanks techdude2000. I agree the service manual is not clear about whether the valve should be open at idle. It states:

Start the engine and open the throttle slightly to be
certain that air is sucked in through the secondary
air intake port.
If air is not drawn in, check the air supply hoses for
clogs or disconnection, and check the PAIR control
solenoid valve.

After doing the test I noticed that at idle the valve is open but not a lot of air is being drawn in and more is as you open the throttle – until 1200 to 1500 rpm when the solenoid closes. I’m assuming that’s why the manual says to “open the throttle slightly” – so that the suction is more noticeable. I’m thinking that it’s working correctly. Does that sound right to you? You wouldn’t want to take your bike apart and test yours would you?? Just kidding…

Thanks…
 

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GL1800 Doctor
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Not today, but the next time I change the air filter I definitely will test this system's operation and take notes. I might even hook up a light so I can see what the solenoid does while driving down the road. I've been doing a little research and almost every system I've found on autos keeps the valve shut at idle after the engine is at normal operating temp... It is open during cold engine idle, but they all shut it after warmup. I'm guessing they do that since the engine is being run very rich on purpose to similate the choke function and the emissions are high during this warmup period. I think if your's is still open at idle with a hot engine, then you have a problem. The only way to tell is to take it apart, run it until the temp gauge goes to the famous almost half way point and then see if you have air flow on the hose at idle. Maybe someone out there with their bike apart will do this test for us.
 

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My 98 SE had a hard time starting and idling when cold, once warmed up it ran fine, the dealer replaced the PAIR valve and it fixed the problem
 

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2 years after this thread i may add something .. :roll:

i got a bike acts like this ..

cold engine idle .. bike start normal at RPM (1500-2000) .. i cant notice any thing ..
hot engine idle ( RPM 700-800) .. engine is running rough .. exhaust little rich

then i increased the throttle slowly .. at the point RPM 1200-1500 i hear a sound like ( BOOQ ) as if a vacuum shut off something .. then the engine run perfect ..
i located the sound from PAIR SOLENOID VALVE ..

the shut off sound is very clear and its like a knok .. not a slowly vacuum ..

i should check it tomorrow and update you ..
 

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GL1800 Doctor
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20,592 Posts
2 years after this thread i may add something .. :roll:

i got a bike acts like this ..

cold engine idle .. bike start normal at RPM (1500-2000) .. i cant notice any thing ..
hot engine idle ( RPM 700-800) .. engine is running rough .. exhaust little rich

then i increased the throttle slowly .. at the point RPM 1200-1500 i hear a sound like ( BOOQ ) as if a vacuum shut off something .. then the engine run perfect ..
i located the sound from PAIR SOLENOID VALVE ..

the shut off sound is very clear and its like a knok .. not a slowly vacuum ..

i should check it tomorrow and update you ..
Abady, you can plug the port in the air box bottom and just leave it if the system is malfunctioning. It's used for US emissions and you can probably ignore those in Dubai.
 
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