power boost vacuum advance unit

[saltyfj1200rider]

I am a new owner of a 1990 fj, I am vary impressed with it overall. I have a problem with the idle hanging. I can use the clutch to pull down the rpm's at a stop and it will idle ok but  the motor dose'nt drop between shifts as it should. I cleaned the carb's and it was somewhat better,but still hanging. I disconnected the  power boost vacuum advance unit and pluged the line ,the hanging idle was gone but a slight reduction of performance was noted. Should I replace the advance unit or is there a better fix?

[moonrunnah]

just my 2 cents but is throttle sticking open a little i had that problem and i was just a little adjustment and it was fixed

[saltyfj1200rider]

I checked it, cables are good with no binding

[saltyfj1200rider]

Using the motor to pull down the rpm's would eliminate that possibility.A stuck throttle is A stuck throttle. Thank's

[FJmonkey]

Air leak on your intake side, spray WD-40 (Or is that carb cleaner?) around the carbs and intake boots during idle. If the idle changes, you have a leak.

[saltyfj1200rider]

I also tried that, no leaks found. I just bought a good used sensor on Ebay $30, I will post how it worked out Thank You.

[moonrunnah]

how high is the rpms at idle

[56 CHEVY]

Could one or two plugged pilots be a possible cause? My guess would be a lean condition also.

[mreed112]

Make sure that you have no cracks in the hose going to the unit especially where the hose plugs to the #2 intake.  I have had that problem a couple of times.

[Pat Conlon]

I was not aware that the 1990 FJ's used a vacuum advance. I thought they were a DCI ignition.

My' 92 has a vacuum hose coming off the #2 carb manifold which runs up to the front under the fairing for the reserve petcock functions.

[weymouth399]

My' 92 has a vacuum hose coming off the #2 carb manifold which runs up to the front under the fairing for the reserve petcock functions.



You may want to check that out, it would be the only one.

Bob W

[Pat Conlon]

So Bob, the 90's have vacuum advance? What would the vacuum hose on my '92 do?

[Travis398]

The digital box alters the timing, but it uses sensors to determine the adjustments needed, (e.g. pick up coil and pressure switch.)

[andyb]

Think you guys may be barking up the wrong tree.  I'm guessing a synch would fix it.

[Travis398]

I'm guessing a synch would fix it.

I think so too