2F running a little rich...

[cbmontgo]

I moved to Colorado from the flatlands a few months back, and my FJ60 seems to run a little rich ever since I got to 6,000' altitude.

Would you guys recommend that I start with the HAC valve (it may be faulty) or does it only control the timing advance and not the actual mixture?

 

[RredFJ40]

someone with more knowledge may chime in here. But until they do, I think the HAC only changes timing - not carb mixture. I adjusted my mixture for my 4,100' altitude.

 

[cbmontgo]

someone with more knowledge may chime in here. But until they do, I think the HAC only changes timing - not carb mixture. I adjusted my mixture for my 4,100' altitude.

How did you adjust your mixture? Isn't there a set screw for mixture on these Aisin carbs? I was told there is not, but it seems logical that there would be.

 

[inkpot]

Howdy! The mixture screw is "Idle Mixture" only, and does not effect the running mixture. The only way to change that is to replace the jets. John

 

[NocalFJ60]

Why do you think it is running rich? smell? mileage?

Start with the HVAC valve and system like you are thinking. I think it does change the mixture some not only the timing. Have to look at the FS smog manual.

 

[2mbb]

As shown in the schematic below, the HAC does advance the distributor as well as leans out the primary low & high speed circuits as well as the secondary high speed circuit. It could be your HAC is bad or maybe the carburetor ports are clogged.

 

[lehiguy]

Check the filter under the HAC valve. It can't do it's job if its clogged with crud as most are.

 

[cbmontgo]

Thanks, guys. I am going to check the HAC valve and see what happens. I am talking to CDan about buying a new one through Toyota.

 

[NocalFJ60]

Thanks, guys. I am going to check the HAC valve and see what happens. I am talking to CDan about buying a new one through Toyota.

I have some used ones if you need one. I could check them and see if they are good.

 

[cbmontgo]

I have some used ones if you need one. I could check them and see if they are good.

Thank you, although the one I have installed now is one that I bought used, so I want to get a new one to be sure.

 

[NocalFJ60]

Thank you, although the one I have installed now is one that I bought used, so I want to get a new one to be sure.

I understand. The valve is either open or closed based on the altitude. You should be able to tell if it is good or bad by following the procedure in the FSM.

 

[michael.e]

Hey guys,
Can someone direct me to a thread/posting that explains this further. I am trying to troubleshoot my rig and I want to check this out.

Thanks,
Emee