308 GTS QV Idle

My 81 idles at about 1100 & drops slightly after the emissions system kicks in.


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My 84 QV also idle at around 1200 rpm (1000 is normal) but when I checked the rpm with with my Snap On timing light, it reads at 1000 rpm, so this tells me my tachometer is not 100% accurate.

 

My Euro warm (tach) idle is in the 1300-1500 range. Higher than my other modern cars, but those also have a lower redline.

 

That is the correct idle speed according to the owners manual and workshop manuals.

 

My ‘84 QV idles at 1100 rpm. Dumb thought.....but have you checked your floor mats? They notoriously get scrunched up to the gas pedal and increase idle speed.


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The WUR device is adjustable. There is a small brass nut on the side that allows for adjusting the amount of air that makes its way thru the by-pass portion of the WUR. You can make the car idle faster or slower depending on how its adjusted.

 

I'll look into that... I had too low idle at one point (cold idle = car dies under braking), which was corrected after I fixed a vacuum leak. It would up at this higher point, which I've just kind of lived with.

Floor mats are definitely ok though, and throttle cable is new and properly adjusted.

 

Is that the proper way to adjust the idle on a QV?

 

No, the WUR has nothing to do with idle speed adjustment on a QV! (Assuming, of course, that the WUR is functioning correctly)

There is an adjusting screw on the throttle cable pulley end of the throttle plate of the throttle body, and a large screw on the underside of the throttle body for the idle air bypass. Those two are adjusted in a specific sequence to set the QV idle.

 

The WUR is a electric thermostatically controlled device. It is open when cold and slowly closes as the car warms up. Basically, it allows air to pass into the manifold when the valve is open which increases idle speed (only when cold) as the device warms, the air valve slowly closes and the idle speed will returns whatever the throttle and air by-pass is set to (RPM wise). The WUR only affects cold idle RPM. 12Vdc is applied to the WUR when the car is started and from that time on the air valve starts to slowly close. When the auto is off, the 12Vdc is removed and the valve slowly starts to open again for the next cold start. The adjustment on the WUR will determine how fast the car idles when cold. Set your idle speed when the car is hot, then you can use adjust the WUR when the car is cold so that it idles at 1200-1500 rpm when cold or whatever speed you want. Hope this helps.

 

No, no, no, the WUR controls the fuel flow, in association with the fuel distributor. What you're describing is the auxiliary air valve , which sits under the expansion tank.

 

FerrariDoc-You are correct. I don't how I missed that. It is the the Aux air valve. It sits under the expansion tank on some models, not all. Thanks

 

No worries. Sometimes we chase down a topic so closely, we forget to stop and take a breath

 

Fwiw - just got my idle adjusted, using the throttle plate screw and air bypass bolt (both @ plenum). Holds nicely at around 1000-1100, and doesn't die after a quick rev in neutral. Thanks for the thread.