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On 13 Sep 2006 at 4:58, Big Al wrote: > My 1970 FI automatic starts up very well (although I still need to do a > full tuneup). > > But I've noticed something. After the engine gets to about operating > temperature (around 15 min time idling) the throttle decreases and then > it gets hard to throttle up. > > I'll recheck the timing and the valves, but could there be a sensor that > might be sending the message to the control box causing this throttle > down (and also the poor throttle reaction)? > > Or does this engine need a retorquing? (I haven't checked that yet) The idle speed drops as the AAR (auxilary air regulator) warms up. This is part of the design, and it means that your AAR system is working properly. My first guess is that your idle speed is set too low. It needs to be set with the AAR fully warmed up and the idle speed at its minimum. If you set it when the engine is still too cold, then the idle speed will be too low once it's warm. This might make it baulky. You can mimic the effects of a fully warmed up AAR by pulling the AAR air input hose off the air cleaner and covering the end with your thumb. Set the idle speed with the hose blocked off and it will be right. BTW, you also want to make sure that you set the timing with the engine speed below 1000 rpm. Otherwise, you won't be getting the advance you need. This would also have the effect you describe. -- Jim Adney jadney@vwtype3.org Madison, WI 53711-3054 USA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~