Another question for the MFI Gurus -
#1
Instructor
Thread Starter
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Here's what I'm dealing with:
My new car is a 74 with 2.7 and has a MFI and a few things are just not quite right on it. For one, the clean air hose from the heat exchanger to the thermostat is missing so the car is running very rich. I have ordered the part and hope it helps. Secondly, the shut off solenoid (just below the thermostat) was disconnected and I've noticed that when the throttle is in the idle position that the idle microswitch is not being pressed down by the screw. When correcting this by attaching the power to the solenoid and engaging the idle circuit the car idles but when the throttle is pushed down and the idle microswitch is now in the up position the engine just dies. IT seems like the shutoff solenoid is engaging and shutting off fuel to the engine. What can be going on? Any suggestions?
Thanks a bunch
Lefty
My new car is a 74 with 2.7 and has a MFI and a few things are just not quite right on it. For one, the clean air hose from the heat exchanger to the thermostat is missing so the car is running very rich. I have ordered the part and hope it helps. Secondly, the shut off solenoid (just below the thermostat) was disconnected and I've noticed that when the throttle is in the idle position that the idle microswitch is not being pressed down by the screw. When correcting this by attaching the power to the solenoid and engaging the idle circuit the car idles but when the throttle is pushed down and the idle microswitch is now in the up position the engine just dies. IT seems like the shutoff solenoid is engaging and shutting off fuel to the engine. What can be going on? Any suggestions?
Thanks a bunch
Lefty
#2
![Post](https://rennlist.com/forums/images/icons/icon1.gif)
TONS of reading...every word of it valuable.
<a href="http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm" target="_blank">http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm</a>
<a href="http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm" target="_blank">http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm</a>
#3
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The shut off solenoid is controlled by the rpm transducer which puts out 12v over 1600 rpm. If you close the microswitch the 12v passes through yo the shut off solenoid which will shut off fuel delivery. There should be 0v out of the RPM Transducer under 1600 rpm. I would check your RPM Tranducer, bet its putting out 12v under 1600 RPM.