I am experiencing some idle issues with my 74 1.8 L-Jet. The idle is high for about 20 minutes and then comes down to around 800 rpm once the engine is good and hot. Up until then it will idle around 1400 rpms. I assumed there was a vacuum leak so I went through everything and even did a pressurized smoke leak test. No leaks.

Next up was the AAR. I have collected three and bench tested all of them. They all close up in around 3 minutes which seems about right. All work. I tried one afeter the other and same results.

I thought about it for a bit and it seems once the engine is hot enough it closes the AAR from the heat. This lead me to test the voltage to the AAR and yup NO POWER !

Harness looks fine. Any suggestions where to start tracing this?

I am currently driving the car with out the AAR and it has idle trouble for about 3 to 5 minutes, after that seems pretty stable.

I replaced my throttle return spring on my throttle body and that seemed to help,as it idled all over the place sometimes.

I also replaced the gasket on my oil filler tube,this also seemed to help.

I also replaced my rubber tube from the AAR to the throttle body,auto atlanta just made a order of them,as they have not been avalible for a long time.

I have a 74-1.8L also.
If you pull the oil filler cap off when its runing it should stall out.
I am New to the 914 crowd,so just trying to offer some help.

My best mod on my motor is the Mallory 4554101 optical distribitor really expensive but absolutely amazing how the car runs now.

Good luck with finding the problem,sorry I cant be more help.

If you figure it out and have some time I would like to see a couple pictures of your motor,as I have no idea how to configure my heater lines.
Thanks. Grant

all good things to check. I also had erratic idle due to the throttle plate not seating correctly because of a weak spring.

You have identified a problem though, the aux air valve has two wires that supply 12vdc only when the engine is running. Did you test for voltage at the aux air valve connector in this condition? If so, we need to know what voltage leg is missing. With the engine running, grab a voltmeter and ground one meter lead probe on the negative battery post. With the other meter lead, probe one of the two aux air valve pins. One of those pins should yield 12vdc. If so, carry on with the next test. Put one meter lead on the positive battery post. Then put the other meter lead on either pin of the aux air valve. You should see 12vdc. Depending which voltage you are missing will tell us which way to trace this fault.

Yes I did check for voltage with the engine running. Nothing at the pins. I did try the ground to battery and positive to battery. No voltage ant the connector.

The loom looks fine and haven't seen any evidence of wire damage.

Next will be to test resistance to the wires. Where does the AAR power come from?

BTW: driving the car with out the AAR installed (Plugged the lines) and it seems to run pretty darn good with out it !

Odd, but you can check the continuity from the dual relay at either pins 88d or 88c to one of the pins at the aux air valve connector. Once you confirm 0 ohms, you can proceed with the other pin on the aux air valve connector to pin 34 at the ECU connector, again 0 ohms is what you are looking for.