Aux air regu;ator

[EJP914]

Have '73 1.7 with leaking aux air reg. Have removed it from car and connected it directly to the battery. It heats up ok, but the small cylinder or plunger in the housing doesn't move up and close off. I disassembled the unit as per Kjell Nelin's article on D-Jet FI. (What a job!!!) I placed the top housing (the one with the plunger) in the oven and heated to 250 degrees. Nothing moved. Can someone explain to me how the metallic spring when hot causes the plunger to move up. Not sure where to go next or what to do. Given the price of new aux air reg, I sure would like to fix this. Any further suggestions/comments are appreciated. Thanks!

[bowlsby]

I've (and apparently several others) have had good success just spraying a little WD-40 into the unit to lube the moving parts..I guess they corrode and stick over time.

It worked well for me.

[Dave at Pelican Parts]

The spring is actually made out of two different pieces of metal that are bonded together. When the two metals are heated, they expand at different rates. This means that the spring either coils a little tighter or uncoils a little bit, depending on which side the faster-expanding metal is on. (I forget.)

I suggest spraying some *good* penetrating oil (not WD-40, something like Kroyl or PB Blaster) into the opening. Then use a flat-bladed screwdriver to twist the slot that the spring goes into.

The center post is actually a rotary valve. There is a passage bored through it. When the post rotates, the passage is moved more into line or more out of line with the inlet and outlet pipes.

Hope this helps.

--DD

[ELI PITTA]

After you take the unit apart you will need to polish the shaft and the area where the shaft fits into. Simply sprying wd40 will not work. Polish both and use lithium grease as a lubricant. I have had no problems with mine.

[mejulihn]

I need to be educated here. What are the symptoms of a malfunctioning aux air regulator?

[John Rogers]

The aux air reg lets extra air pass until it heats up from the 12 volts supplpied to the heater element and shuts off. It lets you have a fast idle when cold and lower idle when the engine is warm. It will work without power supplpied to it but will take longer to heat up and close. To see if it is working, remove the hose and see if there is vacuum when cold and again when hot. You can also remove it, see if it is open and put 12 volts to it and see if it shuts in a couple of minutes. The one on our car was soaked in a jar of WD-40 for a couple of days before if finally freed up. I did not take it apart since I tend to destroy small electrical heating elements! Good luck.