Hello everyone,

In going over my car's vacuum lines - waiting for my fuel injectors to be returned from servicing - I decided to replace the hose from the AAR valve to the cold start valve. Then I started to think - a dangerous thing - why do I need the AAR if the cold start valve is disconnected? It currently has no fuel supply so it's not working.

Currently my AAR is stuck open. Should I try to free it and reinstall it, or can I just plug the hose to the cold start valve and not bother putting it back?

Before I pulled the injectors for service, when my car was running (I am getting this car running again from a 3 year sleep) it had a way high idle ~ 1400rpms - so there's undoubtedly vacuum leak(s) somewhere.

Any input is welcome.
Thanks!
Tom
'73 2.0

http://members.rennlist.com/pbanders/djetp...tm#troubleshoot

Fix it and use it.

We just got ours working and it works great.

If you cant get it fixed, the ones that come on a 944 will work but you will need to run a ground wire

stuck open means high idle. You can pull it off, but you'll have to pump it to keep it running when cold. Fill it with PB blaster and let it soak to free it up. It should close byitself when free.

I have always wanted to try one of these....

http://www.partsgeek.com/gbproducts/WC/681...eek+Google+Base

For $20 it might be worth a try and if it works it could save us all lots of trouble....

The AAR keeps your idle up while the car is warming up. It's worth taking the time to fix it. It has nothing to do with the cold start valve. And further, the cold start valve only fires under the following conditions:

The 'engine temperature'* is below 95 degrees and ONLY while the motor is cranking and ONLY for 5-12 seconds (depending on the number of degrees below 95).

*-Engine temperature is measured by the thermotime switch, which is mounted under the main plenum. It's not oil temp and it's not CHT.

They free-up pretty easily with PB Blaster. You can test befor installation; run a couple of small wires from the battery to the AAR while hold up. You should see the orifice in the AAR close in about 2 minutes.

Actually, it's a lot lower than 95 deg. F before the CSV is opened by the thermoswitch (or thermo-time switch). Trigger temps vary by part number, but all of them are below 40 deg. F. This is from my web page (data from Jeff Bowlsby):

311 906 161 : -12 to -18 deg. C / 10 to 0 deg. F
311 906 161 A : 0 to -10 deg. C / 32 to 14 deg. F
311 906 161 B : -2 to -8 deg. C / 28 to 18 deg. F
311 906 161 C : -6 to -14 deg. C / 21 to 7 deg. F

... and as you pointed out, the CSV is open ONLY during cranking. If you have a later car with the thermo-time switch, after the total time cranking exceeds about 20 seconds, the heater in the switch will have opened the bimetallic contacts and it won't operate the CSV any more to avoid flooding.

FWIW, I don't think the CSV on my car has EVER been opened by the thermoswitch. That's what I get for living in CA and now in AZ

I bought a couple of spare AAR's off ebay recently that were in really good shape. Both were still sticky in operation. I inverted them, and flooded the intake port with WD-40 so that it ran out into a rag, then took Q-tips to clean out the ports. I then blew out the remaining WD-40 with compressed air. I then hooked them up to a 12V source and watched the operation to make sure they didn't hang (you can look into the intake port and watch it close). Took a few rounds of cleaning before they both operated smoothly.

I don't think the Nissan one has a heater element, does it? I would think it looks more like a open/shut type. Anyone have one?

Thanks for the replies everyone. I'll try to free it up and reinstall it if I can get it to work. Otherwise, I might be looking for a good used one...

Regards,
Tom
73 2.0

http://www.914world.com/bbs2/index.php?sho...y+air+regulator

One main question I had was could you use one from a 1.8 or 944. YES YOU CAN! despite what the FI sites tell you. I am running one right now. I have been told that some Volvo, Datsun, and other cars run the same type AAR. There is some good info in the link. This site is great for bouncing ideas around and I was grateful for the responses I received.

I had AAR questions a while back. I would definitely run one. Get in on cold morning start your car and your idle automatically goes up about 1,000rmps. The AAR simply allows a controlled vacuum leak into the intake, which in turn jacks the idle up. It is a valve that when cold is open and once you turn your key you are (should be) supplying 12v, so after a little bit the valve closes. Simple but effective. To hook this style up you just need small wire connectors 1 wire negative (ground it some where) other wire positive (I have mine going to keyed positive on coil).
New style like 914 1.8 or 944 Porsche, Volvo, Datsun, and etc.
Click to view attachment

NLA 2.0 style
Click to view attachment

Just a follow up on my question about the AAR;

Thank you for the information on the AAR. I used the pbanders link and serviced my AAR. I tried the 'renew' portion of the doc - spraying WD40 into the ports and leaving it upside down. I did this all last week. Yesterday I blew it out with compressed air, and tested it. After about 5 or so minutes, it was warm and I could no longer blow any air through it - so it works!

Reinstalled it, installed new hoses to it and connected it back up. The male portion of the connector broke at the base of the wire so I had to solder in a splice and new power connector but all is good.

Don't know how it will run yet because I am still installing my serviced fuel injectors and new fuel lines in the engine compartment - but it should be running by this coming weekend.

Thanks for the info.

Tom
'73 2.0