AAR test question

hobieboy · 05-10-2005, 05:46 AM

Need help with testing my AAR...

I am trying to figure out why my RPM does not rise on cold start (even though I have NO problem starting her cold - it always starts on 1st/2nd crank & mixture does get richer).

It seems that there's a spring loaded "flap" inside the AAR but its in a 95% closed position when the car is cold. I used a screw driver to see if I can push it (side way) open & I can.

Is this normal? I would have thought the cold or without-power position would be open? I ran out of time so didnt have a chance to apply 12V to it & see what happens. But did I completely miss the concept here?

TIA...

Ron.G · 05-10-2005, 06:09 AM

I'll be watching this thread also.

Paulporsche · 05-10-2005, 06:17 AM

Check Mystery train's thread on this. It pretty well tells the whole story. That "flap" inside should be open quite a bit at first, and then close down w/ time.

hobieboy · 05-10-2005, 06:55 AM

Hi Paul,

I did read the threads you referred to which is why my dumb question about the neutral/no-power state of the AAR. All other threads imply that it should be fully open when cold. I assume that includes no power?

I don't have a pressure tester set up handy to test the cold/warm fuel pressure, so am trying to diagnose the obvious before I go beg/borrow tools.

So it really sounds like my AAR is not acting correctly? If so, is it rebuildable?

thanks...

jdowty3 · jdowty3's Garage

I don't think it is rebuildable but last year I pulled mine out , flushed it with carb cleaner, let it dry and oiled the rotating plate with some 3-in-1 oil. I also plugged the electrical connector in and watched so see if the plate rotated as the heater element inside worked.

Paulporsche · 05-10-2005, 07:34 AM

Hobie,
If you check Mysterytrain again you will see how he rebuilt his, incl what jdowty did, and rewiring the bimetallic strip to get it to stay open longer. The flap seems like it wants to be fully open when cold, however I think mystery's was only about 3/4 open and worked fine. It has to close fully though.
BTW, are you a surfer or "catamaraner"? I'm not, but I had friends who worked for Hobie Alter (sp?) back in the 60s, making fiberglas surfboards and boats. One of them still isn't right to this day.

Mysterytrain · 05-10-2005, 10:48 AM

Yep, they can be rebuilt but you have to do it. The opening does not have to be fully open the opening is dependent on temperature..so colder=more open. You can test this theory by placing the AAR in your freezer..do it when your wife isn't home.

hobieboy · 05-10-2005, 11:14 AM

Hi Ron/Paul,

Thanks for the comments & suggestions - will probably try the fridge test later tonight

The current state of my AAR - being mostly closed, seems to indicate the culprit.

P.S. - I surf but can't claim to be a real surfer...

clevy70911T · clevy70911T's Garage

Mine has never been fully open, even straight from the freezer. It is maybe 1/4 of the way open when around 40 degrees F. I have adjusted it by "knocking the plug" it to keep the idle speed at 1000 at all times. It's amazing how such little air entering the system can increase the idle speed so much.
You never really said how your car idled when cold. So maybe you dont even have a problem. As I said before, my AAR doesnt really increase my idle rpm when cold, it just opens enough(cold )to keep the speed the same through warm-up.

autobonrun · autobonrun's Garage

How difficult was your AAR to remove?

hobieboy · 05-10-2005, 08:46 PM

Did the fridge test - absolutely no change in the opening

Scott, my car idles at ~500rpm when cold but perfect when warm (950) which is why I started looking at the AAR. My wideband 02 meter says I'm richer when cold so I assume the WUR is functioning correctly. My idle speed DID increase way back when...

Autobonrun - it was easy to remove. Its "right there" held on by 2 bolts & the hoses.

clevy70911T · clevy70911T's Garage

Yep, sounds like your on the right track then. Now apply 12 volts to see if it closes at all and check the resistance of the bimetal strip. Do a search for the correct ohms. I was able to " knock the plug" back and forth on my AAR many times until I was able to get exactly what I wanted. Hitting on the red arrow with a hammer and punch opened mine further, to let more air in when cold. You only need to move the plug about 50-100 hairs and temporarly reinstall with hoses and elec connector. Once warm, take it off and see it closed. You can use a mirror to see this if installed. You might try to clean it and see if you get smoother movement of the plate. Hope this helps.

hobieboy · 05-11-2005, 10:18 AM

I connected my 12V regulator to it as well last night and the flap did not move at all after ~5 minutes. Can the strip be broken or stopped working due to fatigue?

I also did spray lots of caburator cleaner through it to make sure the plate/spring can move freely. No difference. I'll also check the resistance later.

Paulporsche · 05-11-2005, 02:37 PM

Have you tried to move that plate by hand? Actually, you may need a rod inserted into one end to make it rotate.

hobieboy · 05-11-2005, 03:59 PM

Quote:

Originally posted by Paulporsche
Have you tried to move that plate by hand? Actually, you may need a rod inserted into one end to make it rotate.

Yes - tried that with a screw driver. The plate moves very freely though I can tell for sure its spring loaded. So it wants to snap 95% shut.

Mysterytrain · 05-11-2005, 04:22 PM

look for my thread on rebuilding the heating element. These suckers have climbed in price because of the weak dollar. For a few bucks you can get the element to work. I think you want to see something like 33 ohms. Alos you can only go so far with knocking the pin..if you have too large an opening you will start the motor and it will sit there cold rev'ing at 3K..not nice.

Paulporsche · 05-11-2005, 04:33 PM

That was great work, Ron. BTW I enjoyed your website.

I see Hobieboy is located "up north" but I think you are right. He'd have to be way up there to want to keep his AAR open all the time!

hobieboy · 05-12-2005, 07:20 AM

Guys, thanks again for the suggestions. Ron, will re-read your thread carefully

Certainly sounds like I need all the tips to rebuild mine.

With warmer weather and a track day coming up next week, I might again delay taking things apart for the nth time in the last few weeks. But will keep everyone posted of my results.

Paul, yes up North as in further north east of where you are

Might see you at Mosport sometime this summer?