Pulsating Idle, AFM Adjustment?

[rlux4]

Does the pulsing go away as the car warms up? The AAR is for cold starts and only comes into play for a few minutes, so if the pulsing is still there after you've warmed up it's not the problem. Having one that works is a good thing in the winter, so if yours isn't opening to about a 1/4" you'll have poor start ups with winter temps. Again, once the engine is warmed up the AAR is out of play. It should have hose clamps on both ends, snug.
Ron

[joelittel]

The casing is so loose that even with it not working I can blow through it.

[rlux4]

Any air that is drawn in there, or anywhere on the engine side of the AFM is "unmetered" and can't be taken into account by the ECU. The ECU is trying to control the air/fuel ratio for maximum combustion, any extra air in the equation that the ECU doesn't know about is going to affect how the engine runs.
Have you read the FI section of Brad Artigue's manual? It has a very good explanation of each of components and their functions.
http://www.artigue.com/fiatcontent/Arti ... 124_MM.pdf
Ron

[wizard124]

The casing is so loose that even with it not working I can blow through it.

Go here for a better understanding: http://www.fiatspider.com/f08/viewtopic.php?f=5&t=22898

[bradartigue]

The casing is so loose that even with it not working I can blow through it.

If you can blow through the AAR with one port blocked (blow through one side and cover the other) then the thing is junk. If it rattles like a piece of junk is inside of it, then its junk. If it doesn't give resistance when tested with a multimeter then it needs to be replaced.

I would block it off and run the car. It will struggle to idle when cold but otherwise will run fine. If, when the car warms up, the car continues to run poorly then the AAR isn't the whole problem, it just may be part of several components having failed. But you have to start somewhere, so block it off completely, and by that I mean remove it and cap off both hoses so there are no leaks on either side.

[joelittel]

I've replaced all the vacuum hoses with original looking black ones. The silicone ones really tempted me but I read that the inner diameter was different than the stock ones and I dont know enought about the car to know if that could/would ever be an issue.

With the aar blocked off the car idles very well now once it's up to temperature, so I'm on the hunt for a new aav.

With the old aav in place I hooked up a vacuum gauge to the vacuum port on the plenum and got next to no reading on the dial at all. Maybe 1 degree of movement at best. I did not have time to do the same check with the aar out of the loop. But I'm wondering how strong should the vacuum be, 16 to 24"?

I have read the artigue manuals and will tune the car accordingly once I get a new or new to me aar.

So far so good. I'm happy with the changes the new hoses made and have high expectations/hopes for what a new aav will do for me too.

[bradartigue]

The price range on these things is all over the map. The X1/9 version works and is 1/2 the price. Just make sure the mounting holes are correct. One of the vendors has a write-up on it but I can't recall who

[joelittel]

Got a used AAV from Midwest Bayless yesterday. Compared to the price of a new one I feel I got a very good deal and could not be happier with the service. I chose to have it shipped snail mail, cheapest option available, and to my surprise it was here in two days. This may change my opinion on paying for express delivery going forward.

The new unit, although labeled used, looks nearly new. Solid construction, air tight and works well, just like the website said it would be, in fact it's cleaner than the picture lead me to believe it would be.

Popped it in the car and I was shocked at how it transformed my cold start experience. It's 16 degrees fahrenheit out there right now and the car started right up, first try, after sitting for six days in the cold garage. The rpms held steady at about 12k for a few minutes and then settled nicely around 900, just like it's supposed to. In no time at all the engine was warm and the cooling fan cycle began. Not a trace of the pulsating idle I used to see, thank you to everyone who steered me away from tampering with the AFM track. Maybe some day that will be a necessity, but it clearly was not the solution for me at this time.

Last weekend the same routine required me to hold the accelerator down to keep the rpms up long enough for the car to warm up. I didn't take note of the time this required but I'd bet I sat there with my foot on the gas for ten minutes before it would idle on it's own, and even then it was idling very low and slowly warming up.

Without exaggeration I can honestly say this simple fix has made a huge difference in the way my car handles cold starts.

Because I'm certain the old AAV was letting in all sorts of unmetered air I'll go back through Brad's tune up guide and make sure everything is set correctly, but based on how the car behaved this morning I'm already very pleased with the fix.

Thanks for all the input and help guys.

[bradartigue]

Great outcome.