vaf question

[Chobobulous]

Lol to check my iat i used a lighter and an ice cube in a zip lock baggie.

Ok when you said atx psu i thought you were somehow referring to an auto transmission power supply, not the brand ATX. I have ford shop manual and it didnt give me that knowledge lol. I just know that it sends 3 signals to the ecu. Vane position, temp and i assume pressure but im not seeing any sensors that would detect that.

There is on the other hand a gold cylinder in the housing that im assuming does something. I am not sure yet as to what. Inside the housing on the side away from the input pins is a thin channel that runs from the input side to the output. It is partially blocked by that gold cylinder. You can kind of see that channel if you look inside the ends.

[Chobobulous]

Double post.

[sketchman]

Edit. Another thing i noticed was the wear pattern of the electron electronic piece. Only about2/3rds of it is used. That tells me that the vane is never 100% open. This is confirmed by the oil stains in this vaf housing. When the vaf is opened to as far as it was used it only made about a3/4 to a 1 in gap.

Well, that's weird. You're saying you think the flap was only opening a 1" gap ever? If that's the case, it makes it even simpler still, because the ECU may never "need" to see full 12v signal for a mostly stockish B3. That seems really weird to me, though.

EDIT: Just played with it some more. A 1" gap takes a TON of motion from the flap. Like almost 3/4 of the way to full open. So when Matt said it was pegged at 4.5k, it makes perfect sense now. It would seem that there is a huge variance from idle to low RPMs, and then it slows WAY down for the rest of the rev range. This has got me curious now. Can't wait to see what the curve is like.

[Chobobulous]

I guess it makes sense if you think about it. How often do you drive above 5 k rpms. It may have opened more but it looks to me that the majo of driving was do ne with a 1In space for air.

But yea let me get my girlfriend to send me a picture of it and you will see what i mean.

[sketchman]

^That'd be cool. The one I'm playing with is a refurb, so it should be as close as possible to working as it should. I'll probably swap it in to the Festy to run the in car testing.

[sketchman]

Check this out for some further fumbuzzlement. Snapped the VAF specs from a digiFSM I have for a 91 Festy.

It's all out of whack. Says full open is 5v. Not even close to what I'm seeing.

[Chobobulous]

Weird.
Wereyou mesuring the voltage on the right pin? I think its the gold pin. Measure off the gold one and the one 2 to the right of it.

Also maybe you got the2 power wires swapped around?
I can't get that photo to download to my Phone. Pm me an e-mail and ill forward it. And you can maybe post it for me.

[sketchman]

^I sure did get them switched around. It was sending 12v through the 5v pin, and of course that was going through the pot, and it's now fried a strip the width of the contact and won't work anymore. When I finally figured it out it was fried so bad it was working in reverse. 5v at closed and built resistance as it opened. Wish I'd have experimented on an older VAF now. But at least I now know it is supposed to work on 5v, so that means the Arduino can do the job(at least the input and output portions) all on its own.

[sketchman]

Now I'm confused again. If I hook up both 12v and 5v power as the Haynes shows, I get a measurable 0-11.XXv from the sig pin. Without this 12v source and just the 5v source connected, the VAF measures backwards and low. 4.04v down to 0v at full open.

The FSM says it should be 0-5v working correctly. The only thing I can think of is that the 12v switched pins(when installed in the car) use enough current to drop the voltage to a usable level for the VAF, and I have no idea why not having the 12v connected causes reverse operation.

[Chobobulous]

I will experiment this evening been at a training meeting all morning. The circuit board for the vaf is real screwy and. From what i can tell the voltage Is adjusted according to air temp and the 3rd output. Can you scan these pages of the Manuel so i can see them? When i get home ill scan you what i have.

[sketchman]

Yeah, PM sent.

I imagine I'll end up doing away with the IAT and just using a pot to have manual control over it. Kinda like a poor man's old school AFC, and since the signal is supposed to be 0-5v, it'll be no problem reading and outputting the signal with just the Arduino.

[Chobobulous]

I will be attempting a different route. When iget back i will post show you my notes.

[sketchman]

Sounds good.

[Chobobulous]

Ok sketch, here goes.


I have made a graph of the voltages that i measured this afternoon. here it is. The RPMs are approximate and it is just to give me an idea of where about i am sitting and the easiest way to go about doing what i am trying to do. I only went to 5k for the safety of my engine. Its the only car i have at the moment. I was hoping the line would be a little more even.


As you can see mine also goes against that chart that you pulled out of the manual. She had turned the Air Conditioner on and didn't realize it until i was about half way through so that may account for why the numbers aren't perfect. The condenser was kicking on and off the whole time. When it gets a little cooler i will get my girlfriend to attempt to hold it at the different RPMs again.



I have also took pictures of the VAF in action. they go with the photos. look here.

http://s733.photobucket.com/user/chobobulous/slideshow/VAF%20Photos

It confirms what i was saying about the vane never really being all that open.

At the widest i went, 5k it wasn't even an inch open. Granted, i was running it without an air filter and the tube was slightly kinked but these are just Preliminary numbers. I want to see where i am going to have to be working. I was looking through my paperwork and its all useless scribble that you probably wouldn't understand anyways I think faster than i write. I will attempt to tell you what pin does what. (from what i understand)

Looking at the VAF connector, the far left (gold pin to the right side) Pin is the Pos pin for the fuel pump. It reads 12 volts. The next is the connecting wire for the Fuel pump. It is an on off switch. Nothing else. It does not cycle on and off. It is off until you start to crank the engine. After you crank the engine and the Vane moves ever so slightly it completes the circuit.

the 3rd pin from the left is a ground pin. It is connected to the 5th pin from the left. The IAT also plugs into this with one of its leads.

The 4th Pin is the 5v pin.

the 5th pin is a ground pin, it is connected to the 3rd pin.

the 6th pin (Gold pin) is what changes when the vane moves.

the far right pin or 7th from the right is where the other side of the IAT connects.

[Rocketman]

IIRC, the VAF is more load dependent than it is on engine speed. Unloaded tests might not give you the results you're looking for