Õhulugeja ehk AFM

Porschede mootori- ja veermikuprobleemid.
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joonas
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Õhulugeja ehk AFM

Postitus Postitas joonas » 23 Juul 2009 01:54

Rennlistis olid ära märgitud sellised videod http://forums.rennlist.com/rennforums/9 ... ction.html

I put my camera and a flashlight inside the airbox to video what the AFM actually does while driving at different speeds/loads. I started out with just normal driving before getting on the main road for a 1st-2nd-some of 3rd run, taking it to redline. The big question I've always wondered is whether or not the flap ever opens completely, and when...and it looks like it never quite reaches the fully open stop. Then on to some running at different throttle positions in different gears.


Here's a video description of refurbishing a Bosch AFM for a Porsche 924S/944. On a wide open throttle run, it would go flat at ~2000 rpms before getting itself together up towards redline. This is a good thing to check if you're experiencing any kind of random hesitation and have ruled out the obvious stuff, like vacuum leaks, bad plugs/wires/distributor points, oxygen sensor, ect.

This same repair concept probably applies to any other barn door-type AFM, only getting at the inner workings will be different.

This info was mostly from http://www.frwilk.com/944dme/" onclick="window.open(this.href);return false; under "Air-Flow Meter"


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ndrk
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Liitunud: 18 Aug 2008 08:47

Re: Õhulugeja ehk AFM

Postitus Postitas ndrk » 24 Juul 2009 08:49

Lisaks: Nopped http://www.dietersmotorsports.com/tech_articles.html" onclick="window.open(this.href);return false; kodulehelt

To check for WOT operation is quite simple. Get an assistant to press the accelerator pedal to the floor (engine off, of course) while you check for throttle plate movement. You should feel a noticeably firm stop at the floor. All cars have throttle stops. The throttle plate should be open almost a full 90 degrees from idle position. It is also important to check for binding. You should be able to turn the throttle plate another degree or two from the WOT position. This will ensure that no linkage will bind, causing failure or sticking


924/944/968/928 all years: These cars have throttle cables that can stretch as well. Adjustment can be made at the firewall. Some models have bell cranks in the engine compartment as well. The pedal stop screws into floor. (924-944)

DIY Throttle response cam

recently purchased a 1986 Porsche 944 and after a few days of driving I naturally started thinking, “Hey what can I do to perk this thing up?” The second thing that popped into my head was, “while spending little or no money.”

I quickly remembered back to one of my earlier 944 acquisitions that had a small fast acting throttle cam. While this obviously adds no horsepower to the car, it does open the throttle substantially quicker, translating to much better throttle response. Even though the car had a perfectly good throttle cam, it just opened the throttle too slowly. The problem is the “cam” takes up the first half of the pedal travel to open the throttle only 20%, giving a very slow, soft throttle response. The answer seemed simple, remove center cam section from the wheel and reposition the cable anchor to accommodate the new shorter pedal travel.

The decision was made; a new faster acting throttle cam was going to be the first performance upgrade for this car, and it wasn’t going to cost me any money!


Throttle cam modification-


Pilt

1- Remove the throttle cam from the car.

2- Drill and tap a 5mm hole at the farthest end of the solid section of the throttle cam.

3- Drill a .125-inch pilot hole 12mm counter clockwise and 3mm inboard of the original cable-anchoring hole. Then progressively re-drill the hole with larger drill bits until a .250-inch hole is achieved. This step drilling process is intended to decrease the risk of breakage, as the perimeter of the throttle cam is very delicate.



4- Clamp the throttle cam in a vise and remove the center of the cam material not part of the base circle. (A die grinder wheel works best for this but a hacksaw can be used in a pinch)

5- Clean and smooth out new center section as not to cause any abrasion to the throttle cable.

6- Install the newly modified throttle cam on the throttle plate shaft and check cable adjustment.

Pilt

Dual profile feature:


After the new throttle cam is installed the cable can be moved to its original position and a 5mm screw installed at the hole made in step #2. This 30-second operation will return the throttle cam to its original configuration, if desired.
R - stands for Racing

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ndrk
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Re: Õhulugeja ehk AFM

Postitus Postitas ndrk » 15 Juun 2010 15:32

Siin räägib üks kodanik, kuidas ta oma auto 2.0 Mondeo MAFiga käima pani. Kas siinses ringis ei ole pädevat elektriku kes seda asja ära tegema oleks suuteline?

Rennlist Link
R - stands for Racing

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joonas
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Re: Õhulugeja ehk AFM

Postitus Postitas joonas » 16 Juun 2010 10:56

ndrk kirjutas:Siin räägib üks kodanik, kuidas ta oma auto 2.0 Mondeo MAFiga käima pani. Kas siinses ringis ei ole pädevat elektriku kes seda asja ära tegema oleks suuteline?

Rennlist Link
Kas sinul autol on mingi probleem?

Mina isiklikult ei ole mootori juhtimisega ennast kurssi viinud, kuid kõik on võimalik. Õhukulu mõõturi info peab olema ajule n.ö. arusaadav.

Mootorijuhtimise süsteemidega on tegelenud Raceboy ja ühe auto vist ka hüdro(bensiini) lukku lasknud.

http://en.wikipedia.org/wiki/Mass_airflow_sensor

Mida sa tahad saavutada?

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ndrk
Postitusi: 248
Liitunud: 18 Aug 2008 08:47

Re: Õhulugeja ehk AFM

Postitus Postitas ndrk » 16 Juun 2010 11:09

Tundub et praegune AFM on oma aja ära elanud. Segu on kogu aeg väga rikas ja enam kaha keerata ei saa. Mulle tundub et soodsam oleks mingi kompunn välja mõelda, kui uus originaaltükk osta. Siinsamas teemas toodud remongijuhise kohta oskab keegi midagi öelda?
R - stands for Racing

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joonas
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Re: Õhulugeja ehk AFM

Postitus Postitas joonas » 16 Juun 2010 11:22

Clarks lehel on ka testimise ja parandamise juhis. Kindlasti võiks ise proovida.

Kas oled juba vaadanud, millised need rajad välja näevad?

http://www.clarks-garage.com/shop-manual/elect-22.htm

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ndrk
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Re: Õhulugeja ehk AFM

Postitus Postitas ndrk » 16 Juun 2010 14:12

ei ole seda lahti võtnud.
Ma alustan sellest, et testin ära (sisselaske) õhu temp anduri. Lugedes clarksi teksti jäi mulje et minu mured peaksid just vales temperatuurinäidus olema (andur näitab liiga külma õhku). Eks siis sealt vaatab edasi.

Nüüd vaja kuskilt leida vaid voltmeeter 8)
R - stands for Racing

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