924Board.org

[mustangporsche]

what would cause this, when i start the car it fires right up, but when i give it a little gas it wants to die, this only happens when i slightly press the gas, if i give it more gas say 1/2 throttle or so it will rev up fine, but if i give it a little it wants to die? what do u think would cause this?? 81 931 thanks guys

[numbbers]

OK Guys, what acts like and excelerater pump in the CIS? Isn't it the off idle switch?
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1980 924 Turbo

[Joes924Racer]

CO??
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

[Smoothie]

Actually it's the overswing of the air metering plate and arm. When you open the throttle quickly, a bunch more air gets drawn in and the air metering plate swings open, but it doesn't just stop exactly at the correct point for the amount of air being drawn in. It overswings some and that serves as our equivalent of a carbs' accellerator pump.
I read this in a book - didn't make it up. Really.

Mustangporsche - I'm gonna guess your light pressing on the throttle is a slow controlled movement? If you give it quick little "blips", I suspect you'll keep it running because that should give you the plate overswing and richen the mix. This is apparently what you're getting when you hit the pedal harder - overswing resulting in an extra rich shot of fuel.
Your air:fuel mix might be on the too-lean side.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[mustangporsche]

OK THANKS, SO HOW DO I GO ABOUT SETTING THE RIGHT MIXTURE RIGHT, SHOULD RICH IT UP A LITTLE?? I HAVE A AIR FUEL GAUGE AND IT IS READING RIGHT IN TH MIDDLE NOW, SO YOU THINK I NEED TO TURN THE RIGHT A LITTLE??

[Smoothie]

It's not that simple when you have an o2 sensor (lambda) system because as I found while adjusting mine, as you alter the air:fuel the lambda system will adjust and may overcompensate. I turned mine richer (clockwise) in order to lower NOx emissions for reinspection and found the lambda system had overcompensated after my adjustment and actually made it even leaner than it was before resulting in raised NOx. I suggest you have it checked by a garage with an emissions tester. If you must play with it yourself*, be aware that you could be screwing up an adjustment that's actually ok. Mine's ok and it still goes through some ups and downs on cold starting. I just keep it going by blipping the throttle a few times if it starts to stumble, then once it's been running for about half a minute, it's fine.

* - the o2 sensor has to be unplugged (no signal from it to the lambda box (with a little luck, you have the air:fuel gauge tapped in in such a way that you can undo the connector and still have the gauge connected to the o2 sensor (gauge tapped in on the o2 sensor side of the connector))). Check your manual - there may be something else that needs to be done/disconnected that I'm not remembering.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[mustangporsche]

oh great thanks. yah that makes sense why i cant get it adjusted right, the lambda sensor must be over compensating. Where would i disconect the oxygen sensor, is it inside the car under the dash?? not sure cant find it ??

[Smoothie]

It's under the car - attached to the rear of the cross-member that runs under the engine.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox