Lower idle while 85 3.2 is warming up

[Nick Triesch]

My 3.2 runs great but must warm up about 5 minutes or it will die at a light. After 5 minutes it is fine. Also , if I start the car from cold in the garage it warms up correctly. All vacuum leaks were fixed on top end. Idle is correct at around 8.5. Thank you.

[proporsche]

fuel mix....a little too rich...take it to the guy who did your engine recently
Ivan

[Mark's 86]

My 3.2 used to stall occasionally when cold. For example, it would occasionally stall
shifting from first to second following a cold start. I replaced the idle control valve and the issue disappeared. Try cleaning your ICV first and see if that helps.

Mark

[Nick Triesch]

Thank you! But Ivan , the fuel mixture is set by Motronic!

[cabmandone]

Originally Posted by Nick Triesch

Thank you! But Ivan , the fuel mixture is set by Motronic!

Not really, you can set the base idle mixture but you need to make sure the car is warmed up and you have something to read AFR's while making the adjustment to the idle mixture screw on the bottom of the AFM.

[Nick Triesch]

I talked to my Porsche mechanic and he said idle is set by motronic. Those other settings may make motronic work less hard .

[proporsche]

nick, you are really in a dream land.There is a setting for the fuel mix by factory standards if you thing otherwise that is your problem;-) you always make me laugh with your statements;-)))) Just think for a minute..why would the official Porsche manual tell you how to adjust the fuel mix if it would that easy so the motronic will do the work..good luck solving your idle problem;-) and i mean it....
Do some more reading it will help you


Ivan

[Nick Triesch]

I have been doing reading. And what I find is that motronic sets the idle. From lots of sources.

[Nick Triesch]

Check this out.

[mo-mon]

You have a different motronic on your 3.2. There are no knock sensors. The above wiki is for the 964 & 993.

[Nick Triesch]

Thanks! Motronic in 3.2 still sets the idle.

[proporsche]

nick , the idle is set by idle control valve(plus manual screw) and the fuel mix on AFM is set by the adjusting screw..

good luck;-)

[Big Dav]

Originally Posted by proporsche

There is a setting for the fuel mix by factory standards if you thing otherwise that is your problem Just think for a minute..why would the official Porsche manual tell you how to adjust the fuel mix if it would that easy so the motronic will do the work..good luck solving your idle problem;-) and i mean it....
Do some more reading it will help you

I'm with Ivan. You've got to get the mixture right!

My 3.2 was super rich at idle when warm with AFRs in the 10's. It stunk of fuel and would hunt and struggle when cold because the Motronic is just throwing extra fuel in regardless. I tried adjusting the AFM screw out but even with 8 turns out it made little difference even though my O2 sensor and Motronic are fine. Someone had opened my AFM previously and altered the spring so I carefully tightened it one cog at a time and monitored AFRs out on the road. Turns out two teeth is all it needed and with about 1 turn out on the AFM mixture screw it idles at AFR 14.4 when warm. Starts and runs beautifully from cold now. Yours just might need some adjustment to the AFM screw though.

It's a standard tuning issue that should be done every year or so and when you replace an O2 sensor. Check and adjust mixture via the AFM screw and adjust idle speed with the idle control valve jumpered from the port in engine compartment. Only takes a few minutes to do but makes a huge difference to idle and part throttle behaviour. I think a wideband Air Fuel Gauge should be part of everyones garage equipment.

[cabmandone]

Originally Posted by Nick Triesch

I have been doing reading. And what I find is that motronic sets the idle. From lots of sources.

If you'd like I can do a video of me adjusting the idle mixture. I have an onboard AFR gauge and when adjusting the screw on the AFM it does indeed make the idle mixture rich or lean depending on he way the screw is turned.

Do yourself a favor and look up "base idle mixture". It might help you understand where you're mistaken.

Originally Posted by Nick Triesch

I talked to my Porsche mechanic and he said idle is set by motronic. Those other settings may make motronic work less hard .

Not saying this to be a jackass but I'd find a more knowledgeable Porsche mechanic if that's what he said. Setting the base idle doesn't make the motronic work easier, it sets the mixture so the motronic works properly.

I can raise or lower the idle speed with the screw on the throttle body and I can adjust the mixture with the screw on the AFM.

As mark suggested, you might try cleaning your IACV.

[Nick Triesch]

Ok, here is the deal, true, we can adjust the base idle ! But the regular idle is controlled by motronic . It’s in a article right here on pelican!!! BTW, I have shop manual, I know how to adjust the mixture with plug and jumper wire. My car just passed California smog in San Diego! I have a extra ICV, I’ll change that out. Don’t want to mess with settings when car runs so well.