Idle and stalling problem.

[sbarton]

My 1984 911 3.2 Carrera has a hard time idling and will usually stall if I don't give it the slightest bit of gas to get the RPM's to stay at just under 1000rpm. Removing the oil cap does not change the idle. It seems to be worse once the car is warmed up. The car seems to run fine and pull strong while driving/moving.

I've tried cleaning the MAF (I have a MAF conversion) with MAF cleaner, no change.

Any other ideas? What should I look for and what can I do to improve the idle?
Thanks.

-Scott

[dshepp806]

"Removing the oil cap does not change the idle"............

This is usually indicative of the restrictor missing in the oil breather line...you may want to check that it's there...I almost threw mine away the first time I changed out all of the breather hoses....not sure if this IS your problem (exactly).

If it's like my '89, simple enough to pull the breather hose and see if it's there (IN the hose itself)..

Otherwise, it's mixture check time/idle adjustments and simply checking the idle microswith (AGAIN, if it's like my '89)..

I'm sure others will chime in here..


Best,

[stlrj]

Originally Posted by sbarton

My 1984 911 3.2 Carrera has a hard time idling and will usually stall if I don't give it the slightest bit of gas to get the RPM's to stay at just under 1000rpm.

Sounds like your too rich at idle and when you say you're giving it gas to keep up the rpms, you're actually giving it more air to compensate for being too rich.

[sbarton]

How do I fix that?
Thanks.

-Scott

[DRACO A5OG]

Originally Posted by sbarton

How do I fix that?
Thanks.
-Scott

[quote]Compliments of Steve Wong, SW Chip:

Well, if the idle hunts when the air is thinner, such as at altitude, then your car is running richer up there - so perhaps you need to adjust your idle mixture at the air flow meter. This is adjustable via something like a long 3 mm allen wrench up under a plugged hole in the air flow meter. The aluminum plug needs to be removed to access the adjustment screw. Best way to remove it is to drill two small holes in the plug and insert a pair of needle nose pliers into the holes and pull it out. Without complex air/fuel measuring equipment, disconnect your O2 sensor and measure the voltage fluctuation off the sensor with a DVM. Properly calibrated, it should fluctuate evenly between 0.2 to 0.8 volts at running temperature. Turn the screw clockwise to richen, counterclockwise to lean. You basically are adjusting the amount of air bypassing the measuring flap in the air flow meter to set the idle mixture. Attached is a pic of the plug location on the meter.


[quote]

Just did it it is really simple to do just becareful not to damage the connection harness for the O2 Sensor and Don't adjust too lean or it will idle too low no matter how high you set the Base Idle. I set mine to 0.3-0.5 Volts on the DVM (DIgital Voltage Meter) my idleis at 880 RPMs. If you still have a 2K DME ECU your idle is 780 RPMs. Take a look inside the DME to find out if ever been updated, according to Steve, in '86 Porsche updated the ECU from 2k to 4K DME's

Break a Leg!!!

[sbarton]

That looks like the stock AFM. I have an aftermarket MAF system.
Any ideas?

-Scott

[ischmitz]

I think we need a little bit more information to be helpful here.


- How is the MAF conversion realized? Do you have a custom chip going with it or is the signal conversion done in the MAF kit?
- Did you have this idle problem ever since or did it appear at some point?
- If it did appear was it all of a sudden or gradually?
- Did you change anything leading up to this problem (change components, service, etc.)


Cheers,
Ingo