Idle Srew and Air Mixture Screw Setting

Dan Owens · 06-20-2002, 05:41 AM

Okay guys,

For my '84 3.2L engine where would I set the idle speed screw and the air mixture screw as a best guess if I won't to clean out bth passage ways. I would think there is sort of a close ballpark point that you would start at and then adjust from there to fine tune. I may be wrong here on this or it may only be applicable to do the idle speed screw screw and leave the air mixture screw alone.

Dan O - (s)hit it still won't run

PS I got it to run last night for about 3 minutes by holding my hand over the air box snorkel and blocking some of the air flow in. This worked only if I bypass the air mixture by jumping the b to c socket. What's this mean you say, I have no F'n idea. I can't find any leaks in the connections etc so I'm guessing I still have some oil clogging the air mixture or idle speed passages or some component died. If I can't figure it out by Sunday it goes to the shop on Monday.

Jim Sims · 06-20-2002, 06:39 AM

I don't know how these systems measure or meter air flow but I would assume there is some type of heated surface mass air flow sensor downstream of the air filter but before the fuel injectors. Could such a sensor be coated with oil and therefore not measuring air flow correctly? Perhaps finding and then cleaning or replacing this sensor should be considered. Cheeers, Jim

APKhaos · 06-20-2002, 08:10 AM

Like your determination Dan - you are going to WILL this thing right!!

OK, it starts with the idle valve bypassed, but hardly runs.
You got it to run by reducing air in - by blocking off the inlet of the airflow meter.
So....don't touch the setting yet - all they do is bleed more air around the meter, which won;t help with the symptoms you report.

Have you checked resistance of the airflow meter?? The 3.2 DME uses a spring loaded barn door [which probably got bathed in oil when things first went wrong]. Check that the door moves freely - it should be closed normally. You are looking for smooth motion - no stickyness. Movement of the barn door drives a variable resistor [its under the black plastic cover on the AFM]. You should check that the resistance is correct, adn changes smoothly over the range of motion of the door
- use your tester on ohms setting
- remove the connector
- there are five pins, numbered from L to R
- measure between pins 2 & 3
Should be smooth across the range of motion.
It should be really smooth to move, and should return to the fully closed position under its own steam.

Good hunting!

Dan Owens · 06-20-2002, 08:22 AM

Tony,

Thanks for the encouragement here. This car will not beat me after everything I've gone through with it. I haven't driven it in over a year due to a calamity of errors, very long story.

The airflow meter did get a coating of oil and I did clean it out thoughly. The door does move freely and comes back to close on it's own. I haven't tested it with a meter yet.

Dan O