[Paul 78z]

Does anyone know FOR SURE which way to turn the screw on the AFM to lean it out. I have tried both ways just a little and have noticed no difference. I don't want to move it much without knowing which way to go.
THANKS

 

[Unknown User]

> Does anyone know FOR SURE which way to turn
> the screw on the AFM to lean it out. I have
> tried both ways just a little and have
> noticed no difference. I don't want to move
> it much without knowing which way to go.
> THANKS

The screw on the outside of the housing? If it's that one then counterclockwise should lean it out as that opens it up and lets more air past. It is a very small ammount of air that it lets go through though. The only time I noticed a change when adjusting it was on the display on the smog machine. I backed it almost all the way out with no change.

Once you open up the housing you want the contact on the wheel to move towards the front of the car to lean it out. when you loosen the screw that holds the wheel in place make sure you hold the wheel as it is spring loaded and will spin. You can play with it some without loosening it just by pulling the wheel back and the changes in the way it runs are very obvious.

 

[Unknown User]

> The screw on the outside of the housing? If
> it's that one then counterclockwise should
> lean it out as that opens it up and lets
> more air past. It is a very small ammount of
> air that it lets go through though. The only
> time I noticed a change when adjusting it
> was on the display on the smog machine. I
> backed it almost all the way out with no
> change.

> Once you open up the housing you want the
> contact on the wheel to move towards the
> front of the car to lean it out. when you
> loosen the screw that holds the wheel in
> place make sure you hold the wheel as it is
> spring loaded and will spin. You can play
> with it some without loosening it just by
> pulling the wheel back and the changes in
> the way it runs are very obvious.
Are there any other ways besides the AFM to adjust this?

 

[Unknown User]

> Are there any other ways besides the AFM to
> adjust this?

There are other things that will cause it to run rich or lean but that is the main one. The cold start valve could be sticking open, the altitude sensor may be malfunctioning or the fuel pressure regulator may be off.

The AFM is easy to adjust. I wasn't thrilled about popping the cover off and going at it either but it was very simple. Just lean it till it misses and then richen it up a little and make sure it doesn't ping when you step on the gas. If it does then it needs to be a bit richer.

 

[Don]

> There are other things that will cause it to
> run rich or lean but that is the main one.
> The cold start valve could be sticking open,
> the altitude sensor may be malfunctioning or
> the fuel pressure regulator may be off.

> The AFM is easy to adjust. I wasn't thrilled
> about popping the cover off and going at it
> either but it was very simple. Just lean it
> till it misses and then richen it up a
> little and make sure it doesn't ping when
> you step on the gas. If it does then it
> needs to be a bit richer.

Another problem spot when a car is running rich is to check out the FI temp sensor. If it is not functioning properly (ie. bad or bad connection which happens quite often on 20 yr. old cars) then the ECU thinks the engine is always cold and richens the mixture. I would look there first before pulling my AFM apart. Good luck!

 

[Phantom]

> Another problem spot when a car is running
> rich is to check out the FI temp sensor. If
> it is not functioning properly (ie. bad or
> bad connection which happens quite often on
> 20 yr. old cars) then the ECU thinks the
> engine is always cold and richens the
> mixture. I would look there first before
> pulling my AFM apart. Good luck!

I agree - see my posting under Daily Driver is Alive Again. Pull the engine temperature sensor. It is the smaller of the two two wire plug sensors on your thermostat housing. The large one is your thermotine switch which controls your cold start injector. You need to clean the corrosion off the connector where it connects to the sensor and about 12 away where it connects into the wiring harness with bayonet connectors. Mine was heavily corroded in both places. If the ECU get an infinite resistance (open) reading it will run your engine so rich it won't run. If the resistance is a bit high it will run the engine just a bit rich. If yu disconnect the sesor where it bayonets into the wiring harness and jumper the wires together, bypassing the sensor, it will think your engine is at normal running temperature (no resistance)and you'll run much leaner. It's a bit of a bugger to keep the engine running if you start it cold as then you won't get enough choke for normal warm-up but you should see a definite leaning of your mixture.
Hope this helps.
Phantom

 

[Unknown User]

> I agree - see my posting under Daily Driver
> is Alive Again. Pull the engine temperature
> sensor. It is the smaller of the two two
> wire plug sensors on your thermostat
> housing. The large one is your thermotine
> switch which controls your cold start
> injector. You need to clean the corrosion
> off the connector where it connects to the
> sensor and about 12 away where it
> connects into the wiring harness with
> bayonet connectors. Mine was heavily
> corroded in both places. If the ECU get an
> infinite resistance (open) reading it will
> run your engine so rich it won't run. If the
> resistance is a bit high it will run the
> engine just a bit rich. If yu disconnect the
> sesor where it bayonets into the wiring
> harness and jumper the wires together,
> bypassing the sensor, it will think your
> engine is at normal running temperature (no
> resistance)and you'll run much leaner. It's
> a bit of a bugger to keep the engine running
> if you start it cold as then you won't get
> enough choke for normal warm-up
> but you should see a definite
> leaning of your mixture.
> Hope this helps.
> Phantomf

Thanks for all your suggestions. Im going to give it a shot.
Charlie