Air/Fuel Ratio

[Ricker]

Since I just replaced the Fuel Injectors and Idle Speed Motor, I thought it might be a good idea to check/adjust the air to fuel ratio. I have read some of the threads and watched a video and on my Actron Dwell Meter I connect the black lead to ground (easy) and the positive to the orange wire on the diagnostics plug (difficult). That's the first problem. If I have one, I cannot find it. Then if I don't have one, where do I hook the positive lead to? Second my meter does not have a number of cylinders switch so I guess that fine. And third, not sure the reading should be between 15 - 20 (like the video) or some other reading as mentioned in the threads. My car is #11153 January 1982 if that matters.

[Bitsyncmaster]

Since I just replaced the Fuel Injectors and Idle Speed Motor, I thought it might be a good idea to check/adjust the air to fuel ratio. I have read some of the threads and watched a video and on my Actron Dwell Meter I connect the black lead to ground (easy) and the positive to the orange wire on the diagnostics plug (difficult). That's the first problem. If I have one, I cannot find it. Then if I don't have one, where do I hook the positive lead to? Second my meter does not have a number of cylinders switch so I guess that fine. And third, not sure the reading should be between 15 - 20 (like the video) or some other reading as mentioned in the threads. My car is #11153 January 1982 if that matters.

Orange wire is in the diagnostic plug but probably better to find the two pin connector that feeds that plug in the engine harness. That two pin has the orange wire and a purple wire in it.

[iflights]

If you're diagnostic port is still in tact in the engine compartment, I just used a small alligator clip with lead on it connected to the pin the orange wire would be attached to. Top row, right most pin if I recall correctly sitting here on the sofa. No need to disconnect the orange wire from the diagnostic port.

[Ricker]

My problem is I cannot find the plug or orange wire. Any pictures or more specific directions where it is? I'm sure it is right in front of me like thinks in the refrigerator. lol.

[glockworks21]

hiding back here

[Bitsyncmaster]

hiding back here

Yes that is the two pin connector that feeds the diagnostic port.

[Ricker]

hiding back here

Found it! It was tucked back down behind the engine. The plug is connected to something that continues down behind the engine.

[Ricker]

Just to finish up what I did and was asking, on my Dwell Meter I adjusted the fuel to air ratio when the engine was hot, the "computer" was swinging the meter needle back and forth. I adjusted it for the swing between 15 and 20 on the 8-cylinder scale. Seems to be running quite well now.

[Rich]

Just to finish up what I did and was asking, on my Dwell Meter I adjusted the fuel to air ratio when the engine was hot, the "computer" was swinging the meter needle back and forth. I adjusted it for the swing between 15 and 20 on the 8-cylinder scale. Seems to be running quite well now.

That's the target. Glad you found an improvement.

It assumes you've nailed all the vacuum leaks and have verified the hot idle sits with spec: 775+/-50 RPM.

I like to use a multimeter that has a tach function for checking idle speed. The car's tachometer doesn't cut it.

[Ricker]

That's the target. Glad you found an improvement.

It assumes you've nailed all the vacuum leaks and have verified the hot idle sits with spec: 775+/-50 RPM.

I like to use a multimeter that has a tach function for checking idle speed. The car's tachometer doesn't cut it.

All vacuum hose were replaced. And as I understand it the original ECU sets/controls the 775 RPM. I set the idle screw a bit higher but not much.