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[wdb]

Mike Jacques 20 Jan 2001
My apologies to those who asked me to post how to adjust your fuel mix using a dwell meter. I have been traveling for the past few days. First off, this method works on 1980-1982 924's and 924 Turbo's.

1. Engine must be already properly timed, no vacuum leaks etc. 2. Locate the frequency valve test connector. This is a three wire connector located in the engine compartment - left side, right by the entry point for the hose from your charcoal cannister. The wires are colored red, black and brown. 3. The black wire is #17 from the ECU. Pull off the protective rubber cover from the test connector and connect your dwell meter to the prong from the black wire. Do NOT short against the prongs for the red and brown wires. You will have to rig up a small pin connector to attach your dwell meter to the black wire. Ground your other dwell meter connector to a good ground in the compartment such as the strut cap. 4. Start the engine and let it warm up. 5. Leave the Lamba sensor on your wheel well connected. Using your 3mm Allen wrench adjust the fuel mix until the dwell meter reaches 45 degrees. Make sure you have the dwell meter set on 4 cylinder settings. Very small movements with the 3mm wrench will really move the dwell meter so go slow. Allow a little time between adjustments for the engine to react. 6. Your CO should be in good shape as long as all your other systems (ignition etc) are set properly. I can't take credit for this method, its a old short cut for folks that don't have access to expensive analyzers. I picked it up in some book.

Good luck,

Mike
Thanks Mike... It works great, ya know what... I had mine set 'by ear' right on. Mine will rhythmically move from around 40 deg to 45 deg. Back and forth, steady, not erratic. Is this correct, or is it suppose to hold steady at 45 deg.
Some movement is normal. After you get the setting to where it belongs (45 degrees), take your hex wrench out and rev the engine a little. Once it settles back to the normal curb idle, the dwell fluctuation stabilizes. I think the wrench sitting in the screw has enough weight and motion form engine vibration to move the ajustment some, and thus cause some dwell fluctuation. It really is important to plug up the whole for the adjustment screw once your done. This affects CO readings at the testing center. Just as information, my 924 passed emissions testing with a score lower than my wife's new Buick LeSabre after I set the CO using the dwell meter.

I liked the looks of the engine analyzer you ordered. It looks very much like the voltage meters I use.

Mike
For those who may have trouble locating the test connections there are pictures in the Tech Section. The pictures show an old O-scope being used but the idea is the same: checking the duty cycle
John Brown 21 Jan 2001

azndrgn was have some emission trouble so I looked this info up in the archives

[ This Message was edited by: wdb on 2002-07-21 20:08 ]