Here is the procedure for the Digifant system. Note that it is easier as there are no vacuum controls on the distributor.
Engine close to operating temp. With engine off, disconnect 02 sensor and idle stabilizer valve. Check throttle plate adjustment. Adjust stop screw so it does not stick closed. Idle air goes through bypass screw. Check operation of throttle switch. Adjust as needed. Start engine, after engine running, disconnect temp. two sensor. This will cause the ignition timing to default. Adjust timing to proper mark at idle speed. Adjust idle speed to ~900 rpm. Using voltmeter, check O2 sensor voltage, (still disconnected). Should be about .5v. If no reading, rev engine for 30 seconds to heat sensor. Adjust AFM to get .5v. Just get it close. Slightly lean is better. Adjust idle speed again if needed. Shut off engine, reconnect stabilizer valve, temp 2 and O2 sensors. Restart, and check O2 sensor operation. After 30 seconds or so, you should be able to see it working. Dennis
From: Matt Sutton [mailto:msutts@earthlink.net] Sent: Monday, October 11, 2004 11:48 AM To: Vanagon List Cc: Dennis Haynes Subject: Re: digijet FI adjustments Dennis- great layout of procedure! If you had the time at some point, would you consider doing the same for Digifant? Speaking for myself, the Bentley is hard to follow, particularly in the work sequence (and proprietary tools) and I always worry about digging a hole I can't get out of. thanks, Matt Sutton 88 GL Brooklyn NY
Date: Mon, 11 Oct 2004 08:32:19 -0400 From: Dennis Haynes <dhaynes@OPTONLINE.NET> Subject: Re: digijet FI adjustments If you have the Bentley and a good Digital volt-meter and a timing light you can do it. The Digijet requires very specific set up for the throttle plate, ignition timing, idle speed and CO. The adjustment on the AFM is only to help trim the adjustment at idle. Basic setting are as follows: Engine close to operating temp. With engine off, disconnect 02 sensor and bypass idle stabilizer. Check throttle plate adjustment. Adjust stop screw so it does not stick closed. Idle air goes through bypass screw. Check operation of throttle switch or switches. Adjust as needed. Start engine, adjust timing to proper mark at idle speed. Check vacuum advance operation. Opening throttle should quickly advance timing. Further check, remove vacuum retard hose, (one directly to manifold). Timing must advance. If not, hoses are wrong, diaphram is bad, or throttle plate not adjusted properly. Find cause. Adjust idle speed to ~950 rpm. Using voltmeter, check O2 sensor voltage, (still disconnected). Should be about .5v. If no reading, rev engine for 30 seconds to heat sensor. Adjust AFM to get .5v. Just get it close. Slightly lean is better. Adjust idle speed again if needed. Shut off engine, reconnect stabilizer and O2 sensor. Restart, and check O2 sensor operation. After 30 seconds or so, you should be able to see it working. On occasion, you may have surging at idle, especially after a warm restart. If you do, I'll tell you how to correct that. Dennis |
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