Leaderboard

This hose bit me too years ago with my first wd21. I put a zip tie on it which helped it from slipping off when "servicing" things back there. I've got big hands so it doesn't take much to knock things loose.

Frenchy, I believe you are confusing our early fuel injection with more sophisticated modern systems. Modern vehicles use wideband oxygen sensors, which allow their computers to dial in any air/fuel mixture they want, so they can stay in closed loop all the time (once the sensors are warm, anyway). These older rigs use narrowband oxygen sensors, which are useless* for any mixture but stoich (around 14.7:1). The narrowband can't even see stoich--it can only report rich or lean, so the computer bounces the mixture back and forth between them in a zigzag that averages out to stoich. This means these rigs can only run in closed loop for light acceleration and cruising. In any other conditions, they fall back to open loop, and run on stored values. A while back I added LEDs to my dash that mirror those on the back of the computer, and running the computer in one of the first two test modes lets me monitor the operation of the oxygen sensor while I'm driving. The green light flashes with the oxygen sensor when the system is in closed loop. I only ever see the green light flash under light-to-moderate throttle. Under heavy throttle or engine braking, the light does not flash. The light does not flash at idle, either, though I have seen it continue to flash briefly after the engine has returned to idle following closed-loop operation. I assume idle (even warm idle) is set a little on the rich side, and as such cannot be monitored with a narrowband sensor. (*There may be a little more going on here than I'm giving the system credit for. One of the test modes is supposed to tell you if the mixture is more than a certain percentage rich or lean in closed loop, and hell if I know how it's working that out from a sensor that only reads 0 or 1. Nissan may have done something clever to squeeze a little more data out of these primitive sensors, but clearly they were not able to get wideband performance out of a narrowband sensor.) Anyway, Teesetz, good to hear it's back on good behavior, and good luck tracking down any residual gremlins.

Here are some more photos of my setup!