As suggested by an XJ lister, I checked over my meter and there is indeed something flaky about it. I turned it on and with nothing connected, it showed 38V. One sound tap and it settled down. I found that I could spin the selector switch a few times and make it screw up a bit, but after running through the ranges, it settled down. This meter has bounced around in tool boxes, floorboards, saddle bags and my driveway for about 10 years now, so I think it’s due a little crotchitiness, especially since it’s almost always sitting on the 20V range

In any case, with it settled down and reliably measuring 12v and 5v from a known good PC power supply and 9V from a fresh 9v battery and 15.5 from my laptop power supply, I now feel I can trust it.

So, I started measuring voltages on Buzz.

Before I started, the battery was at 12.6V. I turned on the key and saw it drop immediately to 12.4V then slowly ‘drain’ down to 12.1V after 3 minutes of just sitting there with the key on. At that point, running lights, instrument lights and the ECU would be the only current draw.

While cranking, it dropped to 10.5V. As is the current state of the project, it was hard to get him started and running, but once going and warm enough to idle and run, I had enough hands and eyes to watch the meter. At idle, battery voltage is about 12.8V, at 2000RPM steady, it’s 14.1. As I recall, those seem to be reasonable figures to indicate that the alternator is at least working.

The headlight is still quite dim, but it does fluctuate with reving. It still never gets above what I would subjectively call about 40% brilliance. More on that subject later.

The battery itself is still slightly suspect, because the cranking voltage drops pretty deep, so I will probably replace it anyway. I have not checked the spark while cold cranking the engine lately. The low cranking voltage is probably contributing to the trouble starting.

With the battery voltage question shelved for the moment, I set about trying to extract a little better running condition. Another one of those little things bothering my subconscious about the fuel system is the tendency of the fuel filter to run “dry” when the fuel pump is running. The fuel pressure seemed to be ok, so I put it out of my mind. Yesterday, I was browsing some of the MS forums for stuff about power loss at certain RPMs. At least one post suggested that fuel starvation could be a factor. I rev Buzz up and, as usual, it sounds like the engine hits a rev limiter at about 3200 RPM, but this time, I watched the fuel pressure gauge during the event. It bounced down from the usual steady 42psi to about 35, jumping roughly in time with the stutter. Hmmmm.

The return from the regulator for my temporary fuel supply is a clear hose. It’s been handy because I can see flow in it and that gives me an operational check at a glance. Well, an extended bonk against the pseudo rev limiter revealed another symptom that simply hadn’t occurred to me and would not have been easily detected without the clear hose. Bubbles. Lots of bubbles in the return line, but only when the engine is stuttering at 3200 RPM. Hmmmm, ok.

I bypassed the fuel filter and tried again. No bubbles in the return line and while it still sounds like it’s hitting a rev limiter, now it does it at about 4300 RPM and there is no fuel pressure gauge bounce. There is still much tuning to do, but I now feel that fuel starvation is probably no longer a factor.

A tweaked around with the fueling settings in MegaTune, but didn’t make any huge progress. By that time, it was getting chilly enough outside that my fingers, especially on my mouse hand, were getting cold, so I wimped out and packed up and went inside.

The brain, however, doesn’t stop and I began trying to figure out why the lights would be dim when the voltage should be high enough for bright lights. Something to check came to mind this morning….

Alert readers following the blog will recall that when I needed to tap an ignition switch controlled voltage, clips on the stock fuse box were pretty much falling apart in my hand. I had a spare DelCity fuse block, so I replaced the stock fuse block. What occurred to me this morning is that I crimped those connections and perhaps I have a bad enough crimp to limit the current available to the headlight.