Which side of the coil is the fuel pump connected ? The 12 volt feed should be on the left side away from the battery. The only thing on the right hand tag should be the points and condensor or the black wire off the Pertronix If the fuel pump is fed from the contact breaker side it will tend to be shorted out at high speed but get longer pulses at low speed so it stops fuel pumping at high speed. The construction of the fuel pump with a coil in it allows the points to cause enough change in current in the coil to still get a aspark This is related to powering the reversing light from the points side where it dies in reverse..... So there should be a lot of connections to 12 v on the left tag and one wire on the right tag of the coil.... The coil is meant to work down to 6 volts when the starter is turning over.
Right, just done the coil test from coil feed to battery negative and it fluctuated between 12.8v and 13.4v at idle and then hit a steady 13.5v under load... That's not far from the book value of 14.2v so I'm doubtful that the new regulator is going to change anything. I'll fit it for good measure and test but will add a voltage test to the maintenance schedule to keep an eye on the alternator health. My brother suggested a bigger alternator may be necessary once I fit a leisure battery.... But not yet! She is now running a bit rich as there's plenty of fuel in the system... Oh well
For those still following this saga... I've just fitted the new regulator and now get a steady 13.6v at idle and a whopping 13.9v under load measuring from the coil to the battery negative... Turned on the hazards and there was a slight drop but nothing below the previous figures. So I'm missing 0.3 volts from my alternator... where could I have put them... I think I'll put this one to bed until I fit a leisure battery, so there's only one thing left to do.... DRIVE!!!
I'm puzzled by all this. I've been happily driving about for the last year by charging the battery every 200 miles. The battery read 12.6V and went up to 12.8v when the engine was running and the broken dynamo was doing it's best. Perhaps I'm just fortunate not to have an electric fuel pump?
For 3 years since ditching the FI system on my bus it has had the ignition feed to the coil + power up the auto chokes (as VW do) split charge and fuel pump. All my problems have started since the alternator went mental and over charged. Now while testing various methods and with a tempory little by pass wire and the chokes, relay and pump coming off the leisure battery I had a weekend with no temporary conking out episodes. More tests to do to make sure this cures my problem. I'll feed back at the end of September. I have 3 big trips away with he bus planned. Fingers crossed.
I wish mine happened after 10 miles or so but it happened whenever. 3 miles. 100 miles. It was incredibly efficient at being intermittent
