When I attempted to start one of my 1500hl Dolomites this morning the engine did not turn over. A bit of background before I go on. Like the Bumpa's this has happened from time to time but in the end it has always finally turned the engine over and started the car. Back in June I had to hit the starter motor with a hammer before it would turn over so I decided I had better do something about it. I replaced it with another that I had been given but when I fitted that one I found that it did not turn the engine over as fast as my other dolomite starters. The starter motor had come from a dolomite that was sent for scrap and had been in use up until that point. I had considered taking the motor apart to check it over but when I attempted to do this I could not get the bolts out so I decided to just use it as given to me. I have since cut the bolts off and stripped the motor. The only thing that I could find wrong was that two of the brushes were below the recommended length but even after my hard work the motor still runs slow compared to other motors. I have given up on that starter for the time being as it is not the first starter motor that I have come across that runs slower than I would expect. In the end I fitted another starter motor that I had checked out and had replaced the solenoid with a new one because I thought that might have been the problem with that starter. It has worked fine for almost two months but gave up today.
Back to today’s problem. I could not hear the solenoid attempting to pull-in so my initial action was to give both the connect to the solenoid a wiggle and to take the linking plug/socket apart a number of times as I suspected it could be a bad contact at either of these points. When these actions failed I got out my voltmeter and was able to confirm that I did get the battery voltage being supplied to the solenoid when I turned the ignition key to the start position but it did not get as far as the starter motor terminal, hence I suspected the solenoid had given up. My next check was to make certain that both the solenoid and the motor were adequately earthed by connecting one of my jump leads between the motor and the battery negative. Still no joy, so I found a length of wire, fitted a female terminal on one end, so that I could remove the normal feed to the solenoid coil and then connect this wire to it. Next when I touched the other end of the wire onto the positive battery terminal it should have operated the solenoid. This test would have ensured that there was no voltage drops in the normal circuit that were causing the problem.
This still made me think the solenoid had developed a fault so I set about replacing just the solenoid with an old one that I had stripped and cleaned. I was surprised that it was relatively easy to change it over. The most difficult part was clipping the plunger onto the reaction arm of the drive pinion. Once all the connections were made the engine turned over and fired up but there was one final check that I decided to do and this was to check that the battery voltage was also available at the ignition coil during the start period. It was NOT and based on my own experience this does make starting a bit more difficult especially in cold weather so I will have to sort this out.
I have built myself a starter test facility using the engine and the battery that came out of my dolomite that was declared a write off. See attached photo. To make the starter motor turn over all that is needed is a lead with a suitable switch from the positive battery connection on the solenoid to the solenoid operating coil connection. I actually used an old dolomite main lighting switch which can be seen by the battery. I obviously wanted to confirm that the solenoid had failed so I set about fitting it into my test facility. This did not take long and I was surprised to find that the solenoid worked perfectly so I have been asking myself what could have caused the problem?
One possible explanation might be that the drive pinion may have jammed and prevented the solenoid plunger moving.