Jaguar Repair/1984 XJ6 Vanden plas starter problems
Lately my Vandenplas needs help starting. I turn the key, and hear just a click. If I tap the back end of the starter and solenoid with a hammer and try again, it will fire up but sometimes the cranking is irregular. I cleaned up the electrical connections for the earth strap from engine to body, and the 2 main connections on the solenoid - the thick wire to the center post and the strap that connects to the starter. I loosened up the cross head screw for the smaller white wire with red stripe but didn't remove it for fear of not getting it back in since I was doing this by feel and didn't know how long the screw was. I cleaned the connections with brake cleaner and sanded the rings and bases with 400 grit. None of this helped, should I check the relay or do you think I need a new starter ? My battery is only a few months old.
ANSWER: Hi Steve,
The only way you are going to know what is wrong is to run a few simple tests.
First take a 12v test light and put the clip on the negative post of the battery and the probe on the cylinder head and have someone try to start it and when you hear the "Click" note if the test light lights up. If it does you have a ground problem, and if it doesn't you don't.
Second put the clip of the test light on the negative post of the battery and touch the power stud on the solenoid with the probe(the one in your photo with the rubber boot). The test light should light up.
If it is does put the prob on the starter motor post on the solenoid and have someone hit the starter. If the light lights up and it only went "Click", then you have a starter problem. If it does not light up then you either have a starter sloenoid or starter relay problem.
If it didn't light up then move the probe of the test light to the small terminal on the solenoid with the white w/red tracer wire on it and hit the starter and if it lights up with just the "click", you have a bad solenoid and if it don't light up you have eaither a relay or a wiring problem. (the realay is the larger one toward the center on the firewall at the back of the head.
To do a simple test of the starter circuit by bypassing the relay just remove the 12 gauge white w/red tracer off of the starter relay on the firewall and connect a short jumper to be able to touch the positive post of the battery and the starter should activeate even with the key off.
It takes anothe set of tests to test the ignition switch to the relay as another relay and the shifter interupt switch is involved it it. Let me know if you need that set of tests too.
The starter realay is the common failure on series III cars.
Let me know,
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Your step by step tests make perfect sense, I'll try them tomorrow and let you know, thank you so much !
ANSWER: Let me know.
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Looks like it's the starter, I followed the steps from the beginning and the starter terminal on the solenoid lights up when the key is turned to start. The only click I hear I think is from the relay or the ignition switch, I don't hear anything from the solenoid, but power does get to the starter. I guess the solenoid is 'Pre engaged' so there isn't much movement or noise ? If I tap lightly on the starter itself, I usually can get it to work. It's always worse first thing in the morning, then it can work ok the rest of the day. Cold or damp can affect it ? I haven't started looking yet but I guess starters are bought on exchange basis, or do they have to be bought with a solenoid ?
Thanks again Howard,
The fact that the starter post on the solenoid is powered when the key is in the "Start" position clearely shows that the starter is connected. The hit on the starter that makes it work indicates (most likely) that it is a strater motor brush problem.
Most rebuilt starters and new starters come with the solenoid attached.
The starter motor must in itself be good and only a bad connection or a worn out set of brushes. You might open up the starter motor and inspect the brushes and if the brushes are worn down, You can just replace the brushes. If you do that, it would pay you to remove the armeture and use a strip piece of emory cloth or fine sand paper and clean the comutaror that the brushes ride on.
When you purchase a rebuilt starter, there is a "Core" charge, so you will need to turn in the old starter. The auto parts stores don't usually care if it is disasembled or not so you can try to fix it yourself first.
If your auto parts store don't have brushes available, you should be able to order them from Engel Imports, Moss Motors or British Parts Northwest on line.