Hi Guys,

I am at the end of my ideas at the moment.
Every now and then, the car would not start at the turning of the ignition key.
Over the course of last week, we removed the starter motor and had it completely rebuilt. New bearings, new brushes, total cleaning and a new magneto switch.

Initially this seemed to have fixed the problem, but this morning the problem returned. At the turn of the key, the fuel pump starts buzzing, some relays switch on, but the starter remains dead.

Any ideas as to where the problem could still lie?
I'm thinking about a gear selector switch or something like that....the car has been very wet on the inside before i bought it back in January.

Series III, 5.3HE with GM-tranny.

 

My findings over the years and in NO particular order at all.

The Neutral start switch on the gearlever unit is #1 on my list. Sometimes placing the lever in "N" has the desired result, sometimes not.

The starter relay itself is OLD now, and the contacts inside do "burn", and although the relay itself will "click" when the start position is selected, the voltage cannot pass through. Soooo, if a "click" from the relay is heard/felt in the start position, the neutral start switch is working, simple, so that switch can be crossed off.

Running from the starter relay TO the starter motor, is a heavy gauge White/Red wire. Just near the trans dipstick plastic top, there is a joiner in this wire. This spade joiner corrodes internally, and also can be dislodged when pulling the trans dipstick out. Again, a very simple item to check.

Next, take a DVM, Red lead on the White/Red wire AT the solenoid, Black wire on a good earth, and the meter set to Volts DC. Switch TO start position,a nd note the voltage on that meter. It should be battery voltage or very close to that. If that is teh case, the starter is still the culprit.

Engine earth straps are not up to snuff, very, very common on any V12, and they will reek total havoc until sorted. Extra, dedicated earth straps, are what I do to any that cross my path.

The electrical section of the ignition switch is also well documented as a troublesome item, now that it is old. Easily removed, dismantled and cleaned.

 

Thanks for the elaborate tips. Now I have something to go on...great!!

 

What a great post Grant . . . listed, brief but relevant explanations, and a great lesson in hierarchical fault finding . . .

. . . and no spelling mistakes either ??? The night must be young. LOL.

Cheers,

Ken

 

Ken, MAAAAAATE,

I am back in the work force for a week, the "boss" went a cruise.

So earlyish nights, even earlier mornings, YUK, and tolerating people wanting spare parts for a Mazda, Toyota, etc, and thats all they know. apart from the fact its Green, Yellow, whatever, oh boy, how have I lasted 53 years in this stupid industry?????, 2 1/2 days to go, whoopee.

As always, simple fixes for simple cars.

AND

Patrick asked sooooo nicely, how could I refuse?????

Then the XJR and the Black S need some TLC.

 

Problem solved: it was the starter relay, which i replaced for an original new Lucas one from SNG Barratts.

 

well there you go, it HAD to be something.