I've owned and driven my XJ6 for a few years. It has an SII drivetrain installed by a previous owner. I recently removed the transmission for a rebuild and I'm getting ready to put the trans back in. I want to bench test the starter motor first.

I've tried testing it and I'm not having success. Am I doing it wrong?

I've put the starter in a vice and used jumper cables and a fully charged battery. One end of the cables hooked up to the +/- of the battery. Other end I have the positive cable on the + stud on the solenoid (the one that gets wired to firewall post) and the negative cable grounded on the mounting flange of the case. I'm then using a small jumper wire between the S stud and the + stud on the solenoid. I'm getting nothing.

Any corrections or advice welcomed.

 

Your method sounds Ok to me.

I wonder of the jumper cable clamp thingy isn't providing a solid enough ground?

Cheers
DD

 

Thanks Doug. Maybe I'll trying wiring a lead from the neg battery post to one of the mounting holes on the starter flange.

For what it's worth, after I was unable to get results from a bench test I took it to advance auto and autozone since they have bench setups for testing. The setups are hooked to a computer which give direction on the proper connections. The advance auto one couldn't locate the Lucas starter in it's database so they couldn't/wouldn't test it. The autozone one didn't work either, seemingly the computer was getting an error message, preventing 12V from flowing.

 

I've done a test with lessor wires. Only for an instant as they got hoy quick. But, proved up in two events.


1. Starter refused to turn. Bum starter was my conclusion.


2. Cranking accomplished. All is good.


I used some of my alligator test jumper leads. And, a bench battery. - side post screwed up!!! .


Motor ear to battery -. Battery + via a jumper to the big post on the solenoid. Then another jumper to the small post. Solenoid kicked in, motor cranked. Starter assembly OK!!


You can isolate parts and get motor crank only.


Again, only for an instant, too small wires get real hot quick.


Carl

 

Hi Paul. Was this starter known to be working OK before you parted it for testing? I ask, because like Doug suggests, your test method sounds perfect. I would be worried that the second shop system used reported a failure. Suggest you ohm both the solenoid coil . . . if it isn't clicking in, it's fried . . . but also check the main starter windings also. Not much point replacing solenoid if starter is also fried.

Keep us posted.
Cheers,

Ken

 

Ken,
Yes, the starter was working fine. I only removed it as part of dropping the transmission. The rebuild took some time and the starter is such a bear to replace I figured I would give it a quick test before going back in.

I have an ohmeter and will check the solenoid. Can you advise on how to test the windings?

Thanks, Paul

 

Hi Paul.
OK . . . let's do this logically and sequentially. First check the solenoid because, on your earlier test, your modest gauge wire from Battery POS to solenoid with earth bonding back to Battery NEG to complete 'pull in' circuit, should have produced a solid 'thunk' as the solenoid pulls in. Without connecting to the starter, please repeat that test. Only when you get that 'thunk' will the solenoid thus complete the start circuit . . . and the starter, now energized, can do its thing. Is the solenoid now working?

The correct shop method to test start windings is to disassemble and measure resistance between each pair of commutator segments that are PRECISELY opposite each other. AutoElec shops have dedicated test gear, but simple to do DIY. Select first segment, mark it and its pairing at 180 degrees with a small dot of erasable marker; record ohms by probing each; rotate 1 segment; repeat and record for next pair of commutator segments. Continue until you have rotated full circle back to original dotted pair.

All resistance recordings should be typically within 2-5% of each other. Look for any that are 'open circuit'. Next shop test would also include measuring between adjacent windings for 'short circuits' but this is far more complex for DIY and, in any event, would be accompanied by buzzing or arcing, rather than apparently dead.

Some starters have metal cover bands that, once loosened, allow access the the commutator brushes. On these, no disassembly is needed - simply measure resistance between backs of commutator brushes for each pairing, rotating 1 segment at a time, as before.

Regardless of findings, do check commutator 'gapping' . . . correct and polish commutator. Next, check brush length and use any excuse to replace with new . . . none of us enjoy going back to do $10 parts after passing up an easy workbench opportunity.

Best wishes,

Ken