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Need (patient) guidance to solve electrical issue, please.

Moss Motors
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TimPicard Avatar
TimPicard tim Picard
Mount Gilead, Ohio, USA   USA
This might be a back-and-forth posting, so for those faint of heart, I suggest you move one.

If others know their shiz and are willing to help a new guy out - pleased to meet you!

I can do a of lot of work, but am an electronics ignoramus. I refuse to pay someone to do work I can do ... though I need someone's guidance.

In my '65 TR-4 Currently have previous owner-installed Crane Cam XR 700 electric ignition. Car started/ran great; then began to sputter, but run; later sputter and not run; now won't start.

I replaced coil. I do have (at last check) power out of coil, but nothing out of distributor. New rotor.

The optical trigger appears/sounds to be working.

I'm willing to go back to points/condenser if suggested.

I sincerely appreciate any help.

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wyatt Avatar
wyatt Silver Member Wyatt W
penguin point, drift ice, Antarctica   ATA
go back to points xr700 is ancient, points work but be wary of newish lucas points and rotors...problems, get standard blue streaks

spridgettr Avatar
spridgettr William Kern
Pittsburgh, Pa, USA   USA
ancient indeed, but screw the points go with a pertronix and never look back, keep spare points etc in case of failure o and check replace the rotor again, there were MANY bad ones that made the engine misfire

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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
Absolutely nothing wrong with using Crane XR-700, it was always a better design than Pertronix and is still available today. (Although I'll agree, Crane has never done a very good job of marketing it, after they bought the design from someone else.)

Do you have the version with the LED or without ? If present, does the LED blink while cranking the engine?

Also, is your car positive or negative ground? Is there any chance it got switched? The non-LED XR700 has to be changed if you change polarity; the LED version only has to be wired differently.

When you say you have "power" from the coil, do you mean spark? If you're getting spark when testing at the top of the coil, but not at a plug wire, then the cap or rotor have to be bad. As noted, there was a rash of bad rotors a few years back, that would sometimes fail just as you described.

Try connecting a 12v test light from the coil terminal with the yellow wire to either ground (for negative ground) or hot (for positive ground). If it flashes when you crank the engine, most likely the problem is not the XR700.

If not, pull apart the Molex plug to the pickup and inspect the contacts. Sometimes a terminal will get dislocated in the housing, so be sure all 6 of them are in their proper place. Use a screwdriver or paper clip to rapidly tap to short the gray wire to the white wire from the module; with the key on and the test light still connected as above.

If the light still doesn't flash, I suggest double-checking power to the module by piercing the insulation on the wires. In my case, the ground connection had developed corrosion between the ring terminal and screw that didn't show in a casual inspection but was keeping the engine from running.

As a last, final check, I would switch back to points and make sure it runs that way. If so, probably time for a new module.

Oh yeah, you might want to double-check the coil primary resistance. The XR700 expects a 3 ohm coil and hence should work fine with the stock coil. But there is a chance someone has inadvertently replaced it with a 1.5 ohm coil. If so, the module may have failed from overheating. The Crane design is much less susceptible to that than the Pertronix; but it can still get hot enough to shorten the life of the power transistor.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

TimPicard Avatar
TimPicard tim Picard
Mount Gilead, Ohio, USA   USA
Hi Randall.

First I appreciate your time in outlining your questions and suggestions.

1) I do have the LED version and it does light up when cranking.

2) Car is negative ground and am sure it didn't get reversed, though I am capable of that sad smiley

3) The rotor is new from Moss, though the cap is not.

4) I'll do the other test in the next couple days.

Again, many thanks for your support!

Tim

TimPicard Avatar
TimPicard tim Picard
Mount Gilead, Ohio, USA   USA
To Wyatt and William.

I'm happy to sink the bucks into converting back to points but I'm an idiot - is there an outline to revert BCK from electronic ignition to points and plugs?

Also, I see a few Pertronix items listed on Moss - you talking about the Ignitor? Distributor?

Thanks for your ideas - I will do a bit more testing and return with more questions.

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