1980 Tercel distributor pickup coil voltage

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Mike - 03 Jul 2006 16:06 GMT

Would anyone have any idea how much voltage I should measure at the plug on
the end of the distributor pickup coil, while the engine is cranking? I
believe the igniter and the ignition coil are ok, but I have replaced the
pickup coil and still have no spark. The voltage is running around 0.5 volt
I think, when the engine cranks.

This thing has really got me snowed. No spark, voltage across primary of
coil is way too low when cranking the engine. When I put a 1.5 volt battery
across the pickup coil connector (the input of the igniter) the voltage on
the ignition coil primary looks a lot better, around 9 volts I think. With
that test I feel like the igniter is doing its job. The ignition coil tests
ok with an ohmmeter (no opens anyway). To me, everything points to the
distributor pickup coil and I was really surprised when changing that didn't
fix the problem.

Thanks.

Mac

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Ray O - 03 Jul 2006 17:15 GMT

> Would anyone have any idea how much voltage I should measure at the plug
> on
[quoted text clipped - 20 lines]
>
> Mac

Start by checking to make sure all of the connections are good, including
the high tension wires.

You should have battery voltage at the positive terminal of the coil with
the ignition switch on.

Resistance across the primary should be between .3 and .6 ohms.

Resistance between the positive terminal on the coil and the high tension
terminal should be between 9 and 15 ohms.

Here are the specs for a '93 Previa, they should be similar for your car:

The air gap between the pickup coil and the signal rotor (looks like a gear)
on the distributor should be between .2 and .4 mm (0.008 and 0.016 in.).

Resistance for the pickup coil terminals:
NE-G: 155-240 ohms
G1-G: 125-190 ohms
G2-G: 125-190 ohms

On this vintage Tercel, the igniter was a fairly common culprit for no-spark
conditions.

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Ray O
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Mike - 03 Jul 2006 17:38 GMT

> > Would anyone have any idea how much voltage I should measure at the plug
> > on
[quoted text clipped - 44 lines]
> On this vintage Tercel, the igniter was a fairly common culprit for no-spark
> conditions.

I figured the problem would be the igniter, since that is the most expensive
part, but the service manual tells how to test it. You unplug the pickup
coil from the input of the igniter, (momentarily) place a 1.5 volt battery
across the input of the igniter, and measure the voltage between chassis
ground and the negative terminal at the ignition coil. Should be 5 to 8
volts and I am getting about 8 volts there when testing. When I remove the
1.5 volt battery, the voltage goes to 0. With that test I felt like the
igniter was probably ok.

You do mean the coil resistance between the secondary and the positive
terminal on the coil should be between 9 and 15 THOUSAND ohms don't you? 9
ohms would be awfully low I would think.

Thanks!
Mac

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Ray O - 03 Jul 2006 19:11 GMT

>> > Would anyone have any idea how much voltage I should measure at the
>> > plug
[quoted text clipped - 61 lines]
> 1.5 volt battery, the voltage goes to 0. With that test I felt like the
> igniter was probably ok.

The Previa service manual does not list a procedure for checking the
igniter, but it does sound like you igniter is working.

> You do mean the coil resistance between the secondary and the positive
> terminal on the coil should be between 9 and 15 THOUSAND ohms don't you?
[quoted text clipped - 3 lines]
> Thanks!
> Mac

Oops! Yes, the resistance should be between 9 and 15 thousand ohms. Sorry!

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Ray O
(correct punctuation to reply)

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