No Spark at Coil.....ugh

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arynday@gmail.com - 12 May 2008 07:46 GMT

Hello Folks,

My 95 Camry (135k, 4 cyl) cranks strong but will not start, I
determined there was no spark through the wires so I checked for
voltage to the coil, only .2 volts, I understand that it should read
12+ like a straight reading on my battery.
I just re-installed this engine and so clearly I have
monkeyed up something somewhere, I'm guessing it is not grounded
properly somewhere, or a short, etc etc. Any ideas what I should keep
an eye out for? Short of pulling the wiring harness out, splitting it
open and checking the wires are there any other things I have over
looked that I should try?
Much thanks for any ideas! I'm running out of hair to pull
out!!

Zach

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Ray O - 13 May 2008 05:40 GMT

> Hello Folks,
>
[quoted text clipped - 12 lines]
>
> Zach

When you measure primary voltage at the coil, where are you grounding the
negative lead to the volt meter? What is the voltage if you put the
negative meter lead on a chassis ground or the battery negative terminal?
If it is still .2 volts, then the problem probably not due to improper
grounding, more likely a poor or loose connection. If the harness is no
physically damaged or stretched, check the harness connectors to make sure
they are tight, and that the individual pins in the connector are not
corroded or backed out of the connector.

You mentioned that you just re-installed the engine - did it ever run
properly? Are you sure that cam timing is correct?

Signature

Ray O
(correct punctuation to reply)

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arynday@gmail.com - 13 May 2008 05:53 GMT

Hi Ray-

When I checked the voltage I grounded the negative lead on the
engine block and then the chassis, .2 on both. The car did run
correctly, I pulled the engine out to change the rear main seal and to
get a closer look at where it was leaking oil. While I had it out I
just changed the timing belt, I had everything lined up, camshaft at
12 o'clock with the rotor on the 1st wire position, crankshaft was at
TDC.

I played around with the ohm/resistance on the coil itself and
it looked to be within the accepted range, I then undid the power lead
to the unit and was stumped to find only .2 volts. I've started
disassembly again to take a look at the wiring harness, many of the
connectors seem to be one piece units, are they meant to be
disassembled?

Thanks for the ideas!

Zach

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Ray O - 13 May 2008 07:28 GMT

> Hi Ray-
>
[quoted text clipped - 16 lines]
>
> Zach

If you checked voltage with the negative lead of the volt meter on chassis
ground, then a bad ground is not the problem. Check all of the fuses in the
engine compartment to make sure none are bad.

The connectors are not meant to be disassembled, but the pins inside the
connector can sometimes get bent or work itself loose. Look inside the
connector to make sure the pins are not bent or corroded, and you can push
(don't pull) on the wire from the back side of the connector to make sure
they are tight.

I assume that you are measuring voltage with the ignition switch on. How
are you measuring voltage? Are you disconnecting the connector from the
coil and measuring from the side of the connector that plugs into the coil?
Is there any difference if you connect the connector and back-probe the
positive pin? You can make up a jumper wire with an in-line fuse and a
narrow pin at the end and try feeding 12 volts from the battery to the back
of the connector and see if the car starts. If it does, then you have a bad
connection in the harness. To find the break in the connection, look at the
color and tracer pattern in the wire where it plugs into the coil, then
follow the wire loom back to the next connector and look for the same color
and pattern wire at the other end of the loom. Measure voltage at the other
end of the loom until you find 12 volts. The break will be between the
point where you found 12 volts and the coil.

When you changed the timing belt, are you sure that cylinder #1 at TDC
compression and not exhaust?

Signature

Ray O
(correct punctuation to reply)

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