3.8 coilpacks

Got called back to the office this afternoon because a computer was rebooting. The 1994 Trans Sport 3.8 ran beautifully. I shut ijt off, and when I came out half an hour later and restarted it I smelled raw gas from the now cold exhaust, and the engine had a pronounced miss.

I limped it home and disconnected injectors one at a time ntill I found #3 made no difference. I shut it off and pulled #3 plug wire. When I cranked it over there was no spark. I pulled the wire from the coil. Still no spark. I pulled #6 from the coil (opposite connection) and it had LOTS of fire. I pulled the coilpack and replaced it - lots of fire, but the engine still missed. Spark tester showed the second (middle) coil pack was producing a weaker than normal spark - so I replaced it too, and the engine now runs as sweet as ever.

Any idea what would cause 2 coils to "go south" all at once? The other coil pack was replaced something like 5 years and 90,000 km ago. (thruck has over 365,000km on it now)

Reply to
clare at snyder.on.ca
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Its simple really, bad plugs or bad wires will eventually equal bad coils.

Need I say more?

Reply to
Bon·ne·vil

Old age?

Reply to
JHG

Plugs are fine. I'll be checking the wires when it warms up, but the spark testers show excellent spark on all six now. Also, absolutely NO ignition noise on an AM radio held close to the running engine (which is usually a pretty good way of indicating bad spark plug continuity)

Reply to
clare at snyder.on.ca

Is it a HEI spark tester? Either way a spark tester still wont tell you wire resistance. An Ohm meter should always be used. Nothing suprising about having 'new' wires that are bad right out of the box. Wires are also pron to chafing and if not correctly routed or tied down they wont last 40k miles. Factory routing of spark plug wires is pretty bad...

HEI

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Reply to
Bon·ne·vil

I've had these fail, but never like this. Each coil pack fires two plugs at once (one at the top of the compression stroke, firing the cylinder, and the other at the top of the exhaust stroke, doing nothing). A coil pack failure turns the V6 into an odd firing V4 really quick.

The first one sounds like an electrical breakage, the second one normal (for 350Kkm!) wear and tear...

--Ken

Reply to
dye

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