won't start - bad coil

[pollock]

2 weeks ago my merc suddenly wouldn't start. Cranked just fine but wouldn't start on at least 5 attempts. Popped the hood to see if there was anything obvious. Tried again and it started. Drove it for a week and a half and it was fine.

Today it did it again. Tried again 10 minutes later and no luck.

Is it possible for a coil to fail intermittently? I haven't checked to confirm spark. Anything in particular I should suspect?

The car is an 89 with only 60,000 miles.

[phayzer5]

Check the small connector coming off the neg batt cable and make sure that the small wire is still attached...something to do with ecm power I think.

Did you get any sort of stumbling attempt like it fired off one cyl or anything...or just pure cranking and nothing?

Stick a bit long screwdriver in the coil wire and get it braced close to a valvecover and see if you have spark

[gadget73]

More common for the TFI module to do that than the ignition coil. I'd check the connectors on both the TFI module on the distributor, the power connections to the coil, and the coil tower to make sure its not corroded before replacing anything though.

[phayzer5]

Is the no-start condition after its been run for awhile and it just cuts off on you...or when you first get in the car in the morning/afternoon/evening when the engine/TFI is dead cold?

[OldBlue1981]

That's what the problem sounds like. I had the same problem a few months ago. A bad coil was the culprit of my problem. Once I replace it, the car fired right up. Replace it and see if it will fire. Hopefully, that's all it is.

[pollock]

Coil indeed. And the coil tower was mucho corroded.

[pollock]

Well, here's an update. Several days after replacing the coil it did the same thing. I tried to start it, and it cranked with no fire. Three hours later I tried again and it started right up. What's going on here?

I did notice something when it wasn't starting.... a "relay-clicking" sound when I turned the ignition switch on or off under the dash on the passenger side. Maybe it always does that and this was the first time I noticed? Don't know.

Any ideas? Ignition switch? Short in the harness somewhere?

[gadget73]

Have you replaced the TFI module? I still say it sounds like classic bad TFI symptoms. Works when cold, does not work when hot.

[pollock]

Well, it hasn't really failed in a hot-start situation. Although the weather has been in the 100's the last week.

What's a TFI module? can it be tested?

[murphmobile2]

The TFI module is mounted on your distributor, you can have it tested out at AutoZone for free.

It's the rectangular looking part, you'll need a special tool to remove it tho.

[pollock]

I had the module tested and it showed good. This was no surprise, since the car started right up when I moved it into the garage to work on it. I replaced it anyway. I'll report back after a few days of driving.

I also replaced the cap and rotor, plugs, and ignition wires, which were all original.

Replaced the belts too. Why the hell could Ford not have made the fan pulley an 1/8" smaller, so the inside belt would come off without removing the fan?

[mrltd]

You took the fan off? I've never done that with any of the vics I 've owned...

[mrltd]

Gonna also suggest fuel filter....that is a must. Can also cause some wierd issues.

[pollock]

Well, the ignition module didn't fix it. Drove it to work today and tried to leave for lunch - no start.

I haven't verified that it has spark when it is stuck in this condition - haven't been able to because it is so intermittent. But I still think it's ignition rather than fuel because it won't even sputter.

[pollock]

You took the fan off? I've never done that with any of the vics I 've owned...

The fan itself wasn't the problem. The fan/waterpump and pulleys were so close together I couldn't slip the back belt off between them.

Maybe my pulleys are both on the outside edge of the tolerance and that screwed me.