October 31, 2010
How Not to Perform a Tune Up

(Of rotor, distributor cap, spark plug wires, and spark plugs.)

1. Completely ignore any shop manual of any sort. Since you already know how to change this stuff on a Spider, with a four cylinder motor designed some time before Noah picked up an axe, you can change them on a car twenty years newer with two more cylinders. Totally the same.

2. Come up with a really clever idea. Holding the old distributor cap, slowly attach new wires to new cap.

3. Completely ignore any key or notch on the distributor cap. YOU know much better which end is up than the factory ever did.

4. After three tries getting the order right, and a complete do-over because the cap is upside-down, forget there's a special spark plug tool in the trunk. It's much more fun to spend nearly an hour contorting hands, back, and knees while trying various combinations of "normal" tools that almost work.

5. Assume you have now, in spite of all contraindications, actually gotten it right the very first time and try starting the car just to see what happens.

6. Impress the entire neighborhood with an explosion so powerful it blows the plenum (a rectangular aluminum box about 12" x 6" x 2") almost completely off the top of the motor, violently disconnecting at least one fuel injector, snapping the plenum ground, breaking off a piece of the cam belt cover and blowing a cam sprocket cover completely off.

7. Unsuccessfully maintain complete composure as you greet the rest of the family as they arrive from errands exactly sixty seconds later.

8. Scare the wife into complete silence as she realizes it is in fact possible to die playing with cars.

9. Spend the rest of the evening angsting over the fact that you actually managed to blow the wife's car up.

And the correct way is...

10. Wake up the next morning, download the proper page of the shop manual, write out a diagram with the correct firing order, use the spark plug tool in the trunk to remove and replace #5, which is otherwise inaccessible, and re-seat the three wires routed incorrectly by the moron who did the work the day before. Start the motor on the first crank.

11. Calmly trace and reconnect the fuel injector at the other end of the plenum which was causing it to, in the words of The Empress, "sound funny." Repair the ground wire and replace all other covers, clips, and clamps.

I'm not a professional mechanic folks, it's more like I inflict myself on unsuspecting cars.

Posted by scott at October 31, 2010 05:09 PM

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Well, it's good that you're not dead. Aside from that, it's probably pretty good that you didn't actually crack or otherwise destroy any of the difficult to replace components.

Honestly, I'm going to give you support on this one. I've replaced the plugs, cap, rotor, points/HEI, and all sorts of other ignition components. What happened to you shouldn't happen on any normal motor. That shit just ain't normal.

Posted by: Ron ap Rhys on October 31, 2010 09:14 PM

The 'asplodey bit I'm pretty sure CAN happen on any car who's owner is dumb enough to put the ignition wires on in the wrong order. It's what happens when the spark hits on the intake stroke and the intake valve isn't closed. Sets off the whole charge when the only place for it to expand is through the intake structure.

Allowing said owner to PUT them in the wrong order, well, yeah. They took the trouble to cast numbers onto the valve cover, it would SEEM logical they'd cast them into the dizzy cap too. Maybe on OEM ones they do, but on the aftermarket one I had, not so much.

As far as this failure causing a largish bit of metal to attempt departure from the top of the motor... well, you got me there.

Posted by: Scott on November 1, 2010 03:12 PM

That's one of the fun bits about a small block Chevy, Ford, or that other piece of crap company. It's pretty easy to put the engine TDC on 1, then go from there. Hell, I used to have the firing order memorized back in the day.

Of course, we also changed a single plug and wire at the same time so as not to mix anything up. At least (I'm hoping) you didn't do the Ford trick of just bridging the remote solenoid with a screwdriver to start it from the engine compartment...

Posted by: Ron ap Rhys on November 2, 2010 06:29 AM

One-wire-at-a-time is how I do it on the spider. Unfortunately, the Milano's wires come with helpful (and impossible to R&R) bundling wraps and guides pre-installed, so one-at-a-time is impossible. In retrospect, having a diagram and leaving the new cap on would've done the trick.

Posted by: scott on November 2, 2010 07:04 AM

Ahh - that explains much of it. Lucky for me I've only got to do that once every 100K miles on my Xterra.

Posted by: Ron ap Rhys on November 2, 2010 02:51 PM
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