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Old 02-28-2009, 02:40 AM   #1
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There's a good chance that my car's recurring misfire problem will soon be solved.

Background: I've had multiple injectors go kaput in my car, all in the #4 spot. Finally I got fed up and decided to focus on what's CAUSING the problem instead of just addressing the symptom.

Paul came over a few days ago and we dug into the injector wiring harness. First we noticed a problem that severely increased from several months ago: several inches of the plastic near the #4 wires had MELTED AWAY and mated with the EGR valve region. Then we tested the wire resistance; sure enough, the wires for injectors one, two, and three all gave the same numbers; number four was twice as much. So there must be a short in there.

Bought myself a (slightly used) injector harness from Parts Group. Only $45. Planet Miata wanted $140 for the same part!! Hope to install it early next week. Then will post a photo of the damaged harness. It's quite entertaining, when it's someone else's car!

Keeping my fingers crossed about this solving my car's misfires once and for all.
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Old 02-28-2009, 02:55 AM   #2
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good luck, stuff like that can be a real headache.
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Old 02-28-2009, 03:03 AM   #3
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Yup. R = (Voltage / Current in Ohms) ... so if the resistance is twice the normal amount, then the current is only half the normal amount ... and with half the normal current, perhaps my injector isn't firing. Right?

So hopefully that's the "current" problem.
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Old 03-07-2009, 10:29 PM   #4
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Check it out:



I bought a replacement harness for $45 from Parts Group. Paul installed today while my role was to ask a bazillion questions.

Also we had to replace a couple of O-rings because fuel was spewing everywhere.

New problem: OEM radiator no longer sufficient. Coolant is bubbling and escaping via overflow reservoir after I drive for a while. Paul says air bubble somewhere in system.

Meanwhile I got laid off from work last month. So $$ is tight. Do I opt for a Godspeed radiator, or do a coolant reroute instead?
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Old 03-07-2009, 11:18 PM   #5
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Radiator before reroute.
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Old 03-08-2009, 12:04 AM   #6
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Thanks to IM with Savington, now I understand that a reroute is basically unrelated and NOT what my car needs. Yet another MSM owner is slightly less clueless.

Back to radiator shopping I go ....
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Old 03-08-2009, 12:21 AM   #7
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Are you overheating at cruise or WOT pulls? If at low speed cruise you have other problems. If at high speed cruise you have poor shrouding. If at WOT only then perhaps you need to improve shrouding or get a bigger radiator. Do you run an OEM thermostat? Does it ever overheat when when initially warming up before it drops to its' usual running temp? IE warms up, spikes to 230, then runs 215 all the time?
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Old 03-08-2009, 12:30 AM   #8
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I can't answer those questions. I defer to Paul. He was manning the Megatune control panel when we drove around tonight after replacing the injector harness.
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