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coil/wire resistance

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Old Apr 5, 2007 | 12:44 PM
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coil/wire resistance

Over the winter, the 7 didn't move much. Nonetheless I made sure to start is at least once a week to keep everything moving. It started without hesitation every time until mid-January. Now It cranks but doesn't start. I made sure the battery was fully charged and tried again to no avail. I pulled the plugs (which i changed less than 1000 miles ago) and realized i wasn't getting a spark when cranking. I pulled the coils and wires to test the resistance like the FSM says. The specs in the FSM for healthy coils and wires are as follows:

Trailing Coil:
A-B Below 1.0 ohm
A-T infinite

Leading Coil
A-B Below 1.0 ohm
L1-L2 9.6-16 kohm

High-Tension Leads
16 kohm per 1 meter


The coils tested perfectly, but when testing the leads I came up with these numbers:

Trailing 1: 19.65 kohm/m
Trailing 2: 18.25 kohm/m
Leading 1: 18.00 kohm/m
Leading 2: 13.93 kohm/m

Knowing that the FSM specifies 16 kohm/m do you think my wires are ok? I will continue this weekend with testing the igniter.

--Andrew
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Old Apr 5, 2007 | 12:45 PM
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Originally Posted by Black1993rx7
Knowing that the FSM specifies 16 kohm/m do you think my wires are ok?
Yes.
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Old Apr 5, 2007 | 02:45 PM
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From: Indianapolis, IN
Sst?

The instructions for inspecting the igniter say to:

1. Disconnect the igniter connector.
2. Connect the SST

What is an SST? Do i need it to diagnose my igniter?
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Old Apr 5, 2007 | 02:54 PM
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I personally have never seen an ignitor go bad on these cars. You've checked voltages etc to the coils?
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Old Apr 5, 2007 | 03:03 PM
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Originally Posted by Black1993rx7
What is an SST? Do i need it to diagnose my igniter?
That's a special (most of the time non-commercial) tool. In all the years I've been on this forum, I've only seen one ignitor failure reported here. Not to say that isn't your problem, but its extremely rare.

How did you verify the lack of spark?
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Old Apr 5, 2007 | 03:19 PM
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To check the spark I held a plug close to a known ground and had someone crank the engine.

How would I check the voltage TO the coils?
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Old Apr 5, 2007 | 07:43 PM
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You have to hold the metal part of the plug body DIRECTLY ON a solid ground, not near one. You should then see the electrode spark.

BTW, it's not a good idea to just start a stored car repeatedly for short periods like that. Compressing air and combusting create condensation and moisture. When you don't allow the engine to fully warm up for a good amount of time and get some driving in there, the moisture is not evaporated and stays in the engine.

I feel that a good way to keep the bearings wet is to pull the plugs, then crank the engine until the oil pressure light goes off.
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Old Apr 5, 2007 | 10:03 PM
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I know to let the car fully warm up...

I suppose I'll put everything back together and do the spark test the right way and will report back.
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Old Apr 16, 2007 | 11:54 PM
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From: Indianapolis, IN
solved

Problem solved... bad alternator.
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