Low Spark on a 351M
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Low Spark on a 351M
Just wondering where to go from here. Truck is hard to start, but can get it started but am getting a orange spark. I have replaced the starter, all cables, solenoid, spark plugs, wires, and coil. Would it be the ignition module? It is a 351m, auto, 2wd, stock F-150.
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From: Isla de Muerta
MSEE
Joined: Apr 2004
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From: Austin, TX
Measure the voltage across the battery posts. Next, turn the key to RUN and measure the voltage at the positive terminal of the coil (BATT) with respect to ground. The second measurement should be approximately half that of the first.
To be clear, you are to report TWO (2) voltage measurements. You're looking to make sure voltage is not dropping across the power transistor in the ignition module (low primary current).
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From: Wildwood, Mo
So, if you replace the pickup in the distributor, do it without pulling the distributor and you may save yourself a lot of pain. I think a good idea is to spray WD40 at the base of the distributor when you think of it. On the 351M water likes to puddle around the distributor. Patrick
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Thanks guys, I will try all this when I get a chance. Also reading one of the other threads, I am thinking that I may have an "old gas" problem as well. A bit more work but need this to get going. Here I thought I would have this running at Christmas - last year! Thanks again.
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