Date: Mon, 17 Aug 2015 01:14:05 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <email@example.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Coil-itis
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On the primary side the coil gets 12 volt from the ignition switch and the ECU completes the ground circuit to charge it and opens said circuit to make the magnetic field collapse and create the spark. As part of the scheme the ECU varies the dwell based on engine RPM so that the coil does not overheat at low speeds (lots of time for the DC current to flow) and increases it higher speeds to maintain the power needed for each spark. So if the primary side of the coil is failing (gets too hot) you need to look at the ECU and pick up coil. On the secondary side if there is too much resistance the spark at some point will flash through the insulation in the coil and create a failure there. Check the wires with an ohmmeter and make sure none of the resistor ends are not open. One will rarely kill a coil but if you have a bad set!
What you may is an intermittent problem with the wires going to the coil. Of the two black ones one is to bring power to the ECU. It is becoming common for thie wire to fail inside the insulation. You look at the crimp and you think it is good but the strands inside are becoming dust. Cut the end and work back to good copper and use a good sealed crimp connector to repair. You change the coil but really moving things got you working again, for a while. This one has beaten me a few times. The only real test is to use a current meter. You can pull the ECU connector and test the with a meter and it will look good but the circuit will fail when actually loaded.
From: Vanagon Mailing List [mailto:firstname.lastname@example.org] On Behalf Of Bruce Todd
Sent: Sunday, August 16, 2015 6:47 PM
You may or may not read my travel post from yesterday - great trip down the Olympic Peninsula and halfway down Oregon coast. At the heart of the matter was that my coil packed it in about 3 km from home. A mixed blessing of sorts given the rush hour driving we completed in Portland on the I-5, the number of large bridges we crossed, and some of the remote highways we traversed.
I have now replaced 4 coils since July 10 of 2012 = here are the makes of coils, dates of purchase & install and odometer reading in (kms).
July 10, 2012- Beck Arnley Coil (267,951) replaced the original (?) black Bosch coil - I bought the van in the Summer of 2006 (228,394). as a preventative measure.
Sept 28, 2012 - New Bosch coil (270,965) replaced Beck Arnley (failed)
Feb 8, 2014 - Replaced new Bosch Coil with spare (original coil) (279,376) (new Bosch coil failed)
October 22, 2014 - Replaced spare coil with 2nd New Bosch coil (283,980) (Mechanic accidentally kept spare coil which I have not yet got back)
August 15, 2015 - Replaced 2nd Bosch coil with 3rd Bosch coil (289,578).
I just sent off an email to Bosch Canada given that this could be some poor workmanship or perhaps some bad luck on my part. What mechanically or more specifically electronically do people think could be possibly contributing to this issue.
One last thing - I did post last October on the heat I noticed from the 2nd Bosch coil - ? Subject line: Coil Boil
86 Westy Syncro