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Coil operational test & coil fit over plugs

2258 Views 5 Replies 5 Participants Last post by  JimLev
I noticed a mention of this test on the post about spark plug replacement here

DIY for an M54 spark plug replacement on a 2002 BMW 525i E39 - http://www.bimmerfest.com/forums/showpost.php?p=5985803&postcount=1

I am curious to as to what is this test exactly testing and how do I use this test to check on the coils after the spark plug replacement I completed couple of weeks ago.

Another related question is that I found the coils not going in all the way to grab the connectors on top of the plugs. This was on all the plugs and certainly not the issue of the rubber boot from socket stuck to the plug. The coil were just sitting/floating on top of the plugs and I was able to push them in as I tightened the 10 mm bolts.

Is this normal that the coils don't grab on the plugs until tightened with the bolts.

The car is running fine except for some tapping noise I heard when the car was warm which I have read can be related to the ECU getting adjusted to the new plugs.

Thanks for the all the contributors that have posted the DIYs. I would however like to say that it is kind of hard to find 540 (V8) specific DIYs at times.
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Good question!

In Let's talk coil packs.. best brands / prices Jase says:
what is this test exactly testing and how do I use this test to check on the coils after the spark plug replacement I completed couple of weeks ago.
Unless you have an oscilloscope handy ... the resistance check won't net you a bad coil.

The low voltage used by typical multimeters when measuring resistance is not enough to properly test the secondary windings. See if your indy has a "megger" or, read up on using an O-scope (borrow) to test.

I ran the Bentley tests when I got a stumble / misfire on one coil pack. Primary resistance was "in spec" and gave me no info.
The car is running fine except for some tapping noise I heard when the car was warm
If it's new, maybe it is what you said. But also listen to see if it's the DISA.
- How to identify DIfferenzierte SAuganlage - (Differential Air Intake) rattles (0) (1)

it is kind of hard to find 540 (V8) specific DIYs at times.
For plugs, one of these 'might' be for the V8:
DIYs for replacing spark plugs (1) (2) (3) (4) (5) (6)

Also, the 740i E38 team often comes over here; sometimes paying 'them' a visit is worthwhile for their DIYs (which should be essentially similar).
Don't know to what test you're referring. Are you having misfire problems? If not, the coils are okay: the plugs either fire or they don't, and the DME can detect misfires.

THe connectors inside the boot are spring-loaded. You can feel the spring when you push down on the coil. The boot should fit snugly over the insulator.

The tapping noise may be loose plugs. Verify the torque, which s/b 23 ft-lbs.

"which I have read can be related to the ECU getting adjusted to the new plugs." Don't know where you read that!
Testing an ignition coil is no longer simple like the old days.

If you have no CEL, do not worry.
Otherwise a good test is swapping coils.
Bluebee - Thanks a lot for responding to my question. I do however a quick follow up question for my benefit & others too - based on my cursory reading about DISA it seems that DISA is fitted only on I6 and not V8 engines.

Is that correct?
If it's new, maybe it is what you said. But also listen to see if it's the DISA.
- How to identify DIfferenzierte SAuganlage - (Differential Air Intake) rattles (0) (1)
Right, no DISA on the V8's.
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