Can an IGBT be intermittent?

KL7AJ

Joined Nov 4, 2008
2,225
I would expect almost any electronic component to be prone to an intermittent fault. The automotive environment is harsh. Vibration or temperature cycling could in theory affect, for example, an imperfect wire bond inside a semiconductor device such as an IGBT.
What he said.
 

Thread Starter

NMNeil

Joined Jun 18, 2019
15
From my experience @bwilliams60 is correct, most all driver issue come from the coil side of things. When they start to fail the high voltages from the secondary makes its way through the low voltage primary and wreaks havoc inside the pcm.

there is one popular one that I work on from fords that I swear the main problem is the pcb design of pcm. I am no engineer but it seems to me the coils work the drivers so hard they overheat the area and since the controller for them is placed damn near directly under the drivers it fails from this heat, causing a big mess to multiple coils and the pcm. Still it was said to be faulty coils in the tsb put out on it and they designed new ones that helped suppress some of the feedback which seem to help a little.
While waiting for my repaired PCM to arrive I took a closer look at the coil from cyl #6. Primary and secondary resistance was well within specs, no sign of arcing or burning. Took a closer look with a 40X jewelers loupe and discovered that the epoxy sealing the connector to the top had a small crack all the way round the perimeter. Looking closer I found a hairline crack, difficult to see even at such high magnification, running from the connector to the center of the coil. I pulled the other 2 coils from the front bank this morning and they are both showing exactly the same cracking.
So despite being within specs for resistance something is obviously very wrong inside the coil. Not even going to check the rear bank, just changing them all out.
 

bwilliams60

Joined Nov 18, 2012
1,332
Good choice in changing all your coils. Well worth the money and time. I don't warranty a PCM repair on Fords if customer chooses not to replace with OEM new coils. I don't even warranty them with aftermarket coils because they are sure to fail as well.
On another note, any chance you have any pics of these cracks in the coils? I would be interested in seeing the cause of the problem. Moisture obviously takes part in this equation by the sounds of it.
 
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Thread Starter

NMNeil

Joined Jun 18, 2019
15
Good choice in changine all your coils. Well worth the money and time. I don't warranty a PCM repair on Fords if customer chooses not to replace with OEM new coils. I don't even warrnaty them with aftermarket coils because they are sure to fail as well.
On another note, any chance you have any pics of these cracks in the coils? I would be interested in seeing the cause of the problem. Moisture obviously takes part in this equation by the sounds of it.
I'll try and get some photos but the macro option of my camera is not so good.
I've been researching coils and it's a minefield. Amazon have OEM Motorcraft coils for sale at around $40 each but many of the reviews say they are Chinese knock offs, not the real thing. Just out of interest I checked to see who actually makes Motorcraft coils and it seems the OEM is Denso, and they are made in the Denso factory in China!. So it seems that whatever the brand of the coils it's going to be made in China either at an official OEM factory or a local counterfeiting factory.
Gone are the days when you would find a "Made in the USA" label on auto electric parts.
Given the pot luck situation I ordered a set of aftermarket coils ($49 the set with a 2 year warranty and good reviews) I'll just make sure I change the plugs and coils out every 6000 miles or so.
 

bwilliams60

Joined Nov 18, 2012
1,332
Speaking from experience, I think you are going to spend more money on repairs and frustration than what those OEM coils would have cost you. I hope I am wrong for your sake but knockoffs never pan out. There is a reason they are cheap. It can be as simple as the wire or core they use to the fillers that they use for the plastic which will take on water like the Titanic. Let us know how you make out.
 

Thread Starter

NMNeil

Joined Jun 18, 2019
15
My point was that even if you buy the new, branded Motorcraft coils you still have no guarantee that they are the genuine Denso made in China version.
When all is said and done the path of least resistance will be to get the car running then sell it, so the whole coil PCM issue becomes someone else's problem.
 

bwilliams60

Joined Nov 18, 2012
1,332
When you buy OEM, they are built to specific standards and you know you are buying something made for the vehicle. When you buy a knockoff, it is a reverse engineered product with inferior parts. It does not matter that they are both made in China. One has standards and one does not, that is all I am trying to say. I was not aware that you were going to fix it and then sell it off. Just trying to save you some cash in the long run. All good, carry on. Poor pity the guy buying it lol.
 
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