How did 2 new AEM smart coils blew up

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maxiice
Posts: 67
Joined: Sat Apr 13, 2013 5:16 pm
ECU Model: S80 Pro
Firmware Version: 63

Re: How did 2 new AEM smart coils blew up

Post by maxiice »

stevieturbo wrote: Sun May 22, 2022 5:00 pm
maxiice wrote: Sun May 22, 2022 2:51 pm Did some testing today, Just turned on the ignition, and right away 3 more coils started to heat up, and 3 remain cold. the heat sink got up to about 60 degrees in 10 sek, before i cut the power.
So i swapped the coils, and the good cold coils, remain cold, so it must be the coils, that are bad. Now 5 of 8 coils gone bad.
I tested the wiring where the coils was hot, and the trigger signal is grounded, and it was so also where the coils did not heat up.

So i guess the trigger signal stays grounded until it is suppose to fire a spark?
Modern coils with internal amplifiers will charge, draw current when a "Hi" voltage is applied....by that I mean 5v, although in the case of DTA it may be near 12v.

Upon removal of the 5v, the coil will fire. Sitting idle with the coil trigger line at 0v, the coils will be doing nothing, they will not be drawing any current
A scope and current clamp is very handy here for monitoring.

Or even a current clamp linked to the ecu and logged as fast as possible like 1000hz might get you a picture.

If for whatever reason this voltage was high for an extended period...yes it could burn them out. And given they will usually run in the 2-4ms region, an extended period need not be very long.

Although that's some serious heat, very quickly. Although I don't think I've ever powered on one of the coils for 10 seconds to test to see what happens.

Where were the coils sourced from ? Where they in correct AEM boxes etc ?

Sourced from a Norwegian tuning shop. (turbofun) They are the same as from speeding.nu where i got some spares from. Box also.

I did not "hot-wire" the coil for testing, i just put on the ignition. I measured 12v across the 12+ supply and triggersignal. Is that 0v trigger? i guess thats right?
I will be setting up a scope on triggersignal next to se whats up while cranking or idle.
maxiice
Posts: 67
Joined: Sat Apr 13, 2013 5:16 pm
ECU Model: S80 Pro
Firmware Version: 63

Re: How did 2 new AEM smart coils blew up

Post by maxiice »

stevieturbo wrote: Sun May 22, 2022 5:04 pm And if you're intending to use "dumb" inductive coils....DTA can run these directly. There is no need for an external ignitor

Oh realy? thanks, that helps, now i can put on most coils. Yes and unchecke "use external coil amps"
stevieturbo
Posts: 3362
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: How did 2 new AEM smart coils blew up

Post by stevieturbo »

The correct way to test the trigger wire with a meter or scope would be between 0v/battery ground and the trigger wire itself.

Then you should see the Hi/Lo switching ( well not on a meter, it wouldn't be fast enough.

Not sure if any of the ecu inputs would be tolerant of the 12v On state to try and log this on an ecu input or not in lieu of a scope
maxiice
Posts: 67
Joined: Sat Apr 13, 2013 5:16 pm
ECU Model: S80 Pro
Firmware Version: 63

Re: How did 2 new AEM smart coils blew up

Post by maxiice »

I borrowed a scope for testing, but i realy think its not needed, I put in 8 old tfsi coils and let them run i testmod for hours, and nothing happend to them, so i dont think the ecu has a problem.

Have been thinking back and forth on what coils to use, and ended up wit a set of new R8 tfsi coils from bosch, witch are quite powerful and plenty spark for around 100 hp pr cylinder

As for now 7 of 8 coils have let out the smoke.. what gives
stevieturbo
Posts: 3362
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: How did 2 new AEM smart coils blew up

Post by stevieturbo »

Bare in mind the VW/Audi coils run very low dwell times. I think less than 2ms or so, but yes they are very good.

So 7 of the AEM coils have now fried ?

I'd really be checking the wiring and the dwell times/current they are actually seeing and pulling. That seems insane.

I did once buy some standard LS coils that seemed very cheap, but the seller claimed they were genuine takeoffs. Within minutes they were failing, but nothing dramatic like smoke etc.
When I contacted the seller, they refunded me claiming copies were sent by mistake.
maxiice
Posts: 67
Joined: Sat Apr 13, 2013 5:16 pm
ECU Model: S80 Pro
Firmware Version: 63

Re: How did 2 new AEM smart coils blew up

Post by maxiice »

Yes, 7 is now fryed, i think 2 died peacefully, the rest was smoking hot. Dwell is set to 2.5, but it dosent matter for the AEMs They died with just ignition on also.

The tfsi testing was done with the same harness, just cut the aem connector off and put tfsi connector on.
All the coils have their own battery ground wire, head ground wire,and 20a fuse, just one blew. AEM states they can draw up to 19 amp... well well
stevieturbo
Posts: 3362
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: How did 2 new AEM smart coils blew up

Post by stevieturbo »

They absolutely do not draw anywhere near that

When I tested mine, they drew less than the GM D514A coils I had been using for same dwell. At idle with dwell around 2.0ms on mine each coil only pulls around 4A

You'd need to run huge amounts of dwell for them to get anywhere near that. Plus the actual coil connector plug isn't exactly a high current terminal.
stevieturbo
Posts: 3362
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: How did 2 new AEM smart coils blew up

Post by stevieturbo »

Noticed another thread elsewhere about fake coils.

What colour is the epoxy on the rear ? The clones appear to have black, the correct coils appear to have a creamy colour
maxiice
Posts: 67
Joined: Sat Apr 13, 2013 5:16 pm
ECU Model: S80 Pro
Firmware Version: 63

Re: How did 2 new AEM smart coils blew up

Post by maxiice »

Ok, so they seems to be AEM
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stevieturbo
Posts: 3362
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: How did 2 new AEM smart coils blew up

Post by stevieturbo »

Definitely a strange one.
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