new setup melted coils

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Kmsgli
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new setup melted coils

Post by Kmsgli »

Hey guys just finished wiring up a 7MGTE Supra for a friend. Its a microsquirt with the latest firmware and I am having trouble with coils getting hot and appear to be melting.

Background info:
Engine is a 3.0L turbo inline 6
Low impedance RC550 injectors (used in line chassis mount resistors one per injector to control them in two banks of 3)
I am using a quad spark to fire the factory two wire coils.
Trigger off the stock Nippon Denso dual wheel. One 24 tooth wheel and a TDC trigger with two teeth on it 180deg apart.
Using IGN1, IGN2, and WLED to fire Spark A B C on the quad spark respectively. Quad spark is wired ACB to the coil pack itself to accommodate the firing order of the engine.

So last night after completing the wire up i tested for crank signal and got it. Air temp CLT temp work (CLT is off by 20deg) MAP sensor seems reasonable (100KPA when off) TPS works well so i plugged in the coil and the car started in one try. Car idled for a few min while i was trying to chase down a huge vacuum leak. Then the coil pack 10amp fuse popped and i noticed the coil on the right was very hot and had a crack down the middle, i was not sure if the crack just happened or was old. This morning I put a 15 amp fuse in for the coils and fired it up. Idled for a few minutes then popped the fuse and the middle coil was hot this time and the crack was definitely new. I must have a setting wrong or these coils started out shot.

I have attached a pic so you can see the crack in the two coils and the one on the left is the only one that has not gotten hot yet. I also attached my MSQ if someone could check my setting and ensure this is not a setting issue before i ruin another coil pack.

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rickb794
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Re: new setup melted coils

Post by rickb794 »

Installing firmware with the coils powered can cause this.

reversing the spark output (going high vs going low) will overheat coils.
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
socrace
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Re: new setup melted coils

Post by socrace »

Your msq shows 3.1 ms dwell which is fine for edis-6, but pretty sure stock 7m coil packs should not exceed 2 ms.
Bob D
1981 Goldwing motorcycle - microsquirt'd, other stuff
Kmsgli
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Re: new setup melted coils

Post by Kmsgli »

rickb794 wrote:Installing firmware with the coils powered can cause this.

reversing the spark output (going high vs going low) will overheat coils.

Thanks for the response. I did flash firmware with Coil pack unplugged.
The Microsquirt manual says for the quad spark to go high so that is what i have set in tunerstudios.
Kmsgli
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Re: new setup melted coils

Post by Kmsgli »

socrace wrote:Your msq shows 3.1 ms dwell which is fine for edis-6, but pretty sure stock 7m coil packs should not exceed 2 ms.
Bob D
Thanks for the response. On the second startup when i cracked the second coil i did try 2.5ms for dwell do u think that is still to high and setting my dwell to 1.9 or so with a new set of coils would solve my issue?
Kmsgli
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Re: new setup melted coils

Post by Kmsgli »

So i did a bit more testing and found this. I put a new coil pack on the car and clicked the key on with a 10amp fuse feeding the coil pack. It popped it almost immediately. I double checked the power wiring to the coil to make sure it was not shorting out anywhere. I put a new 10 amp fuse in and unplugged the coil pack to ensure it was not a short and it did not pop the fuse. Plug the coil pack in and the fuse pops. This is all obviously only when the key is turned on and that circuit gets power.

Here are the only theories I can come up with;
1) This coil (used coil) is also bad like the first one was?
2) The Toyota coil is super hot and needs a ridiculous amount of amperage?
3) The stock Toyota igniter box has some type of amperage control in it and without it the coils will not work?

I am starting to lean towards number 3 as the fuel pump and injectors have a resistance system in place from the factory so logic dictates they did something simmilar with the coil pack.

Any help is greatly appreciated. Thanks.
jsmcortina
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Re: new setup melted coils

Post by jsmcortina »

Your coil is getting power via the fuel pump relay - right?

Have you tested the coils using the Spark Test Mode?

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

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rickb794
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Re: new setup melted coils

Post by rickb794 »

Measure the primary resistance of the coil?
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
Kmsgli
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Re: new setup melted coils

Post by Kmsgli »

jsmcortina wrote:Your coil is getting power via the fuel pump relay - right?

Have you tested the coils using the Spark Test Mode?

James
Not exactly but yes. The fuel pump relay output is tied to the switch power side of the two relays that power the coil pack and injectors so when the fuel pump is on it sends power to the fuel pump as well as switching the other relays on. The coil pack has its own relay and two circuits (only using one circuit for the coil pack the other one is not in use). Originally I had it wired to key on power but after re reading the manual found it should be only powered with the fuel pump so I changed the wiring around. Didnt seem to change much.

I am starting to wonder if its an issue with the quad spark?
Wired IGN1 IGN2 and WLED (WLED has a 100 ohm resistor from VREF) into coil inputs A B and C.
Grounds on a ring terminal to the chassis.
Output A to coils 1/6 output C to coils 3/4 output B to coils 2/5
hybrid
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Re: new setup melted coils

Post by hybrid »

Manual will tell you that grounds should go to the engine, but I doubt that's causing the coils to melt.
Do not load someone elses tune and expect it to work for you!
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Matt Cramer
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Re: new setup melted coils

Post by Matt Cramer »

What voltage do you have on all three spark outputs with the key on and engine off?
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Kmsgli
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Re: new setup melted coils

Post by Kmsgli »

Matt Cramer wrote:What voltage do you have on all three spark outputs with the key on and engine off?
I will test that but I have found what i believe to be the issue i just don't know what to make of it.
I was testing ground resistance due to the member two posts up that suggested the quad spark should be grounded to the head rather then chassis.
I found continuity between ground and output B (pink wire) with the engine off and coil pack unplugged. This must be running coil B wide open and popping fuses?
Is my Quad spark bad?
Kmsgli
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Re: new setup melted coils

Post by Kmsgli »

Matt Cramer wrote:What voltage do you have on all three spark outputs with the key on and engine off?
I assume you are talking about the three outputs coming from the microsquirt IGN1, IGN2 and WLED?
With key on engine off they have no voltage. When switch polarity and put the multimeter to 12v from the battery and test ground to the ECU outputs pins i have 11.10v (battery is a little dead that's how much voltage the battery has)

Voltage from the quad spark to the coil is as follows;
Key on engine off no positive voltage but also has voltage when i test for ground. Output A (White) has 0V Outuput B pink has 10.8v and output C Light Green has 10.8V
Kmsgli
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Re: new setup melted coils

Post by Kmsgli »

Here is the latest update. I found the quad spark when bolted into the engine bay was snapping the fuse for the coil. When i pulled the quad spark and let it float in the engine bay (not touching any chassis for ground) it did not snap the fuse and ran as expected (the actual ground wires from the quad spark are grounded to the chassis), the tune needs work obviously but I did not hear any misfiring. Can the quad spark body not be mounted to the chassis?
hybrid
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Re: new setup melted coils

Post by hybrid »

Maybe one (or more) of the transistors is shorted to the body of the quadspark?
Depending whether they are VB921's or BIP's, they may need a mica insulator behind them.
Do not load someone elses tune and expect it to work for you!
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Kmsgli
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Re: new setup melted coils

Post by Kmsgli »

hybrid wrote:Maybe one (or more) of the transistors is shorted to the body of the quadspark?
Depending whether they are VB921's or BIP's, they may need a mica insulator behind them.
Was exactly my thought. I will replicate the the circumstances again today to be sure. I will try to click the key on and see if it shorts the coil fuse with the quad spark mounted, then try to run the car with the quad spark not mounted.
Matt Cramer
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Re: new setup melted coils

Post by Matt Cramer »

Check the spark outputs for continuity to the heat sink; there should be 1000 ohms or more. If only one channel has the issue, you can use the unused channel as a substitute.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Kmsgli
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Re: new setup melted coils

Post by Kmsgli »

Matt Cramer wrote:Check the spark outputs for continuity to the heat sink; there should be 1000 ohms or more. If only one channel has the issue, you can use the unused channel as a substitute.

2 of the 3 channels have continuity to the heat sink. Those two channels ohm out to about 1.8 ohms. The third channel I am using does not register a reading for resistance and has no continuity to the heat sink.
Kmsgli
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Re: new setup melted coils

Post by Kmsgli »

Follow up for anyone reading this for future reference. Quadspark was bad and the guys at DIY Auto were nice enough to send me a new unit and the car is running and driving well now. Thanks for all your help Matt you guys at DIY are really the best.
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