Burned up 3 coil packs in 1 day!!!

[rich3389]

I recently put in a eprom ecu with a stage 3 chip in my car, I switched the spark plug wires as your supposed to, 1 and 2, and 3 and 4.
A week later, My car kept bucking and running on 2 cylinders after i drive for a while, I went though 3 coil packs in 1 day, they get so hot they start smoking and it only runs on 2 cylinders after about 30 minutes of driving.
Why is my car burning up coil packs???

 

[silver bullit]

You may have a short have you checked your wiring and who made the chip?

 

[rich3389]

The chip is from dsmchips, I am unsure if it is related or not, I put in the stock ecu after it was running on 2 cylinders, it didn't change anything, and no cel's either.

 

[silver bullit]

Is the ecu in need of rebuilt are the caps leaking? Have you checked the wiring to see if it was messed up?

 

[rich3389]

I opened up the ecu, I didn't see anything abnormal, no leaky caps or funny smells, although I do hear a high pitched noise from the ecu when it is on.
Can a ecu even burn up coils packs like this?
The "new" ecu was in the car for 1 week and I had no problems, until today when I went threw 3 coil packs, they get so hot and actually start melting and smoking.

 

[silver bullit]

May be a de-fault in the ecu chip contact the people you bought it from.

 

[toybreaker]

To avoid some confusion, could you walk us thru the timeline again?

You installed a chip, and swapped the firing order of the plugs.

The car ran fine for a day or two ( ? ? )

Then, out of the blue, with no other work performed it started smoking coils?

^^^please verify^^^

That's definately a new one.

Some more information would help us get to the bottom of this.

Are these factory coils, and are they 1g or 2g coils.

Do both coils smoke, or is it only one of them. (please specify)

Does it run right when you install a new coil pack?

Does the tach work?

Are there any hacks/bodges in the wiring harness?
I see you have some aftermarket electronics installed. Have you changed anything there recently?

Does your safc read rpm correctly?

My gut feeling is that there's a wiring harness issue, and it's just coincidental that it happened shortly after installin a new chip.

If the aftermarket stuff is tapped in around the ecu, just removing and replacing the ecu could have pulled some wires apart, or let some floaters (strands of wires not caught in the butt connectors/wire nuts etc) touch each other or ground. It's as good a place to start as any. Check everything in the area, but especially the wires that run over to the safc.


Why did you have to swap wires?

Is this a different ecu?

Another possibility is a problem in the engine compartment.

Is this a six bolt swap? (your profile doesn't say)

Where is the ignition transistor?

I can see how a problem with the transistor, or it's wiring harness could cause this type of problem.

Give it a thorough visual inspection (or check it electrically if you have the tools (there's a vfac)) You're looking for traumatised wires, or a melted transistor body, or something visibally wrong.

Other than that, you're going to have to use logic, a wiring diagram, an ohmeter, and some patience to get to the bottom of this.

One thing to be very aware of is that the wiring harness over to the coils is probably getting pissed by all the current it's been carrying. It takes some current to smoke coils, and that harness was not designed for a continuous high current load. The coils only see juice for a very short period of time, and then the ground is turned off to fire them. If something somewhere is applying ground to them 24/7, there may very well be collateral damage. (Look for melted connectors on every part of the ignition circuit)

Hopefully, Luv2Rallye or one of the other 2g experts will see this and chime in,
( I don't really do much 2g stuff. )

edit Can you swap in a known good ecu, or at least your old chip? It may be there was a glitch in the chip, or one of the pins got folded under or something really weird. I always go back to the last change when troubleshooting something like this.

Good luck, and keep us posted on what you are doing, and what it takes to fix this. I'm curious!

 

[rich3389]

Timeline...
Got a the dsm chip, ran very strong and everything is well for exactly 1 week.
7 days later, the tach starts jumping all over along with the car cutting out on mild acceleration, not in boost but accelerating.
I changed out the coil pack with a 1g one and then it would misfire constantly is boost, like a machine gun(also blew the ignition fuse), so then I put in a known good 1g coil pack, ran great for about 30 minutes of driving, start cutting out, tach jumping. I pulled into arby's and called my buddy, put in my old ecu and that did not change a thing(hell the coil was already fried!). I was forced to drive it home on 2 cylinders a few miles, after climbing a hill, i smelt burning plastic, I pulled over to see my coil pack was smoking. I let it cool down and limped it all the way home(my car is to low to fit on a trailer).

 

[rich3389]

Update..
I put the coil pack that would misfire under full boost back in, and changed the power transistor, I drove for a few miles, it did not misfire under full boost like the coil previously did. I will see if it starts acting up again once i start driving it to work tomorrow.

 

[rich3389]

Update, Just got another ecu today, put it in the car, went to fire it up, and bam blew ignition fuse, I cant even get the car started now I went threw 5 fuses trying to start my car. I put in the old ecu and it still blew the fuse...I am getting at the end of my fuse....

 

[rich3389]

Checked the wiring from the power transistor to the coil, it only blows one coil when it goes. It seems that the power wire for the coil that melts is a blue one with a white stripe, I checked that one and it is not grounding out.
It only blows the ignition fuse when I try to start the car with the already blow coil pack still plugged in, when I get a working coil pack in, it wont blow the fuse, until that coil burns up.

 

[luv2rallye]

An ECU eprom chip cannot blow a coil no matter what state it's in. You've got a short somewhere. The fact that the failing coil is always on the blue/white wire is a clue. There is no stock blue/white wire on the coil (or on the PT) but there is a blue/red on the coil so I'm assuming the red stripe faded to look like a white. This wire actually goes to the 1 pin "engine speed detection connector" on the firewall and then changes into a black/white wire from there to the PT pin 8. If this wire or connector was touching ground you would have the symptoms you see so examine it carefully. Another possibility is 2 wires in either the coil or PT connector may be intermittently shorting to each other.

 

[rich3389]

An ECU eprom chip cannot blow a coil no matter what state it's in. You've got a short somewhere. The fact that the failing coil is always on the blue/white wire is a clue. There is no stock blue/white wire on the coil (or on the PT) but there is a blue/red on the coil so I'm assuming the red stripe faded to look like a white. This wire actually goes to the 1 pin "engine speed detection connector" on the firewall and then changes into a black/white wire from there to the PT pin 8. If this wire or connector was touching ground you would have the symptoms you see so examine it carefully. Another possibility is 2 wires in either the coil or PT connector may be intermittently shorting to each other.

This is very helpfull considering that my tach starts to jump when the problem starts, then once the coil is blown, the tach seems to read only half of the actual rpm. So you are saying the short is most likely between the power transistor and the coil?

 

[luv2rallye]

Yes. Follow that blue/white (actually blue/red) all the way (literally every inch) from the coil to the PT as I mentioned to look for problems. Remember it becomes black/white at the engine speed detection connector and on to the PT. It may be shorting somewhere in there (unravel the harness to see every inch) if you can't find the short at the ends. The short may be between that wire and ground or to another wire.

The PT provides the tach signal as the "OR" of the two coil signals. So if one is grounded you will only get 1/2 reading.

Also remember the PT is ON most of the cycle which connects that coil wire to ground to complete the circuit to energize the coil. It's when the PT turns off (makes an open circuit there) that the coil fires (coil's magnetic field collapses to induce high voltage). This OFF time is so short (ms) that you can only see it with a scope (although a noid light connected across the coil will dim slightly which is what many mechanics use).

 

[rich3389]

I searched for shorts, did not find any, I got another coil pack and got some new wires on there, I'll see how it goes.

 

[luv2rallye]

Be careful - if there's a short you may just burn up every new coil you use.
Is there some reason you're using 1g coils in a 2g? There may be incompatibility.

 

[rich3389]

I am using 1g coils over 2g only because 1g coil packs are easily found in junkyards and are cheap/free.
They are the same as long as it is not from a 90.

 

[luv2rallye]

... 1g coil packs ... are the same as long as it is not from a 90.

Not exactly. Only their pinout is the same. They have different resistance (and inductance and impedance) on both their primary and secondary. I don't think this is your problem however unless your stage 3 chip is designed only for a 2g coil (eg. pulse width). But even then it wouldn't damage the coil, only decrease performance and/or efficiency. Of course if you're running a 2g MSD ignition system with a 1g coil that may (or may not) be a totally different story (eg. like it using an input voltage of 400V instead of 12V).