Continuously blowing transistors

[obsidian]

I did search and didn't find much info.

So I have a 90 Talon TSi AWD.

I was having clutch issues and a bad oil leak. I drive to my buddies garage and pull the engine and clutch and do a lot of really good work. While doing this, the car has some hack job wiring. My buddy and I correct them as we find them.

So then I go to start the car after about 2 weeks. No spark on 4 and 1. Bad transistor. WTF, car didn't move and it DROVE to the garage. Whatever. I buy another one and the car runs great. Then I let it sit for another week and came back to it today. Guess what. Another blown transistor. Luckily I got a lifetime warranty but what should I be on the lookout for to keep blowing my transistor? This is driving my bonkers and it's making me a bit depressed.

Help me out Tuners!

I could really use some insight here. Anyone have any?

 

[DSM1G90]

have you done anything to check out the coil .. try another coil and see what happens ...

 

[obsidian]

I have a spare coil pack set with the exact same symptoms.

Last time this happened I swapped coils with no change. I replaced the transistor and everything ran great. Did not touch ANYTHING. Turned off car and walked away after letting it run for about 30 minutes at idle to check for leaks and make sure everything looked/sounded good. Came back 1 week later and boom, no spark to 1-4 again.

Maybe this coil pack is blowing it and I should just leave my spare one in to see if that one will blow the transistor.

 

[92AWDHX40]

I would fix that problem before i keep blowing transistors, maybe a bad wire somewhere, we have old cars anything can cause electrial problems. Possible a bad ground, or short, or even a bad wire. I rewired my car from front to back all kinds of learning lessons. Headache.

 

[obsidian]

Well I don't know what is causing the transistor to keep blowing. The affect of the bad transistor is I'm not getting spark on all four. I need to find out why I'm blowing the transistors so I don't keep replacing them. I've searched and this has happened before but the best thread I found is 7 years old.

Things I changed when I did the wiring fix is....

1. Grounded noise filter to intake manifold. Before it was just hanging there. Worked fine before.
2. Removed ghetto connectors on thermostat housing sensors and o2 sensor wiring. Butt connected and heat shrinked wires before sealing them.
3. Ran new ground wire from trans to chassis.
4. Removed inline fuse for the headlights on bottom of engine bay fuse panel.

I've read that a bad ECU could cause this. I've read grounds also but I'm not so sure. I've got a few grounds but I can always add more. The noise filter is grounded on the manifold where it has a ground wire to the chassis also.

This is really driving me frickin crazy. I gotta fix this so I don't keep blowing transistors and having to wait 1 week for a new one to come in. Glad I got that lifetime warranty.

http://www.dsmtuners.com/forums/newbie-forum/47008-1g-ecu-caps.html

This is one thread I've been reading a lot.

So, my ECU is hacked in and I have it on the list to be professionally wired (my friend and I are pretty damn good mechanics and he's a damn good electrician) but as of now, it's still hacked. The thing is, I drove it to the garage and it was fine and now after all of that work, it's bad.

This is really irritating me.

 

[DSM1G90]

True, might have a ground trace in the ECU itself that has opened up, or a driver on the momboard has shorted across that could be knocking out the power transistor with too much voltage on the I/O side of the transistor...

 

[luv2rallye]

1. Grounded noise filter to intake manifold. Before it was just hanging there. Worked fine before.

I hope you mean you bolted the noise filter casing to the intake manifold - not connected a wire from it's wire to ground (because that wire is +12v).

Sounds like you have a short between coil and PT. Check wiring and connectors. With battery neg disconnected you can also test resistance from there to ground.

 

[obsidian]

Yes the casing. I'll have to check for continuity between the wires I suppose. These things are never ending it seems.

 

[luv2rallye]

It's rare but occasionally the noise filter cap can also have an intermittent short with full alt voltage on it. You can try it with and without it for testing to see. Engine will run fine with/without it - it's mainly to reduce ignition noise for the radio.

 

[obsidian]

Well I did your test to see if the transistor was dead for coil 1-4 and it showed good.

I also bought a new coilpack for $90 and it's still not firing.

Things to check further. Rats nest of wiring P.O. left for the EPROM ECU.
CAS wiring
CPS

 

[luv2rallye]

Do you have the PT bolted against the head? On a 2g it needs to be for heat transfer (as well as a better ground connection for the heavy current), 1g is probably the same. If not bolted down it may be burning itself up.

 

[obsidian]

I bolt them down every time I try to fire it up. I figured it was it's own ground so I always do it.

 

[obsidian]

Well I got it fixed. Turned out I wasn't blowing transistors but it was just giving that symptom.

It was the crank angle sensor wiring plug. Somehow it is magically messing up. I replaced the ignition coil and the transisitor twice.

So if you're not having spark on 1-4 plugs, check your plugs 3 times so you don't have to spend money you don't need to.

 

[ed1380]

Bad crank or cam sensor will cause only one coilpack to fire