Ok so i have a lt8 in my 88 2nd gen. It has been running great so far. Well the other day i decided to put a new e fan in. So as i was wiring up the relay for the fan one of wires on the bottom of the relay fell off and it hit the side of the cas, and made a big spark. So i grabbed the wire and pulled it up but on the way it also hit the strut bar and made a huge spark. (ya i know disconnect the battery). Well any ways hooked everything back up and now i have no spark to any of the spark plugs. Any ideas guys? The micro still turns on and everything seems well there. Could i have fried the cas or the coils how can i check? Thanks guys.

 

Which wire fell?

There are check procedures in the FSM to check the resistances of the CAS reluctors. Though if the wire just brushed the CAS body it's not likely they are damaged.

 

not sure which wire it was. All i know is that it is one from the e fan relay with power to it. Ya i checked the resistance also it came back good. could it be something else? Could something be wrong with the ecu even though it turns on?

 

its an lt8.
so your still using factory spark plugs.

their are three things that can cause no spark.
the cas not giving a signal or
no power to the ignitors and coil packs or microtech not triggering.


To check to make sure Crank angle sensor is giving a signal to microtech, on crank check for an orange light on the microtech flashing WHILE CRANKING.

Next if that light is working.
Check the ENGINE fuse in the fuse box as this powers the coil packs. Get a test light and check for 12v at the coil packs.

Triggering of the ignitors by the microtechs is alittle more complicated so try the above 2 first and see how we go.

 

Is it possible that the +12V wire hit the aux output directly on the Microtech?

I don't know how that output is switched internally but if it's just an open collector then connecting it directly to 12V would be very bad. The transistor would fry, possibly damaging other components as well on the board.

 

Aaron i don't think it hit it directly. But if it did fry anything like that could i check to see? And if that happened would the micro still turn on?
And yes when i crank it i am getting the yellow light pulsing on the micro just no spark.
Hey is it possible for the ohms on the coils to check out good and the igniters be bad?

 

It would be very unusual for the ignitors to be bad on all the coils. They are pretty robust.

You can test the coil easily though. Give it 12V at the tan wire, and ground the base of the ignitor. Now get two AA batteries and put them in series. Ground the negative to the ignitor. Now tap the pink wire of the ignitor with the + of the battery. Everytime you do this, the coil will spark. This test is for the leading. Trailing is more complicated.

To me, it sounds like the Microtech has been fried. If you have a scope, scope the trigger outputs and look for a square wave while cranking.

Oh, you can also put it into test mode which will fire ignition and injectors but keep the fuel pump off. Instructions are in the manual (switch to zero cylinder or something like that...).

 

So even if the micro still turns on, it could still be fried huh? Does microtech repair these or no? Can i open it and see if something is fried? Thanks Aaron

 

You can open it. or you can send it back.
microtech can repair it. only problem is their in australia and it sometimes can take a few weeks.

Did you check if the tan wire on the ignitors are getting 12v?

 

ya both the coils are getting 12 volts.

 

So can the micro still be fried even if it still turns on?

 

Yes.