driftin8ez

Ok so ever since i got my car maybe 8 months ago and i was n/a it seemed to run very rich and the plugs would be carbon chunks in only a few thousand miles. Also my n/a was very slow to rev but i just thought it was low on compression or whatever. Now that i've done my tii swap the car still runs very rich at idle. So i went ahead and installed an msd cdi box. Hopefully to help the situation. Well car still runs rich and it all makes sense to me. My leading coil is not firing at all. Im going to say it probably isn't the cas unless both motors had bad ones. So what could it be. If i uplug both leading plug wires there is no sparking and better yet the car runs and revs exactly the same as it always has. How can i test the leading coil? i already tested the resistance between both terminals. They tested out. What about the ignitor?

91verty

this is a very good question. I thought you could not run on only trailing coils? I mean i was under the impression that trails were to just burn fuel left from the leads? But you must remember that every t2 runs rich. And thats a good thing. I would say if your car is running the same only on trails that it is most likely your CAS. But thats just weird that your car would even boost or pull hard on just trail coils. Hummmmmmm.....

RotaryEvolution

iTrader: (30)

carbon chunks are either gasoline deposits from dirty fuels or oil burning off. even if you replace the plugs there is still no change? test the leading coil for spark by putting a new plug in the plug wires and lay it on a good engine ground and crank the engine over while keeping an eye on the plug.

driftin8ez

i have a new plug but it is a trailing plug. the leading coil should be able to fire it right? If so than ya no spark at all. Also you think 2 bad cas's on 2 diff. motors? The inside of my cas looks brand new. no bend fins or rust or anything. also if you remove the plug wire from the leading coil there are no sparks even if you hold it very close to the coil. the trailing on the other hand.... ouch!

Icemark

I am rather skeptical.

You would probably blow a motor pretty quick that was running only on the trailing plugs unless the timing was way way advanced.

You do know the trailing plugs are the ones on the rear coils and are the plugs at the top of the motor.

RotaryEvolution

iTrader: (30)

the coil likely fried from the n/a motor burning oil, carbon on plugs can kill the coils since it can prevent the plug from firing which is hard on the coils. it is doubtful you have 2 bad CAS' with only the leading sensor dead.

driftin8ez

here is my new idea. Maybe it was working fine before but it is def. messed up now. Will an msd 6al box work without one of the rev limit chips in it?

TitosToy

agreed. which spark plug locations are you talking about? front and rear top ones are trailing and the bottom ones are leading

driftin8ez

The ones that are not firing are the lower plugs connected to the coil right next to the battery. The leading plugs. I just did a primitive test to confirm things. I connected a brand new spark plug to one of the leading wires and rested it on the fender. Started the car. Ran completely normal and the plug did not spark at all. No matter what ground i touched with the plug. Turned the car off took out a traling or top plug wire connected the same new plug put it in the same location. Started the car. It ran like i was doing a water treatment or just like i was on one rotor. Which it was. The plug was sparking so much i was afraid to even touch it or leave the car running. Secong test... completely disconnected both leading plug wires and the car ran exactly how it always does and there was no arching. Also reconnected the coil to stock by passing the msd before i did any of these test. So im guessing my ignitor is fried. Can i hook up the msd to somewhere before the ignitor to give the msd the signal to fire or is the msd a spark amplifier? Using the ignitor's spark but just making it stronger. I'll attach a link to the write-up i followed to the T when i stalling my msd to see if i can hook it up anouther way to bypass the ignitor. Also can i use an s4 leading coil pack? There is one at a local yard it can pull.

driftin8ez

oops forgot the link...
http://fc3spro.com/TECH/HOWTO/CDI/cdi.html

driftin8ez

ok so i just back in. Tested the white connector at the coil pack. It gets voltage with the power on. I tested the cas and the resistances are up to spec. I also tested the resistance of the coils. I dont have an ignitor tester but im pretty sure thats where the problem lies. I cant believe that all those posts i made months ago about my n/a motor having no power at all is becouse of a blown leading coil. I cant wait until it is actually running on all plugs.

NZConvertible

Running on the trailing plugs does no damage, but the spark is weak and retarded compared to running on the leading plugs. The engine runs perfectly smooth, it's just significantly down on power. I know this because I forgot to reconnect the leading coil once and drove half way to work wondering why I had so little power but no symptoms of a plumbing leak or engine damage...

driftin8ez

ya, NZConvertible that is why my N/A never seemed to have any power no matter what i did. So im kind of excited to finally have my leading coils firing. My 13bt set-up is real quick now, i wonder how it will be after the coil fix.

tougeFB

I ran on only leading in my first gen.
It ran pretty shitty.
I couldn't imagine running on only trailing.
Doesn't seem like you would get anywhere, and you would have terrible gas milege because of it.
Am I wrong?

NZConvertible

Leading and trailing work totally differently, with the leading doing the bulk of the work. You will barely notice any difference if you run on leading only, unless something else was wrong as well. You will definitely notice if the leading isn't firing, as I described above.

fstrnyou

if it's a stock 13BT, it's not real quick. although, relatively quicker than your equally crappy running NA. the way i see it, your car now is how fast your NA should have been. good luck. i hope you found the problem. and enjoy the ride.

driftin8ez

Fixed my car runs great now. Weeeeeeeeee.