Mallory 685 doesn't work with lt1 pcm
 

I have been having trouble getting my car to fire up while the mallory 685 box is connected. If I use the by-pass it fires right up. This is the second box in two weeks, and I have went over the wiring several times. I called Mallory and the tech line rep told me that the mallory box was not compatible with the LT1 pcm. WTF!!!!! Someone please help. I know there are guys using the box. Why won't mine start?:bang:

Would help if you told us how it's wired. Did you just put it between the ICM and the coil like a MSD? Do you have a link to the Mallory's specs and wiring?

Al 95 Z28 w/ MSD 6AL

it worked on mine and lots of others. the tech line guy is a retard.

works fine on my car.


only thing i noticed was instead of firing right as soon as i turn it over, it takes a second. idk if it's because of the start retard function or what

Do you have it wired to a source that is hot even when cranking.?

I have heard of many people using the mallory 685 on a LT1 car. Not sure if you just got a flaky tech or what. It could just be a simple wiring issue that it causing it not to work properly.

Yes. The constant is wired staight to the battery. I used the MSD harness to "simplify" the install. I did notice that from the factory, the black and red wire (marked A and B on the connector) were backwards. Do I need to change my connection of the positive wire?

I used the msd wiring harness.
black to black
red to red
green to white
orange to yellow

Well, I took a test light and checked each wire coming from the box to the wiring harness, each wire is hooked up correctly. Again, I connected the by pass harness and the car fired right up. WTF!!!. I just got off the phone with summit and they are going to send out box #3. The sales rep apologized and stated "we'll get it right this time". I surely hope so.

On another note, I took the car out and sprayed 50 down the tube....for those who say you can't feel or tell the difference with such a small shot is full of $h!t. It was by no means a rocket car, but it definately added a power you can feel. I sprayed from 65 to 120 and then from a dead stop. I can't wait to get that 150 shot going.