chree

The short version is I installed a new Holley Annihilator ignition box with custom harness for the LT1 and the car won't start.

• Low mile '94 LT1, stock with headers, in a '86 Volvo 740 Wagon with Dr. K wiring harness
• Installing an ignition to help MPG hopefully
• Yes, I should have bought MSD, but $75 < $237; also I've used a similar Holley box for years on my El Camino
• Simple installation, two plugs (puts the ignition box wiring between the coil and the factory harness) red power & black ground
• I also installed a new coil that came with the Holley box, it is supposed to be a capacative discharge specific coil
• The car runs when I switch the harness back to stock
• The car runs better with the new coil, maybe it will fry my ignition module?

Holley's instructions say if no spark:

• Check connection to coil (ok)
• Defective Coil (no since the car runs fine with it wired in stock mode)
• Coil ground defective or poor (isn't the coil on an LT1 grounded through the housing?)
• Poor spark plug grounds (again, car runs fine in stock mode)
• Low voltage during cranking (?)
• Defective ignition box

Any help appreciated.

chree

If you run a MSD box with the plug and play harness, is the ingition module still used? Do those go out often?... they are $80! (guess I'm used to the old skool 4-pin HEI modules ~$20).

I want to put together a box of spares for long trips... I was hoping the ignition box took the place of the module, like it does on my El Camino with HEI.

95zpro

Yes the ignition module is still used; hit their website I think they should have some instructions on how it's hooked up. If I was home I would look it up for you...

dhdenney

iTrader: (53)

Those grounds are the wires next to the coil and should have hoops on them. I always grounded them on the coil bracket stud.

chree

The instructions for the box / LT1 harness are here .

Good news. The ignition boxes pass the spark test. If you power the ignition red wire and tap the white wire to ground you get sparks from a spark plug wired to the coil. Ignition boxes you say? I bought another unit to see if the first box was bad. This second unit also has a more universal harness so I can easily run the test.

So it has to be the harness. I'll reference the harness wires from the ignition box to avoid confusion (they match MSD colors)- the wire colors change on the engine side. With the ignition on I get 11.84V on white wire but no voltage on the red wire. I get 6V on the brown tach wire and the heavy red and black are 12V/ground.

dhdenney

iTrader: (53)

I have a similar problem with my MSD. Tests with the voltmeter show good on the harness and box so I sent it back to MSD for diagnosis and repair. Can you get another harness pretty easily?

chree

No, but the second box has a more generic harness. I'll probably use test leads with that harness to make sure it works, then I'll cut into the LT1 harness.

chree

Would you believe the female pigtail that plugged into the factory coil pigtail was wired backwards? This was a new harness made by Holley specifically for LT1 applications. I traced where each wire went by testing for resistance with my multimeter.

• The ignition-on power wire: red on the box, red coming out of the harness, should connect to the pink on the OE harness.
• The trigger wire: white on the box (separate from the weatherpack connector), black coming out of the harness, should connect to the white trigger wire on the OE harness.

I had to cut the harness cover off and cut/solder/shrink wrap the correct connections. The car fires right up and I noticed improved throttle tip-in and the engine seems smoother.

I will say Woody at Holley tech was helpful to confirm the "tap the white wire to ground" test would work on the Holley box.

The scientific method works!

dhdenney

iTrader: (53)

Cool man so it works? I'm not so lucky. MSD called and said my box was ****.

chree

Yes I am happy now... and I have a spare box. Then after that I can plug it back like stock. Now I need to swap out my Opti (have an MSD waiting, the Opti may be the original ). I also need to get a spare module. I basically want a spare of all the easily replaceable parts in case of an emergency.

I thought no matter what was wrong with an MSD the max you would have to pay was ~$65 for them to rebuild it like new?

i420tom

iTrader: (11)

i had a similar problem.

Some how i screwed up the wiring. I guess the wiring diagram could have been a little more clear but anyhow this is what i did.

i had the trigger input and the trigger output wires reveresed on my setup. The spark test on the box passed by grounding the trigger wire. car would not start with box but all passed all tests except for starting the car. Ended up being an easy fix but i had to tear apart my beautiful harness that i had spent a few hours on. it took a few hour becasue it is a DIS-4 plus box with a delteq setup. 19 connections i had to make with this box. had to redo 8 connections. trigger input 1-4 trigger output 1-4