Itsallgood995

Thinking of adapting a mercury ignition off a 95 baja 7.4 (330hp) to my my set up. I have the OMC EEM ignition which limits my RPMs to 4750 & has a knock sensor. Just want to confirm the mercury ignition also has the knock sensor & no rev limiter. With my 502HO cam I believe I should be aiming for closer to 5200rpms if not a little more.

Itsallgood995

After searching the archives it looks like this is a TB V (92-96) ignition with knock sensor & rev limiter of 5250-5350 which should work for my application.

ballon78

i went through this all last year.....TB V Modual from a 7.4 330hp has a 4750 rev limiter, TB V modual from a 7.4 MAG 385hp has a 5250 rev limiter. It will work on the 502 as this is what i did but the problem with it is that you MUST set base timing to 8degrees whe u ground the purple wire hanging off harness. then the ecm takes over the ignition timing with the knock sensor. you must also run the merc harnes that has the hook up for the knock modual and sensor and ecm.

I hated the TBV its great for stock power, but i went with a D.U.I ignition, one wire hook up, and twice the voltage.

Itsallgood995

Bummer, so I would have to get the mag module for the higher Rev limiter. I actually want the knock sensor, seems like a good safety precaution. Is there a disadvantage I’m not seeing? Does it limit the max timing? I have the vortec heads which I undersatand don't need a lot of timing.

I do have the wire harness, distributer, coil & module so the only thing left is too splice or adapt it to my existing harness.

ballon78

it shouldnt be two harnesses, i have the harness that came on my motor is u want i will sell it. its a tbV from a 98 330 gen6 L29 with vortec head harness, and i also have knock sensor, just took harness off a few days ago and knock sensor. whats the modual you have have for part number....they made two, the new ones i think have didfferent harness, i jus sold all my moduals, they go for big money on ebay.....300-400 bucks

Itsallgood995

I was assuming the harness from my dash was different & would need to be spliced into the mercury harness. After taking a closer look they are both a 10 pin connecter & should plug & play.

One module says 806959-1 7.4L Bravo drive, another says AZCA 888749 & then there is a Blue “Mercathode” with 300A3 & 0405 numbers on it. How much do you want for your harness? I’m not sure if this 95 gen V harness would be different then your gen 6. Does your knock sensor mount on the head or block? My current OMC knock sensor is mounted on the head. The guy I got this harness from seemed to think his knock sensor was mounted in one of the freeze plugs.

Itsallgood995

Wow! You weren’t kidding about those modules. The local dealer wanted $505.00.

It’s a great ignition used on the mags, HP500, 500 Bulldogs & some of the 525sc’s but its cost prohibitive. I’m seeing your point on the DUI ignition.

ballon78

DUI and be done!!!

ballon78

http://www.performancedistributors.com/marinedui.htm