Thunderbolt V swap to Tunderbolt IV
 

I am trying too swap out my TB V iginiton modules for TB IV modules. The reason is too get around the Rev limiter at 5300 rpm. Has this been done and can someone tell me how too do it.

Thanks James

Re: Thunderbolt V swap to Tunderbolt IV
 

Not familar with the T-bolt V, so not sure if this is of any help

http://www.mercruiserparts.com/Show_...L+AND+IGNITION
Item 7a is what I used to eliminate my rev limiter when running my blower motor.



Item 43 is what was stock, utilizzing the rev control: http://www.mercruiserparts.com/Show_...2%2DF213244%29

Re: Thunderbolt V swap to Tunderbolt IV
 

Here is what I have, Number 15 & 20, one is a Spark module and the other is a Ignition module, which one has the Rev-limiter in it and where do I wire in the TB IV module?

Thanks again for all the help, cant aford MSD yet, trying too get by this year.

James
http://www.mercruiserparts.com/Show_...CAL+COMPONENTS

Re: Thunderbolt V swap to Tunderbolt IV
 

The rev limiter is in the ignition module.


Here's how I would do it.

Buy the 7a harness, and the module,
the harness connects up to the coil,
distributor, and module.

Disconnect the existing two wires
from the distributor, tape up, seal,
insulate,....you get the point.

Unplug the TBV module, seal, secure that plug.
( You've now done away with all inputs/outputs
to/from the TBV module)

Unplug the harness forn the knock control
module, secure, seal, etc.

Connect up the purple wire out of harness
7a to + coil.

Connect up the gray wire out of harness 7a
to - coil.

Out of harness 7a, connect up the two wires to
the distributor,( white/red, and white/green)
the distributor should be marked for which wire
goes where ( color)

Harness 7a also has a ground wire, connect to
a good ground.

Mount TBIV module, plug in, you should be in business.

( You now no longer have a rev limiter, or knock
control :eek: )

Doing it this way, you don't butcher up the harness,
and you can put it back to original very easily.

Hope this helps.

Re: Thunderbolt V swap to Tunderbolt IV
 

Thanks, that is great!!

What do I do with the "Spark Module" leave it plugged in or not? That is part # 20 in the pic.

James

Re: Thunderbolt V swap to Tunderbolt IV
 

I'm calling that the TBV module, a.k.a.
the spark module........unplug it.

Re: Thunderbolt V swap to Tunderbolt IV
 

what feeds power to the coil??

Re: Thunderbolt V swap to Tunderbolt IV
 

I am a little confused, what is part #15 then? It has two pin style connectors. In the diagram they are calling that the ignition module. I had one of these go out last year and had no spark to the plugs.

James

Re: Thunderbolt V swap to Tunderbolt IV
 

This is what I have in the boat marked A & B, both of them have a purple wire coming out of them, and they OHM out at the Coil positive terminal. The #A module has the grey, negative to coil and white/green and white/red wires that go too the distributor.

There are two pin connections on #A the small connector has only one wire coming out purple.

Still stumped???? :rolleyes:

Re: Thunderbolt V swap to Tunderbolt IV
 

Did you find the V8 Modules???

Re: Thunderbolt V swap to Tunderbolt IV
 

Yes, that is in the picture marked Thunderbolt IV, I found one for right now, for free to test with. Will buy another if can use them. Just need too know how to wire up.

If you disconect both modules and the wires off the coil, you wont get any power to the coil.

Re: Thunderbolt V swap to Tunderbolt IV
 

The positive voltage ( purple wire)doesn't go through
the module,( to the coil) it juctions in the harness,
another purple wire supplies voltage to the coil.

I'm out of the office for a while, I'm going to sneak
home and get a TBV schematic, I can fax you the schematic,
with the mod's.

PM me a fax # I can send it to.........it will be later
this afternoon before I'm able to shoot it to you.

I've even connected up MSD's to TBV without chopping
up the harness.

The schematic should clear things up

jt.

Re: Thunderbolt V swap to Tunderbolt IV
 

JT, thank you so much for your time. I was able too talk with a merc rep in Richmond and he cleared things up perfect. Just what you said. Both of the modules I have, are to be disconnected. I leave the purple & grey wires on the coil for power and ground wire and make connections to distrubutor and should run. Be sure to recheck timing.

James

Will let you know if it helps any.

Re: Thunderbolt V swap to Tunderbolt IV
 

While you are at it relocate the module from the exhaust manifold to a bracket on the transom. Makes no sense to connect an electrical part to a hot and vibrating component. I think there is a joke in there somewhere?

Re: Thunderbolt V swap to Tunderbolt IV
 

I think his are HP500's, they mount those modules
in the R/H rear of the cyl. head, surrounded by circuit
breakers, start solenoid, the 8 pin plug harness,
just in front of the oil cooler.

They are veeeerrrry difficult to get at.

If your able to get the mounting
screws back in without dropping
one of them.....you're a God :D

James,
let me know if I can be of any more assistance.