I have a ford 302 in my blazer now , and I'm trying to get power into the truck for lights ext. I routed the red coil wire to the positive on the battery and I have power with the key on only , no head lights or nothing when the key is off . I'm not sure what I'm missing all the grounds are grounded , the only thing I can think of is the other wire beside the red wire in the old coil harness needs to either be grounded or ran to the positive . I think the wire is gray or brown , beleive it or not my dogs ate my s10 repair manuel , so thanks for any help you could offer .

 

Okay...to start with, what you are missing is any concept of how automotive wiring works.
There are three wires to battery + in almost all modern systems:
1. To starter for cranking, only
2. to alternator for charging, only
3. system power, directly to main fuse block.

ALL engaging and running power comes from that 3rd wire, no exceptions. Although.. it MIGHT help if we had some idea what generation, if not specific year we are talking about.


You have power with the key on because the coil is always powered. You hooked it straight to the battery, thus everything is feeding backward through the ignition switch to the fuse blocks. Obviously, you havent had the engine running yet because the only way to shut it off is either disconnect that red wire {which connection will end up with you burning up the coil, btw.} or kill the engine by dumping the clutch, etc.

What happened to the wire from the battery + to the main fuse block and power distribution center?

First rule in engine swaps: Never remove from vehicle any wiring connected to constant power or frame.
Second rule: Never remove any wiring connected to the original coil, starter or alternator. Those are the main system power wires.
Third rule: Never remove any OTHER wiring not directly connected to the original engine. The original battery cable and all attached should have been there.
I just made those rules up, but they are true.

What idiot stripped it out? Lemme guess, the dog ate it.

 

The vehicle is a 94 s10 blazer , All the original wires are still in the vehicle and I just took the wires off the starter when I put the new high torque mini starter in . The only wires coming from positive go to the starter and one to the alternator . The 3rd wire is the one I can't find but it has to be there I must be just missing it . So I guess I did not break any of your rules . And I'm the idiot that took it out and if you don't have good words to share please don't . I can do with out your help I will figure it out by myself eventully , But thanks now I know what I'm missing .

 

Find the main fuse block look close for main wiring terminal. May be on underside Run a heavy wire to it.. at least same size as to alternator.

 

Fords use a fenderwell mounted starter solenoid. GM uses a solenoid mounted to the starter. You need to add a fenderwell solenoid and rewire your battery cables on your Blazer to match that of the Ford the engine came out of. Then source your power (reroute the smaller gauge wires that went to the starter on the GM engine) from the fenderwell solenoid.

 

Thanks alot guys for helping me out with this , wiring has always been my down fall . The starter is aftermarket and hooks up just like the stock s10 one did , and the distributor is all chevy parts with the shaft machined to fit into a ford block . I'm going to go out today and find the alternator wires , I completely forgot about the wires that went to the alternator from the s10 harness . This truck is far from being complete though just trying to figure a few things out .

 

Good points. Ford shifted to the delco-remy style in the 90's but a 302 would have the field energized Bendix actuator

Deppending on the ignition system, you need a resistor in the igniton wire from ign sw to coil + and a bypass for more spark while starting, .. why there is a second small post on the starter sol {actually a heavy relay} he points out.

Here is a write-up on the Duraspark II system from late 70 through early 80's.
Note it shows upgrade to MSD and how to wire it.
Duraspark II

Note the duraspark drawing shows second sw in ign sw.

That is really a wire from the fenderwell starter sol SECOND small terminal to coil +

Which makes everything I wrote above pointkess escept for anyone else looking to do a similar swap.

Of course you still have to find out what happened to the wire from Batt + to fuse block.