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I switched over to a Chevy style distributor and now only need 1 hot wire when key is turned on. My question is can I take these two wires tie them together for the hot wire. Or can I use 1 for distributor and 1 for my hot wire for electric fuel pump. Thanks
Are those the two wires that went to the ignition coil +? If so, the answer is no.
HEI ignitions require a single switched 12V source, but they also require quite a bit of current. In a Chevy, they are typically supplied with a 12 gauge wire. In a Ford, the wires to the coil + are resistance wire and the voltage will quickly drop with increasing current demand. The second wire runs to the starter solenoid and is used to bypass the resistance wire for full voltage when cranking. You can use the original ignition + to operate a relay which can supply +12V power to the HEI that should be supplied through the relay contacts via 12 gauge or better wire directly from battery+ and through a 20A fuse. There are no other sources of ignition switched +12 under the hood of a Ford.
On the electric fuel pump, please don't just hook it to switched +12. You absolutely MUST have some sort of safety relay which will shut down the fuel pump in case the engine stops running. This can be another relay wired like the ignition relay and controlled by an oil pressure switch, or from the alternator stator. EFI vehicles use the ECM to control the fuel pump relay and will shut it down if the tach pulses stop.
Are those the two wires that went to the ignition coil +? If so, the answer is no.
HEI ignitions require a single switched 12V source, but they also require quite a bit of current. In a Chevy, they are typically supplied with a 12 gauge wire. In a Ford, the wires to the coil + are resistance wire and the voltage will quickly drop with increasing current demand. The second wire runs to the starter solenoid and is used to bypass the resistance wire for full voltage when cranking. You can use the original ignition + to operate a relay which can supply +12V power to the HEI that should be supplied through the relay contacts via 12 gauge or better wire directly from battery+ and through a 20A fuse. There are no other sources of ignition switched +12 under the hood of a Ford.
On the electric fuel pump, please don't just hook it to switched +12. You absolutely MUST have some sort of safety relay which will shut down the fuel pump in case the engine stops running. This can be another relay wired like the ignition relay and controlled by an oil pressure switch, or from the alternator stator. EFI vehicles use the ECM to control the fuel pump relay and will shut it down if the tach pulses stop.
Ok thank you, I was going to throw a toggle switch in but forgot to write it down. So to be clear, I could run one of those wires from ignition module to a switch for my fuel pump, then run 12g wire to distributor from battery. And will I also need a switch for that or will it be fine.
Ok thank you, I was going to throw a toggle switch in but forgot to write it down. So to be clear, I could run one of those wires from ignition module to a switch for my fuel pump, then run 12g wire to distributor from battery. And will I also need a switch for that or will it be fine.
No.
Read again. I'm talking about relays, not switches. I could hand draw the circuit you need and post a pic if required.
I would like to know why he did not stay with the DSII system over the HEI
Everyone thinks the HEI is so much better when they are both the same.
I have see a DSII system run in the 11 sec in the 1/4 mile and 10 sec on spray all stock.
Dave ----
I would like to know why he did not stay with the DSII system over the HEI
Everyone thinks the HEI is so much better when they are both the same.
I have see a DSII system run in the 11 sec in the 1/4 mile and 10 sec on spray all stock.
Dave ----
I think the perception is that the HEI distributor is "so much easier, just ONE wire!"...
I think the perception is that the HEI distributor is "so much easier, just ONE wire!"...
But IIRC that horse shoe connector he is showing is used with a DSII system and the TFI uses a different coil and connector.
Just to replace a DSII for HEI is stupid in my book even if he has no spark.
There is only 2maybe 3 things that can go wrong with either dist. as they both have the same parts that make them work.
Module, pick up coil and 3rd coil and I would replace just in that order if no spark.
Dave ----
But IIRC that horse shoe connector he is showing is used with a DSII system and the TFI uses a different coil and connector.
Just to replace a DSII for HEI is stupid in my book even if he has no spark.
There is only 2maybe 3 things that can go wrong with either dist. as they both have the same parts that make them work.
Module, pick up coil and 3rd coil and I would replace just in that order if no spark.
Dave ----
I would like to know why he did not stay with the DSII system over the HEI
Everyone thinks the HEI is so much better when they are both the same.
I have see a DSII system run in the 11 sec in the 1/4 mile and 10 sec on spray all stock.
Dave ----
The person that’s helping me do this is a Chevy guy so he’s using what he has more experience with.
The person that’s helping me do this is a Chevy guy so he’s using what he has more experience with.
We could help you more if you listed what year truck you are working on, what is the engine you have and if it is the original engine or what was the original engine.
If you are going to hand wire switches or relays directly to the battery, make sure you use some sort of circuit breaker or fuse as close to the battery as possible. I didn't look at the other poster's diagram, he may have included a fuse or circuit breaker in his circuit.
We could help you more if you listed what year truck you are working on, what is the engine you have and if it is the original engine or what was the original engine.
If you are going to hand wire switches or relays directly to the battery, make sure you use some sort of circuit breaker or fuse as close to the battery as possible. I didn't look at the other poster's diagram, he may have included a fuse or circuit breaker in his circuit.
the truck is a 80 f100 and came with a 300 we put a 302 in it
In that case a DSII dist. dropped in to the 302 and just plug the wire that went to the dist. on the 300 into the 302 dist. and done.
Can even use the same box from the 300 on the inner fender as it will work with the 302 DSII dist.
You would need to make the oil / temp / ALT wires shorter or longer to reach the new locations.
All really easy to do.
Now you got to find wires that are hot in run and cranking, add more wires and a relay to that HEI dist. to make it work.
Oh well live and learn I guess
Dave ----
