HEI/258 Delay in Crank

[Pete88YJ]

Originally Posted by Caver Dave

Where I was going (Thanks Pete!) with the similarity to other ignitions where the coil's fed from OEM wiring... fine *UNTIL* the starter engages & voltage drops to subpar levels (what was happening to mine w/ resisted 10VDC feeding the coil dropped to 6VDC). I added a jumper from the solenoids "S" terminal to feed a full 12VDC ONLY during cranking (so as not to burn up the <12VDC rated coil) it began to fire instantly...

I'm surely no ignition genius, but I think that's a pretty typical setup Dave, in ballast-resistor style igntions. You feed 12V to the coil for start, then drop it down to the ballast resistor feed on run. At least my old Jag was setup that way stock, before I put the pertronix and a new 12V coil in.

As for an HEI - I run one in my 88 with a weber. Been great for a long time. I took the power feed from one of the old wires that fed the stock ignition module. I think it was a yellow wire.

As for relays and pull-in voltage, I can't say. Check with the manufacturer of the relay I guess. I would check into using one of the wires from the old module, as LEVE suggested, and as has worked for me for years, directly into the HEI.

Good luck
Pete

[LEVE]

Pull In Voltage... good gosh, you're getting too darned technicial. Don't worry about that right now. If you're really concerned about pull in voltage... it should be listed in a spec chart. IMHO, you're chasing wild geese if you start looking that close.

But now I've got mention that the Oil Pressure Gauge and the Oil Pressure Relay feed points are not the same point, electrically.

Remove the relay, and opt to feed the distributor with 12Vdc from the old ignition module harness (red wire... on the 2 wire connector) and tell us what happens.

Remember, a Jeep's like almost everything else... you can get complicated, or you can keep things simple. Me, I like to keep things as simple as possible; if you don't you increase the chances of being led down the garden path.

[jeeperjohn]

Originally Posted by 84_CJ7

Got it.

But, to kick a dead horse. . .

The voltage at the oil pressure wire is -
key off - 0vdc
key start - 12vdc
key run - 12vdc

All that wire is doing is sending the signal to the relay to open the voltage from the battery.

It either gets the full 12vdc or nothing.

Now that horse has been kicked - I agree that it makes sense to bypass the relay to see if it makes any difference.

If it does? - bad/sticking relay?

Not to keep beating a dead horse but I can't help but wonder if 12 volts is maintained as the key is turned from run to start and back to run. Again, not trying to beat the horse, but also not assuming the wire stays hot.

[84_CJ7]

To clear things up, I never had trouble starting the CJ - it just concerned me that it would only catch when I released the key.

I replaced the relay with a new 12v 30a 4 pin. Went to crank it and it was running before I could release the key. I guess the relay I was using from the beginning was a little to sensitive to the pull-in voltage.

Learned something new.

[CJ7Taz]

I see you got fixed. I’ve had my DSL and phone out from Tuesday morning until Friday afternoon. Long story and I’ve asked for explanations.

It wouldn’t be the pull-in voltage. The relay would already be closed in the run position before the key was moved to start. Even if it dropped out going from run to start, it would pick back up long before the starter began to turn, engaging the Bendix and saw enough load to cause a voltage drop.

The hold in voltage is usually pretty low so it should not have dropped out with the lower voltage during the start cycle.

Whatever it was, sounds like it’s fixed for now anyway.