Tried to fire up the car tonight and it would fire and quit as soon as I let the key go from starting. I checked the power wire to the distributor with my test light and it was very very weak. So I ran a wire straight from the battery to the distributor and it fired right up and ran first try. I have a GM HEI distributor and have never had this issue before. It is a 70 cutlass 350. I don't think it's a ground as everything else is working fine. What else could cause this? Any help would be appreciated, thank you

 

You can remove the alternator and have it checked at a local auto parts store. You can even have them check it on the car if you don't want to remove it.

 

Olds64, did you reply on the wrong thread?

 

It has nothing to do with the alternator and everything to do with the wire from the ignition circuit. Trace the wire from the "Bat" terminal on your HEI cap to where ever it's coming from, you have a bad connection.

 

x2 on the Dist Batt Terminal. original points systems ran on less voltage make sure you have a FULL 12 volts to the distributor.

 

Was the wire that you ran from the battery negative or positive? If it was positive then the problem is probably not a ground.

Low primary voltage to the coil is from either a bad connection as mentioned by a previous poster or that the pink resistance wire to the primary side of the coil from when the car had a point style distributor was not upgraded. HEI distributors require full battery voltage, point type distributors use full voltage only in the cranking mode and reduced voltage in the run mode to prevent burning the points.

 

Ok that is good info, I did not know that. The car was already converted when I got it so I'm not sure what they did or if they did it correctly. The only thing I do know is before I swapped the engine out it was working. Although I do not know if it had a full 12 volts or not. The wire that is going to the distributor looks like a tan or faded orange with a white clip. I will trace this wire and see where its coming from. If the conversion was done correctly where should that wire be coming from?

 

Easiest w/HEI is a wire from the spade terminal in the fuse box for ignition

 

I would recommend checking this wire with a volt meter, and letting us know what the actual voltage is.
The original points ran on 8-9 volts, but the HEI wants 11-14.
If you put a meter on it and it reads 8v, that points strongly to the likelihood that the HEI is being fed by the old resistance wire, rather than by a new wire.


Smart move.
As has been said, that pretty much rules out a bad ground (as you didn't change the ground characteristics, but then again, if the engine cranked, you must have had a good ground to run the starter, right?), and points to low input voltage.

A bad connection is less likely than the resistance wire still being active, since bad connections seldom provide "kind of enough" current, and are usually just all-or-nothing.

Ideally, your HEI wire should come from a soldered connection to the heavy pink wire from the ignition switch.
It is also possible to run it from the IGN tap on the fuse block, but that's just not as secure as a solid connection.

- Eric

 

I plan on bringing a voltmeter home and checking the voltage that was my next move. The only thing that is weird to me is that it worked before on my old engine. Although as I stated I did never check the voltage. This may be a stupid question but is it possible that it had enough voltage to keep cranking an older worn engine but not enough to keep cranking a fresh rebuilt engine? Thanks for the help

 

This was my next move if I can't figure out what the problem is. Thanks for the tip

 

bear in mind, that resistance wire will show full battery voltage to a high impedance voltmeter. the resistance wire resists the flow of current, if there is no appreciable current flow in the circuit, there is effectively no voltage dropped by the resistance wire. with the addition of a relay driven from that resistance wire, and a minimum 12-gauge wire from a switched & fused high current source, to the relay, you'll have reliable power for the hei system. of course, to complete the circuit, the relay will require ground for the coil, and a 12-gauge wire to the BAT terminal on the distributor cap, from the relay. fusing for this circuit should be 20 amps. you can accomplish this via fusible link or a standard inline fuse(slow blow fuses are better in this circuit).


bill

 

Not that weird. I don't know why, but this is a story I've heard a number of times:
HEI worked well on resistance wire, then suddenly didn't.
I have no idea why it happens, but it does.


Not really. If something like that is going to happen, it will break up at high RPM or under high load, but not at idle.


... IF it has no load on it, so be sure to check voltage with the HEI connected, not with the wire hanging free.


But, remember, GM never installed a fuse in the ignition circuit, whether points or HEI, so it isn't strictly necessary to do so.

- Eric

 

... IF it has no load on it, so be sure to check voltage with the HEI connected, not with the wire hanging free.

Good to know, I was going to check it with it unplugged. I will make sure to check it while connected. Thanks I will let you know what I come up with

 

You can tell the resistance wire by it being very stiff compared to a standard wire. I did the relay setup described above which ensures battery voltage to the distributor.

 

Plus, it's shiny silver in color, rather than copper-colored.

- Eric

 

Silly question, but if the resistance wire cuts the voltage when it is running, why would it not show the 12 volts with just the ignition on whether or not its plugged in?

 

Because the HEI si still drawing current when the engine isn't running, though it does draw more when running than when not running.

Points, on the other hand, may draw no current when not running, if the points are in the open positon.

- Eric

 

Condenser??

 

bill

 

Your description was completely clear to someone well versed in electrical theory, but, I think, less so to the complete amateur, who doesn't even have a voltmeter at his house.
I felt it sensible to spell out your correct but complex statement.


The ignition circuit is still connected to the same fusible-link-protected circuit either way.
If you choose to add an additional fuse, that's fine.
However, I find it interesting that the only circuits in the car (as far as I can tell) that were unfused were the cranking circuit and the ignition circuit.
The cranking circuit is high-current, only used very occasionally, and controlled by a momentary switch, so I suppose they figured it was not necessary to spend the money on a 30 or 40 amp fuse for it.
The ignition circuit could easily have been fused, but was not.
My personal belief is that the designers felt that the risk of sudden loss of power, possibly from failure of a faulty fuse, rather than from a defect in the ignition system, was greater than the risk of a short, which could be corrected by turning off the ignition switch.
Regardless, they chose not to fuse this one circuit when they easily could have done so,

I would not argue against fusing this circuit, but I feel that in the interest of clarity it must be stated that it was not fused when the car was made.

- Eric

 

If you add a fuse in the circuit, does that make you a fusilier??

 

What!?

I don't know why I made that reply. Maybe I'm loosing my mind.

 

clearly, not.


bill