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Username Post: 1972 ss 454 run issue        (Topic#338626)
kljfamily 
Forum Newbie
Posts: 3

Reg: 08-27-16
08-27-16 02:51 PM - Post#2648057    

Hello,

I have a 72 ss 454.

It was running fine no issues, driving it 50 plus miles each week. I let it sit for awhile during a move for a few months and of course the battery died. While charging on high AMP ( I know dumb) I lost track of time and the battery blew up. My fault entirely...

I Replaced the battery, checked the fuses and went to start it again but the engine will only run when the starter is engaged. As soon as i let go of the key and the ignition turns to run the engine dies. If I keep it engaged the engine sounds great and roars to life easy with no hesitation. Let go of key and dies...

I have traced over most of the wiring but cannot seems to find where the issue is.

My assumption is either the key ignition has come bad or there is a break in the wiring somewhere.

Has anyone else seem this happen? If so some pointers on where to look next would be great.

The distributor is Ac Delco with coil on cap, no A/C, new battery, new starter and I also drained the gas tank and refiled with fresh in case gas had gone bad from sitting.

Thanks
Kris



 
raycow 
Honored Member
Posts: 27474
raycow
Loc: San Francisco, CA
Reg: 11-26-02
08-29-16 02:08 PM - Post#2648438    
    In response to kljfamily

The starter solenoid has a set of contacts which bypasses the stock coil resistance wire when the engine is cranking. That's what your engine is running on now. However, that bypass was for the stock points ignition. Since your non-stock HEI shouldn't be using either the resistance wire or the bypass, you will have to figure out how it is wired now. In other words, start from the +12V in terminal on the HEI and trace that wire all the way back to the ignition switch until you find the break.

IMO, the break was either caused directly by the battery blowing up or by something you did to the wiring when you replac3ed the battery.

Ray

Those who choose an automatic transmission want transportation. Those who choose a manual transmission want to drive.


 
bobb 
Super Senior Member
Posts: 5327
bobb
Loc: paradise
Reg: 09-05-03
10-01-16 09:25 PM - Post#2654408    
    In response to raycow

if you have an hei it needs to be fed by a big wire, like 12 gauge. your stock electrical system is not setup to do this. i would probly recomend using a cube relay which the stock ignition wire would trigger and run 12 gauge feed to it then 12 gauge to the hei. you would need to make sure the stock ignition wire will supply enough voltage to turn the relay on. i do believe you have a resistor wire other than a resistor. the wire will look different than normal wires.

70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
kljfamily 
Forum Newbie
Posts: 3

Reg: 08-27-16
10-03-16 11:35 AM - Post#2654666    
    In response to raycow

ok...first thank you for the reply..this has stumped me for some time now. Currently there are 4 wires to the starter.

1. The main battery cable that is obvious to the big post.

2.yellow wire from the coil over cap to right side of starter.

3. Purple wire also on same post as yellow.. I am assuming this is to the neutral safety switch?

4. this is an odd wire it is on the left small post and is a braided wire. I am guessing this is the resistance wire you mentioned that I do not need since I have a coil over cap.

I am in the middle of unwrapping electrical tape and following the lines back. My question is then what do I actually need and what can be removed so I can get this going again.

Also would the neutral safety switch be a possible culprit? I have a 700r4 tranny. The vehicle will only "start" in P but does nothing in N.

I replaced the external voltage regulator and harness as it was beat up and the red wire going into it was broken. I had hoped this was the issue but sadly it made no difference.

thanks again





 
kljfamily 
Forum Newbie
Posts: 3

Reg: 08-27-16
10-06-16 10:51 AM - Post#2655221    
    In response to kljfamily

UPDATE! IT LIVES!

Thank the two guys that responded I know electrical issues are tough to diagnose. So given the advice I was poking around and decided to try and run a jumper cable from the ignition on the fuse panel straight to the distributor. When I did this the car started right up with no issues and purred like a kitty. So there is def a break someone in the original cables that were re-purposed by the P.O. when he installed the HEI So at least now I just have to replace that ignition wire to the distributor and I am back on the road. Prob replace it with a 12ga or 10ga rather then the 14-16 that is there now. Thanks again for the help.



 
bobb 
Super Senior Member
Posts: 5327
bobb
Loc: paradise
Reg: 09-05-03
10-14-16 10:51 PM - Post#2656607    
    In response to kljfamily

well good for you. glad your on the right track. not much need for thanks. we help others who need help so that the classic motoring community will thrive and not get beat up by their own cars. this also keeps the cars from being given up on.

70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
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