now that the weather is starting to get warm im trying to get my 70 chevelle ready for spring. ihave posted this problem befour but had no suxcess at fixing the problem. when u turn the key to the start position the car fires right up but as soon as you let the key go and it springs back to the run position the car dies. sometimes if u levae it for a day or two it will start back up and have no problems for a few weeks and then it will happen againe. i have tried replaceing the ignition switch and that didnt help. when in the run position the wire from the ignition switch to the coil gets a full 12 volts so i do not belive it can be anything haveing to do with the igniton switch. it is a 1970 chevelle with a 406 small block and a 700r4. any help would be apreciated becuse i really dont want to have to go throgh the wireing with a multi meter testing every wire and i have asked serveral mechanics and noone can seem to help me and i want to drive it when it gets nice out without haveing to worry about it not starting at some random place. thanks

I haven't a clue but it definitely sounds like an electrical issue. So even when the car shuts off on you, you still have the 12 volts at the coil?

What distriutor, points type?

Last time I had one with those symptoms it was getting power to the coil from the bypass wire during cranking but no power to the coil with the key in the "run" position.
It had a bad resistive wire.

Also could be a bad connection ar the bulkhead connector possibly.

Try running a temporary jumper from the battery positive to the coil's + terminal or the HEI's "BAT" terminal.

If your ruuning stock points ign you should not have 12 volts to coil after motor starts and key is released. 12 volts should be at coil only be when cranking over the motor with key i full start position.

When the motor starts and key is rleased thats when you should get approx 7-9 volts tothe coildwith stock points ign.

Now if your running electronic ign you should have 12 volts to coil/ign ater the motor starts and you relase the key.

But as mentioned above you definately have an electrical issue ofsome sort.

If you have stock points ans are getting 12 volt allthe time to the coil that will brn up the points and poss condenser too and will cause motor not to start or run very long after those parts are fried,same may go for coil too.

Also,when cranking to start motor the starter solenoid sends 12 volts to coil for craning only,then when motor starts key is released the solenoid returns to the idle position at which time its supposed to drop the 12 volts from going to the coil too.

My suspician is that the starter solenid is going bad in a sence that it doesnt turn off the 12 volts to the coil after motor starts & key is released.
Then i think that causes another problem whereas the ign switch cant switch over to the 7-9 volt reistance line untill the solenoid swithes off the 12 volts for cranking and thats where i think your problem could be. That very thing happened to my friends 70 ss 396,drove us nuts untill we fiurged it out.

Check these things out and let us know how you make out.

Scott

it is an accel hei distributor so there is no ballast resistor and it does need the full 12 volts the starter selonoid does seem like it could possibly be it because a friend of mine said that he thought he saw sparks comeing from it one night after haveing this problem but i dont understand why it would run for as long as the starter was engaged and the all of a suddon die when ther key was relased

John,as i stated prior the starter solenoid sends 12 volts to hei ign when cranking but then its supposed to back off the 12 volts when the key is released after motor starts.

Maybe the solenoid is getting stuck inbween the cranking to start and motor running key released modes not completing the starter off/12 volts from solenoid ending circut which in turn may not let the 12 volts from the ign switch take over to keep motor running.

For a temp fix try running a wire from the pos batt term and have a friend hold the wire close to the batt/12 volt side of your hei.

Then crank the motor to get it started and and have you buddy hold the poss wire with 12volts on the power term of the hei at the same time.

Now release key after motor starts and if it stays running after you release key with your feind holding the direct 12vols to the hei ign then we know for sure its not getting power after motor starts.

Now for a temp fix you could either find an accessory that only runs 12 volts with ign on and run your hei off that or you could hook up a toggle switch and turn on the 12volts to hei when you release key after the motor starts that would come directly from the battery. But be forewarned going that route would require you never forget to turn off the 12v to the he when motor is off or at the lest you will run the battery dead,next could fry/overheat elec module,or worst case start a fire so be carefull.

This would get you by for the time being so you could drive & enjoy the car utill you find the problem. But i would bet its somewhere inbetween the starter/solenod & ign sw starting circut is where your problem is which you seem to already know so get going on the diagnostics so your ready for the good weather just around the corner.

If it were me i would just run a new wire from trhe ign sw that supplies 12v after the motor has started & key is released rather then try to find where the broken wire is if it turns out to not be the starter solenoid .

Scott

i think ill remove the starter and take it to have it tested and that should be able to tell me if the selinoid is bad or not and if thats not it ill go threw the wireing like u said and eather replace it or check the resistance i just bought a nice wireing manual that tells the resistance that all those wires are supposed to have. but i hope it is the selinoid nice and easy fix ill try that this weekend and hope it works. thanks

Before you do that just try the jumper test I mentioned above.
It sounds like the coil is not getting power with the key in the "run" position and is only getting 12 volts during "cranking"

I really doubt that the starter/solenoid has anything to do with the problem because it's doing what it's supposed to be doing and starters have nothing to do with the ignition system getting power after the engine starts.
A starter solenoid sends power to the coil via the bypass circuit only during cranking.

In fact you don't even need that bypass feature any longer if the original points distributor is gone but it doesn't hurt anything to leave it.

its gettin 12 volts wile in the run position i havent checked it during the cranking position. at least if it wernt getting 12 volts wile in the run position it would make sense to have it die, but everything appears to work correctly thats why its so confuseing

there is a 12 V starting bypass wire on the outer terminal of the solenoid. it goes into the harness and comes out at the distributor. on the old factory resistance wire setup it was crimped into the same terminal the resistance wire went to at the coil. One time at least 25 years ago I had one that that shorting the resistance wire to ground. I clip those off when running an HEI now.

If you have an HEI in there now you shouldn't be using the old resistance wire at all. Go to the BATT terminal on the HEI and look at the wire that's connected. If it's a fabric covered yellow wire you're still using the resistance wire. If it's not follow that wire to wherever it goes. I poked a small hole in the firewall and ran a 12 gauge wire directly from the HEI BATT terminal to a male spade in the fuse block. There's usually one marked IGN right in the middle of the block. Don't hook any other wires to it or the terminals on either end of it. You don't have to poke a hole if you have the large plastic christmas trees gizmos holding the steering column to the firewall. Just cut off the very tip of the tree deal inside the engine compartment, poke the wire thru it.

For test you can unhook whatever wire is connected to the BATT terminal of the HEI and run a jumper directly from the positive battery post to the HEI. If it won't run that way something is wrong inside the HEI. DUring testing unhook any wire connected to the TACH terminal on the HEI. If there's a TACH wire and it's shorting out or the tach is bad it will kill the ignition.

i dont have a tach and i am not useing the factory resistor wire i am already have a 12 gauge wire in its place. i looked at my selinoid quick last night and for somereason the power wire from the batter to the selinoid is loose but sense my garage isnt heated i couldnt stand the cold for long enough to fix it i did wiggle it and try to start it no luck but i wounder if that might of happend to move enough to be able to arc out to the other wires and mess them up. at the moment tho its snowin and were lookn at about 8 inches only in new england can we go from 65 degrees to 8 inches of snow in a day so doesnt look like ill be driven it any time soon now

I got 18" of snow all totaled yesterday & last night in dutchess cnty NY.,took 3.5 hrs to show blow driveway & clear walk.(PHEW)

We went from 71deg on Wed to 18" 2 days later.(Thats MARCH for ya)

Scott

well it was finally nice enough to work on my car today and it turns out that it wasnt the starter selinoid i really dont know ware to go from here i have tryed just about everything, and to make things worse i saw another 70 chevelle driving around wile i was out this morning and i was in a honda so i almost cryed. but any outher suggestions would be appriciated

Ignition Switch?

first thing i tryed

first thing i tryed. i replaced it it didnt help.

Now that I re-read your first....my bad for not noticing that you already tried an ignition switch:clonk:. I hate to say this, but from my past experience.....i have never.....repeat.....NEVER had any luck with ACCEL junk!! That Accel HEI would be the first thing I would check out. I had bought a brand new Accel coil from a speed shop that acted up like that once in my 72 Elky. It would be ok for a few miles (2?).....then it would just shut off when it got warm. I could barely get the car home. Put an MSD coil in from my Velle (once I got home) and the problem went away.

im not sure that could be the problem because the car will run fine as long as the key is in the start position, i would think that if it were a ditributor problem it eather wouldnt start at all, or it would start and have a problem after it had been running.

well i spent all weekend going over the wires againe with a multimeter and still no luck. but if anyone could tell me whare the yellow wire on the starter selinoid goes to it would be good i couldnt test it because the tube the wires are in split one goes threw the fire wall and the other just countinues around the engine bay. and any last ideas on what the problem could be would be good cause i replaced everything to the starting system and cant find the problem.

The yellow wire goes from the "other" small post on the solenoid to the + post on a stock coil. This provide +12V during cranking (only) when using stock ignition. I assume you hooked your HEI to the IGN post on the fuse block?????? This post has power both during cranking and the "ON" position.

yes i did so that must not be the problem thanx

well after all the head aches i finally figured it out. all along it was one of the first things i checked. the wire going to my coil that i checked with the multi meter and was getting a full 12 volts in the run position ended up haveing a break in side the jacket, so what was happening was that when the car wasnt running but was in the on position the current could flow but when the motor was starting and the motor was rocking the current would stop flowing because of the break. turns out that all this time it was just somthing that i had overlooked. thanks to everyone for there suggestions

Try running a temporary jumper from the battery positive to the coil's + terminal or the HEI's "BAT" terminal.


Before you do that just try the jumper test I mentioned above.


But how could THAT cause it to die with the test I mentioned to do?

hmmm ... :confused:

ya i fugured sense it was reading 12 volts already in the run position running the temporary wire wouldnt help, but i finally thought about it the othet day about the fact that the motors moving wile its starting so the wire is is moveing not stationary like when i had tested it.:clonk: