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strange problems when starting

1K views 4 replies 4 participants last post by  corenele 
#1 ·
hey all,

I'm experiencing a very strange problem when I try to start my motor. The vehicle is a '69 chevy with a 350. It's running an HEI distributor with an upgraded pertronix coil. I have a high torque mini starter (hitachi motor) that supposedly draws low amperage. my problem is such:

I turn the key to ignition, the starter cranks the motor over, the motor cranks and cranks for as long as I hold it, and it's not until I let the key off of the ignition position, that the thing finally fires, and generally manages to start up as long as i give it a little bit of throttle. I thought I might have problems with my starter switch, but the problem doesn't seem to happen all the time, mostly just when the motor is a little warm from driving around.

Any ideas on this one? Thanks in advance for your input.

cheers
The Blonde Weasel
San Diego, CA
 
#2 ·
Sounds like you're ignition bypass is not working. Most vehicles have a circuit in the switch to power ignition when cranking. I think GM runs off the starter, so you may have forgotten a wire on the starter or you may have to run one,I would hink that a replacement starter(regardless of mfg.) would have the circuit in it. I don't have any GM wiring diagrams handy but if you check one out you can determine where it is supposed to feed from. Most Fords are in the ignition switch, so if that happens it's usually the switch.
 
#3 ·
My setup was always something slightly different from the wiring diagrams... now, bear with me because this has been my first real vehicle i've worked on, so i only know wiring based on what i have, compared to what the 1969 diagram says i should have.

originally my vehicle was equipped with a points distributor. there was a lead coming from the starter, which plugged into the positive terminal on the dist. now when i purchased the vehicle, the previous owner (who, as i've learned over the years, really knew *nothing* about how to wire a vehicle properly) had upgraded the dist. to HEI, and wired the positive feed for the coil directly to the ignition terminal on the fuse box. It's always just kind of worked. I recently replaced the motor in this vehicle, but swapped it with an identical block. As far as I know, everything is wired the same way as it was before, and I never had this problem in the past.

hope this helps.

oh, another problem which is somewhat related to the electrical... sometimes when the motor is hot... and only when it's hot, i get some strange readings on my voltmeter. at random times, the voltage will spike towards 0V for a split second, then go back up to normal. It seems to be independent of whether the car is bouncing up and down (i thought it might be a short, some bare wire hitting the frame or something, only when i'm hitting a bump, but that's apparently not the case). i actually suspect it's the bearings in my electric fans starting to go, the housings for the motors are all rusted, and chances are the insides aren't too much better off. the way i figure, the bearings start to freeze up, the resistance in the motor goes way up as the motor is binding, causing electrical draw to momentarily skyrocket until the fan breaks itself free.

perhaps this is another issue entirely.

The Blonde Weasel
San Diego, CA
 
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