The Stovebolt Site Forums The Shop Area The Electrical Bay Ignition problem

Hi all,

I have a 1966 GMC 3/4 ton pickup w/120K miles. Engine is 305V6. I have been having ignition problems so I replaced the starter solenoid. Unfortunately when I turn the key, I get nothing. Battery is fine and alternator is new.

Could it be a voltage regulator issue? I welcome any thoughts. Thx

Tim

Hello Tim and welcome to the 'bolt. I'm going to move this to the Electrical Forum where you will get better answers... and please re- introduce yourself in the welcome forum.. and post some pix when you get a chance.

What does a starter solenoid have to do with ignition?

What are the symptoms of your ‘ignition problems?’

Ed

..........welcome to the Bolt. You are now home.

I'm assuming your "ignition" problem is actually a "won't crank" issue. We tend to give advice here based on people being able to accurately describe what's going on. For instance a "no crank" problem (engine isn't turning) gets different advice than a "doesn't start" problem (engine turns but won't run). Reading between the lines of your very ambiguous post and making a lot of assumptions makes me believe you're actually describing an "engine doesn't crank" problem. Replacing the solenoid won't help- - - - -you probably have worn out brushes in the starter itself which is preventing the solenoid from getting a ground that allows it to pull the starter gear into engagement with the flywheel and start the engine turning. You can confirm that by having someone hold the key in the start position and tapping the starter housing (lightly) with a hammer. If that makes the engine start cranking, get the starter rebuilt by a competent professional, or replace it. Good luck!
Jerry

Uh, I'm not that well versed with many of the GM V6's starters. But be cautious when taking the starter off the bell housing. Most have shims, if one exchanges for a new or rebuilt you may find it very annoying trying to get it adjusted so the solenoid gears hitting the ring gear correctly so it is not too long. I had a V6 El Comino that I exchanged for a rebuilt rather than have the original rebuilt. I sure did learn to take a GM starter off & on fast after a few hours. I agree with Hotrod, tap that thing lightly while someone turns the key. Doc.

Doc, the ones with shims usually bolt to the block, not the bellhousing. Since the pinion gear on that type of starter is slightly below the center line of the flywheel, shimming it further down keeps the teeth from bottoming out in the flywheel gear. The bellhousing-mounted ones generally don't give any problems. A sneaky trick to check tooth engagement is to paint a dozen teeth or so of the flywheel gear with a rattle can and spin the starter with the ignition disabled to see how much paint gets rubbed off. About a 90% tooth engagement with a bit of paint still showing at the bottom is ideal.
Jerry

What (if anything) did the starter do before you changed it? Crank slow? Click and nothing else?

A little more details would be helpful.

Pretty sad and frustrating, but it happens all the time with new guys. I don't know why. They ask for help and then go to sleep. If you are too busy, don't ask for help until you are not too busy.
1. Ignition problems= not specific. I assume "I get nothing" means no grinding no noise no clicking no buzzing.......
2. Voltage regulator has nothing to do with cranking
3. Alternator has nothing to do with cranking (you must have an externally regulated alternator) You say battery is fine.
4. "Battery is fine". With what you have said so far, you are not experienced in electrical, so how do you know battery is "fine"? Did you test it?
5. Jump the starter down at the solenoid. This will bypass the ignition switch and some wiring. It will isolate to the solenoid, starter and battery cables (if battery is actually "fine"). I doubt it.
6. Your 66 GMC 305 V6 starting system is no different than a Chevy. No shims. No nothing special.
7. Please provide the solenoid part number, where you got it and a picture, or careful statement, of how you wired it.

Right now you have a "no crank" situation. We don't know what you had when you decided you needed a new starter solenoid. You called it "ignition problems". We are glad to help you but don't analyze the issue, or give it a name, just state what the motor is doing or not doing. We will ask specific questions and get you fixed. Provided you have not fallen off the edge of the earth and have no computer service.
It's good, especially when new to a forum, to monitor your own post because you have good folks taking the time to help.

I don't know if you can post pics while moderated. Stay safe, See you next year.

My apologies folks. I’m definitely a “new guy” and trying to figure out this Stovebolt platform. That and the holidays are the reason for my delay in responding. Yes when I turn the key in ignition, the truck doesn’t crank. The Generator light is illuminated and gages activate but no crank. I’m able to jump the start at the solenoid and and will try and tap starter to see if engine cranks.
I purchased this truck two years ago and am still learning my way around this engine which was marketed as a half-million mile motor when marketed back in 1966. As a new guy, Please don’t take the naive questions personally.

Based on comments above, it appears one option is to rebuild the starter due to potentially warn brushes. LMC Truck doesn’t appear to have a starter for the 305V6 so is a rebuilt starter my only option? Also where can I look to research rebuilt starters for sale?

Thx

New Guy

I appreciate the advice. I’ll report back on your comments shortly.

New guy