The Stovebolt Site Forums The Shop Area The Electrical Bay flickering light problem

My '51 3100 with a '56 235 has been sitting awhile, so I fired it up today (after trading the 5 year old battery in for a new one), and took it out for a ride. Actually, my 04 Silverado duramax kicked into limp mode, so I limped home in it and switched over to the bomb. The 51 has been my daily driver for about 8 years until it stripped it's timeing gears last year. Got them changed out this summer, but I've been spending so much time working at our property, the 51 has been left sitting at the house. Anyway, after I got the new battery in and poured some gas down the carb, it fired up and I wanted to take it for a ride and get it warmed up and charge up the battery, too. It was about dusk, and I noticed the dash lights were sort of dimming and recovering. Not full time, but every 5 or 10 seconds, they'd fade a bit and come back. Then I noticed the headlights were dimming at the same time and rate as the dash. I figure a loose ground, but since it's had a shop install the new gears, and it's been running a little rough ever since I got it back, it might be anything. Oh, yeah, since it wasn't running as smooth as I would have liked, I've recently changed the rotor, cap, points, condenser, coil and resistor. I put new cables on it last year. Anybody have any suggestions or ideas on where to start looking? Thanks, Lee

Assuming you still have the foot actuated dimmer switch, disconnect the plug and clean up ALL the connections. Others will be along with more detailed fixes.

I'd check the generator. Just a WAG, but maybe the brushes are dirty from sitting? Sounds like your voltage is varying. IIRC, the dimmer switch connections would only affect the headlights being downstream of the headlight switch and dash lights.

What effect does the dimming have on the ammeter? Is is fluctuating also? If so, maybe the voltage regulator needs attention.
Kent

Thanks, guys. The voltage regulator is one thing I've never changed, so that's a good point. The dimmer switch has been, but I've had my doubts as to whether I've got it wired correctly (I've got a brighter light pointing at the road when it's dim, but the lights look dimmer to me when they're on high beam), so that's doable. I rebuilt the generator a couple of years ago, but now that i think of it i haven't oiled it in quite a while. Thanks again for these suggestion, guys. I'll try to get out there today and knock out this list, although it's pretty nasty out there right now. And Happy New Year to you all, too!

I had a long response typed, and fat-fingered a key and erased it! Try cleaning the regulator points, but NOT with a file or sandpaper. Regulator points open and close with a slight wiping action, supposedly to be self-cleaning, and scratches on the contacts can cause them to stick. Use a clean business card, or a slice cut from an index card to burniush the points. Dosconnect the Battery wire from the regulator first, to prevent closring the cutout relay accidentally and causing a short through the generator. Use the card stock to scrub the contacts and remove any oxidation they might have built up from non-use. The cutout relay snaps closed and stays that way as long as the generator is producing more voltage than the battery, but the current and voltage regulator points vibrate several times a second as they perform their function. The voltage regulator (in line with the F wire) operates much more than the current regulator. It usually only functions for a short time adter startup while the generator is refilling the battery after the starting load is drained from the battery, or if a high constant drain such as a winch or other high current accessory is being used.
Jerry

Thank you, Jerry! For the idea and the detailed explanation. I had no idea the points in a regulator moved differently from the points in most other things. (I just repaired our Cuisinart toaster the other day, and I had no idea they had contact points, 2 sets of them, and that was the solution to that problem. Didn't know they use electromagnets to hold the plunger down, either. The older I get, the dumber I feel.) Electric and all it's formulas has always stumped me, and I've spent most of my life working with all kinds of electricity. It's almost like I missed "that week in school" when I was supposed to learn the basics of the subject. I didn't get out there today to check anything since it's been wet, nasty and cold all day. But that will be first on the list, along with what the other ideas above. Thanks again. I'm sure glad this forum is here.

Ok, I just got in from checking and cleaning the points on the voltage regulator. While I was at it, I cleaned up the 3 wire fittings going into the regulator, just in case. But I have a question. What type or rating is the condenser that is connected to the current regulator pole on the VR? http://pic20.picturetrail.com/VOL1373/13685773/24611517/414500074.jpg I don't know if it might be a problem here, and it's been on there since I bought the truck, but I can't find any mention of it in the shop manual. Could it be a cause of this? Do I even need it? What am I suppose to replace it with (part #, etc). Anyway, I'm getting ready to take the truck out for a test run, but I thought I'd get on here and ask about that condenser before I go. The problem may be fixed from just cleaning up those points, I hope, but I'm still curious about what to replace that condenser with, since they don't last forever.

Secondly, while I was under the hood, I pulled off the headlight dimmer switch wires to switch them around, since I'm still not sure if I have it correct. What I did notice is that the wire has been spliced, as if new fittings were put on at some time, but the fittings and the wire they're on, which has been spliced to the wiring harness, are as old and dry rotted, way worse than the original wiring, it seems. I'm going to stop and get some new fittings at NAPA when I'm out. The switch should be good, since I just replaced it spring before last. But those fittings and the inch or two of wire that they're connected with are in pretty sad shape. I'm glad that was mentioned. Those fittings need replaced. Back in a bit to let you know how the regulator cleaning went.

That condenser was probably put on there for radio noise suppression. They were not stock as far as I know (my truck didn't have one). It has likely failed (maybe shorted inside). I would toss it and see what happens.

Radio noise suppression. As Kevin said, it really doesn’t need to be there.

Maybe mine didn't have one because it didn't have a radio to suppress!

I figured it was for something like that. I'll pull it off the VR post and see what happens.

I got the truck started up last night for a minute, and sitting still, anyway, the dash lights seemed steady, but I didn't go anywhere to really find out how it will do when it's being driven. I was so happy that I got it running (had to pour a little gas down the carb), but then it would die within about 10 seconds. I guessed that the fuel filter might have gotten old and clogged, or maybe the gas tank had some junk at the entry to the fuel line (it's happened before, multiple times), so I got in the wife's car and headed back to NAPA for a new fuel filter. I've always used the clear plastic filters so I can see what's going through it , or not, and it seemed like it looked dry. I switched it out, and the fuel started flowing, so I re-attached it and gave it a shot. Let me say that each time I've tried to start it, it feels like it's really struggling to crank it, like something's holding it back. Could a new set of timing gears do that? I'm pretty sure the old set was the fibre type. I bought steel (aluminum?) for replacements.
Anyway, I had to pour a little gas down the carb again, it started up and the dash lights held steady, and I let it run for a few minutes to make sure it wasn't going to die from gas starvation, then I shut it off and went in and told my wife the good news. I came back out a few minutes later and it was dragging again. Since it was getting dark and misting freezing rain, I quit for the night, but intend on getting back out there today and hitting it again. Thanks very much for all the input, everybody. Like I said before, as much as I've worked around electricity, including rehabbing a half dozen houses and their wiring systems and welders and machinery since I was 20, I am still stumped to this day as to why electricity still eludes me. Thanks, fellas. I do appreciate it. Lee

Timing adjusted wrong can make it seem like the engine is laboring to turn over.

Have you tried cranking the engine with the ignition off to see if the draggy start is ignition-related or the fault of bad starter performance, engine friction, etc.? If it cranks at a normal speed with the ignition off, you've got an ignition timing problem. Otherwise, look for inadequate size battery cables, poor connections (especially grounds), or a low battery. A 6 Volt system should crank at a voltage of at least 4.5V, measured at the battery posts, or a 12V system should be above 9.5 volts, assuming you've got a fully charged battery. The cranking voltage should stay at or above those numbers for a minimum of 15 seconds of continuous cranking if the battery reserve capacity is good. Don't do the extended cranking test more than once every 20 minutes or so, to avoid overheating the starter windings.
Jerry

Ok, I went out and tried to get it to turn over, but no luck. It's just really feeling like it's dragging and I bought a brand new battery that's reading 12.8v out of the truck. I came in and found Jerry's suggestion, and by then I already had the battery out of the truck and on the charger, just to be sure. Ran back out and hit the starter pedal, and nothing! (Then I remembered the battery was inside on the charger-oops). Took it back out there and put it in and tried cranking it with out the key on, and it did great. Sounded like any other day before all this mess started. Switched on the key, and it sounded good, too! After about 2-3 seconds of cranking it fired up, and I pulled the throttle to hold it until I got out and replaced the filter and breather cap and shut the hood, then jumped in and took off. Runs ok, but it's got this ambling sound like rocks rolling around in a cardboard box, the best I can describe, when it's slowing down or at a stop sign. Drove it out to the highway and about 5 miles on that, then came back to the house and backed it into our so-called drive way so I could be on a level spot (we live on a hill, so most of my mechanicing is done on the curb, on a slope) so I could hopefully get to work on adjusting the valves and timing before it cooled off. When I switched it off, I couldn't resist turning it back on again, just to make sure all was well. But when I turned the key and stepped on the starter, it was chugging and straining again, almost sounding like a dead battery. I was keeping an eye on the ammeter while I was driving, and although it showed it was on the draw side instead of the charge side, I realized I had the heater blower on, and that leveled out as soon as I turned it off. So, now I'm wondering if it's the timing (my guess, since it just had the gears changed and never did this before), or the starter dying on me, or maybe like somebody mentioned, my generator rebuild from a few years ago has some dirty brushes to clean up. Or could it be the regulator going that's causing all the problems. I don't know. But it always seems like my two trucks have this thing where when one goes, the other goes on the blink. Oh, well. It's 3:25, which means I have about an hour till dark, so any tweaking with the valves and timing will now be tomorrows work. I'll start with the valves and timing, then the starter, then the voltage regulator. If anyone has anything to throw in here, I'm all ears. I'll be glad when this is done and I've once again forgotten how much I appreciate a truck that starts every time and gets me from point a to point b without even having to think about it. But, on the other hand, that's what I love about this truck. It's fixable, and fixing it doesn't involve computer chips, unnecessary fuses and breakers, and repairs I can actually figure out (with time). Thanks again for the help and ideas, guys!

Some starters have a bushing in the nose of the starter, when this bushing gets worn things are not lined up and the starter is weak, bushing easily replaced.

Ed

Any idea where I can locate the parts? I'm going to get it rebuilt, although my long time starter/alternator builder has retired. Since I've already rebuilt my generator, I think I can handle the starter. Unless I want to pay $200 for another one, a rebuild looks like it's inevitable. Thanks, Ed.

What did your rebuilder do with his parts inventory when he retired? If he's still on the green side of the grass, you could probably purchase a lifetime supply of brushes, bearings, bushings and other small parts from him if he had any left over when he closed the business.
Jerry

I might try going through every single connection on the engine side to make sure they are clean and tight. Remove both ends of the battery cable and use some scotch brite and an old style battery post clamp cleaner. They still sell them at most parts places. Disconnect each connection from the battery positive to the voltage regulator, and the regulator to the harness and the generator. take them off and clean them good. Make sure there is a good, in fact very good, ground. Add a ground strap if you have to, and make sure there is a ground wire at the voltage regulator. Also check the wires at the coil. Remember, star tooth washers are your friend.

Doing the above is easy low hanging fruit. Once you are confident that all connections are clean, tight, and that you have sufficient grounding, then you can move on to other things. Me, I would check the timing next.

Well, I've actually had two different rebuilders retire in the last 10 years. The last one sold out to another guy, who then proceeded to not do a very good job (so I heard, never got to try him), which ended up with the buyer going out of business and closing up shop. I don't even know who he was, and my guy sold his house with the shop and moved, and I can't find him. I must admit, I haven't had to look for anyone since then, and although classic parts sells the starter for $199, I saw on Rock Auto last night I can get one for about $85.

Mike, thanks for the advice, I will try that before I go any further.

I spent the afternoon yesterday taking the new battery back to NAPA. After getting the truck started the other day, I had to wait to get back to it since it was getting too close to getting dark outside. Since it started "dragging" again when I tried to start it as soon as I had it out for a 10 minute ride. I even pulled the battery and took it inside and hooked it up my charger and let it charge all night (although it started it's float cycle before I went to bed.) Yesterday I went out and put the battery in, turned the key, hit the starter, and nothing. I turned the lights on and checked them and they were barely lit. Checked the battery with my multimeter and it read 7.5v (??) Pulled it, took it back to NAPA for an exchange, back to the house and to try again hoping this would be the time I could start it, take it for a 20 minute ride and get started on adjusting the valves. Just to make sure, I wanted to check the head lights to make sure it was the battery and not the truck that was dimming the lights, and when I pulled the light knob, it came out!! I messed with it a few times, but it's not staying in, so I started wondering if it's part of the problem. Since I have a new light switch on standby, I decided to stop right there and change out a possibly shorted light switch. I'm beginning to think this will be another 'parts replacement party' job. Is it the timing? Is it the starter? Is it the generator? The light switch? Who knows? All I know is I've got two trucks down at once. Stay tuned for the next episode.

Disconnect the wire from the big starter terminal to the ammeter to isolate the rest of the electrical system from the starter and see if the battery keeps a charge overnight. Once that wire is disconnected, an ice pick type test light connected from the battery cable terminal to the ammeter wire SHOULD NOT light up unless some kind of accessory is turned on, or there's a short that's causing a constant battery drain.
Jerry

Will do, Jerry. I ended up not even looking at it yesterday, but will now, although it will be after 3 o'clock. Thanks, you're a great help.

Hey, jerry, I got it started yesterday evening! I guess that old battery was the problem, I hope. Napa checked that battery when I took it back and they showed it at around 8v. They thought I got a bad one (or dropped along the way). We'll see what happens when I go out this morning and try it again. But I've got another question about the brake (stop lamp) switch. I'm going to post it separately, I guess.