The Stovebolt Site Forums The Shop Area Engine Shop I could use some diagnostic help.

1958 235 bone stock.

I hadn't started it in a while so I fired it up today and turned it around so I could face it into the garage to work on the rear brakes. It was running great and was idling in the driveway when it just stopped. I went to fire it up again and it will try to start but seems to have no response to the throttle when I try to give it some gas to keep it going.

I have spark. The fuel pump is pumping plenty of gas. When I pump the throttle I can hear it squirting gas. What could it be?

I just realized I should have posted this in 'Engine and Driveline'. Ooops!

Here's a little more info. I'm beginning to think the problem could be electrical. The carb and fuel system seem OK. The main thing I have noticed is as long as I have the starter engaged (foot start) it starts but as soon as I release the starter it's like I have turned off the ignition, not so much as a sputter. I am an idiot when it comes to electrical stuff (it's black magic) so if anyone could help me out with some info I would appreciate it but you might have to explain it to me as if I were a 10 year old.

There must be a separate ignition circuit for starting? What could possible causes be? Is there some voodoo encantation I can utter? Will the electrical gods be appeased by a sacrifice?

Any chance that it has been converted to 12V and has a ballast resistor?

The '58s were 12 volt factory. I have a suspicion that perhaps either there's a loose connection at the ignition switch (green wires on the switch) that go to the coil, or perhaps the switch itself may not be making good contact internally. On the starting circuit, there as a heavy purple wire that come off the starter that bypasses the resistor, giving full 12 volts to the coil. This is only engaged during starting when the pedal is depressed. That's why it's trying to start and seems to want to run with the pedal depressed.

AHAAAH!, this is starting to make a little sense to me. Thanks Bill. You've been very helpful to me today in a number of various posts.

I guess this brings up a series of questions:

So it sounds like my problem is not with the purple wire because it wants to run when the starter is engaged, correct?

Where does the purple wire connect?

Where does the ignition resistor come into play and where is it wired to? Could it be the resistor itself thats the problem?

I will check the connections on the ignition switch first thing tomorrow. I assume that I may able to jump across the connection on the ignition switch if the switch itself is the problem and that should give me a diagnosis about the switch, right?

Like I said, I'm kind of an idiot when it comes to electrical but this sounds like it could be on the right track if I can figure all this out. I just have to get the old girl started and back in the garage. Thanks again.

My 48 does this once in a great while. It will run great until the fuel in the bowl of the carb runs out and it will die. Crank and crank with no start. Tap on the side of the carb a few times to get the float to unstick and release the needle and seat and she'll fire in a few minutes, after to bowl refills.

It's done it to me twice, once along side of the road and once down in the woods hauling firewood up to the house. I decided to diagnose it the second time it happened. Found the ignition system working fine so I primed it with some gas and it fired. The fuel filter was still full so I thumped the carb with a soft faced mallot and it fixed it.

Hope that all that's wrong with yours,
Scott

Thanks Scott.

I already took apart the carb and everything seems to be in order. The float is not stuck and it's getting plenty of gas. Then it dawned on me that it seemed to be OK until I released the starter switch which makes me think it's electrical.

That purple wire runs off the side of the starter switch (the on on the starter that the foot pedal operates) up to the Start terminal on the ignition switch. When the pedal is depressed, it closes both the starter contacts and a second set of contacts for the purple wire. This bypasses the normal power for the coil (green wire) and bypasses the resistor also. The resistor is wired in to the circuit going to the col to cut the voltage down, usually about 6.5 volts or so, to keep the coil from overheating.
You'll want to check all of the connections, both at the dash switch, but also at the resistor itself. Checking the coil wires wouldn't hurt either.

if you just want to get it moved make a jumper wire with alligator clips on each end and hook one end to the coil and the other to the battery cable on the starter,if it runs fine then you know you may have a loose wire or problem with ignition switch. good luck.

Hi Mike, Run a jumper wire with alligator clips from the big + starter lug up to the + side of the ballast resistor....this bypasses the ignition switch. You've now "hot wired" your engine. If it cranks (using the ignition switch or the footstomp starter) your problem COULD be at the ignition switch. If it doesn't, hook it to other pole on the resistor or directly to the coil + terminal. Crank the engine, if it fires up you know the resistor COULD have expired. It won't hurt to run the coil on 12 volts to get the truck back into the garage with the jumper wire. You can do these little checks without disconnecting any of the wires that are already hooked up.

To verify that it isn't your ignition switch, hook one end of the jumper wire to the resistor where the ignition wire hooks up...the other end of the jumper to the + terminal on the coil....if it cranks you've verified that the ignition switch is good and the resistor is bad. The ballast resistor drops the voltage to your coil after the engine gets started on a full 12 volts....reduces point burning.

If you're working on the brakes on your truck you really should be able to handle some simple electrical tests. With an old truck it's good to have an inexpensive little test light and a couple jumper wires with clips. Clip the end of the test light to some clean part of the engine (ground) and touch the sharp probe to any electrical terminal.....if it's "hot" (12v) the light will light up!

With a test light you could verify that the wire from the ignition switch was hot, that the ballast resistor was conducting the current through it's little resistor coil and that it was getting to the + side of the coil. It's really that simple! However, a warning...once you've got a test light and jumpers you'll want a multimeter so you can test continuity!!! That's what missing somewhere in your ignition system now. And then it's a timing light.....and on and on and on......electricity is a whole lot more fun than brakes!!!!

Dave

BTW...sharp website!!!

That's great info guys! Dave, I believe I have a test light somewhere around here. I definitely have some jumper leads that I use on occasion. It should be a piece of cake now that you and Bill have explained in simple terms how the system in my truck is wired. I have no problem with the mechanics but I've always felt a little electrically challenged, This sounds pretty simple actually. Thanks again.

I'm glad you like the website Dave. Thanks.

get a new balast resiter its fryed bit you or at least tunn on your key and se if it gets hot if you dont have a balast then its built into your coil so you will need to get a new coil with resister built in

Your truck has an external ballast resistor. Should be located on the fire wall. Follow the wire from the coil + terminal to the ceramic device on the fire wall- thats the ballast resistor.

Harvester

Yep, it was the ballast resistor. I bypassed the resistor and it fired right up. It literally took me 5 minutes to diagnose it and replace. Napa had one on the shelf. Thanks for all your help guys!! I owe you a couple of beers!