Intermittent starting problem

[dzbowtie]

Hello all,

I've been having an intermittent starting problem with my truck. When it happens, I turn the key on, my red brake light turns on, but nothing happens (like a dead battery). However, battery is good and it doesn't always happen. The only relays I have is for the headlights.
The curious thing is I can attach jumper cables, or battery charger and it'll fire right up and never give me a problem. I dont even have to allow time to charge. Its almost like I just need a little extra power for the starting. Alternator works also.
Could this be a starter issue? I'm just lost as to why this happens sometimes and not consistently. I appreciate any help guys. I hate to carry a portable booster lol.
This is a 70 c10 with 350/th350.

[garyd1961]

Make sure all your cable connections are tight and clean including the starter and all grounds. Make sure you have a good ground from the engine to frame.

[Steeveedee]

Bring a test light with you from now on. The next time it happens, check the fat purple wire on the ignition switch. If it doesn't get "hot" in the start position, the contacts are worn. Is it the original ignition switch?

Also, it is a fairly common problem that the starter gets heat soaked, and the truck won't start until it cools off. I had the same problem with my '69 Camaro, but it usually happened after I had been driving it at speed, like 100+ MPH, for awhile. Since you probably had the hood up, the engine cooled off by the time the jumpers were hooked up, so it started right up. My truck has had a hot start problem for decades. I put in a reduction gear permanent magnet mini starter, a ground cable straight to the starter, and added more ground straps. It still gives me a problem, but about 3% of what it used to be like.

[dzbowtie]

The ignition switch has been replaced 4-5 yrs back due to not having keys when I bought the truck. The starter I am using right now is a jegs brand mini starter, also used 4-5 yrs. I have a multi meter in the truck and will try it next time it won't start. The switch is a LMC brand and may not have been the best choice. I'll check the starter connections also

[spoon3210]

your starter solenoid might be the culprit. Hold the key in the start position and have someone hit the starter with a hammer. if it starts you need a new solenoid.

[Steeveedee]

Originally Posted by dzbowtie

The ignition switch has been replaced 4-5 yrs back due to not having keys when I bought the truck. The starter I am using right now is a jegs brand mini starter, also used 4-5 yrs. I have a multi meter in the truck and will try it next time it won't start. The switch is a LMC brand and may not have been the best choice. I'll check the starter connections also

Based on this, I'd say that it is still heat soak. Has this been a problem the entire time you have owned the truck? What I'm driving at is, when did you notice the problem, what have you noticed made it better (or not) when replacing parts, that kind of thing. I'd be interested in getting data such that an actual solution was found, and could be made known here. I did all the stuff as posted above and still have an occasional problem with starting my truck hot. If we could get enough data, we could find a solution and make the hot start problem go away. Having to sit while the problem resolves itself is not an acceptable solution, in my book. It isn't acceptable to me that I pull into a gas station, while towing my camping trailer, and have to wait for it to cool off enough to get it to start again, when the other guys with their newer diesel-powered rigs pump their tanks full, and can fire up and drive off, except that they have to wait for me!

[dzbowtie]

I questioned the heat issue myself, having dealt with this in a camaro I used to have. However, this doesn't happen only when hot, there's almost no rhyme or reason as to when she'll decide not to start. Like mentioned previously, I did find it awful strange that merely putting jump/charger to it will fire it right up. I'm thinking the issue is limited to the ignition, wire to the starter, and starter/solenoid itself.

[davepl]

It's NOT heat soak, you DON'T need a heat shield, you DON'T need a new starter, and you DON'T need a Ford solenoid. All of those are reasonable suggestions that might help or work around the problem, but they're not the problem.

The problem is the purple wire.

From your ignition switch leads a purple wire. It runs through the neutral safety switch, then out to the starter solenoid.

Somewhere in that circuit you have a bad or weak connection. Sometimes people try to install a kill switch in this circuit (bad idea). Sometimes an ammeter pickup has been spliced in there. Whatever the reason, it's a bad circuit. Could be in the neutral safety or ignition switch themselves, but I've never seen either as the cause.

Proof? The Ford solenoid approach usually works because all it does is replace the purple wire with a bunch of other heavy gauge wires that use the weak purple wire to trigger a stronger solenoid signal. If there were a genuine starter, solenoid, or heat problem, the Ford solenoid to kickstart the GM solenoid would do nothing.

If you can short the starter terminal to the main lug with a screwdriver and it cranks, you know I'm right :-) Just be careful, don't weld anything with the screwdriver! All I'm saying in this step is "make your own purple wire circuit and see if that starts the starter to prove that it's the purple wire", if that makes any sense.

All of the above is predicated on one assumption - that when you turn the key, NO sound comes from the starter. If it's clicking or clunking, I'm 100% wrong. But if it's silent...

[hamjet]

You might as well check the small wire going from the + battery post that goes to the passenger fender stand off block. maybe when you're jumping the battery you're moving the wire a little causing it to make the circuit.. can't hurt..

[davepl]

Sometime when it doesn't start like that jumper the solenoid post to the battery post with a heavy gauge wire and see if that causes it to crank. If so, there you go.

[davepl]

Ah, I see. I'd earlier said the Ford solenoid just took the place of the purple wire, but it appears from the diagram that it unions the starter and solenoid together and then engages them as a unit using the Ford solenoid. My bad.

Still preferably to me to find the problem in the crank circuit wire, but this'll fix it.

[Steeveedee]

Originally Posted by davepl

Ah, I see. I'd earlier said the Ford solenoid just took the place of the purple wire, but it appears from the diagram that it unions the starter and solenoid together and then engages them as a unit using the Ford solenoid. My bad.

Still preferably to me to find the problem in the crank circuit wire, but this'll fix it.

The fix you mentioned earlier for the start circuit purple wire is a good one. In my case, it cranks hard when hot. If I open the hood, it cools enough in about 10 minutes and will then start.

[weq92f]

If anybody does the screw-driver trick/test, please use caution:

From below:

lift and support the vehicle with multiple failure tolerance ( jack stands, a jack and wheels under there with you

Use wheel chucks.

make sure the transmission is OUT of gear, in Park or otherwise secured against the starter causing the vehicle to move off the jack stands

From above:

Same thing about the tranny being OUT of gear.

Stand to the side

-klb

[davepl]

Originally Posted by firedemon

yes exactly and the reason it works is it only takes 3 to 5 amps from the purple wire to engage the ford solenoid instead of the 50 to 60 the gm solenoid takes . and because the gm is now getting all the amps it can ask for on the s terminal it will usually turn over way easier . its also way more gentile on a nearly 50 year old key switch and neutral safety and bulkhead connector kind of like the headlight relay mod way less chance of a fire or burned wires . however don't do this for a modern hi torque mini starter the starter will actually generate a small amount of electricity winding down (when you let go of the key ) and back feed from the battery terminal to the s terminal through the solid lug and keep the starter engaged . mini starters have the same current draw on the solenoid 50 to 60 amps so most of the time mini starters are a waste of money unless your running some serious compression . but if you are running high comp a ford solenoid is still a good idea just wired differently .

It works, no doubt, but so do the 50 year old purple wires in my Camaro, my 2 Pontiacs, and my truck. So long as they're not damaged, they'll start the car properly no matter the temperature for 100 years, I'm sure.

My only point is why not fix the truck rather than patch it up? You're going to be relying on the purple wire anyway to fire off the Ford solenoid, and while it certainly will take less amps than the hot Chevy solenoid, you're still going to be relying on a circuit that has undiagnosed failure in it somewhere.

Now if the Ford setup is inherently better than the Chevy, you could argue for the conversion so long as originality isn't a concern. I can see the argument for not having the solenoid down by the hot exhaust, etc.

[KQQL IT]

I also approve of the Ford solenoid. For purely not having battery voltage at the starter.

And I've also learned the Chevy mini starters do not like the jumper wire from battery to start terminal, it will hang the bendix in the flywheel a 1/2 second longer than it should.

It shouldn't work, but my 68 and 73 both have a ford solenoid and a jumper wire down to the start solenoid. Weird but works.

[dzbowtie]

So guys, update on the starting problem. Reading another post by VetteVet, I ran jumpers from power wire/purple wire on starter and solenoid. With the use of a push button, the starter turned over. I then moved to the cab. The power wire in the back of the switch was receiving 12volts per the multimeter. Then I jumped the red power with purple wire on back of switch, again starter turned over. So, this leaves the switch itself not making the connection all the time as it should. Hopefully a replacement will fix this problem...

[VetteVet]

Originally Posted by dzbowtie

So guys, update on the starting problem. Reading another post by VetteVet, I ran jumpers from power wire/purple wire on starter and solenoid. With the use of a push button, the starter turned over. I then moved to the cab. The power wire in the back of the switch was receiving 12volts per the multimeter. Then I jumped the red power with purple wire on back of switch, again starter turned over. So, this leaves the switch itself not making the connection all the time as it should. Hopefully a replacement will fix this problem...

Well maybe:
If you jumped the ignition switch when it was in an intermittent phase and not working and then it worked when you jumped the switch, I'd agree. I'm thinking that's the case. Otherwise there's the possibility that it might be the neutral start switch not closed by the position of the gear selector, or the connection between the purple wires in the firewall block behind the fuse block.

It might be worthwhile to wait until the no start happens again and then jump to the ignition side of the neutral start switch. Don't bump the shift lever and if the starter turns it confirms that the key switch is bad. If not jiggle the shift lever and see if the starter turns then.

It is quite common for the NSS to get out of adjustment or wear down where it won't close the circuit between the purple wires.

[HO455]

Originally Posted by davepl

It works, no doubt, but so do the 50 year old purple wires in my Camaro, my 2 Pontiacs, and my truck. So long as they're not damaged, they'll start the car properly no matter the temperature for 100 years, I'm sure.

My only point is why not fix the truck rather than patch it up? You're going to be relying on the purple wire anyway to fire off the Ford solenoid, and while it certainly will take less amps than the hot Chevy solenoid, you're still going to be relying on a circuit that has undiagnosed failure in it somewhere.

Now if the Ford setup is inherently better than the Chevy, you could argue for the conversion so long as originality isn't a concern. I can see the argument for not having the solenoid down by the hot exhaust, etc.

Back in time before mini starters I dealt with this issue on my daily driver GTO (the only car I owned) With a set of headers and the 10:1 compression that Poncho would eat a starter solenoid every couple of months in the summer. I couldn't tell you how many times I had to push it out of a gas station. Toss in weekend drag races and it got to be a real problem. (Nothing worse than losing because your car won't start) I tried buying a new GM starter ($180 bucks in 1983. Big money for a sailor) but it only helped a while. I rewired the neutral safety circuit (purple wires) with 10 guage high temp stove wire and connectors. I replaced the neutral switch and bypassed the bulkhead connector. It all only helped some. I ended up putting a push button override in the circuit and only then was I able to start the engine every time I wanted to. The Ford solenoid is just a variation of that idea.

[garyd1961]

What size battery cables are you using? I went to 2 gauge cables on my truck. I'M not sure what came from the factory but most have been changed over the years and my truck had 4 gauge cables when I got it.

[dzbowtie]

I know this thread is a couple months old at this point, but just to recap:

at times, the starter does not want to turn over, almost like a dead battery. the red brake light in the dash will come on.

I tested with a jumper wire, the power wire and ignition wire at the starter...the starter will turn over.

when I would attempt to start the truck with the key, I could hear a click but nothing happens. almost like the starter is stuck.

at this point, I used the jumper wire on the back side of the ignition, which the same happens. I could hear a click, but no turning of the starter.

I hooked a push button to the starter with alligator clips, bumped it over 1 time.

from there, I could start the truck with the key. almost like the starter was stuck, but once bumped over with the push buttom, the key ignition worked.

vettevet, help me out here!!!

thank you

[davepl]

Sounds like I already covered this exact problem in my manifesto about the Purple Wire.

Your solenoid circuit has too much resistance in it. Bad switch, neutral safety, or far more likely, a bad splice in the purple wire.

[dzbowtie]

Dave,

Would this explain why, when this happens, I can put jumper cables in from another vehicle and she fired right up with no issue every time?

If the purple wire is the culprit, is there anything I can do to help until the wire can be replaced?

Thanks again

[cleszkie]

Originally Posted by dzbowtie

If the purple wire is the culprit, is there anything I can do to help until the wire can be replaced?

Thanks again

Install a Ford solenoid LOL.

[davepl]

Originally Posted by dzbowtie

Dave,

Would this explain why, when this happens, I can put jumper cables in from another vehicle and she fired right up with no issue every time?

If the purple wire is the culprit, is there anything I can do to help until the wire can be replaced?

Thanks again

I don't remember... I think jump-starting helped when it happened to me. It makes sense that it might bring up the cranking voltage enough that it can overcome a marginal solenoid circuit.

Basically, if you can start it by "hot wiring" the solenoid pole on the starter, then you know the starter and everything else is good, so it must be the circuit. So if you can start it with a screwdriver or jumper lead, that's a pretty good indication.

This happened to me 30+ years ago when I was 17. I had no idea what caused it, but for some reason turning the motor over by hand with the fan would sometimes help. Pouring water on the starter would help. Eventually we figured out the screwdriver trick and my passengers all got good at it.

Not sure how I finally figured it out. Ultimately the cause was a poor quality splice where I had tried to install an ammeter or kill switch or something. But about 3 years later my brother had a similar problem and the shop replaced a ton of parts, without luck, only to find out it was the same thing (purple wire!). So it's kinda stuck with me.

[leftybass209]

New parts don't necessarily equal good parts. Getting a "click" sound (from any component that doesn't function) simply means there's not enough current supplied to operate it efficiently, or the component is broken.

The current issue can be caused by either a resistance that's too high, or not enough current from the battery.

High resistance can be caused by bad connections, old wiring, brittle wiring which may be broken under the conduit, corrosion which may not be seen, especially if it's crept under the conduit. It can also be caused by a mechanical fault. If you have anything worn in the engine, or the starter, it increases mechanical resistance which puts a larger strain on the battery, increasing the amperage to start the vehicle.

A good battery is 12.65+ volts DC. A battery that reads even 12.40 volts, is only 75% charged. However, that is only the voltage provided, not the current. The battery must be load tested to find out if it truly is good. A proper load test should be done to half the CCA of a battery 2 times for 15 seconds each. Wait 30 seconds for the battery to recover, and the battery should read 9.6 volts or higher. Walk your local auto parts guys through the process as they probably don't know the proper way, because they load test dead batteries all the time without properly charging them, then incorrectly tell the customer the battery tested bad.

You can do a voltage drop test on your battery cables as well.

1. Disable the ignition or fuel system on the truck. Fuel is better because it doesn't flood the cylinders, but harder unless you have an electric fuel pump in which case, remove the fuse and start the truck until it dies.

2. Connect one lead of the voltmeter to the starter motor battery terminal and the other end to the positive battery terminal.

3. crank the engine and observe the reading while cranking. (disregard the first higher reading.) The reading should be less than 0.20 volts (200 millivolts)

4. If accessible, test the voltage drop across the "B" and "M" terminals of the starter solenoid with the engine cranking. The voltage drop should be less than 0.20 volts (200 millivolts).

This test can be done from the batt. terminal to the connection on the cable. From one end of the cable to the other end of the cable, or from the batt. terminal to the S. terminal on the starter. Each test tells you the resistance of that particular connection.
This test is only to check if the cables and connections are okay. A starter amperage draw test can determine if the starter motor is at fault, but requires a current draw tester such as a VAT 40/60 or the newer fancy Snap-on machines.

An 8 cylinder with typical compression should draw somewhere around 185-250 amps (normally less than 150 amps) at room temp.

Having said all this, I wouldn't suspect any of it is your problem. The start system on a classic vehicle is notoriously easy to work on. There are only 4 components and their associated wiring. Battery --> Ignition Switch --> NSS --> Starter solenoid. You've addressed the components, but the wiring is still old. I'd rewire it. All the parts to keep the wiring original can be found through various vendors.

It's also possible to do voltage drops on ANY of the wiring between any of the components. Higher volts or millivolts simply means increased resistance under load. It's such an underrated test but extremely effective.

Regarding Ford Solenoids. They are usually band-aids to existing problems. The GM starter system IS just as reliable as the Ford starting system. However, the Ford solenoid is usually implemented when people don't understand electrical systems, jump online or talk to a friend who suggests they pick up a "cure all" Ford style solenoid. They work, plain and simple. However, to use an instance that most people understand:

if I told you to wrap a leaky radiator hose with tape and it'd save you from having to replace the hose (supposing the tape would in fact cure it), would you Band-Aid it or correctly replace the hose?