Hot Start Solution fo my Truck

[Steeveedee]

For a few decades, my FIL's truck has had a problem cranking over when hot- just would not turn over, or turned over slowly. It was a known problem, and meant that each time his family went on a camping trip, if the truck got shut off, there was a minimum wait of at least half an hour before it would easily crank up again. It used to start OK, but at some point, that ability went away.

I know that people have gone to some lengths to get around the problem, including wiring in Ford solenoids to the start terminal. My wife inherited this truck 6 years ago when her father died.

I was working mucho overtime (in fact, I worked so much overtime that I invested the money, and retired at age 62). Now that I am retired, and got in a position where I had to depend on the truck for daily transportation instead of occasional use, I decided to track down the cause. Looking at other threads both here and on a Buick forum where I also am a member, I realized that this is a problem for a lot of older vehicles. It has been said by many that all you need are a new battery, new cables, and a good starter, maybe a heat shield, etc. I won't argue that a new vehicle doesn't have these issues. But some of the older ones do. I had to ask myself, “why”? I had done all these things already- new battery, new cables, new permanent magnet reduction gear starter motor, timing set properly (I put in an HEI, so points were eliminated, and shouldn't be the cause, anyway).

So, what was I left with? Hard cranking would be caused by voltage drop through the system, drawing large current. Looking at some threads, it occurred to me that I needed a better chassis to battery to body ground. I bought a couple ground straps and made sure that the block was grounded to the cab. The factory ground strap went from the cab to a valve cover bolt, which, IMHO, ain't good enough. I removed that strap and replaced it with one of the new straps, from the cab to the back of the passenger's side head. I sanded the head so that the strap had a good connection. The other strap was connected from the frame to the exhaust manifold on the driver's side (not original, but at this point I was grasping at straws). It started better, but the starter still had to grunt when hot. But I knew I was on the right track, because it improved.

It occurred to me that there was still too much resistance in the cranking circuit. In order to remove as much resistance as possible, I bought a new battery ground cable and ran it all the way to the starter, and put it under one of the starter bolts.

Truck now starts easily, hot.

Why?

Well, here is my thinking- when a vehicle is new, all connections are clean and tight. When the engine comes out for a rebuild, the following things can happen-

The block gets hot tanked, and painted nice
All the brackets and the bolts all get cleaned up and painted nice

Now, it all goes back together, and it's fine...for awhile, maybe the problem never crops up.

I worked for GM for awhile. When a vehicle is assembled, all the parts are clean, the bolt threads are only solvent-wetted, there is no corrosion, pretty much anywhere.

I live in an irrigated desert here in California, and had starting issues. If you live where the roads are salted, you can get (even ever-so-slight) corrosion between the parts. Given that the bolts attaching the brackets and such back during any maintenance, and especially at a rebuild, it is possible that they were just a little rusty from the hot tank and not being dried soon enough, whatever. Maybe the block rusted slightly in the threaded holes, again, slightly. Slightly is all it takes, when you are running 100-150 Amps through a normal starting circuit, which only increases when the resistance increases. Resistance also increases with temperature, which is why your truck starts cold, but doesn't when hot. Add the paint between the parts that you put on to make it look purty, and there you have it- and the threads maybe aren't clean like factory, to boot.

This worked for me. Maybe it will work for you.

[trac209]

Interesting idea to fix a very common problem,thanks for the idea

[Dagr8npwrfloz]

Good post! I've often ran a jumper cable to the starter to diagnose a bad ground... Never really considered leaving one in permenantly...but...why not? Fixed the problem and deleted a lot of future searching for "the next weak link" . Thanks for the great idea!

[Boog]

From well back in the 60's GM vehicles have suffered from hot start problems after a couple of years and some sooner. They were all just fine when new. A fresh battery helped for a while but the issue would come back. Big block engines were more prone to have it. My dad and I would take our starters to a local alternator and starter shop. There he would rebuild an OE starter with 4 fields instead of 2 fields and 2 shunts. This did make them stronger and curb'd the hot start issue on most cars. This beefed up starter, clean cables and fresh battery seemed to be the answer back then. We never understood why the cars started fine when they were newer though unless the starters just weren't strong enough to begin with. I wouldn't think a one or two year old car with original battery cables, grounds, etc and good state of engine tune in our part of the country would have been a victim of corrosion at contact points. I'm talking about low mileage cars that had seen only regular service work.
In the late 60's to early 70's the parts stores began selling a fixit kit consisting of a ford type solenoid to install on GM cars. Some said it helped by moving the solenoid to the inner fender panel so it was kept cooler, less resistance gained. I never tried it as it deviated from the GM design and used a ford part. Practically new cars with modifications like that just wouldn't do for us.
Steeveedee I agree with your finding of clean grounds being as important as anything to a solid electrical system.

[Andy4639]

As stated before on this great site. Grounds are your friends on these trucks and that goes for any old vehicle you may own. You can never have to many grounds!
Just something else to think about to. Relays will take a lot of load off the electrical system. I have them in all my power hungry circuits and mine does great.
This is why GM, Ford and all other's went with them in the new models.

[davepl]

99% of the time the "no start hot" is a bad/cut/corroded/pigtailed purple solenoid wire, but of course the other 1% has to be something, and the ground is the exact other side of the equation.

I don't think a vehicle with a proper battery ground needs a second, but clearly something was amiss with your main one. Easy fix!

When I did my frame-off I bought 3 packs of ground straps instead of 1. Four on the engine, one at the trans, bumper to frame, everywhere. I had a lot of powdercoating done so it was especially important in my case.

If I had a dollar for every ground issue I've seen in my lifetime, I could afford to pay someone to fix my next ground issue for me at $85 an hour!

[leftybass209]

You've uncovered the mystery that is resistance. Someone who doesn't understand electrical components has a hard time understanding the effects of heat and resistance. Often times that leads to throwing a bunch of money at the problem until it goes away, often replacing things that never needed to be replaced.

I'll never understand the arguments for using Ford solenoids when many people have used standard GM starters with headers and hot start all day long.

[Andy4639]

I never ran headers on anything until I put the LS motor in my truck. I never had any problems with either of my small blocks cranking. I have a factory starter on the LS and S/S headers and so far over 2 years of driving with no problems.
Good wiring and good grounds makes a lot of difference in how all thing's run.

[Steeveedee]

I think I wasn't clear on the original post. The battery negative cable now goes directly from the battery negative post to the starter motor, using one of the starter bolts, not bolted to the front of the block. That one ain't connected anymore. I think that GM could do that from the factory, but it's a lot of money for that extra amount of cable. The new cable is about 52" for my big block engine. I did add two different braided straps first, but they didn't help all that much.

Always happy to help, if I can.

[cleszkie]

Well, I went the remote solinoid route many years ago, despite it not being original GM. Not only does it give me gaurateed cranking, it provides an easilly accessible 12 volt keyed power terminal for the relays that run my fans, fuel injection, A/C, spot lights, etc.

[CG]

Well weather you believe the remote (Ford) solenoid works or not, its the only thing that made my truck finally work correctly.

Frame off build, all new grounds on bare metal with a little dielectric grease. All new wiring harness done correctly.

Long tube headers were causing heat problems with the starter. Went to a GM late model truck high torque mini. Still gave me problems now and again. Wired in the remote on the firewall. Never had a starting problem again.

[vics stuff]

As mentioned earlier is the importance in a good ground. Many have missed , that in order to have and maintain a good ground you should always use external star washers between the frame and the wire terminal end . With this , the star washer will bite into both the frame and wire terminal ends. Look at how the manufactures do it.
Vic

[davepl]

99% of the time people just bypass a bad purple wire with a Ford solenoid. That's all they accomplish.

Fix the purple wire, no solenoid needed.

[leftybass209]

Originally Posted by davepl

99% of the time people just bypass a bad purple wire with a Ford solenoid. That's all they accomplish.

Fix the purple wire, no solenoid needed.

Yeah, exactly! Getting people to understand WHY they are installing a solenoid instead of fixing a wiring issue is the hard part.

I'm starting to love complicated electrical issues more and more. One day, I may even be able to reach out and grab the shadow of VetteVet, but i'll probably be long dead before that happens!

[davepl]

I'll take a shot!

The single most common cause I've seen is people cutting that wire and reconnecting it poorly. The connection corrodes a little, the resistance goes up, it can't push enough current to fire the GM solenoid, and you get a "no crank".

People then use a Ford solenoid. The purple wire that used to fire the GM solenoid now just fires the Ford solenoid, which is smaller, so less work. That Ford solenoid now does the work of firing the GM solenoid that the purple wire used to do on its own.

Why do people mess with the purple wire at all? Well:

a) To install a true ammeter gauge inline (though not the right place anyway)
b) To change from a column to floor shift, or anything that monkeys with the neutral safety
c) Home brew kill switch (security, prevent cranking)

You can diagnose this by hooking a volt meter to the battery ground and to the starter lug WHERE THE PURPLE wire connects. The reading is only useful while cranking, or while attempting to crank. You can see the voltage drop when it's a bad connection.

The Ford solenoid bandaids this by getting a better voltage to the starter terminal by bypassing whatever bad connection the person or a previous owner did on the purple wire when they installed the ammeter, kill switch, or whatever.

[swamp rat]

Ya know its funny, i rebuild my engine a bit over 20 years ago and installed headers at the same time, before the rebuild i never had a heat soak problem or any hot start issues, after the rebuild and headers i installed the same starter and cleaned all the connections, especially my grounds, Humm did i scrape the paint off the block where the starter mounts?? Don't know but shortly after that my problems started.

I installed the ford solenoid following the advice of a local auto electric place and have been trouble free every since. If i had read this back them i would have given the battery ground to starter bolt a try!

[davepl]

This horse is a gonna take a beating before I'm done with it.

If you're using a Ford solenoid to crutch the purple solenoid wire, you likely do not have a ground issue, because the Ford solenoid is on the power side, not the ground return, so it can't help much. It can provide a better current path but not a better ground path (engineers who know which way electron flow goes - humor me).

So, I don't think in your case it'd be the ground. More likely the (now famous) purple wire or the guts of the neutral safety/starter switch on the column.

[custom10nut]

Ok, back to the part of this discussion that involves running the "Battery Ground Cable" to one of the "Starter bolts". To do this is simple, but where does it get mounted, to the starter mounting bolt? If not, where?

[Steeveedee]

Originally Posted by custom10nut

Ok, back to the part of this discussion that involves running the "Battery Ground Cable" to one of the "Starter bolts". To do this is simple, but where does it get mounted, to the starter mounting bolt? If not, where?

Yup, one of the mounting bolts. That eliminates a lot of potential bad connections between.

[cleszkie]

So help me out here. When I installed my remote solinoid way back when, I also installed a jumper strap between the starter motor and GM solinoid. It was my understanding that this jumper bypassed the GM solinoid. So why are some people claiming that using a remote solinoid is still effectively using the GM solinoid? I don't think that is and acccurate statement.

[leftybass209]

Originally Posted by cleszkie

So help me out here. When I installed my remote solinoid way back when, I also installed a jumper strap between the starter motor and GM solinoid. It was my understanding that this jumper bypassed the GM solinoid. So why are some people claiming that using a remote solinoid is still effectively using the GM solinoid? I don't think that is and acccurate statement.

Look inside a GM starter. It is not physically possible to bypass the solenoid in any way, shape or form, because it uses electromagnetism from the current drawn to operate the pull in winding, which pulls in a plunger, that gets held in place by the hold-in winding. That plunger is attached to an arm, which engages the drive gear into mesh.

I just tore down a reman two weeks ago, they haven't changed yet.

[davepl]

The GM solenoid still has to be used because it also serves the purpose of pushing the starter nose gear to the ring gear. Without it, the best you could do would be to spin the motor inside the case.

Your jumper isn't needed, but it allows for one heavy wire to fire both the solenoid and the starter. But rest assured the GM solenoid is still there, being fired, and doing its job. Since you've (I think) got it wired so the starter and solenoid are "one" but the starter lug isn't normally connected to the battery as it would/should be, that's all.

It's the exact same as if, when you turned the key to activate the purple solenoid wire you also hooked up the battery cable to the starter at the same time.

[leddzepp]

A thermal wrap around the solenoid/starter eliminated my hot start issues with an OEM starter. I've never had that problem with a mini starter.

[davepl]

Originally Posted by leddzepp

A thermal wrap around the solenoid/starter eliminated my hot start issues with an OEM starter. I've never had that problem with a mini starter.

In both cases that is because keeping the starter temp down, or using a gear reduction with less contact surface, both serve to reduce the voltage needed to fire off the solenoid so will "crutch" a marginal solenoid wire circuit.

Your grandpa's purple solenoid wire in his '63 Biscayne Four Door always worked because no one monkeyed with it, cut it, or otherwise compromised it. Otherwise GM would have had a rash of warranty work every time it got hot in the South.

I'm talking about stock setups; I'm sure it's possible to cook a starter enough with headers that some insulation is required.

I don't think the starter-to-block ground is a common problem, as once you managed to get the solenoid to fire you'd still have a marginal starter ground so it'd crank slowly best case.