Hot starter issues?

[CST10]

Hi guys

I have an issue. When the truck is cold it will fire right up. Once hot, sometimes it would restart and sometimes it wouldn't. Once it cooled down it would fire back up.

I originally thought vapor lock issues. Insulated all fuel line, new electric fuel pump, etc.........when hot or cold, I always have 7.5 psi on the gauge by the carb.

Someone told me this could be a starter solenoid issue that is causing this issue.

Anyone ever heard or had this issue before.

[FirstOwner69]

Google the forum for "heat soak". You'll get lots of info.

My truck suffered from this starting at about 85,000. I'd pull into a gas station, and when I tried to restart it would just click. I'd push it out of the way and let it sit 5-10 minutes and it would start right up. It's usually the solenoid or the starter itself. These trucks had the starter pretty close to the exhaust pipe. You can try insulating the starter or make a heat shield to put on the exhaust pipe. I'd probably start by replacing the starter/solenoid with a mini starter.

[LockDoc]

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It could also be the fuel boiling in the fuel bowl after you shut it down. How thick is the gasket between the carb and intake?

LockDoc

[FirstOwner69]

When you say "...sometimes it would restart and sometimes it wouldn't". Did the engine turn over, or did nothing happen when you turn the key? That would help the diagnosis regarding the possibilities mentioned thus far.

[cdowns]

7.5 is too much pressure at the carb you should b at 5 for proper operation
do you have a phenolic spacer between the carb and the manifold to make sure that the gas does not boil out

[CST10]

No gas boiling in the carb bowls. Holley recommended 7 psi max - 5 psi min on fuel pressure.

It did nothing, no click or anything but had power and fuel pressure.

I do have a 1/8 gasket under the carb, the carb is cool enough to touch your hand on it and hold it there for a while without burning yourself.

[FirstOwner69]

Originally Posted by CST10

It did nothing, no click or anything but had power and fuel pressure.

Based on that, I'd vote heat soak. Come to think of it, I don't think I had a click either. Just absolutely nothing.

[davepl]

Have you or anyone before you every cut or spliced the main lead that goes to the solenoid? It's usually purple. If that's not a perfect connection when the starter gets hot it can't provide enough amps to even engage the starter. When it cools down, it'll start. If cut it needs to be a clean, oxidation-free, very good soldering job.

This is particularly common if someone has previously tried to install a "kill switch" in that circuit or cut the wire under the dash or if the neutral safety is marginal. Or if an aftermarket shifter has been installed and its neutral safety isn't robust enough.

Other than physical inspection of that entire circuit you should check the voltage drop to it. Have someone turn the key to crank while you check the voltage at the purple wire. It's only valid when there's a load but the magnet should be trying to engage.

If you're seeing good voltage then it's probably the solenoid itself.

[BLK96]

I fixed mine using a Ford solenoid mounted where junction block was. Use a piece of heavy copper (I used romex ground) to tie battery and start terminals on solenoid together. Run start wire (small one) to S terminal on Ford solenoid. Route positive battery cable thru Ford solenoid to Batt term on starter. Heat soak issue solved.

[davepl]

Originally Posted by BLK96

I fixed mine using a Ford solenoid mounted where junction block was. Use a piece of heavy copper (I used romex ground) to tie battery and start terminals on solenoid together. Run start wire (small one) to S terminal on Ford solenoid. Route positive battery cable thru Ford solenoid to Batt term on starter. Heat soak issue solved.

If I understand what you mean, you're using a Ford remote solenoid to trigger the GM integrated solenoid on the starter?

Ingenious way to get around the problem, but I'd wager if your factory harness was in proper condition it would be unnecessary.

Remember, it's not heat-soak preventing the starter from working. It's heat soak making the starter's solenoid harder to engage. Thus when you do not have full amps available at the GM starter because of a harness issue, it's dead.

You've worked your way around that by using the Ford solenoid to delivery a full current/voltage to the GM solenoid. I'd call it a band-aid, but a robust one.

PS: I had this problem for TWO YEARS before I figured it out. My buddies became incredibly adept at jumping out, popping the hood, and shorting the solenoid terminal to the starter terminal with a screwdriver. You'd think that'd clue me in that full voltage would have solved it, but I was young...

[davepl]

For CST10, you can check my theory with a heavy-duty lead from the battery to the solenoid terminal. Just a heavy gauge piece of wire about 4 feet long to test between the positive post and the solenoid terminal. Hold solenoid terminal and touch it to the positive post on the battery (or even starter, but it can be crowded down there). If that fires the starter even when heat-soaked, my description should be the correct one. You can also do it with a screwdriver as I mentioned above, but you run the risk of some unintentional welding and for all I know a battery explosion.

[asolde]

My starter was cranking hard (like my timing was off) when it got hot. I verified correct intial timing at idle. I took the truck over to oriellys and they tested it. It was intermittent... one time it start right up and the next time it started hard. I would bet from what you discribe your starter is ready to change. Take it over to your local parts store and let them test it for you.

[jordanblea]

Had the same heat soak issue as well. Mini starter is a good way to gain some clearance from the headers (80 bucks shipped). When you're having the issue get a water bottle of cold water and squirt it onto the starter, might take 2 bottles but that'll help dissipate some heat right away and it should start up for ya. That way you don't have to wait for it to cool down.

[jordanblea]

Had the same heat soak issue as well. Mini starter is a good way to gain some clearance from the headers (80 bucks shipped). When you're having the issue get a water bottle of cold water and squirt it onto the starter, might take 2 bottles but that'll help dissipate some heat right away and it should start up for ya. That way you don't have to wait for it to cool down.

[davepl]

I think its up to the OP to try the direct-to-solenoid test and see if that fixes it. Throwing parts at it like a mini starter without knowing the why gets expensive. Especially if the real fix is as simple as a bad crimp connector somewhere.

[jordanblea]

Originally Posted by davepl

I think its up to the OP to try the direct-to-solenoid test and see if that fixes it. Throwing parts at it like a mini starter without knowing the why gets expensive. Especially if the real fix is as simple as a bad crimp connector somewhere.

I wonder how close the solenoid is to his headers. Mine were like 1/2" away. Most of the year it's fine but when it starts to hit 90+ mine would heat soak here and there. Clearly it's up to the OP to do what he wants. If his solenoid is that close I would bet it's heat soaking, and if not the mini starter is a cheap upgrade if he didn't need it (lifetime guarantee too). If it fires cold just fine and he's not having any boiling gas issues, my bet would be the solenoid. A bad connector would give him the same issue hot or cold?

[davepl]

I have no doubt it's heat soaked. But it should still work. After all if they could make them crank over in a big block C3 Corvette it should be trivial in a truck.

I hope its the solenoid. 20 minute fix. But if its not, lives have been ruined and marriages destroyed. Oh wait, that's an exaggeration, but it can be a seriously annoying problem to chase down if I'm right.

No, a bad connector shows up only when hot (unless it's really bad I guess). That's what makes it so insidious, and why I'm pushing on this topic.

Here's the typical workflow:

- Works when cold
- Does -nothing- when hot, no click, no nothing
- User waits for it to cool, but gets mad because this happens all the time now
- User starts carrying water, turning engine over by hand with the fan, urinating on starter, whatever it takes.
- User replaces solenoid. No change.
- User replaces starter. No change.
- User replaces ignition switch. No change.
- User replaces neutral safety switch. No change.
- User finds where some 70s hippie spliced the wire with a crimp connector
- Remove crimp connector, clean wire of all oxidation and corrosion, make a proper soldered connection [or replace that section of wire with same color and gauge]
- Drive it like you stole it

Thing is that its easy to test with a volt meter (again, only when engaged, ideally when its still cold and cranks). If you don't have within about half a volt at the solenoid wire what you do at the positive post while cranking, there you go. Or maybe it's a full volt. I'd imagine as long as the solenoid is seeing 12V while cranking that's all it needs to tolerate. But I'm not sure what the lower limit would be to engage a heat-soaked solenoid.

[jordanblea]

Originally Posted by davepl

I have no doubt it's heat soaked. But it should still work. After all if they could make them crank over in a big block C3 Corvette it should be trivial in a truck.

I hope its the solenoid. 20 minute fix. But if its not, lives have been ruined and marriages destroyed. Oh wait, that's an exaggeration, but it can be a seriously annoying problem to chase down if I'm right.

No, a bad connector shows up only when hot (unless it's really bad I guess). That's what makes it so insidious, and why I'm pushing on this topic.

Here's the typical workflow:

- Works when cold
- Does -nothing- when hot, no click, no nothing
- User waits for it to cool, but gets mad because this happens all the time now
- User starts carrying water, turning engine over by hand with the fan, urinating on starter, whatever it takes.
- User replaces solenoid. No change.
- User replaces starter. No change.
- User replaces ignition switch. No change.
- User replaces neutral safety switch. No change.
- User finds where some 70s hippie spliced the wire with a crimp connector
- Remove crimp connector, clean wire of all oxidation and corrosion, make a proper soldered connection [or replace that section of wire with same color and gauge]
- Drive it like you stole it

Thing is that its easy to test with a volt meter (again, only when engaged, ideally when its still cold and cranks). If you don't have within about half a volt at the solenoid wire what you do at the positive post while cranking, there you go. Or maybe it's a full volt. I'd imagine as long as the solenoid is seeing 12V while cranking that's all it needs to tolerate. But I'm not sure what the lower limit would be to engage a heat-soaked solenoid.

The water trick is a good one!! lol. I only had to do that once, usually it would crank and crank and then start. The first time it did nothing I hit it with the water and I drove home and ordered a mini for the clearance, just had to clock it towards the block away from the headers (obviously lol). Id just replace all wires and starter at the same time personally. Like I said cheap upgrade and a lifetime warranty either way. If it continues to heat soak it's just gonna wear the thing out and kill it all together eventually. Remote solenoid or mini imo.

[CST10]

The water trick sounds like a good idea in a pinch to get moving again. It's only happened recently with the 90 *+ weather.

As far as the wiring, I did notice when I was under there tapped on the starter with a screwdriver handle that there IS a crimp connection on the S lead wire.

I never thought of that as a possible issue, thanks guys. I will try that out first and report back with the results.

I also have what I tend to think is a rather small hot lead from the battery to the starter. That would be the second thing to replace if the crimped wire solution doesn't fix it.

Exhaust manifold is approximately 1-1 1/2 inches from starter also.

[FirstOwner69]

Originally Posted by CST10

I also have what I tend to think is a rather small hot lead from the battery to the starter. That would be the second thing to replace if the crimped wire solution doesn't fix it.

Is this in addition to the battery cable? Does it come directly from the battery? Where is it attached to the starter?

[franken]

Why not measure the voltage at the solenoid with the key in the start position? Chances are its low.
Measure the battery voltage with the key off as well.
Clean ground connections and move the ground to the block.
If the solenoid never engages, there's no chance of the issue being with the large + battery cable.

[Lattimer]

I've been through this. My truck had all new wiring to the brand new GM starter, and would heat soak and either crank very slow or not crank at all in the summer. Had to douse it with water a couple of times to get it started.

I did both the mini starter and the Ford solenoid, and the problem is gone completely. 95 degrees and running for hours, it will start back up flawlessly.

Jegs sells a kit for the remote solenoid that works pretty good and wasn't too expensive. Also gave me a nice spot on the firewall to pick up battery power for other things.

[BLK96]

davepl you are probably correct about a robust band aid. I also prefer not having the always hot large batt cable connected at starter. Pretty tight there. I like the Ford design better. That cable only energized when needed. Although Ford started doing something similar in 92 when they went to perm. magnet mini starters. That's another story.

[davepl]

Originally Posted by BLK96

davepl you are probably correct about a robust band aid. I also prefer not having the always hot large batt cable connected at starter. Pretty tight there. I like the Ford design better. That cable only energized when needed. Although Ford started doing something similar in 92 when they went to perm. magnet mini starters. That's another story.

That's true... I've never had one hit an exhaust manifold yet, but I bet it's quite the light show if it happens.

I had an ammeter wire short out internally once (same ammeter that caused my first bout of this problem). I ran and opened the hood and the insulation was already gone and I had two runs of almost white hot wire. Hard to imagine what a #00 battery cable would do!

[CST10]

It was the starter. Changed it. Ran it idling with ac on for 30 minutes, it got to 210*. Shut it off for about 4-5 minutes. Fired right up. Shut it back down and let it soak another 4-5 minutes. Fired right back up again.

Looks like the starter was going bad.

Thanks everyone for the advice and help. Much appreciated.