Slow starting when hot

[pmschmitt]

Thanks. I went back to try starting it 3 hours after it wouldn't fire and it cranked right up. So I'll be doing some diagnostics tomorrow to see why.

Battery alone has a 12.16 reading with positive and negative in hooked. I went to crank it to get a reading when it was running and it would just crank and crank and not fire again after sitting literally 5 minutes.

I will post more updates as I trouble shoot

 

[traintech55]

Thanks. I went back to try starting it 3 hours after it wouldn't fire and it cranked right up. So I'll be doing some diagnostics tomorrow to see why.

Battery alone has a 12.16 reading with positive and negative in hooked. I went to crank it to get a reading when it was running and it would just crank and crank and not fire again after sitting literally 5 minutes.

I will post more updates as I trouble shoot

If it is the starter, the newer ones with the bolt in solenoid are way better than the old ones.

 

[GJS]

While the engine is running, how many here have grabbed the coil wire with one hand while leaning on the radiator support with the other hand?

Never done it, but seen it and it looked mighty uncomfortable.

 

[pmschmitt]

Trickle charged all night and battery read 12.2 V with colt meter. I gotta get another set of hands to see the draw across the battery when trying to start but I will update.

Can someone remind me again why it may be the starter even though it is cranking? I always thought when starters went out they just quit.

 

[Big_John]

Can someone remind me again why it may be the starter even though it is cranking? I always thought when starters went out they just quit.

The starter can also not turn the engine over fast enough to start the car.

But... Is this the problem?

Your issue seems to be that the car won't start. That's an ignition or fuel problem.

The secondary issue seems to be that the starter turned over slower as you drained the battery trying to start the car.

So do I have that correct?

So...

Let's try to recreate what happened....

The car was hot. You tried to start the car and

A. The starter turned the engine over just as fast as it always does. The engine did not start.

B. After trying for a few minutes, the starter slowed down.

Do I have that correct?

Let's address the starter slowing down first.

You have a battery that is at least 3 years old. That makes it suspect. You've charged it and the voltage is still not 12.5 volts as TrainTech told you it should be. That shows you have a battery that is going bad. It kinda works.... The car starts when things are good... but let's you down when the car is hard to start.

I would replace the battery at this point. You can take the battery into your local automotive chain store of choice and they can load test it for no cost.

With that problem addressed, now we can figure out if there is a primary issue why the car didn't start when it was hot.

 

[Cags70PolaraConvert]

I don't have the diagnostic expertise as the others helping you, I just know that I moved my coil to the fenderwall and after Traintech helped me with my charging issues (my mechanic removed my voltage regulator) it was better . Still slow to start when hot, but now I am talking about letting it crank for 3 to 5 seconds and it starts. Before I was having the same problems you were and that is really no start when hot. My starter was turning the engine fast enough to start the car I believe so as they are saying, its either electrical or fuel.

 

[pmschmitt]

Big John... Yes you have the scenario correct. And I agree battery moth likely bad. I will replace and report back.

 

[pmschmitt]

Used voltmeter to test battery when cranking. Would drop to 8 and failed to start car. Just replaced battery and voila started right up. We will see if that still occurs once it is hot now.

 

[pmschmitt]

Ok still have a problem. Car cranks right off when cold have replaced battery but if the car has been running a while and I turn it off it does not want to start.

Can when warmed up and running on the highway is running around 210-215. When the car is turned off the heat sink takes it to about 240.

When I turn the car off after getting to running temperature I do hear hissing and popping coming from motor after turned off. I just rebuilt the carb before this started happening. The carb runs fantastic on the road and starts much better during cold starts but has this new problem. I have the taller carb gasket that came with the rebuild kit on. The car is running 93 octane.

rhe starter turns fast initially but slows as I continue to crank. Thoughts? Fuel issue? Starter issue? Electrical issue? Thoughts on where to trouble shoot from here. I would rather not just start replacing everything without knowing the actual problem. Thanks

 

[cantflip]

Ok still have a problem. Car cranks right off when cold have replaced battery but if the car has been running a while and I turn it off it does not want to start.

Can when warmed up and running on the highway is running around 210-215. When the car is turned off the heat sink takes it to about 240.

When I turn the car off after getting to running temperature I do hear hissing and popping coming from motor after turned off. I just rebuilt the carb before this started happening. The carb runs fantastic on the road and starts much better during cold starts but has this new problem. I have the taller carb gasket that came with the rebuild kit on. The car is running 93 octane.

rhe starter turns fast initially but slows as I continue to crank. Thoughts? Fuel issue? Starter issue? Electrical issue? Thoughts on where to trouble shoot from here. I would rather not just start replacing everything without knowing the actual problem. Thanks

Do you know how to do a voltage drop test? You will place a voltmeter lead with alligator clips on the battery positive and the other on the starter B+ terminal. Position the meter so you can see it while cranking. Any reading above .5 volts indicates a problem. If the positive wire passes repeat the test on the ground by clipping to the battery negative and the engine block... also .5 or less and you have eliminated the cables, starter itself is the likely culprit (parts store can bench test the starter). If a cable fails, clean the terminals on both ends and retest... still fails you need the cable.

 

[pmschmitt]

Do you know how to do a voltage drop test? You will place a voltmeter lead with alligator clips on the battery positive and the other on the starter B+ terminal. Position the meter so you can see it while cranking. Any reading above .5 volts indicates a problem. If the positive wire passes repeat the test on the ground by clipping to the battery negative and the engine block... also .5 or less and you have eliminated the cables, starter itself is the likely culprit (parts store can bench test the starter). If a cable fails, clean the terminals on both ends and retest... still fails you need the cable.

Do I need to test it when it's hot or does it matter? Thanks

 

[cantflip]

Do I need to test it when it's hot or does it matter? Thanks

No, not really, if you have a cable problem it will show cold. I imagine clipping to the starter would be less fun hot too.

 

[saylor]

hey man -

210-215 is too hot IMO for a run temp. like yesterday I was 185-190 running up here in dallas.

if I sit at a red light for 5 minutes it will get to 200-ish. turn it off and heat soak goes way up there but comes down immediately after a restart.

i dunno if you already did this but this test is also free: turn the car off after running it. let it sit 5 minutes. pull the air cleaner off. manually pull the throttle cable a coupla times. do you get squirts of gas in the carb? does it sizzle/vaporize/go away?

try not to die -

- saylor

 

[pmschmitt]

Saylor
I am running a 195 thermostat as per the FSM but agree I don't like it running at 210-215. I replaced the old thermostat when I got the car and it was a 165 I believe. I know the thermostat is working as it drops down right at 195. But then will slowly rise up to 205-210 when driving in highway. If I'm really pushing her she'll get to 215 and I then back off.

The radiator was just taken out and tested 2 months ago. I hAve flushed the coolant and added clean 50/50. I have a reservoir tank. Running too lean? Other thoughts for running too hot.

Other folks thoughts on highway operating temp of 210 in a 440 in September incentral texas. Outside temp is 85-90 100% humidity.

 

[Gerald Morris]

If you're running @ ~215 F then you might want to make a checklist of your cooling apparatus. Do you have a good fan? How about a fan clutch for the highway? How is the water pump doing? How BIG is your radiator and is it optimal for low altitude and high temperature? What pressure is your radiator cap rated for? Even with a 180 F thermostat, once it opens wide, then the engine will heat up to whatever its going to do, so I don't think a lower temp thermostat will buy you much on those long Texas highways. I run in Arizona and Mathilda RARELY gets over her 190 F norm, even when its 110 F outside. Having a 6 blade, 18" fan turning all the time likely has something to do with that, though I plan to get a clutch on it this winter.

The old 383 normally starts on the first slight bump of the starter, but sometimes when hot I have to crank for a few seconds. The carb is starting to leak, and my distributor is just AMAZINGLY worn out, but despite these flaws of entropy, the damned old motor runs quite well.

Anyway, I'm convinced having a really good radiator makes a lot of difference here. I've got an old 22" one meant for high altitude with an AC which is a bit rare and lauded for its superior quality, despite extreme age and scarcity. I'd LIKE to replace it with a good aluminum one, but little things like paying R-E-N-T get in the way here, and the old one keeps doing its job very well.....

I harp on cooling because I suspect you have a bit of an issue here. Hot intakes and carbs will make an already gasping engine fail, especially when starting. Even at those low Central Texas altitudes, 100 F air is mighty thin! Trying to mix such with petrol in a hot intake system is apt to bugger things up.

Try rigging a mister into your air cleaner. More than a few carburetated car engines have done like Chuck Berry's famous Maybelline when they get a little cool water mist into the fuel/air mix on hot days. You should be able to find something at Home Depot or Walmart for under $20. See if this improves things for you. A little water adds working mass to the fuel/air mix in the cylinders too, improving the compression and power stroke. I KNOW my Mathilda runs BEST in a light rain. If I were having blues like yours, I'd try the mister one afternoon.....

 

[pmschmitt]

ok. Did voltage drop last night and never read more than 0.4 on both positive and ground. I unhooked the foul during this and the starter never got sluggish during cranking like it does when hot. Based on the voltage drop I can rule out the cables it sounds like and I have a new battery so we are left with starter?

As for the operating temp/ cooling system I have a 26 in radiator with a shroud on a 7 blade fan with a fan clutch. Increased temp happening on highway not in traffic. Fan clutch replacement ?

 

[Ripinator]

ok. Did voltage drop last night and never read more than 0.4 on both positive and ground. I unhooked the foul during this and the starter never got sluggish during cranking like it does when hot. Based on the voltage drop I can rule out the cables it sounds like and I have a new battery so we are left with starter?

As for the operating temp/ cooling system I have a 26 in radiator with a shroud on a 7 blade fan with a fan clutch. Increased temp happening on highway not in traffic. Fan clutch replacement ?

Have you done a pressure test on your cooling system? You mentioned earlier that when you shut off the engine after it warms up thoroughly, you "hear a pop and hissing." If there is a small leak of pressure anywhere in the cooling system, it will gradually overheat as you drive. Also, check out your radiator again. You mention it was drained and it tested ok, but unless that was done by a competent radiator shop, it may NOT be ok. Over time, radiators pile up crud from the bottom and gradually clog up half the radiator.

Oh. . . And your hard starting problem sounds like a bad coil to me.

 

[BJS racing]

You may have gone over this already and I missed it. When it is hot what voltage do you have going to the coil while cranking? Can you post a pic of the starter relay you have on your car? It is possible that either the relay or the ignition switch is dropping crank power to the coil and this could be causing the issue. You should see 12v to the coil while cranking and roughly 7-8 while it is running.

 

[pmschmitt]

Cool has 9v going to it while running but less when cranking. Looks like 4v during cranking.

 

[pmschmitt]

Cool =coil