Hard starting when warm

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Hard starting when warm

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Hard starting when warm - 4/23/2007 5:36:25 PM

andykbob

Posts: 43
Joined: 8/18/2006
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Hey, I seem to have a problem starting my 351 when its warm. It turns over fine when it's cold, but when it's hot, it barely turns over and sometime it just won't turn it over. I had the battery checked and was told it was fine. The batterey, voltage regulator and alternator are new. I was told that my timing could be too advanced so I backed it off. It seemed to work for a day but then it did it again.

Any thoughts?

Post #: 1

RE: Hard starting when warm - 4/23/2007 5:39:37 PM

Smothers

Posts: 755
Joined: 12/28/2005
From: North Idaho
Status: offline

Check the timing. If timing is too advanced it will act the way you just described.

edit: I just read the last 2 sentences of your statement. I was too anxious to be the one with the answer

< Message edited by Smothers -- 4/23/2007 5:41:19 PM >

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Post #: 2

RE: Hard starting when warm - 4/23/2007 5:40:05 PM

Derf00

Posts: 5451
Joined: 2/22/2005
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What type of distributor are you using?

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Post #: 3

RE: Hard starting when warm - 4/23/2007 5:57:39 PM

Soaring

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Joined: 10/29/2004
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The next time it happens open the hood and get your ear close to the carburetor. If you hear fuel boiling, then you are suffering vapor lock. Get a 1" phenolic spacer under that carb and make sure your gas lines are not near an exhaust manifold.

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Post #: 4

RE: Hard starting when warm - 4/23/2007 6:04:33 PM

toolwench

Posts: 239
Joined: 2/16/2007
From: near Los Angeles
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Do you have headers? Your starter might be getting heat-soaked.

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Post #: 5

RE: Hard starting when warm - 4/23/2007 6:14:56 PM

Derf00

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Joined: 2/22/2005
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quote:

ORIGINAL: toolwench

Do you have headers? Your starter might be getting heat-soaked.

Actually, excellent point. Long tubes will most commonly create this scenario. When I used to work auto parts this was one reason. You can get a heat insualtion mat to put over the starter to protect it from heat-soak if that's what it is.

Vapor Lock is also a possibility but the difficulty in turning over would not be a symptom of this.

I was going to go with an electronic ignition box mounted on or near the distributor that overheats but then that too would not account for the lack of or difficulty in turning over.

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Post #: 6

RE: Hard starting when warm - 4/23/2007 6:42:06 PM

Soaring

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Joined: 10/29/2004
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quote:

ORIGINAL: Derf00

quote:

ORIGINAL: toolwench

Do you have headers? Your starter might be getting heat-soaked.

Actually, excellent point. Long tubes will most commonly create this scenario. When I used to work auto parts this was one reason. You can get a heat insualtion mat to put over the starter to protect it from heat-soak if that's what it is.

Vapor Lock is also a possibility but the difficulty in turning over would not be a symptom of this.

I was going to go with an electronic ignition box mounted on or near the distributor that overheats but then that too would not account for the lack of or difficulty in turning over.

I beg to differ. Vapor locking makes it difficult to start an engine. Symptoms include the engine not being able to turn over fast enough to start.

(in reply to Derf00)

Post #: 7

RE: Hard starting when warm - 4/23/2007 6:49:18 PM

ponyx2

Posts: 208
Joined: 8/30/2006
Status: offline

Check the starter draw with an amp meter when warm. They are cheap and VERY easy to use. Sounds like a heat soaked starter to me, but test it.

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Post #: 8

RE: Hard starting when warm - 4/23/2007 7:07:01 PM

andykbob

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Joined: 8/18/2006
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Thanks: Yes I have long tubes headers.
It's a Mallory Distributor Ignition.
I will check for Vapour lock.

Ponyx2 How exactly do I test it and what should I get for draw if it is the starter that is pouched??

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Post #: 9

RE: Hard starting when warm - 4/23/2007 7:30:46 PM

ponyx2

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Joined: 8/30/2006
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Ammeter gauge clamps on the pos cable, readings over 400 mean it is drawing way too many amps.

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Post #: 10

RE: Hard starting when warm - 4/23/2007 7:40:44 PM

mat11089

Posts: 693
Joined: 11/30/2006
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What a bad coil?Ive come across same symptoms and that was the case.

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Post #: 11

RE: Hard starting when warm - 4/23/2007 7:47:54 PM

Soaring

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Joined: 10/29/2004
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quote:

ORIGINAL: mat11089

What a bad coil?Ive come across same symptoms and that was the case.

The car starts fine when cold. If it was the coil it would be the same symptom when it was cold. But, just to make sure, use that same multi-meter and check the DC voltage at the coil when it is hot. It should be just under 10 volts DC.
So, there you are. It is most likely one of these guys.
1. Timing too advanced
2. Vapor Lock
3. Hot starter
4. Bad coil.

Let us know which one it is.

< Message edited by Soaring -- 4/23/2007 7:53:25 PM >

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Post #: 12

RE: Hard starting when warm - 4/23/2007 8:09:55 PM

andykbob

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WOW 400 amps. Doesn't that seem super high? I don't think my multimeter will measure that. What should a normal draw be?

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Post #: 13

RE: Hard starting when warm - 4/23/2007 8:50:00 PM

andykbob

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Joined: 8/18/2006
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OK. I measured the volts at the coil when cold and when hot, it is measuring approx. 4 dcv.

Also I don't have a meter that will measure 400 amps. Max is 20 amps.

Please comfirm units of measurement.

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Post #: 14

RE: Hard starting when warm - 4/23/2007 8:54:45 PM

Soaring

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quote:

ORIGINAL: andykbob

OK. I measured the volts at the coil when cold and when hot, it is measuring approx. 4 dcv.

Also I don't have a meter that will measure 400 amps. Max is 20 amps.

Please comfirm units of measurement.

Run, don't walk to the nearest auto supply place and get a new coil. You found the problem.

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Post #: 15

RE: Hard starting when warm - 4/23/2007 9:20:58 PM

andykbob

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Joined: 8/18/2006
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K, I just bought a new one with 2 minutes before they close. I will install it and see how it goes

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Post #: 16

RE: Hard starting when warm - 4/23/2007 9:50:17 PM

andykbob

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Joined: 8/18/2006
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Damn it ALL.....I changed the coil and its still doing it..!!!!!

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Post #: 17

RE: Hard starting when warm - 4/23/2007 10:02:21 PM

Soaring

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Going back to my original post. Do you have a spacer under your carb? And, check out that new coil. What are your getting DC voltage wise now? If still 4V then your alternator and battery need to be checked.

< Message edited by Soaring -- 4/23/2007 10:04:24 PM >

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Post #: 18

RE: Hard starting when warm - 4/23/2007 10:17:54 PM

67SuperSnake

Posts: 313
Joined: 3/26/2006
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quote:

ORIGINAL: andykbob

Damn it ALL.....I changed the coil and its still doing it..!!!!!

The coil shouldn't keep it from turning over when it gets hot. Since you backed off the timing, you are probably heat soaking that starter. Two fixes:

1. Build a heat shield out of thin aluminum between the headers and the starter (if you can)
2: Get one of the newer type starters that are much smaller than the original (if they make then for your engine)

< Message edited by 67SuperSnake -- 4/23/2007 10:19:59 PM >

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Post #: 19

RE: Hard starting when warm - 4/23/2007 10:39:25 PM

Soaring

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Joined: 10/29/2004
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It may very well be a hot starter, but I will bet that is is the most common problem with hot engines that don't want to start is that it is a vapor lock problem.

(in reply to 67SuperSnake)

Post #: 20