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HARD starting when engine is warm

Old 01-25-2010, 12:17 PM
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Car: '91 LS6/T56/9"
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HARD starting when engine is warm

So here's the situation. My 86 Z has a Jegs mini starter, battery relocated to the trunk, and a duralast battery. (I forget what the CCA of the battery is)

When I start the engine cold, it'll crank as long and hard as ever. But after the engine's reached operating temperature, it turns over very VERY slowly and more times than not won't even start.

What the hell could it be? Higher output alternator? Optima battery?

Another little quirk is that the stock voltage gauge only reads the normal aprox 13-14.5vdc after I give the engine a good rev.

I doubt it's the starter cause it's new and did the same thing with the stock one. Any thoughts?


Last edited by robguitargod1; 01-25-2010 at 12:30 PM.
Old 01-25-2010, 02:27 PM
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Car: LOWERED ♦ CRIMSON METALFLAKE
Engine: ► 400 KUBES ◄
Transmission: 765R4
Axle/Gears: EATON POSI 4.56
FIRE !

You can empty a CO2 fire extinguisher on the starter to see if it has a heat problem.


Happy Racing!


If People Drove Any Slower They’d Be Going Backwards

When you see fog or “running” lights on in good weather beware. Low performance driver ahead.

How bout those nitwits too scared to drive without headlights in the daytime, and the nitwits that need headlights for a little rain

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Old 01-25-2010, 03:12 PM
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Re: FIRE !

huh?
Old 01-25-2010, 04:46 PM
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Re: FIRE !

Is it possible the stock battery just can't keep up with the added resistance of the starter/positive lead warming up and the relocation? I'm thinking this summit alt would be a nice upgrade: http://www.summitracing.com/parts/SUM-810351/



And this optima: http://www.summitracing.com/parts/ULT-9051-160/

Old 01-25-2010, 05:34 PM
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Re: FIRE !

I know you said you have replaced the starter with a mini version but it sounds like heat soak. Is the exhaust stock and in stock location with respect to the starter? Any chance you're running lean (hotter than normal exhaust)?

Those are the things I'd be curious about.
Old 01-25-2010, 05:36 PM
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Re: FIRE !

Originally Posted by robguitargod1
Is it possible the stock battery just can't keep up with the added resistance of the starter/positive lead warming up and the relocation?
That is an interesting question. What gauge wire did you use for the relocation?
Old 01-25-2010, 05:49 PM
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Re: FIRE !

Stock routing. Edelbrock headers and Y pipe. Are you saying heat shielding wrap on the headers and/or starter?

It's 1 gauge wire from this kit.

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Old 01-25-2010, 08:21 PM
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Re: FIRE !

Assuming that your connections are clean, that wire is fine and the additional 10' of circuit shouldn't be an issue. This makes me return to my first suspicion… heat soak. I’d try an inexpensive heat shield for the starter and see if that helps.
Old 01-26-2010, 12:50 PM
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Car: LOWERED ♦ CRIMSON METALFLAKE
Engine: ► 400 KUBES ◄
Transmission: 765R4
Axle/Gears: EATON POSI 4.56
FIRE !


Originally Posted by robguitargod1
huh?
In other words a when a CO2 fire extinguisher is sprayed on an starter, it cools the starter.

Therefore if the problem is caused by the starter being too hot, cooling the starter, and waiting for a minute for the heat to be drawn out to the case, then cranking it - if the starter turns faster you know heat in the starter is the problem.

It’s now worth the effort to heat shield the starter.


Happy Racing!


If People Drove Any Slower They’d Be Going Backwards

When you see fog or “running” lights on in good weather beware. Low performance driver ahead.

How bout those nitwits too scared to drive without headlights in the daytime, and the nitwits that need headlights for a little rain

.
.

Old 01-26-2010, 12:55 PM
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Transmission: T56
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Re: FIRE !

Gotcha. I'll be buying some exhaust wrap from Pepboys tonight.

Last edited by robguitargod1; 01-26-2010 at 01:10 PM.
Old 03-16-2010, 03:21 AM
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Re: FIRE !

Did you solve your problem?
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