Hard starting when engine is warm

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Apr 7, 2003 | 12:36 PM

jblak687

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Hard starting when engine is warm

My truck has been having it's share of trouble recently. When the engine is cold, it starts just fine. But if I've been driving for a while, and try to start again when the engine hasn't had much of a chance to cool down, it cranks very slowly. Usually will fire after about 3-5 seconds. Once it started, the problem has happened every time the engine was sufficiently hot. I have never had a problem when the engine has cooled down for a while.

I have been doing some reading on vapor lock, but I don't think that is my problem. Any other suggestions?

Jon Blakemore

1991 F150, 302 V8, AOD

Apr 7, 2003 | 12:54 PM

greenpus

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Hard starting when engine is warm

If the starter is turning the engine very slow when it is hot then your starter may be going bad or it is suffering from heat soak.

I have had starters go bad or have heat soak because they are too close to the headers. When the starter gets too hot it usually turns very slow

Just something to think about

Apr 7, 2003 | 12:58 PM

jbalestri

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From: Billings MT

Hard starting when engine is warm

Does it crank smoothly? Or does it lope? Easy, then hard, then easy?

It could be the starter, but I am also questioning the timing.

That's about the only two places I could think of to look into.

Apr 7, 2003 | 01:03 PM

greenpus

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Hard starting when engine is warm

Also make sure your battery + - cable to the starter is clean and tight.

Apr 7, 2003 | 03:48 PM

jblak687

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Hard starting when engine is warm

Jbalestri,

I replaced the starter when the problem started, as I thought that is the issue. As to your question of "lope", I'm not sure I can describe it that way. When I crank it, it's slow but seemingly pretty even.

Why would the timing be different when hot and cold?

Apr 7, 2003 | 04:04 PM

jbalestri

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From: Billings MT

Hard starting when engine is warm

The advance on the timing. it seems to me that when an engine is cold, the timing is retarded, so that it burns rich. as the engine warms up, the comp advances the timing. If the timing is out, it will be hard to start. I might be backwards on the timing thing, but:

I made the mistake of timing an engine cold. Man, that thing fired right up cold. But, if I was to go get gas or run into the store, I would have to sit there and let it crank a few seconds until the baby would fire. I timed it warm and never had a problem. Fired first time, hot or cold. Maybe this was a fluke, maybe a non Ford issue (this was my ol' K1500).

Reading out of my Haynes manual, step number 2 for checking the timing is to start the engine and let it warm up to operating temperature.

I might be wrong, but it won't hurt to check it.

Apr 7, 2003 | 05:11 PM

Ford_Six

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From: The Big, Oregon

Hard starting when engine is warm

My first guess would have to be timing. What is it currently at? The reason I say this is because when the engine is cold, there is very little atomozed fuel just hanging around in the cylinders, so it is harder to ignite. When it is hot, all the fuel in the cylinder is atomized, and just floating around. If your timing is overadvanced, this mixture fires too early, and pushes back against the starter.
By "loping", he means that if it cranks normal, then nearly stops, then cranks, every time a piston comes up. If it just cranks slowly in general, then it would be an electrical problem.