Since as far as I can remember my truck (see signature) starts right up when the engine is cold. After driving for a while and trying to re-start the engine, the starter has to turn quite few times more before the engine starts. It always start but it's annoying to hear the starter running more than it should.

To see if the staring time improved replaced the following: spark plugs & wires, rotor, rotor cap and ignition coil, poured some injector cleaner, upgraded from 2G to 3G alternator, fuel filter.

Even with all this replaced it still doesn't start quickly when the engine is warm.

What else should I change/check?

Thanks for any ideas

 

I have a '92 f150 SCLB with the 351W v8. It also starts right up when cold but will crank longer than I like when hot. It always starts, however. I did the similar tune-up as you did with a little improvement, but not as much as I hoped for.

If this engine was carbureted, like my old '76 Dodge, I'd be suspecting some vapor lock problem. The fuel rails on the 351w sit on top of the engine where they can soak up heat when the hot engine is turned off and sits awhile. I wonder if some of the fuel in these rails is vaporizing and this requires the engine (and the fuel pump) to crank longer to bring up enough liquid fuel to start the engine. I did notice that the hot engine will start right up quickly if I restart it within a few minutes after shut down. The longer the hot engine sits, the more likely it will take longer to start. This seems to back up my theory.

I have a couple of ideas to check. First, maybe someone could measure the fuel pressure in the rails at hot engine shut down and then every minute or so for 5 or ten minutes after, then while trying to start under the excessive cranking conditions. My fuel pressure gauge won't connect to the rail fitting (darn Harbor Freight thing!) so maybe someone could do this. The second idea would be to figure out some way to insulate or shield the fuel rails from the engine heat. I wonder if this has been tried?

One of my sons had a Jaguar XJS with a V12 engine. The engine compartment was really crowded and hot! This car ran the fuel line through a coil inside an extension of the AC system in the engine compartment to cool the fuel. It never had a hot start problem.

 

This is exactly what my truck does. I didn't noticed/realized this until earlier today