240 z will not start when hot

[Chris Thomas]

I have a 240z: new engine, new carbs, new fuel pump, new points, condenser and coil. Car start OK when cold (or after it has cooled down), but will not start after it get hot. I thought vapor-lock and put ice packs on the fuel line... didn't work. I'm really stumped... should I continue to look at the fuel system or the electrical system or what?

[esmit208]

CHRIS

What year is the car? The later S30' didn't have much of a VL problem even in hot climates. There might be a connection of some sort that is not that great once the car does warm up. The next time you have this issue take off one of the fuel lines off and turn the key to let the fuel pump energize if you have an electric pump. Disregard this if you have the mechanical pump. Have someone inside the car so you don't fumble and get gas on a hot engine. This will confirm whether or not fuel is being pumped. I will watch this space for any results.

[SteveJ]

What is the car doing? Is the starter engaging? If it is cranking, do you smell any fuel near the intake or exhaust?

Did you check the gap/dwell on the points? Have you checked to see if you have a spark when it's hot?

[5thhorsemann]

I would think if it was a fuel delivery or electrical issue you would stall at some point prior to your destination. Did you try the choke to start when she is hot? could be it starves for fuel with the hot manifolds. you could squirt a few cc's of fuel into the vacuume port on the balance tube and see if she fires and stays running, that will narrow things down a bit. BTW, do you have flat tops or early SU's.

[SteveJ]

Actually, one of the signs I read of a coil failing was hard restarting when hot. If it was a 280Z with the hard restarting hot, I would have guessed ECU as well. The OP hasn't tried to answer some of the questions I posted, so who is to say what it is? Vague descriptions usually draw vague and/or differing opinions.

[hogie]

I had a similar hard start problem last year and I think being too rich caused my problems. It got better as I got the fuel mixture closer to right.