1.7 hot starting problem

[donandreasen]

I have a 73 1.7 that will start cold perfect and runs perfect at all temps. When it is warmed up if I sit it for 10 minutes or so it will crank and not start. I'm getting fuel and spark. The spark appeals to be weak. It will push start. I suspect a voltage drop under crank start not giving the injection and computer enough juice to work properly. The ground strap appeals to be ok. What about a bad cold start valve? It's frustrating. I just purchased the car and the prior owner had spent thounds on this car it is very well maintained. It has a new battery,starter,plugs and plug wires. All connections and vacuum lines appeal to be secure and proper. Any help????

[Dave at Pelican Parts]

The cold start valve only works in fairly cold temps. <50F? <30F? Don't know exactly. Check for ground on the thermo-time switch (probably on a bracket off the manifold) and for +12V on the other wire. Both are required for the injector to squirt--but it wouldn't for a warm start anyway.

If the spark really is weak from the starter pulling the voltage down, then new wires might help. That is, the wire from the battery to the starter, the tranny ground strap, and the battery gournd strap. Clean up the ends and the attatchments very thoroughly (wire brush is good) and see what happens.

You might want to verify that the spark is weak when cranking while warm. That may help you avoid replacing the wires without fixing anything.

Good luck!

--DD