Hot start problem

[Olivera]

Looking for some advice on a hot start problem I have with my Escort Cosworth.

Car starts fine from cold, but when hot the starter motor turns very slowly and usually fails to start the car (sometimes you can get lucky and it will start).

I've previously replaced the battery, so it's now about 12.7v with the engine off. With the engine running it's about 13.5v. This hopefully indicates the battery and alternator are fine.

Now I also did a voltage drop test to the starter, one lead of the multimeter at the +ve battery post, the other at the power in to the starter. This gave:

cold - 0.01v
hot - 1-2v !

So looks like the power cable to the starter is the culprit?

[stevieturbo]

Starter takes a lot of current so some volt drop is inevitable.

Check wiring, connectors, grounds etc

[Penelope Stopit]

Olivera said:

Looking for some advice on a hot start problem I have with my Escort Cosworth.

Car starts fine from cold, but when hot the starter motor turns very slowly and usually fails to start the car (sometimes you can get lucky and it will start).

I've previously replaced the battery, so it's now about 12.7v with the engine off. With the engine running it's about 13.5v. This hopefully indicates the battery and alternator are fine.

Now I also did a voltage drop test to the starter, one lead of the multimeter at the +ve battery post, the other at the power in to the starter. This gave:

cold - 0.01v
hot - 1-2v !

So looks like the power cable to the starter is the culprit?

cold - 0.01v Is not possible, you should be getting a higher reading than that from a 100% good circuit

0.75volts is the limit for the volt drop on the live side of the circuit

hot - 1-2v If the battery is good, the engine not tightening up when hot and the wiring is good, that volt drop is pointing to the starter drawing too much current when hot

[chimp427]

Considered using a jump lead from battery positive to solenoid battery terminal to see if it cranks any better?
It may not fit but worth a try just to help you eliminate something.