940 LPT 2.3 problems starting in damp

[Laird Scooby]

Originally Posted by haymitch

There was a typo in my email above, when I wrote 'I also tested the negative battery terminal to chassis ground' I meant to say I tested the positive battery terminal to the bolt at the end of the battery - body earth strap. Wouldn't you expect to see the same voltage here as between the battery terminals? Sorry - I'm confused to why the readings from positive to this ground would behave different to positive to other grounds in the engine. For example, with the engine off I measured 12.53V between the positive terminal and the each of the grounds at the rear of the engine bay.

I've checked the air filter I still need to replace the vacuum lines. I'm also going to reread this thread make a list of all the suggestions that have been made in this thread and work through any outstanding ones. For example, I still need to better check your method of engaging the starter once before cranking the engine fully again. I've done this once, but not directly after the hot start problem happens.

Did you recheck your voltmeter was still working after that test? Assuming it was, with bolts that have been on there for quite some time, you often have to use the point of the probe to scratch the head of the bolt to ensure good contact.

If you check batt +ve to engine block you should get the right (battery voltage) readings both running and not running.
Also if you check engine block to battery -ve with the engine running, it will show up as a small voltage if there is a bad connection.

Bit of a wild card thought crossed my mind. After switching the engine off, put your foot on the brake repeatedly and count how many pushes it takes before the pedal goes hard. Should be in the region of 4-5 pushes, any less and it might point to a problem.

Then keep your foot on the brake and maintaining an even pressure, start the engine and the pedal should sink slightly as the engine starts and builds vacuum. It should do this in a matter of a few seconds. If it takes longer or the engine is harder to start then i think we might be looking at the non-return valve in the servo hose.