300TE won't start after 7 day break

[johnmccavert]

I have a 300TE, 1989, 175,000 miles. When the car is used regularly, it runs without any problems; starts first turn of the key and runs smoothly both hot and cold. However if it is left for more than a week, it becomes very hard if not impossible to start. When turning it over, there is no sign of firing until I release the ignition key, when the engine seems to try to start and fails and smoke appears from under the bonnet, through the radiator grille; it occasionally backfires from under the bonnet as well. Eventually, the car starts and runs fairly smoothly when cold. Then when it is warm, it loses power and cuts out altogether under load. It restarts with difficulty. This continues for a couple of days and then the car returns to its usual troublefree self. The longer the car is unused, the more trouble to get it going again. I was away for a month and now it won't start at all. Any ideas would be much appreciated.

 

[wireman]

Perhaps there is a collection of water inside your distributor housing or some other damp trap on the high tension side of the ignition system.
Dirt build up on HT parts can collect damp and stop the sparks from going where they should.

Clean your HT leads up along with the parts around their connections.

Remove the Dizzy cap and rotor arm to ensure they are not damp or dirty.

Avoid using water displacers (WD40 etc) they can become dry and sticky making the system more vulnerable to dirt build up and thence dampness. Wipe the parts clean whilst its still wet if you do use it.

 

[television]

Yes as wiremans excellent post, and every time, I light spray with silicon may help, and welcome to the forum

 

[johnmccavert]

Perhaps there is a collection of water inside your distributor housing or some other damp trap on the high tension side of the ignition system.
Dirt build up on HT parts can collect damp and stop the sparks from going where they should.

Clean your HT leads up along with the parts around their connections.

Remove the Dizzy cap and rotor arm to ensure they are not damp or dirty.

Avoid using water displacers (WD40 etc) they can become dry and sticky making the system more vulnerable to dirt build up and thence dampness. Wipe the parts clean whilst its still wet if you do use it.

Thank you for your replies (including Malcom). The distributor cap and rotor arm have been replaced and the leads and plugs have been checked. They are all clean and dry. Do you have any other ideas, please?

Regards
John

 

[antijam]

Is your battery in good condition? Sounds like a weak battery robbing the coil during starting. A poor battery can inhibit performance even when the car has warmed up.

 

[television]

Is your battery in good condition? Sounds like a weak battery robbing the coil during starting. A poor battery can inhibit performance even when the car has warmed up.

I think that you have something here, the starts when releasing the key bit is the clue here