280SE starting problem

[OzBenzHead]

Folks:  I obtained a secondhand dizzy - not reconditioned - installed it three weeks ago, and have had no further starting problems.

May as well stick with that one for now, but I shall be pricing rebuilt/recond units for when the time comes that this secondhand one dies.

[WGB]

I had a similar problem with my UK 450SEL in the Australian Heat. I am assuming you have the mechanical K-Jetronic sustem.

Idle slowly deteriorated as the car got hotter, wouldn't start when hot and blew a lot of black smoke.
I read the Bosch Book and decided it had to be the warm-up regulator.
Replaced it with a new one at about $AUD 250 and no problems since.

Here is a photo of what a K-jetronic warm-upo regulator looks like - http://www.southportfuelinjection.com/Warm%20Up%20Regulators.htm

I also replaced the missing underbonnet insulation as there seems to be a lot of heat soak when parked in the sun.

The Warmup regulator has a slide in it like a Motorcycle carb that is open when cold and has a built in thermostat that closes it as the engine warms up. At least I think that is the correct way around.

Another name for it is the auxillary air device and it's job is to let in extra air when the engine is cold and raise the idle - but to close as the engine warms up. On a V8 it is on the front of the inlet manifold. Not sure where it is on the 6 cylinder but it will be somewhere on the inlet manifold in a place that is heated by water.

Can be removed and put in hot water and tested just like a normal thermostat.
I have a picture somewhere of new and old in the same glass of hot water with one closed and one only partially closed

Regards

Bill Babe

[OzBenzHead]

G'day, Bill.

No - it did only happen in Summer (two of them) and, for the first summer, only when car was already at standard operating temperature. This summer it became more random - didn't matter if car was hot or stone cold. Car would either start first crack (as always had) or wouldn't start no matter how much one cranked it. Not a hint of it firing.

Full thick heat blanket under the bonnet.

Tested the cold-start switch (the thermo-timer device), tested the cold-start injector - all checked out fine (regular injectors were all replaced a year ago). Fuel pressure was normal when tested, pump tested okay. Went through everything fuel related and gave up on that angle; then checked the ignition timing. The dizzy wouldn't hold still at the 3,000 revs engine speed and refused to hold any new settings. Tested the vacuum advance and that was okay, too.

Tried oiling the shaft: no difference.

None of this had any effect on the car once started and driving.

The only fix was to take Allen key to dizzy securing bolt, loosen, give the diz a couple of quick twists from one extreme to the other, put it back where it was, and retighten the bolt. Always worked (but damned inconvenient when the shopping was melting in the back seat!).
It seems that the advance plate would mechanically bind in whatever position it was in at engine shutdown.

Not one that anyone seems to have experienced or heard of, but there you go. It's now on record.