Hot starting problems.......

[maston]

My 390 has decided to take ages starting when the engine is warm.
Yesterday (luckily I had parked by South Ockendon Motor Spares) it refused to start.
Now I remember a PH member stating that problems with the engine starting when warm could be down to a vacuum leak between the top of the plenum and trumpet base. After buying some temporary gasket sealant and smothering all around the join it fired up
Thank you to whoever posted about the problem.
Currently I have unplugged the cold start injector too and although the starting is better it is still not right.
I think my aux air valve is sticking a bit too, could that be the problem ?
Any help greatly appreciated.
Regards
Ian

[MrPicky]

The first thing to check is the temperature sensor at the top of the engine near the thermotime switch (I assume this is a flapper engine).

A good test once the engine is warm is to short out the connector and see if it is better.

Russ

[RustyNailer]

I had the same problem on my 350i a few years back. It was the starter motor had been baked due to the positioning very close to the exhaust manifolds. Tried a new starter and it was fine after that.

Rob

[maston]

Russ/Rob,
Thanks for your replies.
I have already replaced the CTS and starter motor less than a year ago so I hope they are still ok?
What symptoms would a dodgy aux air valve produce ?
Am beginning to think this may well be the culprit ?

Regards

Ian

[Wedg1e]

The aux air valve would have minimal effect; if it was stuck shut when warm that's not a problem, it's supposed to be closed by then anyway.
If it's stuck open then it'll weaken the mixture to a degree but almost certainly not enough to prevent starting - turn ignition on ond poke the throttle a few times to get the injectors all firing and there'd be enough excess fuel lying around to make it catch once you crank.
A major air leak would be more likely - or an electrical issue.

[maston]

Ian, thank you for that tip. Will try that should it happen again.
On a completely different subject, are you able to make a k&n filter holder plate jobby for me when you have some spare time please ? I have seen the chrome stalks you made Mark, they look excellent.
I am having difficulties in tracking one down?
Let me know how much you want

Many Thanks

Regards

Ian

[Wedg1e]

maston said:

Ian, thank you for that tip. Will try that should it happen again.
On a completely different subject, are you able to make a k&n filter holder plate jobby for me when you have some spare time please ? I have seen the chrome stalks you made Mark, they look excellent.
I am having difficulties in tracking one down?
Let me know how much you want

Many Thanks

Regards

Ian

YHM chap