1990 C2 manual initial start up issue.....

[993 C4]

Dear colleagues,
I need a bit of advice please ?
She hasn't been started for around 9 months and the tank is 3/4 full, so this afternoon thought I'd fire her up and go for a run. Basically she usually takes no more than 2-3 seconds to fire when left for several months. This time it took 20 + seconds and when it did start it filled the garage with black smoke as if it was over fuelling and was hunting away like mad. Eventually what seemed like a relay cutting in / or out (?) illiminated the smoke and the 'hunting' and settled down to a normal idle, and with that took her out for a 30 minute run. It went as well as usual apart from a sudden loss of power when pushing on through both right and left hand bends....symptoms reminding me of fuel starvation when hussling Escort RS1600's back in my youth !....but feel confident that is not the source of the issue.
Any pointers would be great.
Many thanks,
Nick.

 

[stevehumphreys]

A couple of thoughts, the black smoke may have been caused by oil seepage from 9 months standing. Similarly, fuel loses octane over time and depending on how long the fuel has been in the tank, it may have list sufficient octane to cause the hunting. Just a thought, if you start the car again, do you still get the black smoke?

 

[993 C4]

Hi Steve, no...she re started absolutely fine when putting her back to bed, as it were. The fuel, V-Power, was used to fill her up when last used around 9 months ago and still has 3/4 left.
Regarding the cold start up issue could it be anything to do with a relay not operating as it should on start up ?
Cheers.
Nick.

 

[stevehumphreys]

I would put the black smoke down to oil seepage concerning the poor running, I wouldn't rule out octane degradation. Did the car have power connected e.g. No flat battery. If the battery did go flat, might be worth topping up with more v power then taking the car for a 20 minute drive varying revs etc once it is warmed up, then see how it feels. relays tend to be on or off I had a similar hunting problem when idling, this can be caused by the idle micro switch, relatively easy to swap out if you have small hands!

 

[993 C4]

The battery is always disconnected when not in use and the battery itself is very recent. The cornering issue loosing power is very concerning. As soon as I'm on the straight it runs and pulls fine.
All very strange...

 

[Steve Brookes]

Lots of turning over but slow to start can be the sign of dodgy DME relay. Similarly, loss of power when cornering can be attributable to the relay cutting the fuel pump. It would be worth changing it for a new one to see if it's as simple as that. Avoid the cheap aftermarket ones though. Porsche original every time for these. Probably over 50 quid now but it's always worth having a spare.

 

[Dekker]

Another item worth looking into is the fuel filter, doesn't cost much to replace but worth changing along with the DME to rule out the cheaper items before delving deeper.