CUTS OUT INTERMITTENTLY IN THE WET-HELP

[Dockrell]

One area to look at is just under the distributor cap - there is a seal inset into the alloy base. It gets hard with age and could let moisture into the distributor. Its quite hard to see it but it is shown in the PET diagram for the distributor. This seal only applies to the 2.5 and 2.7 litre cars not the S2's.
New seals are available from your local Porsche Centre but do make the distributor cap a little more difficult to fit - especially the bottom clip.

Mike
White 2.7 automatic

 

[blacksuz]

Dizzy bottom screw loose and reference sensors insulation gaps are the faults so far. Checked all earths, ECU, relays etc and all ok. I have not been able to change the seal inset into the base of dizzy as need to be on track at Silverstone tomorrow. It will rain in the afternoon so hopefully it will get a good test. I reckon its water in the dizzy as it was wet and this has only happened since garage fitted new dizzy cap. Put plenty of damp start on it but will have it to bits again in the week to fit new seal along with some other stuff. We will see[]

Thanks everyone for the help, its been very useful

best
blacksuz

 

[peanut]

I think its more likely the problem was the reference sensor which got disturbed when the dist cap was fitted.
Its that sensor that the ECU uses to control the HT spark from the coil by pulsing the ignition amplifier.

good luck

 

[MGBV8]

ORIGINAL: blacksuz

Not finished my overview of all possibilities yet but found the Dizzy bottom screw out so water may have been getting in there............ anyone got some good tips for getting the bottom dizzy cap screw seated as its really hard to get at and it needs pressure due to spring tension.

[]

I use a screwdriver bit in a 1/4" drive ratchet. You can get your whole palm behind it and push it in this way.

 

[Mike_Pollock]

I use a screwdriver long enough to wedge my left hand behind (use good gloves if you want to retain skin on the back of the hand though!)

 

[Eldavo]

I use a very short stubby screwdriver and wedge it between the screw and the headlight bar, this gives the required tension and you then just give it a turn to lock it in then pop the screwdriver out.

 

[blacksuz]

Sliverstone was very wet most of the day and the car drove without any hiccups and no problems on the wet Motorway on way home . Cutout problem solved I reckon. []

Peanut, can you let me know exactly where the sensor is in relation to the dizzy as I don't recall seeing this sensor. Do you have diagram.


Thanks too all for support and yes it was difficult to get bottom screw in dizzy but used stubby and wedge it in then turned with plumber grips. Some damage to hands........oooch![]
cheers

blacksuz

 

[peanut]

what year is your car ? if its early then the sensor may be next to the crank position sensor on the clutch bell housing. On later cars its just behind the dist cap and reads the crank position directly off the cam shaft .
There was a thread about this a few weeks back where someone had the same symptoms and it turned out they had disturbed the sensor when replacing the dist cap.

 

[bertelli_1]

8v models have 2 crank sensors on the bell housing, no cam sensor. 16v models have a single crank sensor plus a cam sensor behind the top cambelt housing.

 

[peanut]

thanks bertelli theres a lot of confusion about these sensors. I read on rennlist that someone thought the S2 only had a crank position sensor which doubled as a speed sensor also.? can't see how lol.

As I understand it the sensor on the camshaft tells the ECU the engine speed so that it can adjust pulsing of the ignition amplifier and coil for correctly timed HT spark .

 

[blacksuz]

Hi Peanut, my car is MY89.

Does anyone know where I can get technical information about the ECU so I can understand exactely what it controls and when?

blacksuz

 

[peanut]

you'd need a 'Bosche Fuel injection and Engine Management' book.[]

Have you still got an intermitant running problem ?

 

[blacksuz]

Hi Nick, no car is running perfectly at the moment and has been in the wet all day Sunday on track and driving home on motorway. No issue since drying dizzy and securing bottom screw. Also put plenty of damp start covering over it and all the other electrics.[]

Thanks for the tip re the ECU info. I just want to understand more so I can fault find with some sensible knowledge and logic as opposed to just logic and guess work.

I will try and source the Bosche Fuel injection and Engine Management book

best

blacksuz