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CUTS OUT INTERMITTENTLY IN THE WET-HELP

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blacksuz

New member
I have 944T which cuts out in the wet. On the way to Brands Hatch yesterday it cut out after about 50miles. Stayed out of the spray and got to the track. On track in the wet for a few laps and it broke down. Had to be towed back to the pits [:mad:]. I drove it home at lunchtime in the dry and it was perfect. It only seems to do this in the wet so far.

If anyone could give advice as what to look for I would appreciate it.

[:(] [:(] [:(]

blacksuz
 
Good point as HT leads are fairly old. I would expect it to misfire but not cut out totally if it were leads but I will investigate. Dizzy cap replaced 6mnths ago but coil could be a possible.

Please keep the ideas rolling and I will check out tomorrow in the rain.

best

blacksuz
 
Good luck with the fault finding blacksuz.

Did you go to Brands with Gary and Nick perchance?
 
if you don't find anything amiss with the ignition components it might be worth checking around the Fuse/relay box and the ECU beneath the fuse box on the passenger firewall . Any water falling on the scuttle should drain away but the drains may be blocked .

I can't see how road water could reach the ignition leads or inside the distributor cap ? if it did, none our cars would drive in the wet [;)]
 
Have seen it with old leads were the insulation is breaking down or a damaged dizzy. Although in this case a new one has been fitted.
 
I'd agree with checking the passenger footwell for water. But, if there's a water issue there why would it only appear in the rain? It doesn't miraculously dry out when the rain stops, but holds water and builds up a long-term problem.

Most poor running problems are caused by old and worn electrical or fuel system parts, hence the obvious advice that too many 944s have knackered leads, dis caps and rotor arms. I can't see how they'd be so much more affected by rain, though?

So....I'm not sure what would cause it to be only causing a problem in the rain. As has been said, most 944s have old ignition parts that cause general poor running, but if rain affected them very few cars would work in the UK. [8|]
 
Paul when ignition leads have poor insulation the electrical energy from the conductor inside can track to the outside. Water (unless it is absolutely pure) is quite a good conductor and if the leads are also wet can cause the electrical signal to short to deck and not reach it's intended destination - usually the plugs and hence engine cuts out. Electrical energy like water will always take the easiest or first path to ground. That is where it wants to be. Age old problem with old and tired electrics.
 
Paul when ignition leads have poor insulation the electrical energy from the conductor inside can track to the outside.
Click to expand...

Makes sense, pop the bonnet on most 944s in the dark and look for the worn HT leads. [&:]

My only question was why, as most 944s are running below perfect, but still going pretty well on probably, original leads, dis cap and crumbling rotor arm, would rain not be killing them all? I'd still check them all as a first point of call on a car that dies in the wet, but I'd have expected them to show problems more generally?
 
Yes, will pop bonnet tomorrow night to see if I can see anything arching. Could be DME I guess, as problem started after DME had been played with by tuner. However, still puzzled that it only happens in the wet.

Biggest problem is repeating the fault as its very intermittent and has only happened in wet conditions so far.

Thanks everyone for your ideas, I have a whole list of things to try but am going to take it very systematically ie check all the obvious no invasive things first before starting to follow the Clarks procedure guide of fault finding.

More ideas the better[;)]

best

blacksuz
 
Could be DME I guess, as problem started after DME had been played with by tuner.
Click to expand...

Ermm......question answered? [:D][:D]

Seriously, I'd guess this could be more a combination of a few worn-out parts and damp getting in to the car. I'd be surprised if it was one specific part getting drenched in the rain; is the car used regularly, or was it brought out of damp storage for the track day?
 
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.

[:(]
 
A really, really, really long screwdriver so that you can clear the badge panel and get in an angle or buy the expensive Porsche special tool. Also if you remove the cover 3 x 10mm bolts I think the whole thing will come out with the cap attached. You will have to move the belt cover out the way though. Bit fiddly but possible.
 
Thanks Rob will try the long driver approach and see how I get on. Need to get sorted for Silverstone on Sunday so no time to buy tool, although I could limp up to Sliverstone and get Fernsport to secure it if I get really stuck. Just hoping that it cures the problem other things look fine. Although still to check crank sensors.

:rolleyes:
 
I'd be tempted to start with the main earthing points first especially on a car this age that hasn't had much use or work done on it for a while. Rotten job but I doubt that there is one of our 20+ year old cars that wouldn't benefit from better earths.
I'd clean points
MP l, (under rear hatch lock behind carpet )
MP ll & MP lll are located under the dash adjacent to the fuse/relay box . Probably need to remove the glovebox! (earths the ECU and ignition amplifier etc)
Earth strap between engine & chassis (rear of cam case to firewall)
 
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