Damp Q 944

[Logie]

Hey all,

With the recent torrential rain, this morning it took 3 attemps to start up the car and i had to use a bit of gas to keep it alive, but once it fired up, it was ticking over okie.

But driving it, unless i was smooth and didnt push hard on the gas. It was stutter and bog down. Im not sure if theres damp getting into part of the spark system of something?

Best thing was comming to a round about in rush hour and the car dying and coasting around at 5mph trying to get it started

[nos4a2]

I has similar yesterday - missfire during the wet weather on anything more than half throtle, OK on a steady throtle. I've assumed damp HT leads - mine probably need changing anyway!

[Brett928S2]

Hi Logie

As an ex mechanic and race mechanic....the usual cause of this is basic parts NOT having been CHANGED on a service....plugs,distributor cap,rotor arm and leads...

Note I said CHANGED ...not checked....

Dizzy caps and rotor arms as an example are whats called "breakdown parts" in the trade....that means they get checked on a service (hopefully) and you wait until they fail or missfire to change them...

Mine are CHANGED every 2 years (14000 miles) like clockwork...

I change my leads every 3 years (21000)...

Plugs every year (7000)

Hope this helps

All the best Brett

[nos4a2]

Well, she ran fine today after drying out in the garage over night.

I will be taking Brett's advice - it looks like the ProMAX ignition tune up kit is just the job http://www.promaxmotorsport.com/

[JED944]

Sounds like the dreaded damp stuff to me.... I killed my 944S2 (temporarily) after cleaning and rinsing the engine. Numpty!!! Took 4 days, a hairdryer and half a can of WD40 to get going again. Purring like a kitten now though!

[Li Moo Bai]

Brett928S2 said:

Hi Logie

As an ex mechanic and race mechanic....the usual cause of this is basic parts NOT having been CHANGED on a service....plugs,distributor cap,rotor arm and leads...

Note I said CHANGED ...not checked....

Dizzy caps and rotor arms as an example are whats called "breakdown parts" in the trade....that means they get checked on a service (hopefully) and you wait until they fail or missfire to change them...

Mine are CHANGED every 2 years (14000 miles) like clockwork...

I change my leads every 3 years (21000)...

Plugs every year (7000)

Hope this helps

All the best Brett

Brett

He could try servicing the dizzy/rotor first. I did this at the weekend with mine (8v 944). once I had scraped away arcing deposits and cleaned it out with some acetone it was as good as new!

[Brett928S2]

Li Moo Bai said:

Brett928S2 said:

Hi Logie

As an ex mechanic and race mechanic....the usual cause of this is basic parts NOT having been CHANGED on a service....plugs,distributor cap,rotor arm and leads...

Note I said CHANGED ...not checked....

Dizzy caps and rotor arms as an example are whats called "breakdown parts" in the trade....that means they get checked on a service (hopefully) and you wait until they fail or missfire to change them...

Mine are CHANGED every 2 years (14000 miles) like clockwork...

I change my leads every 3 years (21000)...

Plugs every year (7000)

Hope this helps

All the best Brett

Brett

He could try servicing the dizzy/rotor first. I did this at the weekend with mine (8v 944). once I had scraped away arcing deposits and cleaned it out with some acetone it was as good as new!

Hi

As you found out ,scraping the deposits away works....temporarily!

When you scrape them away you INCREASE the spark gap that it has to jump in the dizzy....which WEAKENS the spark....and also increases the chance of "tracking" ..which is the spark tracking down the cap to earth...which means you start getting missfires...

Change it lol...and the rotor arm

All the best Brett

[Li Moo Bai]

Brett928S2 said:

Li Moo Bai said:

Brett928S2 said:

Hi Logie

As an ex mechanic and race mechanic....the usual cause of this is basic parts NOT having been CHANGED on a service....plugs,distributor cap,rotor arm and leads...

Note I said CHANGED ...not checked....

Dizzy caps and rotor arms as an example are whats called "breakdown parts" in the trade....that means they get checked on a service (hopefully) and you wait until they fail or missfire to change them...

Mine are CHANGED every 2 years (14000 miles) like clockwork...

I change my leads every 3 years (21000)...

Plugs every year (7000)

Hope this helps

All the best Brett

Brett

He could try servicing the dizzy/rotor first. I did this at the weekend with mine (8v 944). once I had scraped away arcing deposits and cleaned it out with some acetone it was as good as new!

Hi

As you found out ,scraping the deposits away works....temporarily!

When you scrape them away you INCREASE the spark gap that it has to jump in the dizzy....which WEAKENS the spark....and also increases the chance of "tracking" ..which is the spark tracking down the cap to earth...which means you start getting missfires...

Change it lol...and the rotor arm

All the best Brett

Brett

Thanks for the advice,

Gaps were fine so I left the new dizzy cap and rotor in the box. If you are careful not to grind away at the contacts you can keep the ignition sweet for the expected life of the dizzy (obviously at some point contacts will erode beyond their useful life).

Anyway I was trying to save the OP the expense of new bits if his current should prove to be servicable.

Changing things out without inspecting condition having a go at servicing them is the modern approach though I guess.

[NJH]

Li Moo Bai said:

Brett928S2 said:

Li Moo Bai said:

Brett928S2 said:

Hi Logie
Anyway I was trying to save the OP the expense of new bits if his current should prove to be servicable.

Changing things out without inspecting condition having a go at servicing them is the modern approach though I guess.

Do leads really actually wear out? or are problems with leads mostly caused by breaks internally? The reason why I ask is that my S2 has the same leads on it as when I bought it 6 years and 70K miles ago. However in that time the cap and rotor has been changed many times. These parts are wearing out the whole time the engine is running. Leads can be expensive so it seems to me a waste of money to replacing them like a service item.

[Brett928S2]

Hi

As long as you CHANGE the cap and arm and plugs...the leads only need changing if they are breaking down with age and missfiring..

Easy way to tell...wait for a damp evening..preferably raining and dark...

Lift bonnet and watch.....if you see ANY sparks across leads,,,sometimes if bad they are like a light show lol..then they NEED changing....if not they are probably ok

All the best Brett