Porsche Enthusiasts Club Forum

Hi, first post on the forum so bear with me. I have a 944S2 1991 with 91K miles and so far it has not let me down except usual battery problems in the Winter.

However it has started to show real problems starting when hot, the engine cranks over really well but it takes an age for it to catch and fire up. Sometimes it will almost start then splutter and die, eventually it will go but usually after 2/3 minutes of trying.

It starts first time and hardly needs to turn obver when cold so don't think it is my immobiliser, I have ordered a new DME relay and hope this will cure it any other ideas?

David

I would have a look at the temperature sender as when these fail they can make the ECU think that the engine is cold all the time. This means that it tries to run a rich mixture when the engine is already warm, so it isn't keen on starting and can flood.

Hello and welcome,

It might also be worth cleaning up the speed and reference sensors (if you can get them out) as this helped my hot starting problem.

All the best,

Andy

Good luck with it, I'd start with the DME and take it from there.

My moneys on the temp' sender. Let us know

Changed the DME relay last night and on second examination the one I swopped out was not very old and the more recent 993 version. But never mind swopped it out ran the car until hot and when I tried to re-start it took some turning over to get it to fire, not as bad as before but probably not as hot so think I will try the temperature sender next.
Thanks for all the good advice.

When it turns over before it starts is the rev counter bouncing? If not then it will probably be a speed senor either dirty or starting to go intermittant, if it does then I'd just swap the temp sensor.

Not sure what you mean by bouncing or turns over but every once in a while when I turn on the ignition the rev counter needle goes over scale then back to zero. Looks cool just like a Ducati but it doesn't do it every time and there is no needle movement when turning over except just to lift it off the stop due to the engine turning over. Forgive me for my stupidity but which temperature sendor are you referring to obviously not the one which reads water temp inside the car but if so this works fine.

By bouncing, I mean bouncing off the stop, whilst tuning over on the key, but before it actually starts.

The temp sender is the one that feeds the DME not the temp guage one. I don't know which one it is without the manual.

Might be the check valve on the fuel pump letting fuel drain back out of the rail back into the tank. Mine did that and then magically fixed itself..

Temp sender for the DME 944-606-125-00. Bet Bert Gear has one.

Another thing to try - I recently had my injectors cleaned, and where before it would take several cranks to fire when warm, it now usually fires first turn of the key. Alternatively, cleaning the earths & checking Fuel Pressure Regulator are other candidates that may be worth a look.

Well whether changing the DME relay sorted it out I am not sure but the hot starting problem has gone away.

Ummm.... I'd check the battery earths at that point. Seems to be a common issue on ALL the transaxle cars, from what I hear.