Fortuna

I need help!
Porsche 993 Cabriolet 1994.

After 30-40 minutes the engine is running (driving a car). I turn off the ignition. After that, I pytas start the engine. Starter spinning, but the engine does not start. Through 15 to 20 minutes of waiting, the motor again to start.

I also noticed that at this time does not work drive the folding roof.

How should I fix the problem?

ToreB

Have you checked/changed the DME relay? This can fail due to internal solder problems. DO a search on the forum for details. Some say that a spare DME relay should always be brought in the car as standard.
Cheers,
Tore

Kein_Ersatz

Winner, winner, Chicken Dinner. Cranks but will not fire, always check the DME first.

Kika

clearly check the DME relay.

I had a similar issue with my 911SC as the starter began to fail. when cold, it started fine, when hot, would not engage. basically what was happening is the spindle would expand due to the heat, and it was getting stuck. Short term (emergency procedure) was to hit the starter with a hammer to jar it loose, or push start the car, longer term, I replaced the starter.

Fortuna

Thanks for the advice. I'll check the DME relay.
How is the mechanism Lifting roof convertible with DME relay?

At that time, when the engine does not start (can not start the engine), I just do not operate the mechanism for lifting / lowering convertible roof?

Vorsicht

Check fuse for the top. Probably these are two different things and not related.

If the DME relay is not the problem I would check the battery. If the battery is losing charge it may not be strong enough the spin the starter to the speed it needs to start the car.

Also, do an advanced search for "hot no start" looking at "titles only". Good luck.

Ed Hughes

I wish people would describe issues more clearly. The way I interpret this is that the starter is simply spinning, but is not turning the engine over. If I am wrong, then stating "engine cranks over, but will not start or fire" would be a more accurate description than "starter is spinning".

JimPA

My car would sometimes crank but not start. I could create this behavior if I "bumped" the starter and released the ignition switch before the car started. The cause was a failing flywheel reference sensor in my car, not the DME.

nile13

Нажмите на педаль газа, примерно наполовину, потом заводите. Если заведётся, дайте знать.

For those of you in non-Russian speaking world, press the gas pedal half-way and try to start the car. if it starts OK, the issue is quite possibly the fuel pressure regulator.

CalvinC4S

The way I read it, your ring gear is on backwards;but then it would never start.

Fortuna

Приятно видеть на форуме человека, который говорит на русском

Возможно я немного некорректно описал проблему. Она в следующем.

После вождения машины или просто когда машина стоит с заведенным двигателем не менее 30 - 40 минут, я выключаю зажигание и останавливаю мотор. Затем я пытаюсь снова завести мотор, стартер крутить коленвал, но мотор не схватывает и не заводиться. Несколько раз при этом я замечал, что в этот период так же не функционирует и механизм работы крыши моего кабриолета. Затем примерно через 15 минут, мотор легко заводиться и снова функционирует механизм работы крыши кабриолета.

Предохранители я проверил, все в порядке.
DME реле заказал новое, чтобы исключить возможность дефекта моего реле. Новое реле привезут через несколько дней.

Что еще я должен посмотреть и проверить ?

nile13

Like I said, when the car does not start when hot, try pushing the gas pedal half way in and starting it again. I'm currently having this issue sometimes and it's related to dying Fuel Pressure regulator (FPR). It's always related to hot re-starts in my case.

Why the cab roof would not work in this situation is a mystery to me. It is possible that so much power is taken from a battery that it simply doesn't have enough to move the roof. it's both strange and, I think, a little unrelated. It could be the fact that parking brake is down at this point? It needs to be up for the cab roof to work.

PS. For a Russian version of this we ca try PM.

Dplus

The cab top only works when the engine is running; get the car started first and then try it.

nile13

That's incorrect.

IXLR8

There is also a fuel pressure retention versus time specification which is related to the check valve at the fuel pump.

It is specified in the factory repair manual.