88 Carrera Cutting Out Problem

EDDIE1468 · 05-13-2002, 02:09 PM

SPUTTERS OUT INTERMTENT AT FIRST,NOW CAN'T DRIVE IT.WILL CUT OUT AT ABOUT 3000RPM.TO GET IT STARTED AGAIN I HAVE TO OPEN THE TROTTLE HALF WAY,GET LOTS OF SMOKE.ONCE IN A WHILE AT IDLE IT WILL START TO SURGE ON ITS OWN TO ABOUT 2000RPM BACK TO IDLEAND SO ON.OPEN THE THROTTLE AND STALLS.ANY SUGGETIONS WOULD BE GREATLY APPRECIATED.THANK YOU

88911coupe · 05-13-2002, 02:20 PM

I think the first thing to check would be the DME relay since they are known to go bad. Easy to check and cheap.
Good Luck

EDDIE1468 · 05-13-2002, 03:00 PM

COULD YOU TELL ME HOW TO DIAGNOSE THAT RELAY?I HAD IT OUT JUST TO CHECK THE CONNECTIONS

Early_S_Man · 05-13-2002, 03:34 PM

You don't diagnose the DME relay ... just buy one, since you need a spare for your glovebox, anyway! Put it in, and you will notice immediately whether or not it fixes the problem! If it doesn't, put the old one in your glovebox as your spare.

You have a Bentley manual, right? Haven't you seen & read their recommendation to keep a spare DME Relay in the car at ALL TIMES as a precaution against getting stranded with a dead car?

ChrisBennet · ChrisBennet's Garage

My friend Mark (a cleverer man than I) when faced with a dead DME relay at the side of the road simply removed the relay cover and jammed something behind the relay contacts to force the relay closed.
-Chris

EDDIE1468 · 05-13-2002, 03:57 PM

DON'T HAVE ANY MANUALS.JUST GOT THE CAR A COUPLE MNTHS AGO.SOUDS LIKE TOO MUCH HAPPENING TO BE JUST A RELAY.THE DME AND RELAY WERE NOT BOLTED DOWN.THE GENIUS BEFORE ME LEFT IT LAYING THERE BOUNCING AROUND.ITS SCHEDULED TO BE PICKED UP TOMM AND TAKEN TO THE SHOP.MAYBE I'LL TRY A RELAY FIRST .

stlrj · 05-13-2002, 05:38 PM

Lots of smoke means very rich to me and the only thing that could make it run that rich is a malfunctioning head temperature sensor or it being disconnected in the engine compartment.

Cheers,

Joe

Wayne 962 · Wayne 962's Garage

You can get one here:

http://www.pelicanparts.com/catalog/shopcart/911M/por_911M_electr_main.htm

Also, get one of these:

http://www.pelicanparts.com/catalog/shopcart/911M/por_911M_electr_main.htm

-Wayne

MarkD · 05-14-2002, 03:02 AM

Eddie,
it's possible that your DME is failing. That series of DME's has a manufacturing defect that causes the spark to become intermittent or fail completely. I have fixed this in many Porsche (and BMW) DME's from the mid-eighties. (I call it a manufacturing defect because it's not a failed part - not enough solder was applied by the wave soldering machine)

There is a large transistor mounted on a heatsink inside the DME which controls the ignition coil. There are 3 connections from this transistor to the PCB, and the solder at these 3 points breaks to create a bad connection. I have found this problem by visual inspection even before it caused any symptoms.

If you open the DME and remove the PCB from the metal base, (6 screws and 2 plastic reatainers must be removed) You can check for this and re-solder the 3 connections, saving yourself the price of a DME.

Mark