Ongoing problem with carerra 3.2

swedebasher · 04-12-2007, 10:00 AM

I'm back again, my 1984 3.2 carerra is still suffering from the really poor running if it even starts problem, I took it to the garage and he told me that my fuel pressure regulator was faulty and that there may be an motronic fault, I got him the fuel pressure regulator and had some cold solder joints done on the ECU and returned the car to him today, he now tells me that the part he told me to get was wrong and that he meant the fuel pressure damper, also says the ECU must be faulty as the car has dumped a load of fuel into the sump and now wont even start, I am at my wits end with this as what seemed a simple problem has now turned into a major thing, any advise guys as I cant keep throwing money I aint got into this motor, I was told they were bullet proof.

mschuep · 04-12-2007, 10:27 AM

If the diaphragm inside your fuel pressure dampener (fpd) has failed, it will dump a lot of fuel back into the intake through the vacuum hose attached to the backside of the fpd...my understanding is that is was designed this way so that fuel doesn't just spew all over the engine bay and catch fire.

mschuep · 04-12-2007, 10:33 AM

check out this thread for more info on the fpd...

MOTRONIC: Fuel Pressure Regulator?

mhinch · 04-12-2007, 10:36 AM

Have you changed the DME relay, it could be at fault, (only costs £25GBP) worth changing if you havn't changed it recently. Do you know if the spark plugs are sparking when you spin the engine over?

Mark

mhinch · 04-12-2007, 10:38 AM

And someone posts a far more educated suggestion, shows I'm still learning.

Mark

swedebasher · 04-12-2007, 11:29 AM

Have not changed the DME relay (it does click etc so assumed it was working), and the spark plugs were changed 3 weeks ago, the car is just flooding horrendously and dumping fuel into the sump.

Rot 911 · 04-12-2007, 11:31 AM

The relay is probably fine then because the DME relay is also the relay for the fuel pump. If it was bad the fuel pump wouldn't be working.

EAP · EAP's Garage

Please let me know what you find...
I have an '84 Carrera 3.2 and cannot figure out why it's flooding. I have changed just about everything (pos. sensors, DME relay, CHT sensor). I have noted that there is 12V on both sides of the injectors...I have not opened the DME at this time. As far as I can tell, there should only be voltage on the red/white wire to the injector and the other wire is the ground to the DME at #14 and #15 positions. Any ideas???

WydRyd · 04-12-2007, 03:10 PM

Yeah, that was my post above... it was my damper. It had a torn diaphragm and it was bleeding fuel into the intake via the vacuum port. Once I replaced it, the problem was fixed

You'll have to crank the motor over and over and over again for the residual fuel to dissipate out of the motor, but it will eventaully fire up. Once it fires up, take it for a spirited drive to clean it out properly.

Once you get home, let the car cool down for a while and flush out your oil and fill with fresh oil, just in case your oil got contaminated with fuel.

It's unlikely you have a DME problem. The Damper is the culprit here. BTDT!

Look at it this way, you'll have a VERY clean intake and combustion chambers

swedebasher · 04-13-2007, 03:28 AM

I have today had the car transported to a Porsche specialist who is gonna take a look for me although he cant get it in for 2 weeks due to workload, I will post details of what he finds as and when they happen.