84 944 N/A Wont Start. (DME Failed?)
07-22-2003, 04:13 PM
#1
Three Wheelin'
Thread Starter
84 944 N/A Wont Start. (DME Failed?)
Hi there,
Whereas we have all seen this topic a thousand times, I would love some help with my particular set of circumstances.
I have a 1984 Porsche 944 N/A. It decided to die on the highway the other day forcing me to tow it home and now I am trying to diagnose where the problem lies.
1. I checked the fuel pump / DME relay and swapped it out with a new one.
2. I checked wiring behind the relay to make sure it was secure.
3. I checked for spark, and there is a bright spark, at each plug.
4. I hotwired the fuel pump at relay so it would always run. It is noticeably still working (Loud hum , etc)
5. I checked that an appropriate amount of fuel was pumping out of the fuel rail as per the Haynes manual. The fuel pump definetly seems to be ok.
6. I removed one fuel injector wire and tried to start the car, it still wouldnt start
7. I placed an LED + resistor in series with the injector wire to the DME and the positive battery post. The LED did not blink. Hence I do not believe the fuel injectors are firing.
8. There is a noticeable lack of wetness to the spark plugs / smell of gas which also leads me to believe the injectors are not pulsing.
As far as I know this means that for whatever reason my DME is dead. However I don't have a spare one to quickly check that theory.
So can anyone think of anything else I can check?
I found a couple of threads that alluded to a specific transistor failing in the early DMEs causing no injector pulses. I couldnt find any real details on this however. (In either the web forum or the email list server)
I would really appreciate any help anyone good give me.
I believe the DMEs are only the same from 83-85.5 then they changed somewhat.
Thank You
Kirk
Whereas we have all seen this topic a thousand times, I would love some help with my particular set of circumstances.
I have a 1984 Porsche 944 N/A. It decided to die on the highway the other day forcing me to tow it home and now I am trying to diagnose where the problem lies.
1. I checked the fuel pump / DME relay and swapped it out with a new one.
2. I checked wiring behind the relay to make sure it was secure.
3. I checked for spark, and there is a bright spark, at each plug.
4. I hotwired the fuel pump at relay so it would always run. It is noticeably still working (Loud hum , etc)
5. I checked that an appropriate amount of fuel was pumping out of the fuel rail as per the Haynes manual. The fuel pump definetly seems to be ok.
6. I removed one fuel injector wire and tried to start the car, it still wouldnt start
7. I placed an LED + resistor in series with the injector wire to the DME and the positive battery post. The LED did not blink. Hence I do not believe the fuel injectors are firing.
8. There is a noticeable lack of wetness to the spark plugs / smell of gas which also leads me to believe the injectors are not pulsing.
As far as I know this means that for whatever reason my DME is dead. However I don't have a spare one to quickly check that theory.
So can anyone think of anything else I can check?
I found a couple of threads that alluded to a specific transistor failing in the early DMEs causing no injector pulses. I couldnt find any real details on this however. (In either the web forum or the email list server)
I would really appreciate any help anyone good give me.
I believe the DMEs are only the same from 83-85.5 then they changed somewhat.
Thank You
Kirk
