944 injector wiring problem
 

Early 85 944
12 volts one side of injector plug,10.5 volts ground or ecu side when all injectors unplugged. Everything I read says no voltage on ground or ecu side of injector plug,any ideas?

Most likely a short under the rubber boot of one or more of the connectors. The insulation gets crispy and it chips off right where the wiring enters the connector. Gently cut off the rubber-boot with a razor. It's glued to the wire & connector and trying to pull it off will break the rest of the wiring.

Inspect each connector where the wire goes into the connector. See if one of the connectors has its bare wires shorted across to each other. Separate the shorted wires and re-measure the voltage on each terminal.

Might as well replace all the connectors. I cut them off 6" from the end and butt-solder new ones on from NAPA. Two styles available:

NAPA - CRB 218457 (new style with finger-operated spring)
http://s7d9.scene7.com/is/image/Genu...Company/472170

NAPA - CRB 218545 (original style)
http://s7d9.scene7.com/is/image/Genu...Company/646677

944 injector problem
 

Thanks for your help,when I unplug the ecu the injector plug ecu side does not have power,I think I have a ecu problem

I think power to injectors come directly from harness at firewall that connect to rectangular plug above the brake-booster.

No power would be sign of DME relay problems. The DME only handles the grounding of the injectors to make them fire.

early 944 injector problem
 

replaced DME and still have 10.5 volts on negative side to dme injector drivers when all 4 injector connectors unplugged. When I unplug the dme no voltage,this eliminates short in injector wiring harness. I think my next step is to replace relay fuse panel as this was corroded and wet when I purchased. I removed fuse relay panel and cleaned all connections but cannot clean or check internally. Any suggestions?

Sound like bad harness, mine is bad but on the coil trigger shorted to like five other circuits.

Does the car run properly?

Car seems to try to run,cam crank timing etc is properly set. Ordered central fuse relay board,old one was wet and corroded. Just about the only thing I have not replaced. Have tested everything and injector wire having power on ecu,dme side is the only problem.It is not shorted ! Thank You

I have a early 1985 Porsche 944.I have 12 volts on fuel injector plug with key on not running on red wire side and 12 volts on grey wire injector driver side to dme,key on not running with one injector unplugged. when I unplug all injectors I have 12volts on red wire and 10.3 volts on grey wire injector driver side dme,key on not running. Please would someone check to see if this is the same on your running car! I have checked and tested everything I can and it acts like it is out of time when trying to start. Checked timing and everything is lined up,cam crankshaft etc. Only thing I can find is power on grey wire injector plug that I believe is not supposed to have. If I unplug dme and fuel pump relay I do not have continuity or short of injector harness. ThankYou for reading and trying to help me with this nightmare.

I'm currently have the same problem. No start! Power on both injector wires and no shorted on any wire.

Did you find out what is the culprit? Thanks.