Crank no start - 82 911sc ROW

[yahh]

I have an 82 911sc ROW that we pulled the motor out for service. The motor is now back in and we can't get it to start.We have verified it to have spark. It doesn't sound like the fuel pump is running while cranking unless I have unplugged the lift plate. The CDI box hums the entire time while we are cranking. So far I have found replaced a relay because the old one appeared to be arcing occasionally. Another strange thing is that it seems like when the pin for 86 is inserted, it cuts power to the fuel pump. If I angle the relay and don't touch 86 the fuel pump will prime.

[G450X]

I had a similar issue with my '82 a few years ago. CIS is very sensitive on system integrity. Double check all components for a vacuum leak (I had an air box leak).

[ossiblue]

Originally Posted by yahh

I have an 82 911sc ROW that we pulled the motor out for service. The motor is now back in and we can't get it to start.We have verified it to have spark. It doesn't sound like the fuel pump is running while cranking unless I have unplugged the lift plate. The CDI box hums the entire time while we are cranking. So far I have found replaced a relay because the old one appeared to be arcing occasionally. Another strange thing is that it seems like when the pin for 86 is inserted, it cuts power to the fuel pump. If I angle the relay and don't touch 86 the fuel pump will prime.

I may be misunderstanding your concern, but the bold parts of your post are not necessarily problems.

The fact that you can't hear the pump run during the start cycle may be just that--you can't hear it. Unless you are down near the pump, the noise of the starter motor usually will override the fairly quiet noise of the fuel pump. The pump is not supposed to run with the ignition ON and the engine not running.

As far as pin 86 of the relay, it's doing exactly what it's supposed to do. With ignition ON, the relay gets power to 86 and 87a. Power to 86 activates the internal relay coil, and switches the ignition power through the relay from terminal (87a, power when ON) to the start terminal (87 power from the start circuit). Since the ignition is not in START position, the fuel pump will not run--that's why when you maneuver the relay, the pump goes off.

Insert the new relay, and connect the afs sensor wire. Turn on the ignition to ON. Does the relay "click?" It should. Lift the sensor plate in the intake while the ignition is ON. Can you hear the pump run and feel/hear the injectors vibrate? They should. If both the above check out, the relay and pump are doing their jobs.

Since the motor was out and we don't know what you mean by "service," your non-start can be due to many things other than the relay/fuel pump. Have you checked the CSV for function? Did you prime the fuel system once everything was back together? Are you certain the timing is correct? Are the valves adjusted? Have you checked the fuel pressures with a gauge set? I'm not familiar with ROW engines, but if it has a frequency valve and a DME (which also has a relay) under the passenger seat, those need to be checked for proper function as well.

Keep us informed.