Mercedes-Benz Forum banner

‘79 450SL - no power to FPR

360 views 8 replies 4 participants last post by  Milktruck 
#1 ·
I’m struggling how to test now that power to FPR is isolated. I’ve tested with known good relay to eliminate the relay itself.

This car is Kjet with an icu NOT ecu. There is no 6-pin relay.

Do I jump pins on the ICU? And if so, which ones?
 
#6 ·
I think the '79 has a safety switch on the air flow housing. It is blue and located on the right side between the FD and the air intake. If so the FP only receives power when cranking. Try unplugging it. Someone posted the pump should run continuously with it unplugged.
 
#7 ·
Good call.... and I've tried it to no avail. What strikes me as odd is that it ran for about 15 mins (weak idle, stuttered when I feathered the pedal, then seemed fine), I turned it off and it cranked back with a simple twist of the key. Since then I've not been able to get the pump to run and when rechecked the FPR plug is getting no power. Won't trip a known good relay.

When I began this journey, the car would not turn over the starter in park. Only in neutral. I have a new NSS to install, but since I've started messing around - the car will crank with the gear selector in park.
 
#8 ·
Perhaps the pump died?
Original pump on my car seized but it did not blow the fuse.

WUR receives the power from the same relay. If Crank will produce ~10V or more during cranking at the WUR, perhaps the pump is dead (seized or open circuit) or wires to it.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top