TwinTurbo.NET: Nissan 300ZX forum - Electrical / Fuel pump issue
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Subject Electrical / Fuel pump issue
     
Posted by Drk93TT on April 16, 2022 at 7:40 AM
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Message So a week ago the car was running fine, parked it in the garage to straight wire one of the PTU connectors (sub harness connector to get rid of the other connector that was pretty corroded just to get rid of it). Also replaced the coolant temp sensor connector.
I have verified that all wires are connected correctly and soldered/covered with shrink tube. I also replaced the knock harness female end to sensor as well as the blue idle air 2 pin connector while I was there. (had a code 34 that was solved by this) however the car has not run since all this was repaired...

I went to start the car and it has a healthy Crank..... no start.

-Code 55 no issues seen

-Fusible link Green 30 amp is good.. I even switched it with another one.. still nothing.

-I have spark (removed a coil and grounded to plenum with a plug cylinder #1)

-CAS removed and spin ... can hear it clicking every ~1/8 turn. Seems like in same spot the click comes from but Im told that should be ok..

-CAS connector is good, clean

-Plenum grounds good and clean

The fuel pump is not priming when key on.... the fuel line after the underhood fuel filter is weak and not stiff.

Also, I do NOT feel the green relay clicking when I key on to crank.

-I have tried to Bypass the FPCM with jumper wire and a ground per CZP guide to bypass the control module with no luck.

-When I connected 12v B+ direct to the fuel pump with it unplugged and provide ground to the other terminal at pump, it WILL prime and buzz like it is working.

-Swapped Green relay to see if it would click at the Fuel pump relay position... Nothing.

I have also done a few tests per the FSM..


The first check A CHECK POWER SUPPLY
check voltage indication should appear for 1 second after IGN key on
- I only get 3.0 mV (millivolt) here.... manual doesn't specify but seems low?


3 continuity checks all are GOOD with continuity..
-B+ to relay
-Fuel pump relay and Fuel pump
-pin 18 at ECU connector to Fuel Pump Relay


At this point Im wondering if something is wrong w the ECU.... Any help is appreciated.

IMG-9242
IMG-9256
IMG-9257
IMG-9260

     
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