Dougswd21 Posted August 15, 2014 Share Posted August 15, 2014 Figured I would start a thread about my 89 4x4 Pathy. I wanted to add a 4x4 to my stable and really like my 92 hardbody so I thought I would keep it in the Nissan family. Enter this Pathy, found it on craigslist for $500, came with an extra set of wheels and most of the rust taken care of. Got it home and did a full tune up added some fresh gas and it drove fine for a few days. Then developed a pretty bad hesitation and stumbling with any throttle input and absolutely zero power. Isolated it down to a bad fuel pump, it was only pumping out 8 PSI independent of the FPR. So that’s on its way from Rockauto (has been vital so far) The only real plans I have after I get it driving is a minor lift and get it DDable. Still needs a radio, really clean up the interior and it should be good to go. Oh also the A/C works! Pictures coming soon!! Link to comment Share on other sites More sharing options...
MY1PATH Posted August 16, 2014 Share Posted August 16, 2014 GOOD FIND! Link to comment Share on other sites More sharing options...
Dougswd21 Posted August 21, 2014 Author Share Posted August 21, 2014 Alright tracked down the low power issue to a bad fuel pump, replaced that and the truck ran great for a minute then died. No spark. No power from the ecu to the main relay and no light on the ecu. Fuse is good. Any ideas? Link to comment Share on other sites More sharing options...
Nefarious Posted August 21, 2014 Share Posted August 21, 2014 The ECU usually sinks power which means it switches the negative end of the circuit. The power should be supplied from the battery to one end of the fuel pump relay coil and the other end of the relay coil is connected to the ECU and acts as an open circuit until the ECU switches closed which completes the current path. The ECU doesn't supply the current to the fuel pump relay it receives current FROM the fuel pump relay and switches the connection to ground closed. Is the fuel pump relay energizing? Can you hear it click when the vehicle is set to the ON position? If the coil is engaging but there is no voltage at the at the fuel pump itself then you have bad wiring (open circuit) somewhere in the wiring between the battery and the fuel pump. (the switched wire) If you aren't getting any voltage to the coil of the fuel pump relay then check the wiring and fuse ahead of it in the circuit where it connects to the battery, if you are getting voltage at the battery end of the fuel pump relay coil only and none on the ECU end then either the relay is dead, the wiring between the relay coil or the switch in the ECU is dead. If you have voltage on both ends of the relay coil but no relay actuation then you have stuck relay contacts. If the coil checks out okay and the relay is closing then there is an open circuit somewhere in the wiring of the switched end of the relay. Time to bust out the multimeter and get to work tracing where there is and isn't voltage and I can help U further from there Link to comment Share on other sites More sharing options...
Nefarious Posted August 21, 2014 Share Posted August 21, 2014 There are more specific tests I can give you to narrow it down to a single point but I need more info first on what is going on in the circuit. Link to comment Share on other sites More sharing options...
Dougswd21 Posted August 27, 2014 Author Share Posted August 27, 2014 The ECU isnt coming on. I am not getting power to pins 27 and 35 as indicated by the service manual. Link to comment Share on other sites More sharing options...
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