I have a 99' Isuzu NPR with the 4he1 which was delivered for airport service and it arrived in terrible condition. Cold starting the engine will smoke excessive gray fuel smoke and idle badly, and once warmed up it would still smoke a little less. i suspected the cold start solenoid was not actuating properly. I attempted to remove the circuit to energize it with 12v direct from the battery and the threaded terminal disintegrated the solenoid insulator. I started the engine with the solenoid disconnected and it smokes even more, which makes me think it was indeed the solenoid. Now i installed a new solenoid by depressing the lever inside the solenoid case through the bleed screw hole and passed the solenoid plunger under the lever, but the engine wont turn over. Bled air out of the system from the bleed screw at the pump, to the filter bleed screw and at each injector and still cant get fuel to pump. The primer pump seal also seems to be bad, but even with getting fuel up to each injector it wont turn over for a second. I should also mention that there was no CSS relay behind the glove box which shouldve been the location if there was any to begin with, and there was no blown fuses or any shorts. Now what ive read that i fell into a trap of thinking the solenoid can be replaced, but it might require re-timing the pump. Its either that, or maybe the plunger on the solenoid isnt on the correct side of the lever causing the fuel to shutoff? The solenoid came out fairly easy, but there was no way of checking the correct position of the plunger when removing. I couldnt find a single zexel pump manual which covered service procedures. If the pump does need to be re-timed, is that something that requires a zexel tech to bench rebuild?
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