Q45 cranks but wont start after fuel injector replacement

EvanSeiglerEvanSeigler Member Posts: 1
edited October 2021 in INFINITI
I recently replaced 2 injectors on my 1991 Infiniti Q45. The car was running just fine, aside form the 2 bad injectors anyways, and now it wont start. It is getting fuel pressure but the injectors arent firing(tested with a noid light). I have low compression on one of the banks but again, the car ran before I changed the injectors. I have also had issues with a cam sensor but to my knowledge it was just the connector which I cleaned up and it worked fine.


  • eliaselias Member Posts: 2,209
    a caveat is that i know nothing about this particular vehicle - it may not even have half of the parts i refer to - please refer to the manual to verify/match-up with any advice here:

    cam position sensor may need recalibration at a minimum and maybe a swap? does it have a cam position sensor, yeah, it must. if the car were new enough to have OBD you could consider whether it was throwing a code indicating insane cam position readings? ECM might disable fuel injectors in that case to prevent damage. Maybe pre-OBD engine electronics is smart enough to do the same thing even though there is no code to throw.

    aside from that , your diagnosis method is on track - the circuit to the injector is incomplete or engine computer/circuitry are intentionally not powering the injectors.

    If it was me there would be a 114% chance that I damaged the electrical connector to the injector either on removal or install - use best flashlight and/or magnifier you've got to look at every tiny little wire/metal/pin inside both ends of all the connectors. the slightest visible damage any one of tiny metal pins strips in those connectors needs to be eliminated as possible cause for no-injector-firing. get new connectors? sometimes a pin is totally missing due to design, other times it has broken/snapped-off due to corrosion or mechanical damage. compare with the manufacturer spec to see how many pins/wires there should be visible in/on the connectors.
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