Code 45 Leaning injector 91 nissan pathfinder California

[msavides]

I have a 1991 nissan pathfinder with a code 45 leaking injector code

Things I have tested/replaced

Fuel Pressure / regulator (tested good)MAF sensor (harness and sensor) Cleaned/ replacedFuel filter Replacedreplaced all 6 injectors with rebuiltReplaced TPS with newReplaced O2 sensor with newSwapped out ECU with known goodTested for vacuum leaks (no leaks found)Checked Engine Ground ( 0.00ohms)

Engine has full power and runs perfect. no stumbling accel problems.

The engine does run rich. so I think it is something to do with the mixture.

any help would be greatly appreciated. I have been troubleshooting this for 3 years now.

Mark

[Infinitiguy19]

Check to make sure the fuel system hold pressure for more than 10 min when the truck is off. If the pressure is lost look at the fuel injector o-rings.

Check the MAF sensor harness, wiggle it and if the idle changes then replace it.

Check the Catalytic converters.

You have changed a lot so how rich is it running to be a problem.

[msavides]

It is not the running rich that bothers me. It is the bright yellow light that keeps popping up. Also I have to deal with smog every 2 years and it would be nice to pass the visual inspection without worry.

It does not seem like it runs that rich when warm, only really notice it when cold but that is normal when still in open loop.

I just checked the MAF wiring harness plug and it ohms out at 0.00 and there is no corrosion either the sensor or the plug. I also checked pin 115 on the ecu it also ohms out at 0.00 so the ground is good there as well. Also no change in idle when wiggling the MAF Plug

I checked fuel pressure but i did not check leak-down fuel pressure. I will have to do that this weekend..