Ok, so here is the situation.
11/1985 Nissan 720 Pickup, Z24 Carbureted engine, Five Speed Manual Trans, 4 Wheel Drive with federal Emissions.
I have been trying to pass a California Emissions test.
The Symptoms are as follows:
Slight surging at idle
When the RPMs are held at 2500 with the vehicle in neutral it will surge to between 2200 and 2900.
Emission numbers are well within spec for the idle circuit, but at the High Idle (2500 RPMs) My Hydrocarbon numbers are elevated and the CO numbers are higher then allowed.
The Following has been replaced within the last month:
Cap, Rotor, Plugs, Wires, Catalytic Converter, Oil, Air filter, Valves adjusted and timing set to 3 BTDC.
I suspect an O2 sensor or the Air Fuel ratio Solenoid inside the Carb. I have not yet preformed a Self Diagnostic on the ECCS.
A test of the BCDD was within specs.
A test of the O2 Sensor is to follow.
I refuse to throw parts at a problem, and this puzzle is driving me crazy!
Any Insight, or good Ideas?
Saturday, February 11th, 2012 AT 5:58 AM