85 Z31 M/T engine problem. - Nissan Forum
Z31 300ZX(T) 1984-1989 Zs - Engine and Chassis Discussion

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post #1 of 1 Old Apr 14th, 2019, 05:29 PM Thread Starter
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85 Z31 M/T engine problem.

I have an 85 Z31 and for a while now I have been unsuccessful in finding why my car won't run properly. For starters, the ECU is throwing a code 23 (idle switch). The car will idle up as normal but try to die intermittently as it idles dropping in rpm. Any pressing on the throttle kills the engine almost immediately. Strong smell of fuel in the oil as well as the exaust. No smoke or anything else is noticeable. In all my attempts to find the problem I have removed the intake, checked all the fuel injectors for leaks, replaced the FPR along with the fuel and vacuum lines. Installed a new mass air flow and all the piping leading up to the TPS has been cleaned. Tested the plugs and resistance to all these parts as well. No change so I then went to the plugs wires and ignition coil. All new tested and greased. With the plenum off I replaced all vacuum lines that I could locate (including the ones that send coolant through the throttle body) this had no effect. I then replaced the distributor cap and rotor because there was significant arch damage. Still no change. Lastly, I changed the oil because after all the misfired attempts to get the engine running right the oil was smelly of gas. Does anyone have any other suggestions that I might look into? Any input is appreciated. (On a side note, if it is an electrical part, harness or connector. It has been tested although I'm sure skimmed over quite a few) thanks again!

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