| Chris:.. Thank you for the detailed history.. And the ECU talk data.. that helps.. I'm thinking I'll start by doing a little teaching.. The Only Signals a an ECU needs to make an engine run properly are RPM and Air Flow.. Everything else is extra info that will make the engine 'Perform better'.. And a 'Qwerk' of the Nissan ECU is the ECU does not know the actual Ignition Timing, it only knows the timing it is requesting.. When a 'Completely warmed and Happy' Nissan ECU/Engine is in 'Idle mode' the ECU will REPORT that it's idling at 15 Deg. A timing lite is required to see what the actual Ignition timing is, and then you adjust the CAS to get the two to agree.. If your ECU talk is Reporting an Idle if 16 Deg, its not warm and happy at Idle.. This is LIKELY because you said you think you have fuel washing, and have to let it warm up completely.. The TPS is used to let the ECU know when you have closed the Throttle, and then the ECU will settle in at Idle Mode.. Timing at 15 Deg, and if you have AIV's turn them on and richen up the Idle Mixture, or if its a Post 92Machine, no AIVs but the Fuel mixture goes back to Stoch on a Slow Cycling of Rich Lean.
When the TPS is not set properly, the Idle Switch in the TPS wont get set, and the ECU wont go to Idle Mode.. There is a 'Backup' of the TPS/ECU able to assume a Switch Defect if the TPS Voltage goes below about .45 Volts.. There is a Setting Procedure for all of this.. you must do this or the Idle Stuff will not perform properly.. The MAF is something the ECU MUST Have to get the Mixture Properly/ And the Voltage per Air Flow MUST be exact.. or the ECU has no way to know how much fuel to feed.. If you are having MAF Voltage issues, this can be a Problem.. WHAT IS THE MAF VOLTAGE AT IDLE WITH THE ENGINE RUNNING.. please report the MAF Voltage at RPM and I'll compare it to mine to see if you are in the ballpark.. The 'Voltage Part' of the TPS is used to know when you open the Throttle, and how quickly you open it.. The MAF id located a few feet away from the T-Bodies ( Depending on Turbo or NA ).. when you quickly Open the T-Bodie, that Column of air will actually 'Stretch' and flow into the engine before the MAF will see and respond to the Air Flow Change.. So you will get an 'Instant' lean spot in the Air Fuel Mixture.. So the ECU will Blindly ADD fuel to the Mixture the Faster you open the Throttle.. The Nissan will run with the TPS Disconnected.. It will have issues getting to idle properly, and will have a Lean Spot when you accelerate.. but it will run.. and do no damage.. Here is a link to my Zed I made for another Post..
https://youtu.be/ASfXPlzLJkM
Notice the O2 Sensors. They go from Lean to Rich and back again.. This is normal 'Closed Loop' behavior.. If you do not have that 'Cycling' of the O2's when your Engine is at 'Steady State Running' then your Fuel/Air Mixture is not in 'Closed Loop' and you have a Problem.. The 'Diaphragm Thing' on the back of the Intake Manifold, is the Air Regulator.. It's all part of the Idle Air Control Scheme for the ZED.. the Important Part is that ALL three of these things are somehow Bypassing Air around the T-Bodies.. But they are still introducing Air that has been Measured by the MAF.. So that air is still Measured and accounted for by adding fuel.. the ECU has no way of knowing how much Air came through the T-Bodies or the Idle air Control Stuff.. Nore does it care.. And yes, the Air Regulator can be removed.. However, you must Plug off both sides of it.. I just stuffed a Cut Bolt into the 1/2 hose that feeds the Balance tube from the Center on the Back.. that is the Out Tube from the Regulator Only.. the Other Two Idle Control Valved feed directly into the Manifold at the Back. Cj
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22:58:15 09/09/23
