It connects to a solenoid valve on the top front side of the engine.
My setup is the same as yours. You described the connection to the back of the vacuum reservoir just as it should be. There is a piping route inside the reservoir that connects the actuator hose to the solenoid. Doing that IACV relearn procedure may be all that is needed.Basdog539 wrote: ↑Thu Mar 06, 2025 4:10 pmThe idle was hunting until I cleaned the iac valve. It's now steady,not perfectly smooth but way better. Is it possible that I just need to do the idle air volume relearn? Thanks for the help.
I forgot to mention I currently have the swirl valve actuator connected to the back of the small black vacum box. I tried to follow the dotted lines in the factory service manual and that is where it looked like it connected to.
Yikes! Me too. I'm thinking an air intake leak at the intake manifold gasket to the head, on the driver side. Not sure why your mass air flow sensor is flagged (P0102) unless it too is loaded with dirt/oil or why your knock sensor is flagged as well (P0327). The IACV is definitely a problem (P0505), but hopefully the relearn procedure will take care of that. After it's cooled down, getting those STFT readings may give you a clue.
No. The procedure requires normal operating engine temperature and the transmission has to be warmed up as well. You can get the LTFT and STFT readings without the engine being warmed up, so you can see if bank 2 has high percentage numbers, an indication more fuel is being delivered to make up for too much air, if there is a leak in that side of the intake manifold. You are right to check for an ignition fault. If there is no spark happening or the coils wires are plugged into the wrong coils, those fuel trim numbers will be negative percentages.
Yeah...I take for granted that I always seat my connections well, and I do have a bit of OCD. An ill seated coil harness connector is sort of common on these older rides. Pins get worn from oxidation and multiple disconnect/reconnect uses. Had an issue once with a bad connection, but with an ever so slight twist of the flat pins, the contact was made solid and the issue went away. You may have dodged a big headache, looking for a major cause to the issue, when it was just an old connector.I believe those rpm ranges are well within spec.Basdog539 wrote: ↑Mon Mar 10, 2025 9:45 amEverything was good until yesterday evening then the high idle came back. When in drive it idles at 750rpm but in park it idles at 1000-1100rpm. Nothing was changed, the only thing I have done was to bleed the excess air out if the cooling system. I have performed the idle relearn procedure twice but it has not helped. I do currently have the throttle body coolant lines bypassed however I do not think that should effect it as the ambient air temp is taken before the throttle body.
The IACV relearn procedure is a pain for all the precise timing required between performing all the steps and for the preconditioning requirements that must be met before you begin the process. If after step 8, your idle is not at 750 + or - 50 rpm, something is wrong. There is only one other manual adjustment, aside from this calibration, that can be done and must be correct before doing this IACV relearn procedure. Check your TPS adjustment for being properly set and adjust it as needed and reset memory. Other than that, the notes from the FSM points to a number of other issues to investigate.
I wasn't aware that it was even possible for the ignition advance for each cylinder to be different or that other scan tools could give you the ignition advance reading for each cylinder. My scan tool reads out only one number. Maybe my basic scan tool just gives the average for all cylinders. I'm not sure what to make of that. I would think varied ignition events would make the engine knock and run quite roughly.
In theory it's possible for any ECU-driven ignition to vary timing from cylinder to cylinder, but in practice it's never done. The only conceivable reason would be to compensate for something unhealthy affecting one particular cylinder, and no one does that.
Was the TPS disconnected? On practically all Nissan engines prior to COP, the TPS has to be disconnected in order to see base timing. If the TPS is plugged in then the timing will be what the ECM decides it wants, not base.
Try not to think about how to deal with dismantling that tube unless you can confirm for certain that is the source of your leak. Hopefully, it's something much less troublesome to correct. You should pick up some fluorescent leak detector dye and a UV light from a local auto parts store or online. Where ever the leak is coming from, a coolant trail right to the source of the leak will light up with the UV light. I hope it turns out to be an easy fix.