(07-06-2021, 09:02 PM)fixkick Wrote:(07-06-2021, 07:52 PM)jwunsch Wrote: Update: 1991 Vitara MT, 2 door, G16a, 4wd.wow, thanks for sharing all that data. nobody has done this and posted the results. for building a fake,IAC valve, due to stock valve IAC stuck.(dead or weak)
Very shortly after experimenting with golf tee I moved the hose on driver's side near driver's right knee and put a moped's fuel valve at the end of the hose to be able to tune the vacuum leak and have RPM control.
cold 200-2200 (fully closed - fully open)
hot 800-2500 (fully closed - fully open)
Note a needle valve would be a lot better for selecting RPM as its designed for gasses, this valve is for liquid so the whole tuning range is around 2-3 degrees of rotation. Bit hard to tune, but it does what is needed.
that gas line valve is prefect. and easy to find too.
the dash gauge water temp uses its own 1 pin sensor and is not used for EFI , not used at all for the ECU for fuel mixing.
nice work and good luck for inspecting, get car hot, turn new valve for 800 rpm and bingo.
as you turn the valve , the ISC will kick in and do RPM controls HOT. to 800. (regulated ISC mode) hot.
i see yours did here. hot >>>> 800-2500 (fully closed - fully open)
the 2500 is because your air leak is more than the ISC can control.
try 1500 rpm cold see if when hot the ISC wakes up at 150F and goes to 800 like it should.
best wishes and cheers to you !
wow I missed your post before with super nice IAC packing job to take it off line..(leaking bad hot) great photos those, and the method is perfect.
any method that can be Regressed easy is best. (blocking the base gasket also kills the air bleed in top of air horn, and is best to keep that working)
Thanks hope that someone having same problems can use this thread to sort out IAC problems. Also my goal here was to try to achieve debug and possible fix for the IAC without removing the TB from the car. I had tested everything else except IAC and checked the TB gaskets.
I have previously diagnosed by ISC being dead too or then impaired by something (bad TV position?). It does absolutely nothing when I turn on head lights or high beams. Hot idle up pin reacts to defroster, but ISC does not.
My hot idle is around 650 with lights and blower. 600 with lights + high beams + blower + seat warmer. 800 when all lights and blower off. Feels like someone has tuned it to 800 on that setup.
Vehicle passed inspection 3 weeks ago. I just forgot to update the valve pic here and remembered it due to the "1989 screamer" thread.
I do not care the hot idle not being modulated as it does not affect my driving at all. Oil pressure is ok enough (light off), battery is charged even on such low RPM and engine never stalls even if I step on clutch and lift throttle suddenly during driving.
Ie the only pain it causes is that it does not keep 800 RPM. But here for pre 92 or 93 cars the emission spec is pretty easy. Certain emission leves & RPM <= 1000.
Newer cars will be tested idle and high RPM and for diesels box on neutral a engine acceleration from idle to max RPM on full throttle to see how much smog an particles they do.