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From the short time I've been watching this I have seen a few things. It appears that it opens to 24% upon acceleration. If you are accelerating hard, and then let off the gas, the valve appears to be opening to 100% perhaps to saturate the intake with Air to counteract the amount of fuel that was previously asked for. Depending on engine load, I can make it open to 100% just by giving it gas, and then totally letting off the pedal. The 100% only seems to happen after I've released the gas.
Strangely, mine measured 24%, 50%, 75% and 100%
F150Torqued you should run some wires in to the cab of your truck and connect the IMRC there so that you can see it. Drive around with the engine's actual IMRC disconnected, it just changes effective runner length anyway, you probably won't even notice and the engine won't know either.
Then you'll have your app readings right next to actual motor movement. Should be fun.
the valve appears to be opening to 100% perhaps to saturate the intake with Air to counteract the amount of fuel that was previously asked for. Depending on engine load, I can make it open to 100% just by giving it gas, and then totally letting off the pedal. The 100% only seems to happen after I've released the gas.
The IMRC only changes the path of the air, the effective runner length, but not the quantity. It gives high velocity at low RPM for better cylinder packing, but opens at higher loads to give the air an "easier" path letting more in for more power. It's an odd thing.
F150Torqued you should run some wires in to the cab of your truck and connect the IMRC there so that you can see it. Drive around with the engine's actual IMRC disconnected, it just changes effective runner length anyway, you probably won't even notice and the engine won't know either.
Then you'll have your app readings right next to actual motor movement. Should be fun.
I would if I could get back there and unplug - re-plug the connector (an 'impossibility' for a 72 yr old geezer). I have positioned a USB camera/light back there and ran watched it with laptop in the cab. BUT, its impossible to tell if what you can see is 'opening' 100% or whatever. It is impossible to position a camera where you can see the whole thing at once.
I've logged the 'IMRC Monitor' PID enough that I believe I have seen all possible range of readings - and FINALLY fashioned a workable formula for a gauge to read 0 - 100%. I can't get mine to do 100% on demand like @Jojodapyro . ?????????
I've received the old unit from @MHOWELL34 that I can 'tinker' with and learn more about it.
That is kind of what I'm after. A shorter distance from TB to cylinder while open? Anyway. I can get 100% on demand. Try it out.
?? Shorter distance from TB to cylinder while open? @BareBonesXL says "The IMRC only changes the path of the air, the effective runner length, but not the quantity"
The 'gizzmo' seems to be referred to as IMRC and/or CMCV interchangeably, and both may be correct. But I understand the purpose to be to alter the speed and create swirl in the air flow at the point of injection for better fuel atomization at LOW air flow rates. (very similar to the 'Variable Venture' carburetors on my old Honda Goldwing).
It is the most curious device on the engine to me. Both banks are linked by solid linkage - yet the PCM can produce a DTC that Bank 1 or Bank 2 is stuck open or closed???l And the device has ONE feedback source (IMRCM - PID 1634). There has got to be an effect that is detectable by sensors unique to each bank. (Fuel trim ???, O2 voltage extreams ??, Crank acceleration - power balance ???)
Does the 100% reading for a brief moment JUST BEFORE it closes provide an effect that is monitored by upstream O2's?? Mine will do that too, but I cannot produce a 100% reading at will under any condition like @Jojodapyro -- and I have not been able to find / locate any binding.
I've seen before that the PCM is supposed to do a self-test every time the ignition is turned on. Also that some scan tools allow control of the valve. Found an old link, you probably know all of this - https://www.justanswer.com/ford/bbhb...-4-2-imrc.html
As I understand it the IMRC opens fully at high RPM and high air flow rates. Basically it opens up another path to the back of the intake valve. Like the Express lanes in Seattle. You probably knew this to.
Is there another connection in the harness for the IMRC? A sub-harness with an easier to reach connection that you can break in to. Need a wring diagram to see that probably.
03-29-2019, 02:31 PM
