MSefi.com read only forum (Jan.15,2018)

Guys,

I was troubleshooting wy my car won't start and wanted to check if the IAC valve works, but whatever I put in at the idle control section, the needle didn't retract. I tried the iac always on/moving only/and the 15 min iac, with different start values. rebooted the ms every time. needle didn't move.. So i tried to switch wires of the iac, at which de needle retracted but then when i tried other settings the needle stays at the fully retracted position.

How can I check the IAC with megatune without a stim? I thought that adjusting the start value and rebooting should make the needle move??

Edd

Only thing I want to try is to set the needle to a prescribed length/or steps using some settings in Megatune to check if my wiring is correct/ms2 works properly. Anyone suggestions so I can try this next Saturday???

By the way it is the GM IAC with the thread on it. A guy I know said something about adding a resistance to one of the four wires, Anyone familiar with this??

Could you post a copy of your MSQ file?

Of course,

I've posted the tune on which the car almost started, on my last tune i was just trying out all settings regarding the IAC valve. but for the IAC I just want to check if ms is able to move the needle.

Edd

Try doubling your time step size setting; it may be that the valve doesn't fully move when the coils are only energized for 2.5 msec.

Ok,

Thanks matt, I'll try next saturday. if I change that, should the needle take a different position if I change the start(retract) value then???

Made no difference at all, I measured the resistance at the connector of the ms2, both sets of the IAC had about 50 ohms. can i test the IAC functions with the stim?

Edd

The JimStim can use alternating bi-colored LEDs to test the outputs. For a normal Stim... well, you could solder an IAC pigtail to it.

I haven't tested the ms on the jimstim jet, but i managed to retract the needle to the position I want, but after i increase the start value(steps) if i decrease the amount of steps the needle won't extend. only if i switch two wires (the blue wires) I can get the needle to extend with the amount of steps i want, but thats only because the switched polarity...thus it won't extend anymore.

resistance on both coils of the IAC is equal, and wiring resistance is neglegible.( measured from the db37 through pins 25 to 27 and 29 to 31 with the IAC connected).

also if i put the amount of steps as a dial on the display of megatune, the amount of steps shown on the dial stays at zero, whatever i put in as start value.

Well anyone ideas on why this sensor seems to work only in one direction??

Thanks guys