Thread: I just spent all afternoon trying to get the stepper to work.

I recently put a new cam in my 3.9 and inter alia switched injectors to Bosch gen111 from gen11.
Now ever since the idle has keep up at 1200RPM, and I set aside this afternoon to fix it.
I suspected that it was a combination of too much advance and somehow the stepper not working, as when I disconnected and plugged the stepper it idled at a good base idle. I also suspected the stepper as I had pulled it apart and oiled it which was all a bit brutal.
Anyway I had a timing light and stepper on order from the USA which both arrived this morning.
So, in with the new stepper and time it correctly. It was about 12 or so before TDC and bought it back to 8. NO CHANGE.
New stepper-NO CHANGE-except the damn thing started at the correct revs then after a couple of minutes rose up to about 1800RPM which meant the stepper had fully contracted.
ANOTHER ECU- NO CHANGE
AGGGH- I then ran a diagnostic on the stepper and it came up as OK
So I then cleaned the MAF and checked the TPS voltage, just for something different to do

By this time I had the royal ****s.

So I pulled the whole assembly off once again , checked for any leaks etc etc , then reassembled with the OLD stepper which I had taken off years ago , and held as a spare, but had NOT worked until now.
This time the bloody thing worked and the idle seems now to be OK, although it is a bit slow to come down

Maybe I held my mouth right this time. I cannot think of anything I actually did to fix it, but hey there you go.

I suspect a bad connection in the 4 pin plug or maybe I haven't pushed it in far enough as the little lock tag is broken off it.BUT the ohms resistance at the ECU plug was correct at about 50 Ohms.All I know is the new (admittedly cheapo) Stepper is just sitting and looking dumb and not winding in on shutdown as it should.
I feel a bit of a fraud pontificating to others when it takes me hours to get a stepper to work and the car to idle.
Regards Philip A

I spent a good while stuffing around with the stepper on my 1990RR a month or so back, very similar situation to yours Philip. Swapping it out for a known working unit (helps to have 3 vehicles with the same motor) made no difference. I discovered a bad connection at the stepper plug- one of the pins was hanging half-way out; fixed this and STILL no better. Pulled off the plenum and cleaned everything out, on reassembly it now sounds much like yours- idle speed is okay, maybe a little high, but very slow to come down. I have lost interest for the time being, life is too short without stuffing around with this for hours on end and getting nowhere. Oh, nearly forgot- I also swapped the ECU with no effect.