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

Background:
The Darkstar idle air control body (available thru DIYAutoTune) was designed using the Niehoff Part# 21774 idle air control stepper motor. The 21774 part is typically found as a replacement for the stock IAC in Jeep engines (e.g. '92 4.0l V6 Renegade).

The Problem:
Last week I ordered a Niehoff 21774 stepper from PartsAmerica.com to use with my Darkstar IAC body. When it arrived, it came in a Niehoff box, but the box also had the BWD Automotive logo on one end of the box. The stepper inside looked just like a BWD stepper that I had picked up from Pep Boys and had the small pintle.

As noted on the DIYAutoTune website and other locations, the 21774 part is often found to have a smaller pintle than the Darkstar body is designed to use. It is recommended that only the Niehoff part (around $44) or the Wells AC320 part (around $76) be used. Using a stepper motor with the smaller pintle causes a constant air leak thru the IAC which often makes the the combo unusable.

I don't know if this affects all Niehoff 21774 steppers or just ones sourced thru PartsAmerica, but I thought I should alert folks to the problem.

This is the 3rd small pintle 21774 stepper that I've had in my possession so I just gave up on finding one with the large pintle. I took a rubber grommet and RTV'ed it to the seating surface side of the Darkstar. This allows the smaller pintle stepper to be used (I hope, I haven't installed it yet).

Heads up.

I talked to a guy I know inside of CSK and it seems that they have been changing suppliers. I will go to the store and take a look at what they have and possibly revise the design a bit. What size engine do you have (Edit: I see, 3.3L, the small pintle might work anyway, it will not seal all the way but it should restrict the air enough to slow the idle if nothing else lets air through i.e. throttle plates)? the small pintle may work fine if you have no vacuum leaks and a larger motor (3-4L). The design is based of a throttle body for a 92' Jeep Cherokee 4.0L inline six. I do know that in the Jeeps the smaller pintle works but the Jeep computer just adapts by moving the pintle closer to closing. Again, the 4L eats a lot of air. I have a design on the table and prototype parts in hand for the Ford PWM IAC and by my measurements it is ready to be used. Jerry has a prototype and I think he was going to check it out before I put in a production order to the machine shop. If you are really interested in using the Ford one let me know (send me an e-mail or PM), Currently I am not sure of the demand for the ford ones so feedback would be nice.

Richard
DarkStar Media LLC
richard@darkstarmediallc.com