Another stepper wiring question.

For discussing how to choose sensors and create a wiring harness for all Bowling and Grippo versions of the MegaSquirt® EFI controller.
Forum rules
Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.

If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).

If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days

The full forum rules are here: Forum Rules, be sure to read them all regularly.
Post Reply
WELDER
MegaSquirt Newbie
Posts: 22
Joined: Tue Feb 23, 2010 5:54 pm

Another stepper wiring question.

Post by WELDER »

Alrighty then. I finally got fed up with the stepper motor doing odd things while trying to get my truck started, so I ripped it off. A few minutes ago, I decided to really see what wires did what. Out of the 5 wires, 2 move the damn thing.

Using a battery charger for a quick power source... With positive on one wire and negative on the other, the motor contracts completely. With the leads switched around, voila, the motor extends fully.

Now, which wires from the MSII harness should I be using (once I know which ones to use, I can swap them around if the motor does the wrong thing :D )

IAC1-A
IAC1-B
or
IAC2-A
IAC2-B

Thanks in advance.

Welder.
kjones6039
Master Squirter
Posts: 618
Joined: Sat Jul 22, 2006 7:02 pm
Location: Eureka, Nevada USA
Contact:

Re: Another stepper wiring question.

Post by kjones6039 »

The manual has all sorts of information on IAC stepper motors including wiring etc.

http://www.megamanual.com/ms2/IAC.htm
1979 Corvette - 383 CID SBC w/ Holley Pro-Jection 900 CFM TBI, 4-85 lb lo-z injectors & Walbro 255 pump
MS2 v3 w/ms2extra 3.4.0 Release
36-1, Delphi LS2/7 coils in wasted spark, driven by v2.0 logic board from JBPerformance
Spartan Lambda Sensor from 14point7
kjones6039
Master Squirter
Posts: 618
Joined: Sat Jul 22, 2006 7:02 pm
Location: Eureka, Nevada USA
Contact:

Re: Another stepper wiring question.

Post by kjones6039 »

Ooops, left one thing out.

From your description it sounds like you have one set of windings open in the IAC motor.

Ken
1979 Corvette - 383 CID SBC w/ Holley Pro-Jection 900 CFM TBI, 4-85 lb lo-z injectors & Walbro 255 pump
MS2 v3 w/ms2extra 3.4.0 Release
36-1, Delphi LS2/7 coils in wasted spark, driven by v2.0 logic board from JBPerformance
Spartan Lambda Sensor from 14point7
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: Another stepper wiring question.

Post by Matt Cramer »

Are you sure this is, in fact, a stepper motor? It sounds to me like you may have a DC servomotor and the other three wires are a potentiometer for an IAC position sensor. What exactly is this IAC out of?
WELDER
MegaSquirt Newbie
Posts: 22
Joined: Tue Feb 23, 2010 5:54 pm

Re: Another stepper wiring question.

Post by WELDER »

Matt Cramer wrote:Are you sure this is, in fact, a stepper motor? It sounds to me like you may have a DC servomotor and the other three wires are a potentiometer for an IAC position sensor. What exactly is this IAC out of?
You may be onto the problem there Matt.

It is from a 91 Chevy Sprint 1L non-turbo.

Welder
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: Another stepper wiring question.

Post by Matt Cramer »

Hmmm, I can't find much information on that one. The nearest equivalent I was able to find in Alldata is a '91 Geo Metro 1.0 liter, and that one looks like it uses a PWM or on/off valve.
WELDER
MegaSquirt Newbie
Posts: 22
Joined: Tue Feb 23, 2010 5:54 pm

Re: Another stepper wiring question.

Post by WELDER »

I am going to scrap using the thing period.

I don't mind keeping my foot on the pedal while warming it up.

Thanks again.
Post Reply