Stepper IAC wiring - pin 29 missing

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Stepper IAC wiring - pin 29 missing

Postby Madkaw » Sat Oct 07, 2017 8:00 am

Well I went to check that I had all my jumpers on my 3X and realized I had broke pin 29 a long time ago , so unless there's an alternative way of wiring a 4 wire jeep IAC , I guess I need a new main board connector?
Thanks
Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
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Re: Stepper IAC wiring - pin 29 missing

Postby billr » Sat Oct 07, 2017 8:18 am

Use pin 36 that was reserved for the single-coil ignition driver.
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Re: Stepper IAC wiring - pin 29 missing

Postby Madkaw » Sat Oct 07, 2017 10:06 am

Okay - I will look at that. Will I set up in the tuner studi differently ?
Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
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Re: Stepper IAC wiring - pin 29 missing

Postby billr » Sat Oct 07, 2017 12:48 pm

No, I don't think anything non-standard is needed in TS. Just be sure the Q16 output ("IbgtOut" pad) is disconnected from pin 36 ("IGN" pad), if there is a jumper already installed between those two pads.
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Re: Stepper IAC wiring - pin 29 missing

Postby Madkaw » Sun Oct 08, 2017 4:42 pm

Thanks so much for the reply. I took a pic of the board since I wasn't sure if your explanation . I am not currently using pin 36 and the board is unaltered 3.57
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Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
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Re: Stepper IAC wiring - pin 29 missing

Postby Six_Shooter » Sun Oct 08, 2017 4:53 pm

Any spare output pin can be used. The pins that are in the manual are simply suggestions to keep things easy across many installs. They are simply a way to get the signal from the inside to the outside. The CPU has no idea what physical pin is used at the db37 connector, so, no, no software changes neded.
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Re: Stepper IAC wiring - pin 29 missing

Postby Madkaw » Sun Oct 08, 2017 5:56 pm

That's good to know - though it's going to take a while for that to sink in. I'm pretty good for following the MS instructions , but things get fuzzy sometimes for me. My thinking is that the software expects to use those wires for a stepper :)
But anyway- looks like to me the pin 36 is good to go

Thanks again
Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
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Re: Stepper IAC wiring - pin 29 missing

Postby Madkaw » Fri Nov 10, 2017 6:08 am

Finally got around to trying my stepper IAC . Could not get it to function properly . The unit is a Borg Warner and it did measure 50 ohms at the center leads . Wired per manual and it would hum but not move . The only combination that would make the stepper move actually ran the pintle all the way out and wouldn’t stop with the in and out test. Below is how it was wired with the top numbers representing the motor wires left to right. Is there a voltage test that can be done to check that all wires are working?

1 2 3. 4
1b. 36. 1a. 2b
Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
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Re: Stepper IAC wiring - pin 29 missing

Postby billr » Fri Nov 10, 2017 7:35 pm

50 ohms from 2 to 3, and 50 ohms from 1 to 4; and no connection from 2/3 to 1/4 or to ground from any pin? Yes, there are voltage measurements that can be made, but it may get a bit confusing. Let me study how slow you can move that thing in "test mode"
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Re: Stepper IAC wiring - pin 29 missing

Postby Madkaw » Sat Nov 11, 2017 9:42 am

So i checked and ohms are the same on 1&4 and 2&4 . Nothing grounds at the motor . Am i supposed to see if any wires from MS ground , because they dont either .
How slow . I could only get the motor to move in one direction at one speed during test - in and out
Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
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Re: Stepper IAC wiring - pin 29 missing

Postby billr » Sat Nov 11, 2017 10:56 am

"1&4 and 2&4 "

Is there a typo there? That would mean either it is defective or not a 2-coil stepper. Avoid typos when posting here, they cripple attempts to help you.

No, when used as a stepper driver, no wires from the MS are "always grounded". None are "always hot", either.

PS: I have to admit, I hadn't seen the photo of your board before, I'll have to peek at that better later today.
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Re: Stepper IAC wiring - pin 29 missing

Postby Madkaw » Sat Nov 11, 2017 2:57 pm

My apologies - I need to proof read my posts.

1&4 read same ohms as 2&3 - approx 50
Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
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Re: Stepper IAC wiring - pin 29 missing

Postby billr » Sat Nov 11, 2017 8:16 pm

Alas, I am not able to see much of the board in that photo. I can pan vertically, but not horizontally.
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Re: Stepper IAC wiring - pin 29 missing

Postby Madkaw » Mon Nov 13, 2017 5:57 am

I would be happy to shoot more pics . Can I ask specifically to what we want to see?
Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
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Re: Stepper IAC wiring - pin 29 missing

Postby jsmcortina » Mon Nov 13, 2017 6:20 am

billr wrote:Alas, I am not able to see much of the board in that photo. I can pan vertically, but not horizontally.

Try opening the image in a new window or saving, then opening. I think it is a phpBB (forum) issue.

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Re: Stepper IAC wiring - pin 29 missing

Postby billr » Mon Nov 13, 2017 10:34 am

I tried both, no joy.
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Re: Stepper IAC wiring - pin 29 missing

Postby Madkaw » Mon Nov 13, 2017 4:20 pm

So do I need more pics?
I tried again today with the wiring . I used both examples in the manual. I can get the motor to run in one direction only - it seems. When I limited the steps (160 instead of 255)and tested home the piston does seem to want to go fully closed or out . Any other tests -like in and out -just makes the piston goes further out until it falls out.
Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
Madkaw
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Re: Stepper IAC wiring - pin 29 missing

Postby billr » Mon Nov 13, 2017 6:35 pm

I will certainly need a different picture format to try checking the board visually.

We can try to do some measurements with a voltmeter, but it might get confusing; writing isn't my forte...

Set the IAC control "Power Between Steps" to "alway on", if not that way already.

Connect one voltmeter lead to ground, and leave it there.

Use the other meter lead to read voltage at each of the four IAC wires, with the IAC connected and not moving.

At any given time, each coil should have near-zero volts on one wire and battery voltage on the other. That is, 1a=0V & 1b=12v would be a good reading; but so would would 1a=12V & 1b=0V. You want to check all four wires to see if two are low (0) and two are high (12V) whenever the IAC is not moving. Then, use test mode to move the IAC a few steps and read again. Do the move-and-read bit enough times to ensure both coils are getting both "polarity" of drive voltage. This isn't a perfect test, but at least a good first step. If it passes this test, it doesn't mean the coil currents are being changed in a correct pattern, but if it doesn't pass the voltage test above, then something is surely wrong with the drivers/wiring.

Clear as mud?
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Re: Stepper IAC wiring - pin 29 missing

Postby Madkaw » Wed Nov 15, 2017 6:49 am

I think I get it- will check it out when I get home - thank you . I’ll owe someone a Starbucks for sure
Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
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Re: Stepper IAC wiring - pin 29 missing

Postby Madkaw » Thu Nov 16, 2017 8:00 am

Okay-test accomplished. Looks like it failed by your numbers.
1a -0v
1b-12v
2b-12v
pin 36-12v
Steve
1971 Datsun 240z 2.4 L6 1975 EFI intake with 1.8 audi Bosch injectors
MS3x 3.57 Ignition LS1 coils running wasted COP, CAS
Madkaw
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