9 replies to this topic

[EuphoriX]

I have a UMS running a SC throttle body on my SPI

Have done some 3D printing to add a sandwich plate to take an IACV

The MPI IACV has the same socket as the SPi stepper motor

Has any one ever run an IACV on a spi men’s unit or similar

Just need to manage the warmup - idle is fine without

(This is just a project to see if can be done without going to a full blown mega squirt or other big boys ECU’s)

Thank you.

[Steve220]

It has been done, you'll need to pin your ecu for it, I THINK you need a 2 pin iacv motor, but worth checking with SC first.

This was my biggest gripe with the system, and typically sc didn't like thenfeedback and gave some tosh about them being fine with ignition idle control from cold. I ditched the lot and went DBW and haltech elite ecu.

[tmsmini]

If you are using UMS, then it is more a matter of what UMS supports. There are unipolar and bipolar valves. There is a Bosch version that is two pin, used on volvos I think.

[EuphoriX]

The UMS is unipolar and want to “dovetail” into this if I can.

Currently looking at 3d printing an alternative housing for the stepper motor to operate a valve

Any circuit diagrams or pin-out/wiring info would be useful as I am keen to try and convert to use a valve instead of the throttle adjustment.

Not sure SC would have much interest to using their throttle body with another’s ECU

That said running a 276 cam with big valve head and once warm the UMS idles very nicely at 850rpm and pulls away nicely too

Edited by EuphoriX, 24 July 2024 - 06:17 PM.

[tmsmini]

This is the Bosch version. I never used it as I planned. The plan was to use Megasquirt on the MPi manifold. These would be mounted remotely and an adapter to the manifold would need to be made. In the USA, DIY Autotune also had a remote style IACV available at one time.

My skills to fabricate the adapter are lacking. For wiring, you might visit the Megasquirt documentation and forums and see if you can translate it to UMS.

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[EuphoriX]

Update: so the MPI is a direct plugin for the SPI stepper - only issue is the coil resistances are much smaller (6ohm) the secondhand IACV I foolishly did not measure and had two coils which were shorts - this burnt out the tracks on the UMS pcb.

Have now mended the PCB and tested with both SPI and MPI steppers - both operate in the same direction.

To limit the current have added a 8.2 ohm resistor in the 12v supply and the MPI stepper still operates happily.

I have not started the engine as yet as there are a few other things I need to attend to - but it looks like using a MPI IACV will do the job

And I can remove the manual value I have at the moment

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Edited by EuphoriX, 27 July 2024 - 03:32 PM.

[EuphoriX]

Update - started fine and works as expected - just need to now tune the warmup

[brivinci]

Man!! You guys are like wizards when it comes to this!! I have toyed with updating my standard SPi system for something tunable....but clearly would be lost before I got started! Very clever things you all are working through.

[sonscar]

I think you would find it less challenging than you think.My concern is you would be paying handsomely for a system and only using its most basic functions.Have a go,you may find it rewarding.Steve..

[tmsmini]

Would you be willing to make others to sell or share the file used to create the adapter? Did you also custom make something for the intake end of the throttle body?