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Old 13th February 2018, 07:22 AM   #1
347Stroker's Avatar
Join Date: Mar 2016
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Speedmaster 8-Stack Injection

Hey guys,

Just wondering if anyone has installed an Speedmaster 8-Stack injection system into their car yet? i don't really have a wiring diagram so that would help but pretty sure ive got them all sorted out anyway.

My main issue though is the cable that i believe to be for the IAC. Ive read that it can be quite a problem to get one to work on the 8 stack and thats if its even possible? Does the car need to actually run the IAC and will the computer still be able to learn what it needs to (speedmaster self learning ecu) without it being connected?

Thanks for your time!


Last edited by 347Stroker; 13th February 2018 at 07:40 AM.
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Old 13th February 2018, 09:45 AM   #2
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Re: Speedmaster 8-Stack Injection

Is there a way to program it for no IAC? I've got the Holley product ECU, which allows that option, so I do not run one.

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Old 13th February 2018, 02:42 PM   #3
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Re: Speedmaster 8-Stack Injection


Yes, I have.

Just to be precise, the mechanicals (inlet manifold, TB's, linkage, etc.) is a speedmaster product. The EFI control system you're working with is made and sold by FAST (Electronic Fuel Injection Leader - FAST(R) - Fuel Air Spark Technology, and it's FAST that provides the post-sale support.

The IAC (Idle Air Control valve) does not have to be used with the FAST EZ EFI 2.0 system. You can use a plain old mechanical adjustment at the TB's if you prefer. The IAC connector will be sending a signal through the cable to modulate idle rpm, but not being hooked up to anything....well, it won't actually do anything. Yes, the ECU will learn just fine without it hooked up.

The IAC can be quite easily used on the speedmaster inlet manifold. There are a number of ports in the plenum downstream of the butterflys in the TB. Use one of those ports to connect the IAC with a good quality (non-collapsable) vacuum tube. The ports are NPT. You'll have to fabricate a bracket to mount the IAC on the manifold. Hook up the connector and you're in business. There is a calibration routine for the IAC and idle speed in the set up routine. Works very well keeping a nice steady idle once set up.

You should have received the instructions and wiring diagram in the box the FAST EZ EFI 2.0 came in.
Attached Thumbnails
Speedmaster 8-Stack Injection-lotus-efi5-jpg   Speedmaster 8-Stack Injection-lotus-efi6-jpg   Speedmaster 8-Stack Injection-lotus-efi7-jpg  

Last edited by Cliffbeer2; 13th February 2018 at 02:49 PM.
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Old 13th February 2018, 06:35 PM   #4
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Re: Speedmaster 8-Stack Injection

Hey terry, im not sure yet. Will have to see if i can find that option on tge software. I dont want to install it all to find out it cant be done and have to remove the manifold again.

Cliff, this is an older version and supposedly either made by fast or has copied fast components or something like that. I will try to post a pic of it. Its speedmaster turnkey efi.

Im still new to the whole iac concept as this is the first efi ive mucked around with. So the idea would be to mount the iac in the plenum underneath and use an existing hole in the top to let the air inside?

Additionally ive come across another hurdle... the carbon canister. It has electrics hooked up from the old motec system but this new setup does not have any wiring for it. Does it need to be connected or will it operate fine without it?
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8-stack, car, iac, injection, speedmaster

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