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RX-7 460cc injector upgrade and motor rebuild - Chasing my idle

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Old Dec 22, 2017 | 04:36 PM
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Default RX-7 460cc injector upgrade and motor rebuild - Chasing my idle

Hi guys,

It's been 2 years since my Miata was last running. I recently rebuilt the 1.6 and installed Rx7 460cc injectors. My tune prior to to the rebuild idled fine and ran fine with the Tan top injectors from the NB miata.

Nothing else changed. Could I have a bad IAC? Why am I running so lean? I am currently reading over a bunch of threads and documents but wanted to chime in to see if anyone can give me any tips on what to look/start with. Any advice is appreciated.

Attached is my .msl attempting to idle.
Attached Files
File Type: msl
WTFMATE.msl (1.16 MB, 119 views)
Old Dec 22, 2017 | 06:26 PM
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RX7 injectors.
thats your problem.
Old Dec 22, 2017 | 07:01 PM
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Originally Posted by WigglingWaffles
RX7 injectors.
thats your problem.
I was afraid it was my injectors. What's the reasoning behind the RX7 injectors being the problem?

Thanks for the reply. I'l toss in my old injectors and see what happens.
Old Dec 22, 2017 | 07:11 PM
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Theyre old technology and are well known to be difficult to tune with. Something about picky pulsewidth i think.
if you can make the step up, i hear EV14s are the kitties *******
Old Dec 23, 2017 | 09:41 AM
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Did you update the REQ_FUEL?

Its been many many years since I played with the setup on MS but I remember you have to tel the computer that you changed he fuel input.
Old Dec 23, 2017 | 11:55 AM
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Originally Posted by Miater
Did you update the REQ_FUEL?

Its been many many years since I played with the setup on MS but I remember you have to tel the computer that you changed he fuel input.
as in adjusting for the appropriate pulsewidth, then yes. In the fuel settings I updated the injector flow rating to 460cc and the software made a recommendation.

I had to fine tune it to get the engine to stay on as it would die. It idles now but high (1500), oscillting rpm between 200 to 400 rpm depending how the motor feels that day, and my AF is pegged lean.
Old Dec 23, 2017 | 12:11 PM
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Changing the injector settings in MS will result in really just a starting point at best.

Need to re-tune your car. It may never be awesome, those injectors aren't the greatest. People ran them for years without wanting to burn their car to the ground, though. With enough time and work, should be able to have something that at least works.
Old Dec 24, 2017 | 10:24 AM
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Originally Posted by ennjay
I had to fine tune it to get the engine to stay on as it would die. It idles now but high (1500), oscillting rpm between 200 to 400 rpm depending how the motor feels that day, and my AF is pegged lean.
so add fuel! make sure all those old-timers are actually firing.
Old Dec 26, 2017 | 12:01 PM
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You have to run kinda rich with this type of injectors usually.
I have found that playing with injection timing can help a ton with RX-7 Injectors.
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