I am having issues getting a smooth idle with the Bosch EV14 700CC injectors that came with my Kraken Turbo Kit.
I have worked with a few tuners now and it seems converting to sequential injection is the solution.
I struggled to find a truly defined write-up on this so I wanted to confirm this wiring for my SpeedyEFI ECU.

So from what I understand I need to wire it like a 95-car which is already sequential.

I am going to add two additional pins and wires to the connector at 2Y and 2Z which are currently empty on my connector.
I have an ECU connector from a 95-parts car that I can de-pin for the additional pins needed.
If I wire it like a 95 car then 2Y will go to Cyl #3 and 2Z will go to Cyl#4.
I would un-pair my injector harness and leave Cyl #1 going to 2U and Cyl # 2 going to 2V with the Oem harness.
The Speedyefi is already set up to use these pins for sequential.
Then change the settings in Tunerstudio under Engine Constants - Injector Layout from Paired to Sequential and retune fuel.
Does this sound correct?
See attached the ECU pinouts from both the 90-93 and the 94-95 cars.

 

Sounds correct. This is what I did in my '91. Sequential injection is a night-and-day improvement everywhere except full throttle. 100% would recommend it. I de-pinned at the OEM injector harness connector and ran new wires.

 

De-pinned at the injector harness. I haven't looked at it yet but where are the injectors paired together on that harness.

if I have this correct I can cut and splice at injector #3 on the yellow wire and injector #4 on the yellow black. I think I will just add a new 2 wire connector for these.

 

You can cut and splice or you can just depin the OEM injector connector and run the new wire straight from the OEM injector connector on cylinders #3 and #4 to run your new wires straight to the ECU.
Throw some shrink tube on the depinned OEM wire and call it a day...

 

So this went ok. It turned out I didn't have an ECU plug to get the additional pins needed for my connector. I tried some pins from some other connectors but they wouldn't fit. They had the weather protection seal on them and they were slightly too large. I headed to my local U-pull yard to find something. This wasn't an easy task as they really didn't have any 90's JDM cars On my way out I snipped a plug off a 2000's Celica that was just hanging under the steering column, a connector to the wiper module. I de-pinned it and thankfully it worked. I will attach a screenshot of the cars that use these pins.
I just cut the wire near the injector at #3 and #4. I soldered and used shrink on my connections. I added a new two wire plug from my parts car .
After I completed I had a hard time getting tuner studio to calculate the required fuel properly and was getting some strange large numbers.
Other than changing to sequential I also changed Injector staging to simultaneous. I think my problem was I needed to actually click on the required fuel tab in order for it to recalculate properly. After doing this I was seeing some better required fuel values. Car started and ran fine. I did have my tuner go over the data log to make any necessary adjustments.

 

Nice write up, thanks for sharing. I assume you didn't have to open the SpeedyEFI because those signals were already wired for injector signals as you said? Seems odd that they'd include the wiring, but maybe they make the same board for all the PNP units.

 

Yes the board is already configured I did not have to modify or change anything on the Speedyefi ECU.

 

Howdy!

i also have the Kraken/Bosch 700cc injectors, I’ve managed to get the idle and accel enrichment to what I would call a “B-Minus” level of refinement, was hoping you could share how this has fared for you over the last several months? I have a batch-fire 1.6 on an MS2PNP. My idle and AE pulsewidths are tiny, only 1.5-2.5ms, and I still have to keep it around 13:1 or so to keep it smooth and mostly stable, it still hunts a bit.

Were you happy with the result of the sequential swap? Or should I forget it and just get smaller injectors? I’m only aiming to hit about 10psi or so, running wastegate pressure for now.

What did you find to be the best place to split the injector wiring?

Thanks for any advice you can offer.

 

I am have no regrets switching to sequential. This allows you to run 1 squirt and you will certainly see a more refined idle. I clipped the wires on the harness on top of the intake. I could revert back easily if needed but highly unlikely.
I did pull the Speedyefi out of the car for different reasons and replaced with an MS3PRO. Much better.


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Sequential was an absolute night and day improvement on my excessive 900cc injectors. There is no reason not to use it over batch. For my conversion I used an NA8 injector subharness and repinned the main harness to match the 8 pin connector (NA6 has a 6 pin)

 

Yes sequential helped with idle. My car idles great at 14.7. The Kraken EV14 700cc injectors are great.
Please have a look at my tune file here for injector settings.
https://www.miataturbo.net/megasquir...e-look-109219/