7MGTE 550cc Grams Injectors

RareForm

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#1
Has anyone had luck with the new style Bosch EV14 550cc injectors offered by Grams Performance (Skunk2)?

https://gramsperformance.com/fuel-i...c/toyota-lexus-supra-7mgte-2jz-non-turbo.html

I installed them about a month and a half ago and immediately (on first startup) the engine idled very rough and lean and would stumble and stall with 30:1+ afr.

After reading these injectors are high impedance (the stock injectors are low impedance), I eliminated the injector resistor which helped a bit; however, it still idles rough at 25:1 afr at 40 psi fuel pressure. I cranked up the pressure to 60 psi and the afr dropped to 21:1, obviously still an issue and I don't like having the fuel pressure this high.

While cruising, the afrs are 15-16:1. It seems the ecu is fighting the injectors to reach stoich. I had some decent wot pulls around 11.5:1, but sometimes it would go over 12:1 (easily adjusted with an afc).

The Grams plug-and-play injector harnesses are useless because they have male connectors where female connectors should be and vice versa, so I soldered the pigtails in.

IMG_20180603_172722.jpg

At first I thought it was a large vacuum leak; however, after checking and rechecking everything and replacing all the suspect lines and hoses, the issue persists.

My buddy with an RB26 installed a set of Bosch EV14 injectors and had the same issue where it barely idled. He had to remap his entire standalone with new injector pulse widths and battery offsets, especially at lower rpms. I don't have a standalone and I'm not going to run one, so this isn't an option for me. I have a lex afm and afc neo.

If anyone has installed these injectors or knows a quick fix, I'm all ears. Otherwise I'll be returning these and buying low impedance old style EV1 injectors from RC (fingers crossed).

Cheers
 

JDMMA70

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#2
Did you add fuel to richen the mixture at idle by chance? Honestly I would've kept the car as low impedence to simplify things. However your idle AFR are way to lean which is why you car is idling like shit. Add some fuel if you can.
 

RareForm

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#3
The amount of fuel I'd have to add would seriously retard timing. I'd rather get it close with fuel pressure and use the afc for fine adjustment.

Grams said I could return the injectors. I'm going to get some low impedance units.