Injector Problems

[DJ2]

Someone help me before I start raping people!


I have RC750's and wanted to get them installed so that I can put my 3076 on soon. I pulled a SHITLOAD of fuel and the AF was at 15.0 at idle and it sounded as though it was idling fine, as soon as I touch the accel pedal it starts to misfire and if I try to drive it it just chugs and misses. I had to mut my S2 injectors back in so that it would run for now. Please help fuckers....

[hozay09]

What are you using to control fuel? Other mods?

[blackbird]

Did you lower the fuel pressure any via an adjustable fuel pressure regulator? If not and those RC's are running on stock 58 psi fuel pressure they're really flowing north of 860 cc/min. That would be trying to run 50% more fuel than stock and by "pulling fuel" I'm guessing you're running one of the piggyback's. A better rundown of the car's current setup might help.

There is such a thing as too much fuel and you should always try to size injectors to the proper application. You may want to just stick with the S2 injectors for now if you're still on a stock turbo.

[2clean2drive]

Someone help me before I start raping people!


I have RC750's and wanted to get them installed so that I can put my 3076 on soon. I pulled a SHITLOAD of fuel and the AF was at 15.0 at idle and it sounded as though it was idling fine, as soon as I touch the accel pedal it starts to misfire and if I try to drive it it just chugs and misses. I had to mut my S2 injectors back in so that it would run for now. Please help fuckers....
afr's at idle are not as important as afr's under boost...what is the afr's while in boost i.e when you get on accelerator....my afr's are as high as 17 at idle but when boosting it is never over 11.8 when on 91 oct and never under 12.2 with 110octane... tho the problem is you will never be able to pull enough fuel from the 750cc injectors with just a safc, put in your stage 2 injectors untill the 3076 is installed........you are runnning way too rich:thumb:

[DJ2]

I am using an emanage, I am looking into getting a return line and regulator so I can lower the pressure to 43 psi, I hope that helps... I think I am going to send the 750's to RC to get them checked. I bought them local off a guy that wrecked his car. I hope nothing happened in the wreck.

[DJ2]

copied from the gallery:

Engine Misc.:

CCA FMIC|MSD Tach Driver|K&N CAI|TurboXS RFL BOV|Greddy CC|Prothane MM Inserts

Turbocharger & Induction:

Still waiting on install: AGP GT3076R, 3" AGP intake

Fuel & Tuning:

Emanage|E01|S2 injectors|Aeroforce Scangauge|Kinetic WGA |S1 PCM|Devil's Own Progressive Water/Alky Injection | 03 Fuel Rail and RC 750cc injectors waiting on install

Exhaust:

Needswings 3" DP W/ Electric Cutout

Drivetrain:

SLOW4DR 70% STS | Weighted Shift Knob

Weight reduction & transfer:

I'm On A Diet?

Suspension, wheels & tires:

Megan Racing Coilover suspension | DC Sports Front STB|Motegi 17X7 R5 Silver Wheels|Michelin Pilot Sport Tires 225 45ZR17

[blackbird]

You might check with RC because if you by any chance you can get a copy of the receipt from the previous owner because they used to offer free testing of their injectors after the sale. As it is you definitely have way too much fuel with them for a piggyback and the fuel trims in the PCM to compensate. Even with a big turbo it may present some challenges getting it to idle and run right during lower boost. You may end up at even lower than 43 psi with a return line kit and then use the vacuum/boost reference feature of the regulator to add fuel pressure as boost goes up (with check valve so it doesn't see vacuum).

Depending on power goals with a big turbo the RC 650's can be a better choice for a lot of people if you also have a return kit and can alter/add fuel via that. It's always better to properly size injectors than buy too big, especially when you can't directly control fueling (unless you have a stand-alone engine management system).

[DJ2]

You might check with RC because if you by any chance you can get a copy of the receipt from the previous owner because they used to offer free testing of their injectors after the sale. As it is you definitely have way too much fuel with them for a piggyback and the fuel trims in the PCM to compensate. Even with a big turbo it may present some challenges getting it to idle and run right during lower boost. You may end up at even lower than 43 psi with a return line kit and then use the vacuum/boost reference feature of the regulator to add fuel pressure as boost goes up (with check valve so it doesn't see vacuum).

Depending on power goals with a big turbo the RC 650's can be a better choice for a lot of people if you also have a return kit and can alter/add fuel via that. It's always better to properly size injectors than buy too big, especially when you can't directly control fueling (unless you have a stand-alone engine management system).

I hear ya on the proper size injectors... The guy I bought them from had the 3076, 750 injectors with return and regulator, map clamp and safcII (rebuilt motor) cams and a couple other things... so I am assuming I can get this to work once I lower the fuel pressure, since it worked on his car. Oh well, I am in the market for a return line and regulator so anyone with recommendations post up...

[blackbird]

You'll have to turn the pressure way down but they should work. Give the choice I'd rather run 650's at higher pressure under boost than have to use 750's and lower it a lot.

As for the return line kits almost all of them function about the same. The two main variations are where/how the pressure regulator gets mounted and how you return the fuel once back at the tank. The AGP kit installs the regulator back near the firewall onto the stock feed tube (next to that nice, toasty hot exhaust system in case of fuel leak), runs a return line from there back to the tank and then sends a regulated amount of fuel to the rail and avoids needing a '03 or aftermarket rail for the return line fitting. Most other kits require a rail with a Schrader valve (which you'll remove the valve to open it up so fuel can flow out) or another port for a fitting. On those setups you run a return line from the rail to the regulator, and then from the regulator back to the tank.

On the tank end you have a couple choices. FWD Performance has a kit where you can install a bulkhead connector fitting into the tank or the fuel canister module so the fuel can drain back while most of the other kits on the market are now using a tube fitting that you cut and place into the stock filler neck hose.

All of them should operate very similarly and it will mostly be your choice as to regulators (Aeromotive and Accufab being the most common), the lines/fittings, price/quality, and between the different mounting setups.

[DJ2]

thanks blackbird!