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Discussion Starter · #1 ·
Hey everyone. I just signed up for this site cuz i just recently bought a 90' LX 5.0. Anyway i wanted to do a few mods so i went with Ford Racing 24lb/hr injectors and a C&L 73mm Mass Air, and a BBK Cold Air intake, and ever since i put on the injectors and MAF i have backfire in the intake and the car drags ass when i try to go down the road. I just set the timing and its fine but i'm not sure what else it could be. Any suggestions would be aewsome. Thank You.
 

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Is your motor stock?24's are to much for a stock 5.0 also do you have the 24 sampling tube in the air meter
 

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Discussion Starter · #3 ·
Yeah the motor is stock. I got them off a friend of mine and they ran just find on his car. I dont know what the 24 sampling tube in the air meter is. I have seen people with a lot bigger than 24 on stock 5.0s and ran fine.
 

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you need to take those off.

im running 24# injectors on a 351w bored .040 over with h/c/i.

more fuel doesnt mean more power. you make the most power running a little lean.
 

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The injectors arent Causing the back fire. Check the firing order. Timing( and just because it reads fine, doesnt mean its set right. You can be a tooth off still) Check for vac leaks. I run 24's on a stock headed 302, and it runs just fine. You have other issues.
 

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Just because you see 24's doesnt mean there is more fuel, the ECM will adjust the pulse width, to try and reach the stoich. A/F Ratio. WIth 24's the ECM is going to Trim the pulse back. IOW make the Pulse Width shorter. Injectors Support power, they dont make it.
 

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he could be loosing power because there wont be a strong spray right? wont it be kind of dripping in compared to the 19#.

it does sound like a timing issue, but i really think the 24s are overkill.
 

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he could be loosing power because there wont be a strong spray right? wont it be kind of dripping in compared to the 19#.
No, it will spray fine. The spray is related to the Fuel Pressure. The ECM controlls just how long the injector stays open(Pulse Width), from readings it gets from the O2's. If its starts reading Lean, the injectors will stay open a little longer, just the opposite if its Rich.
 

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if its not the timing then you have a bad valve or bad spring
 

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No, it will spray fine. The spray is related to the Fuel Pressure. The ECM controlls just how long the injector stays open(Pulse Width), from readings it gets from the O2's. If its starts reading Lean, the injectors will stay open a little longer, just the opposite if its Rich.
makes sense. and isnt there a point where the injector is just too big and the computer can only tell it to open so fast? like say 42#'s on a stock motor?
 

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Discussion Starter · #12 ·
Well i took the injectors off and put the stock ones back on and the stock MAF and now i have no fuel pressure. It will turn over and i can hear the fuel pump kicking on but it wont start. Going to check the fuel filter. Maybe something i didn't connect? Any more suggestions? Kinda of gettin tired of a car that cant seem to run so any suggestions would be really appreciated. Thank you.
 

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makes sense. and isnt there a point where the injector is just too big and the computer can only tell it to open so fast? like say 42#'s on a stock motor?
There is a point where the ECM cant trim back enough on the stock ECM tune. 30's is pushing it without a tune.
 
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