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Fuel Looking for a little guidance

  • Thread starter Thread starter Tufgriz
  • Start date Start date Sep 11, 2025
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    a9l fuel system lean
T

Tufgriz

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#1
  • Sep 11, 2025
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So was running a microsquirt for a few years and decided to swap back to my a9l. Before the micro I was using 24lb injectors and a 76mm c&l and car ran pretty good. After swapping back to the a9l and maf car began running super lean. I was going to use my quarterhorse and turn off emissions and maybe a few little tweaks. The person helping me dial in maf curve and such figure my injectors were plugged up or wore out and so I bought a new set. As we were working in dialing it in we had to scale the new 34lb injectors to approximately 26lb to start eliminating the lean spot. Yesterday I tried another set of know brand new 24lb injectors attempting to use the c&l stock transfer and again as the other two sets of injectors the car is super lean. Newer 255 deatworks pump less then a year old and maintains good pressure. At this point im considering a pretty decent vacuum leak but going to change the fuel filter as well as volume test the pump. The a9l checked out good cap wise when I swapped it back in, but looking for ideas that I may have overlooked. Thanks
 

AeroCoupe

lube between the nut and the face. I know my lubes
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#2
  • Sep 11, 2025
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Kinda hard to speculate if we do not know what the motor is and what all has been done to it. This dictates the fuel that is needed for the application. What fuel pressure are you running?
 
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Tufgriz

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AeroCoupe said:
Kinda hard to speculate if we do not know what the motor is and what all has been done to it. This dictates the fuel that is needed for the application. What fuel pressure are you running?
Click to expand...
38 pounds for fuel engine is a 302 brodix heads, trickflow intake, lunati cam.
 

AeroCoupe

lube between the nut and the face. I know my lubes
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#4
  • Sep 11, 2025
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So I am going to assume a stock short block with a Lumati cam of unknown specs, Brodix heads of some sort, and one of the TFS upper and lower intake combinations....let's just call it north of 275 rwhp. Just me but you are pretty much on the edge of the 24 lb/hr units. Turn the fuel pressure up to about 45 psi and see if that helps. If it does then hopefully the additional fuel pressure solves the problem or the additional pressure helps but you need more so then you are looking at larger injectors.
 
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Tufgriz

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#5
  • Sep 11, 2025
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Car ran fine when first built in 24s might be tad small but going back to the know combo it should run as it once did. When we first started adjusting the tune I swapped to 34lb injectors and it did the same thing and was lean. The only way to get things to start running correct was lower the injector slopes to a smaller injector so that the ecu increased the pulsewidths. When I reinstalled the a9l last fall capcitors were good. Im going to check them as well after work to see if there is any change in them as they were still all stock with the rubber coating still on the board.
 

General karthief

wonder how much it would cost to ship you a pair
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#6
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My question is why go back to the old computer when the microsquirt is more 'tunable' ?
 
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Tufgriz

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General karthief said:
My question is why go back to the old computer when the microsquirt is more 'tunable' ?
Click to expand...
it is, but no one near by to help fine tune and wanted to enjoy the car more. when it was just using the calibrated maf it ran pretty well, could hop in and not carry a laptop around
 

Noobz347

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#8
  • Sep 11, 2025
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Once the tune is done, you don't need to carry around a laptop.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
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#9
  • Sep 12, 2025
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I'm confused, the reason for the microsquirt if for self tuning.......that is tuning it yourself.
 

Noobz347

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#10
  • Sep 12, 2025
  • #10
It sounds to me like the OP had an issue and tried going back to the old EEC and injectors to solve that issue.


It is likely that something was/is already wrong with the combo that neither ECU setup is going to solve.
 
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