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  1. #1

    Default Fuel Pressure 06 R6S

    Hey all, I?ve got a 06 R6S on Alcohol. It has stock throttle bodies that were converted, stock ECU. When I bought the car it was running rough and the injectors that we?re in it were in bad shape so I purchased a set of injectors that Guhl uses (orange O-ring). They were shorter so I ordered injector adapters in order to fit fuel rail. With the old injectors the fuel pressure was at 63psi. With the new injectors I put in the only way it will take full throttle under load is if I crank the pressure up to 100psi. I don?t have a pressure tester to confirm this is the correct pressure. Only other thing I?ve changed is the TPS. What can be causing it to need that much pressure if it is in fact the correct pressure. Also I don?t know how old the fuel in the system is. Could that be a factor?

  2. #2


    My best guess is the injectors you replaced the original ones with flow a whole lot less fuel than the original ones the guhl had in. I would get the correct injectors. Yes, there are other things that could cause this like a bad fuel pump or clogged fuel filter, but if it ran good before, then it probably the new injectors.
    Also if you replaced the TPS, make sure it is set properly. If check the voltage on the signal wire of the TPS it should read around .4 volts at idle. This would cause major problems at the lower throttle positions if it is not set correctly.

  3. #3


    Mike, thanks for your reply. The injectors that are currently in the car are lower injectors from a Guhl system which typically used upper injectors also. Mine only has a single rail setup. Im assuming these injectors flow less since they had another four injectors up top?

  4. #4


    OK, well you definitely need the top injectors unless you get the system completely re-tuned for 4 injectors, which has to be done through the ECU.

    So this is an R6S which only uses 4 nozzles with the stock ignition. Are you using the Stock ignition? Or are you trying to use the all black R6 fuel injection and electronics on this engine?

  5. #5


    Stock ignition. Ok just looked. The injectors that came in the car were 36 lb/hr. The injectors I put in are only 24 lb/hr. Would that cause such an increase in pressure in order for it to get enough fuel?
    Last edited by Rob86B; 05-14-2018 at 11:06 AM.

  6. #6


    Yes, it would , that is a big difference.

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