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Thread: 2016 C7 Corvette Fuel Rail Pressure

  1. #21
    Senior Tuner Ben Charles's Avatar
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    Fix that HPFP... your number 3 I’ve seen

    Email Tunes, [email protected]
    96 TA Blown/Stroked, 4L80E/Fab 9
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    Custom Mid Engine chassis, AKA GalBen C

  2. #22
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    what ended up solving this? I have the same problem and have just replaced the High pressure pump. Still losing pressure above 5900rpm



    Quote Originally Posted by TSerna0331 View Post
    Alright guys I got the car back on the dyno and added a boost a pump to the low side and the low side is holding at 70ish psi and this run in particular at 5000 rpm my HPFP drops from 2900ish to 2100ish and after that it drops from there at 5700-5900rpm it drops straight down to 1000psi. Take into account i did switch the HPFPump back to the lt1 pump and the car went lean and dropped pressure just for testing purposes and when we put the same HPFPump (Z06) we did put a LS7 Lash cap to see if that would help the pressure from dropping off and it didnt so im wondering if the Z06 pump that we got is faulty? and were basically getting (valve float) but in the pump and on the spring, sorry thats the only way i can describe it lol but yea thats where im at now......

  3. #23
    Senior Tuner Higgs Boson's Avatar
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    you're just out of fuel, the low side isn't the holy grail.....

    what is your injector pulse width when you lose fuel pressure? if you are going over 5ms you are done, some like to push it to 6 or whatever but it sounds like you are 9-10 or more.

    this is why meth or port injection kits exist. DI isn't capable.

  4. #24
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    I'll upload the file when I get home. My car is bone stock is the problem. 2015 z06, no mods.

    'm obviously a newbie, and the main reason I bought the tuner was to troubleshoot this problem.



    Quote Originally Posted by Higgs Boson View Post
    you're just out of fuel, the low side isn't the holy grail.....

    what is your injector pulse width when you lose fuel pressure? if you are going over 5ms you are done, some like to push it to 6 or whatever but it sounds like you are 9-10 or more.

    this is why meth or port injection kits exist. DI isn't capable.

  5. #25
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    here is a log of my situation.
    Attached Files Attached Files

  6. #26
    you can change the hpfp and the lpfp without proper sensor changes it doesn't do anything. You must change all associated controllers and calibrate them using z06 data. Also if the cam is different and has a higher hpfp lobe you beating a dead horse. The lpfp drop can only mean if you've changed the pump fpcm calibration or change issues. If its the hpfp its either you don't have the correct corelating sensors or data offset in your tune. If fuel drops your out of it period. A boost a pump if it still leaves you losing low side the pump cant handle it or you've got the wrong controller. The hpfp if your only loosing pressure there you've got a few scenarios. One being improper calibration. Two missing correct sensors with sensor offset data and last the cam has a different lobe on it and you are not getting enough pump. They have said this in previous posts but you must check all data. All sensors. If your using a z06 hpfp and a lt1 pressure sensor your beating a dead horse. Whether people want to admit it or not fueling is the most complicated part or tuning processes especially upgrades. next to topping it off with a cam also

  7. #27
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    Bro,
    I?m not tuning an lt1, this is a factory stock lt4 in a z06. I appreciate what you said and somethings apply, but the factory parts ought to be sufficient at supplying enough fuel? This thing isn?t tuned, it?s factory, with all factory parts, on a bone stock factory motor, original parts in the same car that it was in coming off the line in bowling green.





    Quote Originally Posted by jpierro79 View Post
    you can change the hpfp and the lpfp without proper sensor changes it doesn't do anything. You must change all associated controllers and calibrate them using z06 data. Also if the cam is different and has a higher hpfp lobe you beating a dead horse. The lpfp drop can only mean if you've changed the pump fpcm calibration or change issues. If its the hpfp its either you don't have the correct corelating sensors or data offset in your tune. If fuel drops your out of it period. A boost a pump if it still leaves you losing low side the pump cant handle it or you've got the wrong controller. The hpfp if your only loosing pressure there you've got a few scenarios. One being improper calibration. Two missing correct sensors with sensor offset data and last the cam has a different lobe on it and you are not getting enough pump. They have said this in previous posts but you must check all data. All sensors. If your using a z06 hpfp and a lt1 pressure sensor your beating a dead horse. Whether people want to admit it or not fueling is the most complicated part or tuning processes especially upgrades. next to topping it off with a cam also

  8. #28
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    Quote Originally Posted by ktuck1 View Post
    Bro,
    I?m not tuning an lt1, this is a factory stock lt4 in a z06. I appreciate what you said and somethings apply, but the factory parts ought to be sufficient at supplying enough fuel? This thing isn?t tuned, it?s factory, with all factory parts, on a bone stock factory motor, original parts in the same car that it was in coming off the line in bowling green.
    What was the fix? I have the exact same problem and changed the HPFP and the fuel pressure sensor....

  9. #29

  10. #30
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    Quote Originally Posted by Higgs Boson View Post
    you're just out of fuel, the low side isn't the holy grail.....

    what is your injector pulse width when you lose fuel pressure? if you are going over 5ms you are done, some like to push it to 6 or whatever but it sounds like you are 9-10 or more.

    this is why meth or port injection kits exist. DI isn't capable.
    his car... is stock.

    And yes, the low side runs out of power long before the high side pump does on the pre 2019 z06 c7's. Its fact at this point.

    Stay tuned higgs, Mike has already spoken to the guy who commented below you and above me, C7LT4, spoke to him on the phone and assisted him to understanding exactly what is wrong with the stock tune vehicles, and like our cars, his car is a lemon also. As all of them are... if driven fast enough in the cold.

    The difference between this guy and you... he did not argue with us. And like I just did, he will be getting a new car for free via lemon law soon enough. Your advice is golden on other topics. I respect your intelligence. This topic, im not sure why you insist on trying to paint a false reality, when i explained the problem and solution to you a year ago on the other forum.
    Last edited by irun4cops; 01-31-2019 at 01:57 AM.

  11. #31
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    Quote Originally Posted by ktuck1 View Post
    Bro,
    I?m not tuning an lt1, this is a factory stock lt4 in a z06. I appreciate what you said and somethings apply, but the factory parts ought to be sufficient at supplying enough fuel? This thing isn?t tuned, it?s factory, with all factory parts, on a bone stock factory motor, original parts in the same car that it was in coming off the line in bowling green.
    Its the cold weather and sea level at high speed. Reach out to me if you want to learn whats going on instead of listen to these guys who are on a mission to ignore what i taught them all long ago, as they hope they can alter reality if they come into every thread of every person who has this problem, and pretend as if they don't know what the only solution is by now.