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Discussion Starter #1
Having an issue with the bf's 07 Solstice. Fuel pressure is dropping from a commanded 2,300+ to around 1,200-1,400 at WOT in 3rd and 4th gear. It will briefly rise to the commanded pressure level but then rapidly falls off. As soon as you let of the gas it jumps right back up to over 2,000 psi and then mimics the commanded psi as the car decelerates. Commanded psi stays above 2,300 psi throughout the run so i don't think it is a tuning issue. Car threw a P0087 code once the first time we noticed the fuel pressure issue. Cleared it and although the problem is still recurring the code hasn't shown back up yet. We are monitoring it very closely with HPTuners every pull though and as soon as the pressure starts to drop we ease up on it. So we very well may just not be giving the car enough time to recognize there is an issue and throw the code again. Better safe than sorry. On another note, if the car is not at WOT it will rise to and maintain psi over 2,000 psi for as long as it is commanded. It is just under heavy load that the pressure in the fuel rail tanks on us.

Car is on e47 and is tuned through a reputable tuner with HPTuners. Has a Hahn s20g turbo and full bolts ons. Thought our issue was the LPFP so we bought the Werks 700 hp+ LPFP and installed it. Same issue. Next thought was HPFP. Luckily I have a Sky so we just swapped the HPFP's and we are still having the same issue. Any thoughts? Are there any in line fuel filters? I'm thinking something is obstructing the line somewhere which is starving the HPFP under load. Any help or advice would be appreciated.
 

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You have reach the limit of the fuel system, It's time to add a 5th injector.
 

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Hey everyone, the sol having fueling issues is mine. I didn't think I would have fueling isses just yet tho, I figured I still had a bit of wiggle room before I needed a 5th injector.

What kind of power range is e47 capable of supporting without a 5th injector or cams?
 

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I made 400 WHP with out one. I had fuel pressure problems and really bad injection window misfires. The 5th injector really smooth everything out.
 

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Discussion Starter #7
You have reach the limit of the fuel system, It's time to add a 5th injector.
Damn, didn't think we would need te 5th injector until after we built the motor and were pushing above 400. Oh well, hopefully this will solve our issue and if not it won't be wasted money anyway :)
 

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Well crap! I just thought it had to be something on the car failing or corrupted. I figured if it was time for a 5th injector my tuner would be the first see it, but he was the one who pointed use in the direction of the fuel pumps.
 

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Damn, didn't think we would need te 5th injector until after we built the motor and were pushing above 400. Oh well, hopefully this will solve our issue and if not it won't be wasted money anyway :)
You can make 400whp on pump gas, its just when you switch to ethanol you need to flow more fuel to get those same numbers, and that's when the injectors hit the limit.
 

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Well we figured out what has been causing the loss of fuel up top. The hose to the wastegate had been severed nearly completely in half (held together by thread) so the car was boosting 30lbs with the hahn s20g, hose has been fixed, boost is much lower and the fuel pressure is right where it should be :)
 

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Not sure to be honest, if I had to guess, I probably put the hose in a stressful position and over time it gave into the stress.
 
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