Running Lean Past 10psi, Tuned for 14psi
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Running Lean Past 10psi, Tuned for 14psi
A few days ago I started having some issues with the car. Everything is perfect under 10psi but when I try to push it past I start running lean. Also, fuel pressure drops as soon as the car is turned off. Normally the pressure will stay for maybe 30 second or so but now it just drops.
***PROBLEM SOLVED***
I stopped by my tuner today to chat with them about my problem. They ran the car to get a data log and didn't see anything unordinary. Their suggestion was FPR or pump. They swapped the FPR and everything was good. To those who suggested such, kudos. If I had an extra FPR I would have tried that option at home but I didn't feel like going out any buying one or a pump just to trouble shoot. The great new is that my just gave me a new regulator. However, I had them run the car on the dyno so I didn't leave the shop cost free but it was cool they just gave me a new regulator for free.
***PROBLEM SOLVED***
I stopped by my tuner today to chat with them about my problem. They ran the car to get a data log and didn't see anything unordinary. Their suggestion was FPR or pump. They swapped the FPR and everything was good. To those who suggested such, kudos. If I had an extra FPR I would have tried that option at home but I didn't feel like going out any buying one or a pump just to trouble shoot. The great new is that my just gave me a new regulator. However, I had them run the car on the dyno so I didn't leave the shop cost free but it was cool they just gave me a new regulator for free.
Last edited by mechanix619; 09-11-2010 at 06:12 PM. Reason: edit
#4
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Re: Running Lean Past 10psi, Tuned for 14psi
if you have an aftermarket fuel pressure regulator like AEM the pressure drops instantly and that is normal after you shut the car off. If you have an oem and it drops then you have a leak somewhere between the injectors - tank. check O rings on injectors and fuel rail. good luck
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Re: Running Lean Past 10psi, Tuned for 14psi
if you have an aftermarket fuel pressure regulator like AEM the pressure drops instantly and that is normal after you shut the car off. If you have an oem and it drops then you have a leak somewhere between the injectors - tank. check O rings on injectors and fuel rail. good luck
#6
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Re: Running Lean Past 10psi, Tuned for 14psi
if it always held then it's a leak somewhere for sure, if you have the proper tools you can pressurize the system a little to see where the leak is but its usually easier just to check around the hoses looking for it. good luck
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#12
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Re: Running Lean Past 10psi, Tuned for 14psi
I didn't realize the pressure drop. Mine does the same thing too. I Never notice any fuel leak around the engine though.
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Re: Running Lean Past 10psi, Tuned for 14psi
A few days ago I started having some issues with the car. Everything is perfect under 10psi but when I try to push it past I start running lean. Also, fuel pressure drops as soon as the car is turned off. Normally the pressure will stay for maybe 30 second or so but now it just drops.
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Re: Running Lean Past 10psi, Tuned for 14psi
I think my next move is to find a stock regulator and/or new Walbro pump. Both suck as options because I hate spending money on something that I'm not 100% sure is the issue.
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Re: Running Lean Past 10psi, Tuned for 14psi
I talked to my tuner. They said it is most likely an electrical issue. A sensor like temp sensor is going bad and it's sending a signal to the ECU to lean the fuel fixture. I'm going in this Saturday to run the car on the dyno.
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Re: Running Lean Past 10psi, Tuned for 14psi
Have it checked out datalogging, but I would be suprised if it is a sensor slowly going bad so it is miss reading but not completely out. Anything changed in the setup lately (wiring/parts/sensors/etc)??
#17
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Re: Running Lean Past 10psi, Tuned for 14psi
I agree. Also if the sensor was going bad it would be lean all the time not just under boost. I'm still voting towards bad fuel pressure regulator or perhaps the fuel line in the tank from the pump to the sender. Have you take that out to look at it? Also what is your fuel pressure at idle? Does it go up when you pull the vacuum line off of it? What does it go up to?
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Re: Running Lean Past 10psi, Tuned for 14psi
Perhaps the fuel pump is worn out? If your using more fuel after 10 psi than the worn fuel pump can support, then your fuel pressure will drop and you will lean out. Fuel also might be leaking back past the pump explaining the fuel pressure drop after shutdown.
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Re: Running Lean Past 10psi, Tuned for 14psi
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Re: Running Lean Past 10psi, Tuned for 14psi
I agree. Also if the sensor was going bad it would be lean all the time not just under boost. I'm still voting towards bad fuel pressure regulator or perhaps the fuel line in the tank from the pump to the sender. Have you take that out to look at it? Also what is your fuel pressure at idle? Does it go up when you pull the vacuum line off of it? What does it go up to?
Vacuum = 30psi
No Vacuum = 35psi
I took the fuel pump out last week and everything looked in good shape, but it's worth another look; it can't hurt to look again.
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