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.

 

follow all your fuel lines and check for leaks. and check your fuel filter

 

I don't see any leaks and I changed the filter yesterday; the filter was my first thought.

 

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

 

i do have an aftermarket FPR but the pressure has always held after the car is turned off. I'll check the o rings but i don't see any fuel leaking

 

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

 

Check the FPR itself for a torn diaphragm also. If you are just running stock fuel pressure you may try to swap to a stock FPR for troubleshooting.

 

what fuel pump are you running?

 

I'm running a Walbro GSS342 pump. Everything has been fine for months until just a few days ago. I'm going to take a part the FPR and even see if I can find a stock one to swap tomorrow.

 

So I took everything a part and nothing looked bad.

 

sometimes the fuel hose between the pump and sender starts to seep

 

I didn't realize the pressure drop. Mine does the same thing too. I Never notice any fuel leak around the engine though.

 

Check the hose that attaches to the fuel pump. Also I had that same problem when my AEM FPR was going bad.

 

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.

 

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.

 

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)??

 

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?

 

do you have an aftermarket map sensor? as far as i know all honda map sensors only read up to 10psi

 

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.

 

Yes, I have an aftermarket MAP sensor. If I didn't I would have been experiencing this problem from day 1 considering I am turned for 14psi.

 

Fuel pressure @ idle

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.