Fuel pressure issue - halp!
#16
Addict
Rennlist Member
Rennlist Member
My guess is the pump. Shane's car did this same thing at the Fest a couple years ago. It ran like poo for a couple days and then just died. I assume your guessing it's lean from your wideband, can you also tell that it's running bad? I've had the fuel gauge, and wibeband sensor both go bad, so check that stuff if the car isn't running bad. Either way, with the bigger turbo and injectors, I would still upgrade the pump to be on the safe side. I may be selling my Lindsey HV pump if you want to give it a try.
#17
Thread Starter
Race Director
Well the car not only shows low press on the fuel gauge and lean on the wideband but the car basically chugs when you roll on boost, it runs great with good AFR at idle and cruise but totally is a dog when you roll into it - wont really boost at all...and Dan said when the fuel press was right it ran awesome with good readings so it did work correctly even if it was only for a short time - lol.
I was basically going to go with the HV pump and a new filter so pm me a price on it - thanks Kevin.
I was basically going to go with the HV pump and a new filter so pm me a price on it - thanks Kevin.
#18
Thread Starter
Race Director
Pulled apart the adj regulator that was installed for many years and found a few specks of dirt in it on the return side. I took a pic but my camera didnt save them for some reason.
Im buying a HV pump, plan on replacing the checkvalve as well. Can I pinch a braided fuel line? Just felt a little uneasy about it- thanks.
Im buying a HV pump, plan on replacing the checkvalve as well. Can I pinch a braided fuel line? Just felt a little uneasy about it- thanks.
#20
Thread Starter
Race Director
#25
Rennlist Member
#28
Nordschleife Master
Just make sure whatever pump you buy is a real pump. There are a lot of good fakes on tha market and a fake pump will cost you alot of issues and sometimes a motor. I would give serious thought on who I bought from when it comes to fuel pumps.
#29
Try replacing your fuel filter 1st, I had very simular problems, ended up being the filter was clogged with some very fine soot like a gray/green talcum powder. The filter was only 5 months old and under 3k miles on it, before the I replaced the filter I swapped fpr and pump, relay. Learned a lesson always check the simple stuff 1st.
Semper fi
Semper fi
#30
I'm thinking fuel pump or filter as well. If the fuel rail pressure was high and you were still running lean, it could be injectors clogged with debris, but that's not the case. Nevertheless, it would not hurt to have a look at the injectors. It's winter, and the car's not going far in the snow, so you may as well tear it apart.
You mentioned that swapping the adjustable regulator with the fixed 3 bar regulator helped keep the fuel pressure up after shutdown, and now that makes sense to me. The fuel travels from the tank to the pump, pump to the filter, filter to the dampner, dampner to the rail, rail to the pressure regulator and then back to the tank if the pressure is higher than the regulator's rating.
There are two paths for the fuel to travel back to the tank: a failing regulator and a failing check valve. Therefore, your check valve may not be the only cause for the instant loss of pressure upon shutdown. The adjustable FPR may have been leaking pressure constantly, causing the pressure to be lost when you shut the car down. When you put the new FPR on, the pressure remained for a while after the car is off. It's just a theory, but if the pump had to make up for a faulty adjustable FPR, it may have given up the ghost early.
If your rail pressure is low, it's the pump, the filter or the dampner. These are the parts in front of the rail, so I'd start there.
You mentioned that swapping the adjustable regulator with the fixed 3 bar regulator helped keep the fuel pressure up after shutdown, and now that makes sense to me. The fuel travels from the tank to the pump, pump to the filter, filter to the dampner, dampner to the rail, rail to the pressure regulator and then back to the tank if the pressure is higher than the regulator's rating.
There are two paths for the fuel to travel back to the tank: a failing regulator and a failing check valve. Therefore, your check valve may not be the only cause for the instant loss of pressure upon shutdown. The adjustable FPR may have been leaking pressure constantly, causing the pressure to be lost when you shut the car down. When you put the new FPR on, the pressure remained for a while after the car is off. It's just a theory, but if the pump had to make up for a faulty adjustable FPR, it may have given up the ghost early.
If your rail pressure is low, it's the pump, the filter or the dampner. These are the parts in front of the rail, so I'd start there.