Okay so I have been running a walbro 255 fuel pump but my stock regulator could not handle it so my fuel pressure was at 120 psi, I finally went out and bought an AFPR from Extreme PSI (Fuel Lab 515 kit) After installation we tried to lower the pressure to no avail. I've tried everything from pulling my vacuum line like your supposed to do, to taking it apart and inspecting the diaphragm for damage/debris, also I've tried it with the car on & off. I have not checked my return line for blockage since I just replaced that line about a month ago (but I know it could still be clogged) its weird cause it sits around 97 psi and it will raise above that point and I can lower down but only to about 97-98 psi. Any suggestions or ideas? Had anyone had a similar issue?
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prove_it
Well-known member
Only one thing would do that....
A bad return line.
A bad return line.
Maybe the ECU is not properly duty cycling the fuel pump...
prove_it
Well-known member
/ubbthreads/images/graemlins/confused.gif
Can't tell if your being sarcastic
Can't tell if your being sarcastic
Im not... but i would first check the return line, clogged line would cause high pressure
Haha well here's the kicker... I have a bad ECU (leaky caps) i actually sent a back up ecu i have out to ECMTuning earlier today, so when I get a good one back ill test it out. And as far as the return line goes, when I switched from the fuel cell I bought the car with to the OEM tank I recently installed, I had to buy all new rubber lines, but the return line was cut in half. So I just got the other half of the line & used a barbed connector to join the 2 ends, can't recall the size of the fitting but I know it made the ID of my linesmaller at that point. Now that I think about it I can almost bet that is my problem. It's getting restricted from that brass fitting /ubbthreads/images/graemlins/banghead.gif
check it out before waiting for your ECU to return, it can be your cause!
If it fails, try the ECU...
If it fails, try the ECU...
CutlassJim
Well-known member
The ECU doesn't cycle the fuel pump. On an Evo it does tell it to run at high or low speed but not on a DSM/GVR4.
prove_it
Well-known member
That's why I thought he was being sarcastic. Fuel pump is an on/off device and the ECM uses the main relay to control it. In order to have 120psi you have to have a nearly closed return line.
MellowVR4
Well-known member
Did this issue just happend out of the BLUE?
desant78
Well-known member
Get ballsy-and dumb. Just unhook your return And let it dump to a space (bucket, etc). Quick tell.
slugsgomoo
Well-known member
Have you tried using a different fuel pressure gauge or sender (if electric) just to verify that you are getting the right reading? I've seen some bizarre high readings on both mechanical and electrical in the past (though on the electrical, I think someone put a MAP sensor in the AFPR rather than the fuel sensor).
Other than that, put a hose on the output of the AFPR put that in a large bucket and see if you can drop the pressure to a reasonable rate. If you can, it's a clogged return that you need to address.
Other than that, put a hose on the output of the AFPR put that in a large bucket and see if you can drop the pressure to a reasonable rate. If you can, it's a clogged return that you need to address.
Slugs sugguests a great idea!
Barnes
Well-known member
I like the suggestions, but please don't use a bucket. If you want to do the test, run the hose into a gas can.
strokin4dr
Well-known member
Or around the car back into the fill hole!
Quoting Kelby:
check it out before waiting for your ECU to return, it can be your cause!
If it fails, try the ECU...
okay, I will try to get to it today when I'm done work. Thanks for the help.
check it out before waiting for your ECU to return, it can be your cause!
If it fails, try the ECU...
okay, I will try to get to it today when I'm done work. Thanks for the help.
Yah that fitting I used brought it down to about half it's size... I guess this is why you shouldn't rush things huh? But It was the only size I could use at the time since all stores were closed for the night.
Quoting MellowVR4:
Did this issue just happend out of the BLUE?
no it's always been high since I've been driving it, but since I've switched to to Walbro 255 and the Fuel Lab 515 AFPR it got worse. When I hit boost (I try not to) you can smell the gas.
Did this issue just happend out of the BLUE?
no it's always been high since I've been driving it, but since I've switched to to Walbro 255 and the Fuel Lab 515 AFPR it got worse. When I hit boost (I try not to) you can smell the gas.
Quoting desant78:
Get ballsy-and dumb. Just unhook your return And let it dump to a space (bucket, etc). Quick tell.
that's what I will try doing today, I'm gonna test it before that brass fitting to see if tht is my problem or not. Thanks!
Get ballsy-and dumb. Just unhook your return And let it dump to a space (bucket, etc). Quick tell.
that's what I will try doing today, I'm gonna test it before that brass fitting to see if tht is my problem or not. Thanks!
Quoting slugsgomoo:
Have you tried using a different fuel pressure gauge or sender (if electric) just to verify that you are getting the right reading? I've seen some bizarre high readings on both mechanical and electrical in the past (though on the electrical, I think someone put a MAP sensor in the AFPR rather than the fuel sensor).
Other than that, put a hose on the output of the AFPR put that in a large bucket and see if you can drop the pressure to a reasonable rate. If you can, it's a clogged return that you need to address.
I have 2 gauges hooked up, they are both pretty much giving me the same readings, I know it's not my gauges, something else is seriously wrong. I thought that too but then I eliminated it as a problem
Have you tried using a different fuel pressure gauge or sender (if electric) just to verify that you are getting the right reading? I've seen some bizarre high readings on both mechanical and electrical in the past (though on the electrical, I think someone put a MAP sensor in the AFPR rather than the fuel sensor).
Other than that, put a hose on the output of the AFPR put that in a large bucket and see if you can drop the pressure to a reasonable rate. If you can, it's a clogged return that you need to address.
I have 2 gauges hooked up, they are both pretty much giving me the same readings, I know it's not my gauges, something else is seriously wrong. I thought that too but then I eliminated it as a problem
