odd fuel set up
Thread Starter
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Joined: Nov 2012
Posts: 3
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From: Chicago
odd fuel set up First off, I have a 240sx with an lq4 mostly stock besides an ls1 intake and I believe fuel rails? I'm still very new to these motors and trying to figure out why and if how my fuel system is set up correctly.
From the looks of it, I have stock fuel rails/fpr, I'm not exactly positive if they're ls1 rails/injectors or lq4. But this is how the whole system is set up
walbro 255 intank to a jegs fuel filter, two afpr's, the first one has 3 ports, one is connected from the line after the fuel filter, another goes to the stock rail/fpr and the other line is connected to the other afpr, and then the second afpr has a return line back to the tank. Neither afpr has an vacuum lines connected to them.
I made a poorly visual from paint I included.
A few days ago(before I finally decided to buy the car), it had a walbro 400 fuel pump that died out and they threw in a 255 in the mean time and now its stuttering and wants to die inbetween 2-3k. Could the less flowing fuel pump be causing this?
Coming from small 4 bangers, I've never seen anything like this. Sorry for the long confusing post.
Any help is appreciated!
Thanks
From the looks of it, I have stock fuel rails/fpr, I'm not exactly positive if they're ls1 rails/injectors or lq4. But this is how the whole system is set up
walbro 255 intank to a jegs fuel filter, two afpr's, the first one has 3 ports, one is connected from the line after the fuel filter, another goes to the stock rail/fpr and the other line is connected to the other afpr, and then the second afpr has a return line back to the tank. Neither afpr has an vacuum lines connected to them.
I made a poorly visual from paint I included.
A few days ago(before I finally decided to buy the car), it had a walbro 400 fuel pump that died out and they threw in a 255 in the mean time and now its stuttering and wants to die inbetween 2-3k. Could the less flowing fuel pump be causing this?
Coming from small 4 bangers, I've never seen anything like this. Sorry for the long confusing post.
Any help is appreciated!
Thanks
Can't imagine WHY there are 2 fpr's. It looks as tho they were trying ?? The way it is now, it's a dead head system. [no rail return line], and missed the boat!
Restricting the "main" FPR return line, w/ the 2nd FPR, is screwing w/ the ability to adjust the "main" reg.
Dump the reg that's on the return of the first, plumb that line back to the tank.
The remaining fpr has to have the vac port left open, unless you want to change the inj flow rating to a single value.
Adjust the pressure to 58psi, and retest.
Restricting the "main" FPR return line, w/ the 2nd FPR, is screwing w/ the ability to adjust the "main" reg.
Dump the reg that's on the return of the first, plumb that line back to the tank.
The remaining fpr has to have the vac port left open, unless you want to change the inj flow rating to a single value.
Adjust the pressure to 58psi, and retest.
Thread Starter
Registered User
Joined: Nov 2012
Posts: 3
Likes: 0
From: Chicago
Alright, I removed the second fpr, and set the afpr to 58psi, but it didn't fix my stuttering problem. Also, when I rev it from the tb, is the fuel pressure supposed to drop?
Just want to be able to rev my car past 2k without feeling like I hit a brick wall haha.
Thanks
Just want to be able to rev my car past 2k without feeling like I hit a brick wall haha.
Thanks
Leave the one 3 port regulator, if it has a vacuum port be sure to leave it open
The thing on the fuel rail is a buffer, not a regulator
Fuel pressure should not drop when the throttle is hit. Test the regulator and pump separately for proper function
The thing on the fuel rail is a buffer, not a regulator
Fuel pressure should not drop when the throttle is hit. Test the regulator and pump separately for proper function
