can't adjust fuel pressure to below 55psi - what gives

[nuggets]

I am getting some really odd readings on my newly installed AFPR gauge and I was wondering if any of you have had a similar issue.

My setup is a Walbro fuel pump, Aeromotive A1000-6 regulator, s/s fuel lines, removal of the J tube restriction, RC 550 injectors.

I've had this setup for a few years and originally monitored fuel pressure with a Defi fuel pressure gauge. A while ago I had an alternator regulator freak out on me and it blew my Defi Link control unit, making my gauge inoperable.

I just purchased Aeromotive's 15633 fuel pressure gauge and installed it today.

Here's the problem: the gauge shows my fuel pressure being between 55-60 psi (!). I have tried adjusting the pressure, but I cannot get it below 55 psi. It will adjust higher.

Any ideas on what's happening here? Bad gauge, bad regulator?

 

[TurboStreetCar]

maybe too much pump for the regulator and return line? what was fuel pressure with the old gauge? did you change anything except the gauge? and why is the title to your picture mirrored? lol

 

[MDCmotorsports]

How do you have the gauge plumbed?

 

[nuggets]

maybe too much pump for the regulator and return line? what was fuel pressure with the old gauge? did you change anything except the gauge? and why is the title to your picture mirrored? lol

Ha, I was wondering if someone was going to ask me about the title. I took a video using my laptop and by default it records as a mirror image. To get the photo that I attached, I froze the video and took a desktop pic of the window. Then I reversed it.

As far as the regulator goes, It's been a while since I had my old gauge on there, but if I recall correctly, I was running about 39 psi. It was a digital gauge and I remember the numbers fluctuating a bit, from approx 39 to 44 psi.

I didn't change anything else but the gauge setup.

As far as too much pump, I thought (maybe incorrectly) that this Aeromotive FRP would be fine with the Walbro pump. I'll search and see what others are using with a Walbro pump.

It's really weird in that I cannot get this thing to read below 55psi. I can turn the adjustment screw until it comes out of the unit and it stops at 55. If I tighten it, it does seem to up the fuel pressure so it does seem as though the FPR is working...somewhat.

 

[nuggets]

How do you have the gauge plumbed?

The gauge is in the side 1/8 NPT port on the FPR, which is where Aeromotive states to install the gauge. My old electronic pressure sender was also here.

As far as the entire FPR, I have the port on the bottom plumbed into the fuel return line and the side port on the FPR is plumbed directly to the fuel rail on the front top.

 

[adampecush]

did you change anything else aside from the gauge?

how does the car run? If nothing is out of the ordinary, chances are it could be the gauge. I'd test the gauge to verify.

 

[MDCmotorsports]

Sounds like there is a restriction in the return line some where.

Either before the regulator or after (to the tank).

 

[nuggets]

did you change anything else aside from the gauge?

how does the car run? If nothing is out of the ordinary, chances are it could be the gauge. I'd test the gauge to verify.

I didn't change anything else. Running-wise, I have had a problem with the car missing a bit. I notice it at idle and it's been going on for years. I've checked timing, TPS, CPS, replaced plugs, coil packs, etc. Maybe I have a fuel delivery problem....

 

[nuggets]

Sounds like there is a restriction in the return line some where.

Either before the regulator or after (to the tank).

I'll check into that. I assume that a restriction would lead to the higher fuel pressure, correct?

I have had what sounds like missing, especially noticeable at idle.

Any tips on tracking down a restriction, other than pulling everything apart from the fuel tank to engine (which I'm willing to do if there isn't a more efficient way)?

 

[TurboStreetCar]

You have a walbro or an A-1000 pump? I would doubt a walbro is too much pump for the regulator, unless the regulator is no good there is probably a restriction in the return setup.

 

[jdub]

You have a walbro or an A-1000 pump? I would doubt a walbro is too much pump for the regulator, unless the regulator is no good there is probably a restriction in the return setup.

My setup is a Walbro fuel pump, Aeromotive A1000-6 regulator, s/s fuel lines, removal of the J tube restriction, RC 550 injectors.

I've had this setup for a few years and originally monitored fuel pressure with a Defi fuel pressure gauge. A while ago I had an alternator regulator freak out on me and it blew my Defi Link control unit, making my gauge inoperable.

Were you able to adjust pressure with this gauge? Could be a bad aeromotive gauge you got.

 

[2JZ_MA70]

I had the same issue years ago when I had the 7M. I did try another regulator but it wanst it. Do you have the 255HP wired without the FP resistor?

Mine was back at the fuel tank return line on the fuel hanger, line was kinked little too much.

This is kind of dangerous and I dont recommend it but if you want try it... Get a bucket run a line from the return of the FPR to the bucket and start it. Check and see if the pressure drops.

 

[TurboStreetCar]

Jdub: I was unsure it he was running the a-1000 inline with the walbro, but I see now it's the model of regulator.

 

[nuggets]

I had the same issue years ago when I had the 7M. I did try another regulator but it wanst it. Do you have the 255HP wired without the FP resistor?

Mine was back at the fuel tank return line on the fuel hanger, line was kinked little too much.

This is kind of dangerous and I dont recommend it but if you want try it... Get a bucket run a line from the return of the FPR to the bucket and start it. Check and see if the pressure drops.

Wiring wise, the 255HP is wired using the stock wiring. I still have the resistor in place.

I'll get under the car and check the lines for a visible kink. The bucket idea is interesting...if I can't find an answer doing everything else, I'll try it (and be very careful of course )

 

[nuggets]

Were you able to adjust pressure with this gauge? Could be a bad aeromotive gauge you got.

I was able to adjust the fuel pressure with the Defi. This was about 4 years ago after I completed my rebuild.

I'll do a visual check on the fuel lines from the tank to the engine and see if anything looks abnormal. If all is ok, I'll call Aeromotive and/or Jeg's (where I purchased it) and see if I can get a replacement gauge.

 

[nuggets]

Ok, well here's some more info. I didn't post this before because I thought that the flutter of the gauge needle was normal due to engine vibration. However, when I just googled looking for more information, I ran across a video on youtube of someone's FPR gauge that was fluttering just like mine. This person said that they had air in their fuel line.

Below is the video of my FPR gauge. What do you think? Does seeing the needle do this change the diagnosis?

(sorry for the mirror image video...it's how my laptop natively records video)

http://www.youtube.com/watch?v=PBdihbe43GM

 

[lintlars]

It must be a very sensitive guage, my guage on my aeromotive does not fluctuate like that I just played with it today have you bypassed the factory fuel dampner?The FPD is a return line Im assuming been bypassed since the return line comes from the bottom of your FPR, I did not see in your post .

 

[nuggets]

Well, it indeed was a restriction in the return line. The rubber transition between the hard line and the stainless line became twisted, most likely my fault when either installing the line or moving the FPR (which I did a few months ago).

I removed a clamp, untwisted the line and checked for leaks, clamped it back down and now the FPR adjusts as it should and the gauge is spot on.

Thanks guys!

 

[IJ.]

Diagnosing a problem should start with "What have I fucked with and is it connected to the problem"

 

[charlesshen]

i had a similar problem but on my feed line be for bashed my head for a week and when replacing line with bigger ones i found problem after spending 300 bucks on new pump and lines