I finally got my Aeromotive AFPR installed today and installed a B&M fuel pressure gauge on the 1/8 fitting of the regulator. I reconnected my fuel pump and started the car and then set the pressure without the vacuum line. Throughout this process the gauge worked perfectly and so did the regulator.

After the car sitting for about an hour or so I went to restart it and check everything. The gauge read 0 psi but the car ran and after tapping the guage it read fine again.

There are no leaks in the braided lines or AN fittings or at the fuel rail connection. I teflon taped the adjustment screw, vacuum fitting and gauge fitting but NOT the AN fittings.

Now the gauge only registers after tapping it somewhat violently.

What could be the problem with my gauge? Did I just get a lemon?

Anson

Does it continue to work and register properly until the next time you turn the car off?

If so, remember that the Aeromotive does not seem to properly maintain the 21psi that the stock FPR does when the car is shut off. The fuel slips back, and I assume a bit of air gets into the lines. It'd be possible that an air bubble is getting lodged in the pressure gauge, which would require tapping to dislodge and fill it with fuel again. Is the pressure gauge the highest point (or facing upward) when mounted? In other words, is it facing up, to where any air/vapor would naturally make its way and 'settle'? My own pressure gauge is from one of the side-facing taps, and I occasionally get a similar 'twitching' problem now and again on start-up, where it'll read 10psi low or high, then flicker between the two, then settle on the actual pressure.

No it will not change it's reading at all without being tapped somewhat violently. My pressure gauge is also mounted on a side facing tap so it is not the highest point either. If the car is running and I remove the vacuum line the gauge will not change it's reading unless I tap it again.

Anson

did you use teflon tape on the gage threads? if so, i would check to make sure you did not get some covering the gage hole.

jim

UMR98GSX said:

I teflon taped the adjustment screw, vacuum fitting and gauge fitting but NOT the AN fittings.
Anson

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Maybe it is a gauge issue. Try another gauge. And check the gauge hold like formontoya said.

Get a Water filled gauge!

Eh, water filled gauges are nice to keep needle vibration down, but aren't really neccessary on this. Sounds like you just got a cheapo/defective gauge, and the needle is sticking. Ever see an old WWII movie, where the pilots tap/knock at the gauges? It's because they'd occasionally get stuck, just like yours seems to be. Pick up a new gauge... Autometers are pretty decent.

Alternately, double-check your teflon tape. It's unlikely, but possible that a loose end might have gone over the hole, blocking the upward change. If it won't go down on its own, it's most likely (again) a sticky needle.

I got a liquid filled gauge online for like $16.00 for my FPR, never had a problem with it.

Thanks for all of the advise guys. I rechecked everything and there was nothing blocking the gauge so I went ahead and ordered a CHM liquid filled gauge from SBR since the B&M still wasn't working.

Funny thing though... pulling into my driveway last night I heard something drop through my engine compartment to the ground. I parked and looked around only to find the glass bezel from the gauge broken on the ground. The gauge works perfectly now so I guess the needle was just rubbing on the glass.

Needless to say the gauge works perfectly now but I will be replacing it with the liquid filled since it has already shipped.


Cliffs Notes: Gauge fell apart and fixed itself, replacing with a liquid filled anyway,
won't be buying B&M gauges again

My Aeromotive holds pressure for about an hour but after that it slowly drops to 0. It slowly loses pressure.. Is this normal?

cfisher said:

My Aeromotive holds pressure for about an hour but after that it slowly drops to 0. It slowly loses pressure.. Is this normal?

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Yes that is normal.

andytalon said:

Get a Water filled gauge!

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I prefer liquid filled myself.

andytalon said:

Get a Water filled gauge!

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Well their not water filled, have you seen what happens to water when it sits still for awhile or what it does below 32 deg? They usually use glycerine or a mixture of glycerine and distilled water. Yes a liquid gauge is better to get rid of vibrations in the pointer, which is supposed to make the gauge last longer (less wear on the movement). Remember to pull the plug out of the liquid filled gauge every once in awhile as changes in temp will build pressure or vacuum in the case cause your readings to be off. With the aeromotive fpr reading ~21 psi when you shut off the car, then slowly dropping to 0 I would say this is normal as mine does it as well.

daren_p said:

With the aeromotive fpr reading ~21 psi when you shut off the car, then slowly dropping to 0 I would say this is normal as mine does it as well.

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Didn't you say it drops off relatively quick in the other thread? Mine takes over an hour.

oldman said:

Didn't you say it drops off relatively quick in the other thread? Mine takes over an hour.

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No I don't think so, but who knows what I said . Mine will drop to ~21 psi once you turn the car of but takes an hour or so before it gradually goes to zero.

With my AFPR installed and the pressure dropping after an hour or so it takes me a couple extra cranks to get the car started. Since it seems as though everyone has the same problem of having no pressure to the system after a period of time is there a way to fix that?

Could it be as simple as wiring a switch between the battery and the fuel pump check terminal so that you could just turn the pump on for a few seconds to get fuel in the lines again?

Anson

if you check another thread that i am currently working on
http://dsmtuners.com/forums/showthread.php?t=207720
you will see i have done quite a bit of work/testing of my fuel system in order to get it in line. one of the things i noticed during all of this is that when i got my 255 pump that the o-ring was loose on the id and not really all that tight on the od. the first time i did not use any petrol jelly and twisted it and had to re-do it. the new o-ring i got was a bit bigger cross section which allowed for a tighter fit on the od, but was still loose on the id. the cross section that an o-ring would have to be to seal the line of would need to be pretty big (probably about 3/16" or so) and i have not been able to find one that will seal off completly. mine still falls to about 30-33 at shut-off from 39 (see other thread), then dwindles down to 0 several hours later. however, it fires up as it did before the fp install, typically on the 4th spin. i just might be able to get back to work on the eclipse this weekend to finalize whatever i am going to do related to the other thread.


jim

Even though my fp slowly drops to 0 psi after I shut the car off, I still don't have a problem with it taking longer then normal to start. Mine acts the exact same way as it did before the fuel system upgrade.

Jim and Daren-->

I have a Walbro 255 but haven't installed it yet and haven't rewired the stocker yet. Is it possible that installing a higher flowing pump and rewiring it could solve my extra cranking problem?

Anson

UMR98GSX said:

Jim and Daren-->

I have a Walbro 255 but haven't installed it yet and haven't rewired the stocker yet. Is it possible that installing a higher flowing pump and rewiring it could solve my extra cranking problem?

Anson

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I have this problem now, witha re-wired walbro 255. Takes a few cranks to get started, don't know if the fpr will solve this, but I'm getting one anyways.

UMR98GSX said:

Jim and Daren-->

I have a Walbro 255 but haven't installed it yet and haven't rewired the stocker yet. Is it possible that installing a higher flowing pump and rewiring it could solve my extra cranking problem?

Anson

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With only changing the fpr I can not see why it would take any more 'cranking' to get it started. And I do not think that changing the pump would solve this. As stated, I think the reason that mine (and many others) does not stay pressurized is because the fuel pump o-ring is not properly sized for the bulkhead 'hat'. Mine works great, but as stated, I had to re-do mine as I twisted the origional o-ring and found one that had a slightly bigger cross section.

jim

UMR98GSX said:

Jim and Daren-->

I have a Walbro 255 but haven't installed it yet and haven't rewired the stocker yet. Is it possible that installing a higher flowing pump and rewiring it could solve my extra cranking problem?

Anson

Click to expand...

I wouldn't think the larger pump/rewire would solve the slow starting issue but I could be wrong. Iam running the 255hp and a rewire. Does your fpr first drop to ~21 psi when you shut the car off or does it fall right away to 0 psi? I origionally had issues with slow starting but it was a defective fpr (it would drop to 0 as soon as I turned the car off). Once I got it fixed, no more slow start problems

Have both of you solve the problem concerning vacuum not pulling the pressure down to where it should be?

oldman said:

Have both of you solve the problem concerning vacuum not pulling the pressure down to where it should be?

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I was hoping to get back on the Eclipse this weekend, but life stepped in and did away with that. The car is still sitting in the garage waiting on me to get to work on the last couple of ideas from the other thread. Oh well, thank god for a backup car.

Jim