Weird Sard FPR Rising Pressure Issue

[skiddusmarkus]

I have a genuine sard fpr bought from Japan about 6-7 years ago before all the Chinese fakes started flooding ebay.The issue I have is when I set the fuel pressure to 3 barwith the vacuum pipe off, then replace the pipe tightn up the lock nut etc.I go for a drive and then when I get back and check the pressure it has risen.I have seen it go as high as 75psi (which also raises the idle)when I check it with engine idling.I then repeat the above process to get it back down (which lowers the idel again).
Anyone know why it would rise so high and not fall back down again?The only things I can think are there is some leak on the vacuum pipe or that the unit itself is faulty.I have a couple of spare standard ones which will be going back on for now but I wanted the ability to raise the pressure for mapping with bigger injectors for a better spray pattern at lower rpm's.
I don't think I've installed it incorrectly as there is pretty much only one way to do it that will allow the engine to run.

 

[red reading]

Or the fuel return line is blocked to the fuel tank, probley find the return is blocked in the top of the fuel tank where the tank sender unit is with rust from the fuel return line.

 

[jjs]

hi just fitted one yesterday, would you not have to set the pressure up with the vaccum hose connected, as it will raise the pressure once you reconnect the vaccum hose, ? mine is fitted with the inlet at the side ,same as where the gauge is fitted, and the tank return coming from the rear of the regulator ,

 

[skiddusmarkus]

Everyone always says to do it with the vacuum pipe off.It only makes a couple of psi difference either way as I have tried both.On mine it has 3 threaded holes-2 horizontal ones and one vertical on the bottom.I have one horizontal hole feeding from the furl rail, the other horizontal feeding the pressure gauge and the vertical one returning to the tank.

Danny is the rust a common fault then?I've had a look at those pipes before and they were practicly welded on when I tried to move them.

Edited in a pic of how its installed.

 

[red reading]

Everyone always says to do it with the vacuum pipe off.It only makes a couple of psi difference either way as I have tried both.On mine it has 3 threaded holes-2 horizontal ones and one vertical on the bottom.I have one horizontal hole feeding from the furl rail, the other horizontal feeding the pressure gauge and the vertical one returning to the tank.

Danny is the rust a common fault then?I've had a look at those pipes before and they were practicly welded on when I tried to move them.

I had the same happen to me simon and that was the problem in my car,have also had it in other car's that have been left standing.....The wonders of using steel for fuel lines

 

[skiddusmarkus]

Any tricks to removing them?When I used pliers on the rubber fuel hose as it was too tight to do by hand, it damaged it.

 

[stumo]

I'd move the FPR from the engine and have it bolted to the shell, the vibes off the engine might be causing the problem.

also as Danny has said , check the return.

It could also be a faulty FPR.

 

[jjs]

could try blowing through the return line to the tank first to check if it is clear rather that taking anything apart first .

 

[stumo]

yea, you could try that.

 

[skiddusmarkus]

I'd move the FPR from the engine and have it bolted to the shell, the vibes off the engine might be causing the problem.

also as Danny has said , check the return.

It could also be a faulty FPR.

Wherever you put it in the shell you are next to electrical stuff.I've tried to site it away from things like that as much as possible and made it so that the return is below the level of the leads around the dizzy in case of a leak.
How would the vibrations cause my issues then?Would putting a bit of rubber between the bolts and bracket help?

 

[skiddusmarkus]

could try blowing through the return line to the tank first to check if it is clear rather that taking anything apart first .

I don't have a compressor, would a foot pump be up to it?

 

[jjs]

im sure if you blow through with your mouth should do, would remove the fuel cap first may help, also if it is a problem with the return, you may find the return line pressurised when you remove the fuel return hose,

 

[stumo]

Wherever you put it in the shell you are next to electrical stuff.I've tried to site it away from things like that as much as possible and made it so that the return is below the level of the leads around the dizzy in case of a leak.
How would the vibrations cause my issues then?Would putting a bit of rubber between the bolts and bracket help?

the vibes might be causing the piston in the FPR to stick.

You could try just letting it hang in freeair for a run to see if the same thing happens...


a foot pump would be fine, you just need to find out if you have a blockage.....

 

[skiddusmarkus]

Just a thought, if it was a blocked fuel pipe, wouldn't the pressure build up very quickly and do so on idle too?My issues are after its been driven on the road so has boosted.

 

[stumo]

just making sure you've got everything connected the right way round......

the fuel hose comes from the pump and goes into the fuel rail.

The hose from the rail is going to the side entry on the FPR and the return to the tank is coming off the bottom of the FPR.

 

[skiddusmarkus]

Yep, think you can see most on the photo.Line from the fuel filter feeds the rail, at the end of the rail where the oe fpr was I have an adapter feeding the sard in a side hole, the other side hole feeds the gauge, the hole on the bottom returns to the tank.

 

[skiddusmarkus]

I am starting with the eaisest tests first so I disconnected the fpr from the metal bracket and went for a short drive with a bit of boost.The pressure didn't go up, it actually fallen a few psi from when I last set it so I set it back to 3bar and carried on.I'll drive it to work tomorrow and have a run after and see what happens.

 

[Trip]

I am not seeing the whole picture of the piping you have but are you sure it is connected correct ?

You should have the pipe coming from fuel pump feeding the filter and direct into the fuel rail. The FPR must be connected on the "return" side

 

[skiddusmarkus]

Yes trip that's how its fitted.

Well, the fuel pressure has stayed pretty consistant since I did what Stumo suggested and unbolted it from the engine .I have just cable tied it to a silicon hose for now which is fine as it weighs sod all anyway, its more to stop it moving side to side.
I am hoping this is going to solve the ridiculous fuel consumption I have been having, I did 120 miles on the last tank and that was driving pretty steady with the odd bit of boost.I've also cleaned the hotwire on the MAF just in case.Funnily, I forgot to connect the MAF back up after doing this and the car started and idled exactly the same as before(I'm sure it used to hunt for revs then stall when doing this).Whn I clipped the plug back on it hunted for a second then ran exactly the same as without it.

 

[stumo]

small "s" dumbass