Leeroy_25

I am half way through my single tubro conversion and have got rid of the factory FPR. I just want to be sure I connect my aftermarket one back up correctly.. Am I correct in thinking it must be plumbed to the fuel pipe coming from the secondary fuel rail and back to the tank to work correctly?
Also where do I take the vacuum air feed from. Is it important whether it is before or after the throttle? or even on the inlet side of the turbo?

Thank you
Lee

Zero R

iTrader: (1)

Depending on how you run the setup ie series or parallel, pump>rails>reg>tank. Any manifold source should be fine.

papsmagu

iTrader: (19)

yeah there is a nipple on the inside face of the LIM (all the way at the bottom)....it is supposed to be the most accurate source of vacuum. diagram should help on the location of the FPR

Leeroy_25

Thank you guy's.. I am running the same as the factory arrangement just with an aftermarket reg. So series I presume? pump - rails - reg - tank.

Cheers
Lee

Leeroy_25

I presume the pic posted is a parallel setup??

arghx

iTrader: (3)

that is a parallel setup for an 87-88 turbo second gen using the stock top feed rails

Leeroy_25

I have a 1994 FD3 and My FPR is one in one out on the fuel line.
I assume the FPR vac lines function is for when the throttle is closed and shuts off the fuel supply? or limits it a low RPM before boost kicks in? Is that about right? Would it be wise to put a one way valve to ensure it can only get a vacuum and does not get damaged under boost?
I think I know the nipple you mean.. I blocked it off yesterday before fitting the LIM!! Do I have an alternative vac point as with the LIM fitted and I am not sure I can get at that nipple to put a pipe on now!!? Worse case i'll take it back off! Not a biggy!

Cheers
Lee

Dudemaaanownsanrx7

iTrader: (23)

No do not use a check valve. The fpr main function is to raise fuel pressure as boost goes up. Generally 1:1 ratio. You set the base pressure with no vacuum line connected. Generally around 40 psi, then under vacuum it drops to around 35 psi and as boost goes up it raises to 50 psi at 10 psi boost 55 at 15 etc. The fpr can be connected anywhere after the throttle body. It should see both vacuum and pressure. Again do not use a check valve unless you want a broken engine from lack of fuel under boost.

Leeroy_25

Thanks dudemaaan! Glad I asked that one! When I set the fpr without the vac, do I need the engine running or can I set it from the ingnition on position when the pump pressurises the system?

Cheers
Lee

Dudemaaanownsanrx7

iTrader: (23)

You can set it with ignition on and f/p jumpered to grd in the diagnotic port

Leeroy_25

Err. Not sure how you do that?? Might be easy to run it up?? Anyway.. I am a few days off that. Is the LIM vac point the best palce to come off or does it really make no odds. If it's better to come from there I will.
Cheers
Lee

Dudemaaanownsanrx7

iTrader: (23)

Makes no difference just make sure whatever port you use its vacuum and boost. Because this line is very important i prefer to use one i can easily keep an eye on and regularly check.

teknics

iTrader: (4)

ok maybe someone can help me here.

I just finished converting from a single pump with kgrails, 850/1680 and an aeromotive FPR. Had no problems setting fuel pressure.

Went to a full parallel setup with CJ Walbro holders, -6 lines from pump to rails. Primary line connects to the small metal hose setup on top of the block then goes to primary rail. Seconday line goes directly to the secondary rail.

I then have both lines come out of each rail, directly to the FPR. The FPR then has a -6 return (which first goes through that metal hose on top of the block) and then back to the stock metal return line.

Ever since i converted my lines like that, if i let the car idle, take the vac source off the FPR and block it, when i try to set fuel pressure to anything of 32psi it just wont hold. The needle on the gauge will be steady at 30/32 psi then once i turn the adjustment down it looks like its going up then it falls down to about 25psi and starts shaking/jumping a lil up and down. No matter what I do i can't get higher then a base pressure of 32psi. I tried using a new aeromotive FPR i had around for my other car, no change. Different gauge, no change.

Now if i disconnect the secondary lines fuel pump, and disconnect it from the FPR and plug the secondary port (so it's like im only running the primary rail) the FPR works perfectly, the needle is steady and i can raise fuel pressure as high as I want.

Please someone help me out, Im at my wit's end, the only other thing i can thing of is get a y-block to combine the 2 feed lines and run my rail lines stock-style/series at the engine.

Kevin.

Dudemaaanownsanrx7

iTrader: (23)

Are you sure you have the correct port on the fpr connected to the return line? I don't know if this would cause the problem you're having or not but it's the only thing i can think of.

teknics

iTrader: (4)

yea bottom port is return, 2 sides are primary and secondary lines from rails.

kevin.