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I just upgraded my injectors to 550cc yellow tops out of a subaru.

Since that my Sard FPR guage only reads 22psi. I tried adjusting it and it can go lower than 22 psi but it wont adjust to make higher than 22 psi. The needle shakes at the highest 22 psi figure I can get.

When i turn the key and the fuel pump pumps the fpr guage shows 40 psi then once the car is turned over it goes down to 22PSI, why is this?

My question is, any ideas why this would be happening? (is the FPR faulty?)

Is it safe to drive at 22 PSI? or will it lean out?

To give a background on my fuel system upgrade that also might be linking to it. I replaced the faulty walbro pump it had with a new one and the FPR went up from 40 psi to 50 psi and then just yesterday I replaced the fuel rubber lines from the boot as one had a tiny cut and was leaking and thats when i also replaced the injectors, since then only getting 22PSI on the FPR guage

remove the vac line and see what your base pressure is. then if it wont go any higher than ~45psi try slowly crimping the return line after the reg with some pliers (carefully!), keeping an eye on the pressure, and see if it goes up. if it does the reg is f**ked, if it doesnt your pumps f**ked

ok, so i've just done what you said to do and the guage psi value didnt move. so this would mean the fpr is fine and that my fuel pump is f**ked...

but the fuel pump is a brand new genuine walbro one that just got installed 2 weeks ago. The reason i replaced the fuel pump was because the walbro that was in there would start making loud surging noises at random moments and would keep getting louder until you turned the engine off, also the fpr guage would go nuts surging between 20 to 50 psi etc.

so if it really is the fuel pump, what keeps killing them?

Dodgy wiring or relay ? Possibly have constant power going to the pump u could put a multi Meter on the pump with the power off to make sure it's turning of with when the power is off

Also check what voltag u get at the pump with th power on if it's on factory wiring it will be around 10 or 11 volts any less and there could be a wiring issue

Is it wired directly to the battery or just factory wiring ? I would get the pump rewired to battery if it's factory still there is a write up in DIY section

Are u sure u put enough pressure on the line when u squezed it ?

Edited by BOOZTJUNKEY

re squeezed it to make sure and i was putting as much pressure on it as i could, the needle is just fluttering around 22 psi so i wouldnt have expected it to rise anyway as it cant seem to get past that point. thinking of just getting another fpr to atleast rule that out or in hope it will fix.

check the power to fuel pump ans its only going when car is ON and its not a direct line but gets about 11.5V

+1^^^ Walbro pumps don't like the low voltage the stock fuel pump sees at idle. If it hasn't been done rewire the pump power using a relay as described in the many threads on the subject.

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