The supply pumps are capable of 35-40 psi, if unregulated. I've never seen a GPH flow rate spec on a unrestricted pump, but on a SPICA injected Alfa, you must be able to get .5-.6 gal per minute (measured from the fuel hose exiting the Injection Pump) to meet the use and cooling demands of the Injection Pump.
There is a pressure regulator in the front fuel filter. If you look at the top of the front fuel filter, you'll see 4 fittings. The two closest to the engine run the fuel into the filter then out to the FI pump. The other two are the return line to the fuel tank. In the top of the front fuel filter, you'll see a small hole that leads to the return line. That's where the pressure relief valve is. If there's over 17 psi, then the valve opens and fuel is allowed to flow directly back to the tank. Fuel pressure should be about 10-17 psi in the line. 7 psi turns on the fuel low pressure warning light.
If you are having low fuel pressure problems and suspect a bad pressure relief valve, squeeze the return hose exiting the front fuel filter and see if that turns out the light. If it does, it COULD indicate a bad pressure relief valve (unlikely), but more likely, a failing supply pump. BTW, DON'T buy used fuel supply pumps. You don't know their working condition and when it stops so does your Alfa . . . like right now. It's $160 well spent. How do I know that??? . . . . .
As a matter of fact, my old SPICA fuel supply pump failed yesterday about a mile from home. After having turning off a couple of minutes, it started working again, but then quit altogether by shorting out and blowing the fuse. Since I knew that pump was old, I had a new Bosche pump (from a L-Jetronic system) in the spares kit. With a little rubber padding to take up the size in the bracket and a set of ring terminals (vice the spade terminals on the SPICA pump) I had it running again in a half hour. That was the third SPICA supply pump I've had fail in the Alfa's I've owned. My advice is that anybody that has an old SPICA supply pump of unknown age in their car, should replace it with the Bosche supply pump as a matter of preventative maintenance.
Thanks for the help. Im actually converting to EFI.
I origianlly wanted to run dual webers, but after
doing some research on EFI, I have decided to go
this way. I wanted to make sure I could get enough
PSI from the pump to run some tests with the new
system. Looks like I will have to bypass the
stock filter, cause I really need at least 30psi
for the new injectors.
Reason I am going with EFI is the tunability. Looks
like I can set up my fuel delivery system to
run in economy,performance,or race with an easy
download from a computer. Also I think running
a closed loop fuel system, I should be able to get
very good fuel economy. Looks like the EFI conversion
will be very similar to the cost of converting to
If you are just converting SPICA to EFI, you can keep the stock fuel pump.
On the advice of Jim Steck, apparently, the stock SPICA pump is good to 250hp of fuel flow, at high pressure. He mentioned to me that it normally runs at 45 psi, so running with a regulator to 39 (normal EFI) is not a problem.
To my follow up comment, our turbo Spider still uses the stock fuel pump, and puts out somewhere north of 200 hp. No problems at all. So you should be fine.
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