75 1.8 L-jetronic, Fuel Pres?, Regulator? Pump? Returns??? Options

[Donaldo88]

Hi again. Second post...again on the 75 1.8, a sort of time capsule car, with only 39K miles, which seems to be plausible, and it still has L-jetronic FI. Virtually no miles driven in the year we've had it, because there's one problem after another. The latest, it quit running, with clearly a fuel problem, but I'm not ready yet to tow it. Using Haynes manual, it recommended checking fuel pressure. I special ordered a guage from Auto Atlanta, but I gave up on it ever coming, and canceled it. Rigged up my own guage, but had no tee, so end-connected it into the fuel line on the left bank, looking for 35#. Got 90# on the guage, and squirted a little gas out the return line on the right bank, so shut off switch momentarily. Called Auto Atlanta to see if they recommended a new regulator, as my Haynes book recommended. The guy I talked to asked George, who said "the regulators never screw up, sounds like the return line is plugged up". Seems like if I had crud in the line, it would plug injectors way before plugging the return line. Do you know...if my left bank distribution was open, does that screw up a feedback signal from the injector, causing the over-pressure? Apparently there's check valves in the returns, because the open left fuel line didn't flood the engine compartment with gas, which would be the case if both banks connect together. I see some braid lines when I look up from underneath, but I don't see the two poly lines which exit the engine and go into the tunnel. It looks like I have to take out the fuel tank to see more or clear the lines.....any suggestions, or experience with this?
Thanks,
Don

[SLITS]

In one of the rails (passenger or driver) there should be a tap in the middle .... it is a 7mm bolt (also the fuel line to the cold start injector could be attached there). That is where you tap for fuel pressure. You "deadheaded" the pump and that's why you saw 90 psig.

And 35# is to high and might cause injectors to leak. 30# is the setting.

If you can't find a tap then connect your guage to one of the injector taps on the rail.

Fuel flow: Tank to filter to suction side of pump to discharge of pump to pass side fuel rail across engine to driver side fuel rail to pressure regulator to return line to tank. Fuel pressure to system is measured in the bold area.

The return line is a free discharge to the tank. Take the line off the fuel pressure regulator (hose runs on back of engine to passenger side) and blow into it. If you hear bubbling in the tank or can even blow thru it, it's not plugged.