Fuel Return Kits and NOT holding fuel pressure ... solved.
Ok , many people have posted about having to prime their car , hard starting , and also about their car not holding fuel pressure after installing an aftermarket fuel return kit. My mechanic , Chris Lubonski aka Guygettnby , has finally solved this problem.
First , the basics .....
My car started running like crap all of a sudden. It would stumble under mild accelleration , and every time I changed gears. At WOT it would sputter and detonate real bad. It also started suffering from the hard start syndrome , and i would often have to turn the key to start it three or four times.
Putting a data logger in my car showed my car running VERY rich at idle and light throttle ( 9:1 afr ) , and yet when I went WOT it would go as lean as 17:1 afr ...... WTF ? All this and NOT throwing a code ! After replacing the oxygen sensors and fuel pump , it was still running the same. We had already checked for vaccum / boost leaks , and also for any fuel leaks , and had found NONE. The aftermarket regulator was NOT bad , and was NOT leaking fuel back into my vaccuum lines. On my fuel pressure guage , I could prime the car , and immediately the pressure would go to 43 psi , but would drop to ZERO immediately .... I mean not even any needle creep down action , it would drop like a rock !
Chris then got under the car and asked me to prime it .... I did so and then looked at the guage and it was holding a steady 43 psi ...
He was pushing in and putting pressure on the FACTORY fuel pressure regulator that had been blocked off ..... It was leaking vaccuum around the seal to the tank , and the two O-rings inside. the O-rings were not damaged at all , but the regulator itself was pushing itself out of the tank , just enough to NOT allow the O-rings to seal inside properly , and it was leaking vaccuum.
There are plastic tabs that are supposed to hold the regulator tight in to the tank , but they do not hold it down tight enough. We repaired this by placing small steel spacers ( made from hammered flat nails ) between the spacers and the regulator , forcing the regulator to be pushed tighter in towards the tank.
My car now holds fuel pressure , and bleeds down VERY , VERY slowly after priming the pump by turning the key on. The car is now running perfectly again.
This is also going to be the key for a LOT of people suffering from hard starting syndrome.
Last edited by cp980fps; 02-26-2006 at 09:59 AM.