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.
HTH
Very interesting. I lost count on how many fuel kits over the years I have installed. I cant remember one problem like this. I think maybe its in the way you guys take the stock reg out and/or put them back in. It takes a little pressure to get them in and out, but maybe your damaging them while doing it. The tabs are there to hold them in, if you tweak them... I could see this problem occuring. Good find though man!!
Wow Good find. What about your afr's are they back in line?
However , I'm sure my AFRs will be found to be just fine ... The car runs way too well for them not to be. I'll definitely be re-tuning , since I've changed some things on my car , but the main problem that led to Chris finding this issue , has been repaired.
Your first sign should have been the bleed down of the pressure. If you prime it and it bleeds down very fast, you know there is a problem
We didn't notice my pressure was bleeding down , until after we had checked other things that could cause detonation. When running , my car's pressure was a steady pressure at the guage. Once we found that pressure was indeed leaking down ( this happened when Chris just happened to notice the pressure drop on the guage , right after I primed the car but hadn't turned it over yet ) , we looked at everything a person would expect to find wrong first .... Gas cap , fuel pump , pressure regulator , leaking fuel or vaccuum lines , ect .... the LAST thing you'd normally think of looking at would be the unused factory regulator.
We didn't notice my pressure was bleeding down , until after we had checked other things that could cause detonation. When running , my car's pressure was a steady pressure at the guage. Once we found that pressure was indeed leaking down , we looked at everything a person would expect to find wrong first .... Gas cap , fuel pump , pressure regulator , leaking fuel or vaccuum lines , ect .... the LAST thing you'd normally think of looking at would be the unused factory regulator.
Yea I guess for the average person it would be hard to figure out what was going wrong. This is a good find for people having the problem though. Nice work
Yea I guess for the average person it would be hard to figure out what was going wrong. This is a good find for people having the problem though. Nice work
I'm not average !! You should know I'm far from average .... I'm hung like a Horsefly !!
Really , we couldn't see , smell , or hear ANY leaks at all ... Therefore it was the farthest thing from our minds. Once we DID realize there was a leak , we actually had to find an INVISIBLE leak at that .....
I'm not average !! You should know I'm far from average .... I'm hung like a Horsefly !!
Really , we couldn't see , smell , or hear ANY leaks at all ... Therefore it was the farthest thing from our minds. Once we DID realize there was a leak , we actually had to find an INVISIBLE leak at that .....
LOL. I meant for the average person who hasnt installed 8 gazzillion of them like I have. HAHA horsefly
i have installed a bunch of return line kits.... the problem at hand was the fact that his car ran perfect for 8 months with no problem at all!! then all of a sudden after a snow storm his car began to act like he described. so obviously this was not a problem from installing the return line kit. if it was then why would his car run perfect for that long with no sign of any problems and then over night start doing this??
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Fuel Return Kits and NOT holding fuel pressure ... solved.
This should be STICKIED !!
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