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Stupid fuel pressure regulator question...
- Thread starter shady
- Start date
Not quite how they work, but yes.
Spring pressure is what prevents the fuel from "bypassing" the regulator. Light spring pressure means the pump can easily force the bypass to open, more pressure means it takes more pump pressure to do so.
I just ended up using spacers in the regulator housing to get the most pressure I could get instead of modifying it to make it adjustable. Some trial and error, and the pump peaked at 14PSI, but it worked. Just remember coil bind...too many spacers and the coil binds up.
Spring pressure is what prevents the fuel from "bypassing" the regulator. Light spring pressure means the pump can easily force the bypass to open, more pressure means it takes more pump pressure to do so.
I just ended up using spacers in the regulator housing to get the most pressure I could get instead of modifying it to make it adjustable. Some trial and error, and the pump peaked at 14PSI, but it worked. Just remember coil bind...too many spacers and the coil binds up.
im trying to adjust my jet performance one I just installed and the LOWEST it will go is 15....
It was about 1/3 of the way up its adjustment range when I started and it sat at a steady 15.5..... I backed it all the way off and the needles wobbly (very slightly) at 15 even. wont go any lower... I'm sorta stumped..... new regulator, new gauge/tester, new pump last year. I believe I got the delco cause I made the trip to napa for it and I NEVER go there usually... I check it at idle right?
It was about 1/3 of the way up its adjustment range when I started and it sat at a steady 15.5..... I backed it all the way off and the needles wobbly (very slightly) at 15 even. wont go any lower... I'm sorta stumped..... new regulator, new gauge/tester, new pump last year. I believe I got the delco cause I made the trip to napa for it and I NEVER go there usually... I check it at idle right?
Theoretically if the pump is capable, pressure should not fluctuate (at least long term) whatever the RPM.
Odd that it won't go low enough. Do you have the stock one you can swap back on? As long as you don't let the gaskets sit assembled too long, they come apart pretty easily and normally can be reused.
Odd that it won't go low enough. Do you have the stock one you can swap back on? As long as you don't let the gaskets sit assembled too long, they come apart pretty easily and normally can be reused.
![DSCF3769[1].JPG](https://ck5.com/forums/data/attachments/146/146922-cc57b88f30bbef632629899f8f6436bf.jpg "DSCF3769[1].JPG"){kind=small}
![DSCF3768[1].JPG](https://ck5.com/forums/data/attachments/146/146923-ea613907cb5a20a68a5a72e452198bb6.jpg "DSCF3768[1].JPG"){kind=small}
Another option is to check and see if the stock spring is interchangeable with your new regulator, see if it's a spring issue.
Either way don't see what else it can be if the regulator won't do anything to the pressure.
You contacted jet and asked them what to do? You running a TPI pump, or is this a Delco TBI replacement? You got "lucky" if the stock TBI pump will put out 15PSI, but doesn't really matter at this point since you can't turn it down.
What was pressure before you swapped the regulator? Any chance you've got a restricted return line?
Either way don't see what else it can be if the regulator won't do anything to the pressure.
You contacted jet and asked them what to do? You running a TPI pump, or is this a Delco TBI replacement? You got "lucky" if the stock TBI pump will put out 15PSI, but doesn't really matter at this point since you can't turn it down.
What was pressure before you swapped the regulator? Any chance you've got a restricted return line?
never checked the pressure before it is the TBI replacement and if I remember right it said it was good for like 18.. its the stock spring... I guess it should be alright.... ?? I just wondered if I was doing something wrong...
There wasn't a spring with the regulator so I assume you use the stock one.. I'll leave it as is and see... as long as it runs good and isn't stumbling or anything it should be ok right? A few other people on here are running 14.5-16 and have no issues...
I was thinking of the return line thing when I was out there last time...
wonder how id check that... its not like 40 so I'm gonna roll with it I guess... I was thinking maybe I was going the wrong way, but if I go the other way it put a LOT more pressure on the spring
it is the TBI replacement and if I remember right it said it was good for like 18.. its the stock spring... I guess it should be alright.... ?? I just wondered if I was doing something wrong... There wasn't a spring with the regulator so I assume you use the stock one.. I'll leave it as is and see... as long as it runs good and isn't stumbling or anything it should be ok right? A few other people on here are running 14.5-16 and have no issues...
I was thinking of the return line thing when I was out there last time...
wonder how id check that... its not like 40 so I'm gonna roll with it I guess... I was thinking maybe I was going the wrong way, but if I go the other way it put a LOT more pressure on the spring
Seems odd to me that they would ship a product out and expect you to use an almost 30 year old spring with it, but maybe that's just me. That spring is not approaching coil bind even all the way "loose", right? I know that GM used a couple different FPR setups, I can't remember if the springs stayed the same or if there were a couple different length springs based on the design. Could be a factor I suppose.
As long as you don't have any issues from running that much pressure I wouldn't worry. Open loop idle/cold starts may get ugly, and wide open throttle may be too rich, but without putting a scanner and wideband O2 on it, not really any way to know for sure, other than seat of the pants and perhaps MPG if you watch that sort of thing.
A TBI pump will never hit 40PSI even if deadheaded, they just can't build that sort of pressure. You could disconect the return line and put it in a bucket I suppose, but that assumes the passages in the TBI and the outlet line from the TBI are good.
As long as you don't have any issues from running that much pressure I wouldn't worry. Open loop idle/cold starts may get ugly, and wide open throttle may be too rich, but without putting a scanner and wideband O2 on it, not really any way to know for sure, other than seat of the pants and perhaps MPG if you watch that sort of thing.
A TBI pump will never hit 40PSI even if deadheaded, they just can't build that sort of pressure. You could disconect the return line and put it in a bucket I suppose, but that assumes the passages in the TBI and the outlet line from the TBI are good.
well.. I guess its a moot point now because it quit starting 
has gas still but just wont pop off now like it used to do
I didn't even look after that lol too darn cold... ill wait a few days and try again when I can see what else is happening... I did see on closer inspection that there was a tad more let out so I did that after it quit starting..... thanks for the replies man. have a good night
has gas still but just wont pop off now like it used to do I didn't even look after that lol too darn cold... ill wait a few days and try again when I can see what else is happening... I did see on closer inspection that there was a tad more let out so I did that after it quit starting..... thanks for the replies man. have a good night
