I have walbro 255 LPH fuel pump, Holley tbi unit. I am trying to run 21 psi with my adjustable regulator built into holley tbi unit. cannot get a consistent 21 psi. Dimented told me I need to change teh regulator and bypass the holley one because the return passages are too small causing fuel to back up into the system making pressure inconsistent. I need consisten fuel pressure to tune my car properly.

If you have upgraded to an aftermarket regulator vacuum or non vacuum. post up please. if you have pics i'd like to see what you did. and if you have details on how you did it, i would like to know. I am talking about the fuel lines and everything.

Any info. would be great. Thanks.

 

i have my plate for the block off on my tbi. now i need to save for the regulator. and since i will be doing an ls swap this same reg with a spring swap will run it also. check out this post.


http://www.fullsizechevy.com/forum/g...-tbi-pics.html

 

Yeah I was looking at that one. and thanks for the link. I am kind of thinking since I am doing this I might as well installed a vacuum controlled one. that way I can run lower PSI at idle and increase with RPM.

If I have the fuel pressure gauge on the inlet side of the tbi that should not hurt how it reads pressure should it?

Do you know if a standard TBI regular block off plate will work on a holley tbi unit? I guess I can change the whole unit out to a standard one if need be. I really did not wanna have to get rid of these injectors, but maybe an injector upgrade would be better too. get some nice 80#'s at 13 psi. Thanks for your help one.

 

For the stock unit, for the 80# injectors, I'm leaning toward this. Basically the entire upper half of the TBI unit, I figured I'd change the FPR to adjustable prior to installing. Doing a little research, this should fit the TBI 220 unit that's common on the 305 and 350 motors.

http://www.injectorwarehouse.com/tbi/tb124-2a.htm

 

Yeah. I just didnt really want to run an external FPR because I live in California and the smog issues. but I guess i'll just have to deal with that as I can. I want this car going full strength so I can put money into my other project

 

if you give me till tomorrow afternoon i will measure my uninstalled block off plate and give the measurements to you.

 

Some members has issues with that pump, overflowing the retur line.
A 190 walbro or a TPI pump at such low pressures can deliver big amounts of fuel, without running the risc of that issue.

 

I knew some people were running into problems. but it seemed as though more were doing okay then not performering well so I went with it. I guess I can buy a smaller pump and try that. Aint hard to change the pump. dammit that sucks though.

 

not the best but should work.

 

awesome thanks one92rs

I have not fully decided to either buy an external regulator and plumb it in. or go to a smaller fuel pump. If everyone thinks I can get by with a smaller pump then I might do that because being in california the car has to "look" like it is smog legal for the smog. and obviously an external regulator will stick out like a sore thumb.

 

If it is already in give it a try. The "stock type regulator could not be the problem, the majority of the fuel has to get back in the tank and the return line/evacuation could be inedaquate.

Not sure someone with emission test is using a 255 pump @ low fuel pressures.

 

Yeah very true. I can buy a TPI pump from AC Delco and be god for a long while. That is what I am leaning towards doing because the car pretty much can pass a visual right now with an air cleaner and smog pump reinstall. id hate to have to fight with this thing for all this time, then in a year go through it all again.

 

CA smog regulations = fail