First off, I'll try to provide as much info as I can, then get to my problem. I have a '92 Camaro that used to (that used to be the 305 TBI). It now is powered by a carb'ed 400 with a T-56. I changed the stock electric fuel pump for the 255 lph in tank replacement from Holley which is the exact same thing as the Walbro. I maybe should've (or at least could've) kept the stock one but it had bad fuel in the tank so I figured "while it's out...".

Any way from the stock pick up I replaced the fuel lines (supply and return) to -6AN all the way to the motor. The change in lines happens where the stock ones attach to the lines that are part of the pick up (hope that makes sense). Aeromotive in-line filter to the Mallory regulator, then out of two of the outputs to each feed on the carb. I assume the return line is getting choked at the pick up so I am considering either adding another return or simply a larger one (-8AN), I already have -6AN line so that would be cheaper but maybe not best.

I also am going to add a couple (one on primary and one on secondary) deadhead regulators, just to help maintain pressure. BUT pressure is not my primary issue (I don't think). I can maintain a good steady 7psi when cool.

I THOUGHT I was boiling my fuel until I read a bit about vapor lock and hot soak here. I was thinking I was cooking the gas because I don't (yet) have an isolator spacer installed and to keep the lines somewhat hidden I ran the lines along the frame and up the firewall (basically where the stock ones were), across the strut tower where the regulator is mounted out into the nose in front of the radiator back into the engine bay to the passenger side where the inlets are on the carb. I did this because I didn't see a good way to get across the car since underneath you have hot exhaust and a driveshaft to get around. I thought about crossing in the area where the tank itself is, but then I'd have to run along the passenger side of the frame which obviously is where the exhaust is.

Anyway like I said, pressure doesn't seem to be an issue when cool. The heat (it doesn't, assuming the gauge is right, run hot) seems to be the problem because when I drive the car and shut it off, it just cranks and doesn't want to start. After it sits and cools for a bit it starts. And with it hot the pressure is really weird. It fluctuates from real high to real low quickly and is not stable at all. I read somewhere else about boiling gas and that's where I came up with that theory. I wouldn't have thought that engine bay temperature and the contact with the radiator wouldn't be enough to heat it that much, maybe the isolator is the only thing needed.

I'd like to do whatever is needed all at once (isolator, new return line, re-route), but I don't know if any or all of these things will solve my problem. Also when I did the build I couldn't find anything about where to run the fuel lines. Hence the "I can't be the only one" comment. Certainly with all the modifications some of you have done somebody somewhere has replaced their entire fuel delivery system for something similar. I apologize for the lengthy post, but I didn't want to be the guy like "my car's broke, what's wrong?".

Hopefully I've provided enough information and thank you all in advance for your help and knowledge.

 

Try a return line first.

 

try pressing the "return" (enter) key on the keyboard a few times too, every so often, thats really hard to read.

and install a return line.

 

Not to sound like an ***, but I'm sorry that I didn't break it into paragraphs. I guess it is a little long winded, I was just trying to get as much info as I could think of. If it honestly would help, I'll go back and edit.
Thanks for your response (both suggestions so far), but you say to install a return line. As I stated I do have a return line (-6AN same as the supply). You think I need a bigger one or as I suggested another? I know the minimum the return should be the same as the supply that's why I did that. I just want to make sure I fully understand what you are suggesting.
Thanks again.

 

I went back and re-read and broke it down. Hope it helps.

 

Got an 82 firebird that's been having fuel issues ever since i got her...

 

someone78 - Not sure what carb you are running, or if you fixed your issue yet (it's been over a month now) - but 7psi is too high for most carbs - all I read on mfg websites states 6psi max, most want 5.5 or lower.

tango1112 - we need more info. Better to start your own thread rather than hijack another. Simply stating you have a fuel issue could be one of 100 possibilities. What makes you think you have a fuel issue? What are the symptoms? Have you changed fuel filter?

 

Didn't have plans to "Hijack" another thread... Given that my car's symptoms mirror very closely to the post originators I would not call it hijacking to collaborate towards a common solution would you??? If I were being off-topic or my issue had nothing to do with what was going on then THAT would be a hijack. Helping someone else out and getting help with a common problem is collaboration.

I came across this thread while researching my own issue in hopes that it had already been discussed and resolved to a point I could follow in another's footprints. Yet, it appears that most of the threads that deal with this topic are inconclusive. The initial poster either never resolves the issue OR they never post what eventually fixes the problem. I'm sure that isn't the case 100% of the time, just in the 20 or so threads I've read on topic already. Given the recentness of this one I figured I'd step forward, validate the inital posters inital statement "I can't be the only one..." by acknowledging the he indeed is not.

 

OK - so you too swapped to a 400ci motor with a T-56 and a 255lph fuel pump?

AND you also used -6AN lines/fittings with a Mallory regulator and an inline Aeromotive filter?

See my point tango?

I'm not trying to be a jerk - I'm trying to help you! Unless you have done exactly as the OP, then you do not have the same issues, and thus do not need the same answers. And chances of you having installed and done the same mods as the OP are slim to none.

So - in my attempt to help you, I suggested that

1) you give us more detailed info as just stating you have a fuel issue tells us NOTHING
and
2) That YOU start your own thread so we are not confused here as to who has which problem and why.

NOW - I've spent MY time trying to help you, and you choose to be defensive rather than appreciative and understanding. That's fine - be what you like, but don't expect too much assistance from any of us when we do not know what YOUR problem is, and therefore can't even begin to advise.

I am too in NC - maybe we are close to each other, maybe I can actually come see your problem rather than discussing it online. And I'd be more than happy to (if we aren't far away from one another). I'd also be happy to tune you in to many NC related boards, local cruise-ins, car shows, gatherings, clubs, etc. All because I'm a nice guy, love to talk cars, love to tinker, etc.

AND - this is why I tried helping you at all, because I truly am interested in helping if I can. I wasn't bashing you for hijacking, I was making suggestions for YOUR benefit, not mine.

Now - again - I'm glad to help, as is most everyone else here. But - post up a new thread stating your exact issues, symptoms, mods, etc. so that we can understand YOUR problem and try to help YOU!