VE table changes (increasing size)

[beestoys]

could try some fresh o2 sensors to see what happens, they're pretty tempermental, but i think something else is going on.

what's your injector constant set to right now?

It's 23.594. We had to recalculate because of the fact that the 93 used 22# injectors instead of 24 the 95 ECM was spec'd to. I also am running a higher rail pressure do to a changed fuel pump and dedicated wiring harness. The result was a 50# rail pressure. So per a math formula of 50/43.5= this value is square rooted and then multiplied by 22 which gave me the resulting 23.586 hmmm that's not exactly the same. I'll load in the new value but thinking that small amount shouldn't make that much of a difference should it?

Ok just tried to change it looks like the number there is the closest the hex can create so hence the differences.

[steveo]

woah woah wait what?

50psi from a fuel pump and relay?

i dont think so.

43.5psi should be max for a properly working LT1 regulator. doesn't matter how hard your pump is throwing fuel at it. 50psi is WAY out to lunch

what's up with that?

this is all weird stuff regardless, if you overshot the injector constant, it should be lean, not rich.

[beestoys]

woah woah wait what?

50psi from a fuel pump and relay?

i dont think so.

43.5psi should be max for a properly working LT1 regulator. doesn't matter how hard your pump is throwing fuel at it. 50psi is WAY out to lunch

what's up with that?

this is all weird stuff regardless, if you overshot the injector constant, it should be lean, not rich.

Ok a little clarification the math is done with a max value possible. The 50#'s is with the regulator unplugged from the vacuum port. Running pressure at idle plugged inot the vacuum port and warmed up is 44#'s.

[steveo]

with a stock regulator that's way too high for an lt1, i dont care how much your pump is flowing or how much voltage you feed it; unless i'm way off base and the '93 regulator is higher pressure than the later one?

is it possible your fuel pressure gauge is screwed?

but that's weirder still, as your fuel pressure being ~22.something for normal pressure would increase your pulsewidth calc and your trims would be even further down?

[lionelhutz]

I'm with steveo, if you changed the pump and wiring and the pressure went up the only way that should happen is if your pump is over-flowing what the regulator and return line can dump back to the tank. If that is the case, the pressure won't be stable as the fuel use requirements change.

[beestoys]

I'm with steveo, if you changed the pump and wiring and the pressure went up the only way that should happen is if your pump is over-flowing what the regulator and return line can dump back to the tank. If that is the case, the pressure won't be stable as the fuel use requirements change.

You know got to thinking about this this morning and I will look into the return line. This didn't start happening till after I changed out the pump. Hard start and all is new I am thinking Like you both are that it's a mechanical issue.

I am going to check the return line pressure I have a feeling I am either backing up there or I could have a ruptured Regulator diaphragm and I haven't seen it yet. I'll drop a piece of clear vacuum line in there and light the truck off and see if there is fuel in it. (This was the only way we discovered it on the 2 91 Firebirds with 3.1 V6's we also own.

I'll let you know what I find.

[beestoys]

with a stock regulator that's way too high for an lt1, i dont care how much your pump is flowing or how much voltage you feed it; unless i'm way off base and the '93 regulator is higher pressure than the later one?

is it possible your fuel pressure gauge is screwed?

but that's weirder still, as your fuel pressure being ~22.something for normal pressure would increase your pulsewidth calc and your trims would be even further down?

Ok math should be 50 divided by 43.5 the resultant is squared then multiplied by 22 right?

[beestoys]

Update
found my other fuel pressure gauge older Auto meter. The Craftsman I have is designed for shrader valve hookups. The gauge is good just a pain to graft into the return side the Auto meter should be easier. Also found out that the fuel filter I had installed in the feed line has developed a hair line crack. So now I am going to pick up a factory one and plug it in at the stock location back by the tank. I am really hoping to find out there is a restriction in the return line and that I can get it cleared. I used the factory supply line for my return when we did the instal an made up a new 1/2 supply to feed the pump. It was a pain forming all that up in one piece and getting it in there. I am not looking forward to it but if I have to I'll build another 1/2 for the return line. Hoping to be able to get at least get it checked between the misses birthday celebration my son's replacement cat install on Saturday and the races on Sunday.

[beestoys]

Ok just did the check and here is how it stands. I have a Walbro 255 intank pump with a racetronix power harness and relay to give the pump full system voltage.


Supply at idle 44#
Return at idle 3.5#
Vacuum line for pressure regulator pulled 50#
Return line for pressure regulator pulled 3#

Now I remember when I installed a Holley projection sytem in a Firebird anything under 5# on the return was not an issue.
Anyone have anything to the contrary from a manual or something that would say otherwise. There is going to be some return line pressure just because of the length of the return line and all.

Inputs or insights please

Note I also started a new thread along with this one for others at a later date to make it easier to find our results.