2cub49

My car used to be a stock 350 with cam headers and the Powerdyne blower and 30lb injectors.
The Madtuner tune worked great.
When I wore out the 350 I replaced it with a Golen 383 with 48lb injectors and a new fuel pump as my pressure was dropping to 20 psi in the higher rpms.
However since putting in the 383 the car runs very rich and I have had to up the injector size setting in LT1 Edit to 64lb instead of the 42lb injectors I'm now running and cut the amount of fuel up to 1600 rpm.

My fuel pressure reads 47lb at idle.
I was wondering if anybody had any ideas as to what could be causing this issue.
I spoke with Ion and he said the tune should work fine.
Also now when the car goes into boost it pings between 3 and 4k rpm with as little as 2 lbs of boost and adjusting the advance or the a/f has no effect.
I suspect this is related to the mystery richness issue and having to fool the pcm.
Otherise it runs good.

mrmint69

Why are you not running stock fuel pressure? You are over complicating your fuel system.

2cub49

The fuel pressure is what it is.
It ran rich after the 383 instal right off the bat before I put in the high volume 255l fuel pump.
There is no why I'm not running the stock pressure as I didn't do anything to make it 47.
I thought the stock pressure was 43psi so 47 shouldn't cause it to be 50% higher in richness.
So what is wrong and how do I make it run the stock pressure?
That is what I need to know.

96capricemgr

well with boost you should have a boost referenced regulator. Far as high idle fuel pressure first thing I would check would be disconnected or damaged vacuum line to the regulator. If it is connected it could still be kinked or the like.

The job of the regulator is to keep fuel pressure constant as compared to manifold pressure. Since at idle the manifold is under vacuum we see this as lower fuel pressure because a fuel pressure gauge is referencing from atmospheric pressure not manifold vacuum.

If you have a regulator that can not accommodate positive manifold pressure and reads say 45psi engine off or with vacuum disconnected and continues to only deliver 45psi as boost rises then the manifold pressure can begin to offset the fuel pressure effectively lowering it and at 5psi boost the fuel pressure to manifold pressure difference would only be 40psi effectively lowering fuel pressure even though a gauge might still read 45psi.

Another thought is where did you get the injectors? Is it possible they are just not the size you thought they were? Or that they were 48lbs for an application with drastically different fuel pressure than what you are running?

2cub49

I'll check the regulator.
I have some new blue silicone vaccuum lines to put on tomorrow.
So if the regulator vaccuum line is not there or plugged or disabled the regulator would think it's at WOT is what you are saying?

I believe both the 48s and the 42s I'm now running are Racetronix the 48s came from Jegs and the 42s used from a member on the board here.
Both sets ran rich at the correct size setting in LT1 Edit.

I have a Procharger I want to put on over the winter and want to get this figured out now with the Powerdyne that maxes out at 4.5 psi

96capricemgr

Yes if the vacuum line was disconnected or damaged the regulator would leave fuel pressure at the naturally aspirated(no boost). WOT level all the time

mrmint69

Are you running stock or aftermarket FPR?

2cub49

the problem is the car runs rich all the time and what it does at boost is not the issue.
By this you seem to imply that no vaccuum wouldn"t cause an issue unless it was under boost.
If it's feeding fuel like it thinks the car is at WOT instead of idle then that could possibly be causing the richness problem.
Well thanks I have something to go on.

2cub49

I'm sure it's a stock regulator as we didn't upgrade when the 383 was put in.

mrmint69

https://www.camaroz28.com/forums/fue...or-bad-830413/

Good reading on the regulator. Unless you have to much fuel pressure from the pump that the return line can't handle, this testing will help isolate it.

Powerdyne units can have the pully changed to make more boost. Also if you have little restrictions like long tube headers, you will see less boost on the gauge. I went from 5.5 to 6 psi with stock exhaust to 4.5 max with aftermarket headers and a cutout.

96capricemgr

I was saying that with no vacuum line it would go to NA WOT pressure simply because for it to go above that it would need a boost reference. With the right regulator fuel pressure will climb with boost.

I think lack of vacuum reference could be a contributing issue here.

2cub49

I already have the 2.70" Powerdyne 9lb pulley that gave me 6 psi on the 350 and 4.5 psi now that it's 383 cu in.
I want to run 8 psi intercooled with the Procharger I bought off a member here using a 4.25" pulley.
Right now it has a 3.75" or so 12-14 psi pulley which is too much (for now! going from 4.5) especially with the M6 and 10 bolt rear end.

I'll check out the regulator and return line as a start.

mrmint69

There is a pic on the link for a stock fpr. I would verify that since so many aftermarket ones have problems. I would fix your fuel pressure problem and run the motor as little as possible, until you have all the bugs worked out. There is a part number on the injectors that will verify if they are correct for your application. I have seen so many try to play around with there injector settings and end up making the problem worse. Make it as simple as possible. Your setup isn't that much different and you should not be having these problems if everything is working correctly. You want stock fuel pressure and then worry about the injectors being rich after.

2cub49

Thanks for the link with the pic.
The fpr looks easy to get to which is rare on our FBody LT1s.
I had a bigger problem for the last 2 years that I finally fixed.
The cam pin was the same exact length as the hole in the opti (but that was too long) on the engine Golen sent me and the unbalancing slight pressure was causing the opti to grind up and fail after a month or less.
The AC Delco rotor would break up and fail completely and the car would die while the MSD would fill up with shavings and the car would backfire under load or in the higher rpms.
At least the MSD allowed me to drive it to my lift.
I mounted the last opti on penny thickness washers which didn't compromise the oil seal.
Now that this not supposed to happen unfortunate problem with all the fun of changing optis and caps and rotors several times is fixed I can sort out this richness issue.
I've had it dynoed twice and put maybe 3000 miles on it in 2 years and the plugs look good, the car runs pretty good now as it is with my work arounds but I want to put the Procharger on and the slight pinging under certain circumstances at 2 lbs between 3-4k in 4th and 5th compels me to fix this.
Without the blower I would probably just leave it as it zips right up to 6000 rpm without pinging at WOT.

mrmint69

How are you checking to see if its running rich? Have you checked the fpr yet. Super easy and important next step.