pwrtrip75

iTrader: (8)

This is a carry over and new problem from this thread.
https://ls1tech.com/forums/pcm-diagn...e-maf-car.html

I cannot figure out why this car will not run right. Its got a decent cam, ported heads, headers, 4500 stall.

Car starts out cruising ok, little on the rich side... floor it and it goes to 14.60:1 and falls on its face.

MAF is disabled. all the steps in the directions in the link above were followed.

Fuel pressure gauge is on the car, monitored while driving. starts out at 55psi, and under full throttle goes to 40psi and stays there.

I added 1.25 to the primary VE table to see what it would do and car runs exact same way, same numbers. Its like it has no affect. Injectors are stock and says they are running at 72% at 5000 RPMs at 14.6:1 A/F.

Switched it back to run on MAF, goes to about 15.3:1 even leaner.

This thing has been a nightmare. Anyone care to help out I have the last scan file and the .BIN file I can email you.

I even started over from scratch w/ the stock tune again.... still no luck.

Thanks.

69LT1Bird

iTrader: (1)

First question, what kind of fuel pressure regulator?

2xLS1

iTrader: (25)

Fix that.

69LT1Bird

iTrader: (1)

Pressure should be 58 psi at the rail. If it drops, it may go down to 56 psi on a stock type system.

joecar

Sounds like you have a problem with the fuel pump and/or FPR... [...oh, those guys beat me, they type fast...]

The other problem is that the stoich AFR of E85 (according to your sig) is way different than gasoline, it's something like 9.8... you have to take this into account in your tune and from your wideband (set stoich value to this, and use wideband lambda instead of AFR)...

also with E85 take note of injector duty cycle, you may be running out of injector.

pwrtrip75

iTrader: (8)

stock regulator. I figured if it stayed at 40 adding more fuel would show something??
Hmm. Thanks,.

edwardzracing

iTrader: (59)

Unfortunately if the pump is failing or there is a restriction somewhere... telling the computer to add more fuel isn't going to make the restriction disappear. If you determine it is the pump, I highly recommend doing the trap door method rather than dropping the tank (assuming this is an F-Body). Whatever the case, good luck and keep us posted on what you find... always nice when a troubleshooting thread has a happy ending and the original poster lets everyone know what the happy ending was.

pwrtrip75

iTrader: (8)

The car already has a walbro 255 in it, hole is already there in the trunk. We'll try putting the stock pump out of my other car in to see what it does tomorrow.


Another issue the car always has had.... you cant put gas in it fast. It shoots back out the filler neck. The door inside the tank has been removed and it still does it...???

BLK02WS6

iTrader: (2)

You definitely have a fuel issue...

pwrtrip75

iTrader: (8)

Any ideas why the car wont take gas easily? Tank vent? All emissions are ripped off the car, canister in front...etc.

89 formula350

iTrader: (8)

usually its the evap vent, seen a few cars with a clogged vent hose too

Old Geezer

iTrader: (3)

If the tank has a blocked off cannister line, you have no vent. Is this the case?
If there's no vent, then the psi drop can be the direct result of pulling a vacuum on the tank, causing pump cavitation. If this is the case.. kiss that pump goodbye...

joecar

+1... purge and vent were probably capped off when evap was deleted.

pwrtrip75

iTrader: (8)

The lines are not capped off. Ive tripple checked. Tank has even been out of the car trying to figure this out. I made a run and then took the gas cap off while it was running hoping to hear a pressure difference... nothing.

It could be blocked though, obstuction somewhere. Sounds logical. thanks.

pwrtrip75

iTrader: (8)

there are only 2 lines coming from the tank to the front of the car. one is the fuel line and the other is wide open... I can blow through it into the tank.

pwrtrip75

iTrader: (8)

That is a different car, the car im working on is n/a gasoline.

pwrtrip75

iTrader: (8)

At 40psi shouldnt this be enough to run it? And wouldnt adding 10% to the entire VE table make a difference??? I would think you'd see some increase.
This is the pump in the car.

GSS 340 (high pressure 255):

244 lph @ 40 psi
217 lph @ 60 psi

69LT1Bird

iTrader: (1)

No
No
No
...and fix the fuel pressure problem.

89 formula350

iTrader: (8)

well two things.. #1 you have a fuel tank psi sensor there still right? you can watch that still unless you removed those wires.

2nd its the volume of fuel not so much the psi... the old TBI trucks would and still do get people with this.


also was this car originally a v6 or ls1?

pwrtrip75

iTrader: (8)

its a 97 original V6 car. But EVERYTHING from a 99 formula went into it....everything. There isnt a 97 nut or bolt left on the car.

Yes the pressure sensor is still there.

I hear you on volume.... if the volume at 40psi was decreasing you'd see the pressure drop... it dont... as soon as you floor it it stays steady at 40psi.

We put another pump in it tonight (original one out of my 99 TA that I know worked) and it wouldnt make 5 psi.... weird.

Anyway... tomorrow if weather permits its getting hotwired w/ a relay and the walbro put back in. There is 13.6 volts there... but I have no way of putting a load on it and testing it at what the pump would draw.. That pump is supposed to be about 7-9 amps... maybe i'll rig something up that draws that and test it and see what the voltage drop is. Also have a different regulator to swap.... other than that ???? Maybe throw a match in the gas tank