demonpixel

iTrader: (19)

I have a stock LS1 in my 72 Formula with a carbureted intake manifold. On top of this I have a self-tuning EFI system (The Powerjection I, formerly called the BossEFI system by Retrotekspeed).

It's running pretty good, but I think it's a little rich. The file that I'm using for the system is for a stock chevy 350, and I've confirmed with Retrotekspeed that if I used this file for an LS1, it would indeed run a little rich.

The way a consumer would tune one of these systems is to type in your Target AFR in the Target AFR table (via a laptop), and the efi system will change the VE tables to try and match your Target AFR.

So when I go to tune it today, my plan was to try to lean this out a little based off of what I've read. But since I've never done this before, I'd feel more comfortable if someone could verify that this will work ok with a stock LS1:

• IDLE: set target AFR to 14.7:1 (stoich)
• CRUISE: set target AFR to 16.0:1, lean, economy, part throttle
• WOT: set target AFR to 12.2:1, safe best power, wide open throttle

I'll try to take a screenshot of the software and post it, so you guys can see what the interface of the software looks like (it has gauges in the interface, you'll see water temp, vacuum, rpm, air/fuel, and fuel pressure, as well as the Target AFR table).

So is my "tuning plan" sound? Thanks again for any help/advice

demonpixel

iTrader: (19)

Here are some screenshots.

This one is the base file, before I changed anything:


This is what I changed it to (tried to lean it across the board some):


And this is a screenshot of the VE table when I was sitting at a light, after I put in the new Target AFR numbers:


What's strange is that the A/F gauge on the software stayed at 20 no matter what I did to the AFR tables.

Car seemed to run alright still though; more responsive from part throttle to WOT than before.

I'm not fully understanding the numbers in the VE table though. Anyone know what those numbers mean? I'm assuming this stands for Volumetric Efficiency but does that mean my engine is 39.4% efficient when I'm at idle according to the table?

demonpixel

iTrader: (19)

OK, there is a wideband controller for the O2 sensor, and one of the plugs was disconnected on the back of it. So now the A/F gauge is working just fine, and the car drives great!

EXCEPT....For some reason, I can only drive it about 20-30 minutes before the fuel pump cuts out. I'm wondering if the fuel pump is overheating. It's an external pump, and it's about 4 inches away from a 3 inch exhaust pipe.

Old Geezer

iTrader: (3)

Tank vented?

demonpixel

iTrader: (19)

Yep, the tank is vented.

I put my hand on the pump and it's really warm after the car shuts off. There is no heat shield between the exhaust pipe and the pump. When I let the car cool, the car runs fine, for about 20 minutes. Then it shuts off again So those are other reasons why I think the pump is overheating.

The pump should feel cool to the touch.

demonpixel

iTrader: (19)

Ok, apparently the tank was vented, but not vented enough. I had a 1/4" hose going to exposed air as my vent line.

Once I ran a second vent line which is 3/8", the car ran for over half an hour without the fuel pump whining.