What should my fuel pressure be for a 96 LT1 out of an FBody? At the test port on the rail? I'm runnign pretty lean right now. gona get a lend of a pressure gauge to check it out.. Also is there anythign else I should check out? I can get into the pcm with tunercat.

 

I believe they run at similar numbers to what TPI motors do... should be around 43psi... IIRC.

I wouldn't be as worried about what its doing at idle, but what it is doing under load. If you get on the gas and the pressure drops significantly its more than likely a pump problem.

 

should the fuel pressure remain constant throughout the throttle range / load range?

 

because of the vacuum on the regulator, when you go from part throttle to WOT, the fuel pressure should jump up some... then level off. Then it should remain constant from that point on. Sometimes you will see a slight loss of pressure when you get up in the powerband, i.e. 6000 rpm, which isn't all that uncommon.

 

anything else that could cause it to lean out?

 

Vacume leak, Bad oxygen sensor(s), Bad MAF, Bad MAT, bad CST, if its modded (more than a CAI and exhaust) the tune could be way off, but not likely.

Alot of this stuff should be pretty obvious to see if you scan it a few times, especially if you have another car to compare the readings to.

 

I lost u on this stuff, what is it?
and is there a spec on the O2 sensors? a certain voltage at certain rpm?

"Bad MAT, bad CST, if its modded (more than a CAI and exhaust"

 

The o2 should cycle back and forth from rich to lean at a semi-regular interval. A narrrowband o2 is only accurate for telling if the car is rich or lean so ECM/PCM adds fuel until the o2 shows rich, then takes it away until it reads lean. However if the tune is way off it'll pretty much stick to one side or the other. I've only looked at a few of my friends 93's but I'd assume that the newer ones have dual o2's as well. This should help you out a bit as you can tell if one bank is behaving noticeably different than the other. I think my friends had a difference in 8 or so points on his BLM's between banks, so they will be different, but they should be close.


MAT-Manifold air temp, also called IAT intake air temp

CST opps, sorry meant CTS coolant temp sensor.

if either of these is bad or unplugged they'll read -40 degrees farenheit on the scanner. Just use your head, if something looks way out of wack that may be something to look into. If you want email me a few of your scans and i'll see what i can do.

 

hooked up fuel pressure gauge..

On Start it reads 35psi
Idle 35psi
WOT 42-43psi
shutoff 30lbs but crept up to 42-43psi and stayed there for a time (came back 5hrs later and is was reading around 0psi