ok what can make the lt1 run rich...i know egr and o2 can do it....my ses never stays on long enough to store a code, i've had it checked and nothing is stored...wot it runs great but in slow traffic it acelerates funny, almost like detonation...can a bad fuel pressure regulator cause it to run rich?....i've replaced my tps and pulled my 160 and put the 180 back in..and seems a lil better but i still get what i think is a high idle..almost exactlly 1k

 

Huh? You say you are running rich but you ciomputer never stores codes: how do you know? Are you fouling plugs? (then why isn't the computer storing codes?). Did you remove the o2 sensors and install dummies?: it should still figure it out and store a code. If you fule injuectors are old, dirty, or just broken, that could cause it, and I've had three go bad in five years with two cars, so it does happen.

Anyway, what makes you suspect the fuel pressure? You can dfoes not sound like it has enough mods to have run into problems there. Could be some defect but . . .

the problems in traffic sound like: a) running lean, b) less low end torque (barely possible due to your headers and no cats, but not likely to be the cause).

Frankly it sounds to me like you having something common to many cars tuned by owners with Hypertech or other tuners or computer backpack type kits and adjusters, WOT works okay but intermediate trhottle positions don't. I suggest you take the car to a really good shop with LLS1edit and let them look it over.

 

If you think the car is running rich, and you already checked out the O2 sensors, check the fuel pressure at the FI rail and verify that the pressure regulator is doing its thing. The O2 sensors will compensate for bad fuel pressure, but only up to a point and then the engine will run either rich or lean. The test port is accesible at the rear of the engine under the cowling. Make sure you have a FI test gauge as you don't want fuel spraying around and burn the car down.

The fuel pressure should be 41=47 PSI with the ignition key on, and the engine NOT running. With the engine running the pressure should drop 3-10 PSI, indicating the pressure regulator is working. If the pressure does not drop, disconnect the vacuum hose to the regulator and apply 12-14 in of vacuum to the regulator using a hand pump. Check pressure with engine running & see if it as dropped as required. If still NG the regulator is bad. if pressure is OK, then there is a vacuum leak that needs to be addressed.

The EGR may be sticking or clogged, give it a good cleaning, including the passages. The Engine temp sensor also affects mixture, causing a rich mixture if it gives a false low temp indication. The MAP sensor can affect the A/F ratio also, but usually it goes bad enough that the engine just won't run.

You really need a scan tool and drive around with it plugged in, and see what code is present at the time the SES lite goes on. This will give you a good starting point.

 

i'm thinking that the richness may have been caused by the opti goinng bad and throwing off my timing and a bad iat sensor...once i get the new opti put in, i'll do the fuel pressure tests and see where i stand....and dude thanks a lot for the puel pressure #'s it's going to save me some hunting, apreciate all your help....

 

Good idea, if there are misfires the O2 sensors will definetily see a rich mixture due to all the unbuned fuel in the exhaust.