vette&fun

Hi, just installed an adjustable fuel regulator (set at 49psi). Is there a way to tell if my vette is running rich or lean, so I can adjust the fuel pressure to get the optimum performance :)? Do I need a scantool? I found one for $150. Also, if I already have a laptop, what software and tools do I need in order to scan my vette? Thanks in advance.


[Modified by vette&fun, 10:23 PM 1/14/2003]

StealDads67

What motor are you running .. LT1 or L98.... 49 seems a little high.. they say the optimum is 40psi.... You can go out and get one of those A/F gauge.. but Im kinda skeptical on how accurate these really are.....

The easiest way is to check the plugs..... Check how they are burning... If they are black and covered in sut... your running richj... If they they seem to be white that is the sign of lean.... Also if your running rich you will could be putting a cloud of black smoke out the tail pipes... But like I said.. easiest way is check the plugs

vette&fun

Thanks. I'll check the plugs tomorrow. Just one question, what if the plugs are a little "red"? Also, I forgot to mention that my car is a 93 C4.

StealDads67

if they are red... That means they are really hot and dont touch them!! haha

I honestly dont know and never heard of them being red.... hmm.. maybe someone will chime in

vette&fun

Kevin, did you install the B&M ripper by yourself? Is yes, how long did it take? About the plugs, the last time when I took them out, they were not either white or black. They are turning "red". I guessed was because of the Accel ignition booster and coil

65Z01

You should start with stock fuel pressure and then increase fuel pressure while you monitor HP, either at the 1/4mi or on a dyno.

Mike_88Z51

vette&fun,

I answered a similar thread of your in the Scan & Tune section so if you have thread response email notification you might be seeing this twice.

A scan tool will show if you are running lean or rich by displaying O2 voltages, the Integrator (INT), and the Block Learn Multiplier (BLM) values. An INT reading of 128 plus/minus 6 is the target value in Chevrolet fuel injected vehicles with 128 considered ideal in general. A value greater than 128 indicates a lean condition and less than 128 indicates a rich condition. The INT value is based upon the current O2 sensor readings which vary.

The BLM is the long term version of the INT value. It allows the ECM to compensate for rich/lean conditions over the long term including periods when the engine is not operating in closed loop.

I notice that you are located in the morally and financially bankrupt state of California. If you ever are going to be in Sacramento give me a call and I'll be glad to hook up my laptop with Ease scan tool to scan your vette. We can see what the ECM thinks is really going on.

Mike

TreyZ28

tap into the purple wire from the o2 sensor

i think .7V is good
more is rich
less is lean

i might be wrong on the voltage though

vetracer

while we are on this topic, does a "stinking" catalytic converter give any indication of rich or lean? My car's catalytic converter sometimes stinks like rotten eggs (Recently someone told me "your car just farted") It seems logical that this smell could have something to do with the A/F mixture.

TreyZ28

not sure, but i think that means either
a. your cats "broken" as in not working
b. clogged

I'm not sure about this one though so dont go around saying "treyZ28 said so"
people might take it as gospel :lolg:

I know my car smells like that

my cats in my attic :reddevil

StealDads67

Go with this guys... hes got hit it on the head.... dont waste your time splicing into the O2 line unless your throwing in a gauge, just not worth it to much of a PITA

brookman

A cat that smells like rotten eggs is bad. I don't remember the exact cause of the smell but I do remember that that used to be one of the troubleshooting things to check.

VetBoy89

Fuel additives will sometimes cause plugs to be reddish in color...
http://www.summitracing.com/tech/how...spark_plug.htm

:thumbs:

weracemo

Making a plug check is kind of hard because Idle always messes or cleans things up. Remember these cars are computer controlled. To properly do a plug check you need to heat the motor up all the way and then go beat the hell out of it and then after a long wide open throttle pass you have to shut the motor down and coast to a stop (plug chop) then check the plug. If you warm the motor up in your driveway you will definately not have an accurate reading. I would somehow put a scan tool on the car or (some say they are not accurate) get a shop with a wide band O2 sniffer. The cats will mess you up there also. The best way as people have suggested is to run the car on a dyno and try different settings and if the O2 sniffer is there you can see how she runs. A drag strip is also a good idea along with the dyno. I have worked with Dyno Jet Dyno's since before they were here for cars and now currently use a Superflow dyno. With all my years of experience and hours on the dyno trying to get the jetting on bikes (before they became fuel injected) correct, I have found that you are inside when you dyno sitting still and it just is not the same as outside where the air is cool and rushing in the front of the vehicle.
If it were my car and I was serious about getting the fuel mix right I would go to the dyno with the car already set up with the best recommended pressure and about 30 miles on it so the computer learns the new adjustment. After the dyno run I would drop the pressure about 3 psi and go out for a thirty mile drive and then dyno test it again. Then I would raise the pressure 3psi above the first try and go for thirty miles and then compare the 3 runs. That would tell me the direction to go and then I would keep testing the pressure at the drag strip to see for myself if it is better.
This can get very expensive so another option is to get some sort of scan tool that will show the O2 and and see what the motor is doing while driving it hard.

If you have a 93C4 it has a chip and mods are done by changing or flashing the chip like the bios in your computer not programming the PCM so sorry to say Lt1 edit won't work. I am not sure how much data the scan tools offer for the 93 but they have to be cheaper than the programmable computer cars.


[Modified by weracemo, 6:36 PM 1/16/2003]

Preacher

Umm..... switch it to ethanol? :jester

Sorry... I just HAD to..... :( ;)