ScanMaster Numbers

[SpoolinGN]

All these where taken as the car idled.

Fuel pressure line off- 42psi
O2s-bouncing around in the 400 range
AF-08
L8- bouncing in the 50s
Int-128
BL- goes from 137 to 150 and back.
ATS 128
RPMs- 750-875
TPS-.48
IAC-42

How do these numbers look. Could anything effect the car while at WOT? How can i fix the numbers if they aren't right?

I am new to the tuning of a GN, and i can't figure out where all the numbers should be around because i can't get a straight answer from anybody, So all the input will be greatly appreciated.

Thanks alot
Scott

 

[Mr URL]

http://www.gnttype.org/maint/quickref.html

 

[lyonsd]

Originally posted by SpoolinGN
All these where taken as the car idled.

There's not a lot you can make from the numbers at idle. You can monitor coolant temp and TPS.

O2s-bouncing around in the 400 range

Normally they'll bounce around in a lot bigger range. Like from below 100 to over 800. This is because the computer is taking the O2 reading and using it to adjust the fuel. This is called "closed loop".

At WOT, it shouldn't bounce around too much because the car goes into "open loop" and the computer uses the mass air to control the fuel. So after a WOT run you hit the recall button and that will show you the lowest O2 voltage (the leanest) that your car ran. From that reading, you adjust the fuel pressure.

I am new to the tuning of a GN, and i can't figure out where all the numbers should be around because i can't get a straight answer from anybody, So all the input will be greatly appreciated.

You need to make a few WOT runs, preferrably at the drag strip for a full 1/4-mile. Or use a straight open road with no traffice and a G-tech.

First adjust your boost to what you think your fuel can handle. 93 octane? Then set it to stock - 14psi. Hopefully you'll have an ajustable wastegate rod and an adjustable fuel pressure regulator.

Make a run. Click the recall button. That will show you the leanest your car ran and the most knock-retard you got. Hold in both buttons and it will show you at what MPH the KR occurred at.

If your O2 mv was in the 800s, drop your fuel pressure a couple psi. Repeat the test.

The instructions say "leaner is meaner", so you want to run as little fuel pressure as possible (lowest O2 mV). But if you go too low, you will get more knock and/or slow down. Typically, if your

So as your tuning, keep leaning it out until you start to slow down or get more knock-retard. Then go back to the previous setting.

If you find the point where your car is performing at it's best, you can trying upping the boost a little. If you get knock, then you can try increasing the fuel pressure. But if your car slows down you may as well go back to the previous boost and fuel pressure setting.

 

[blackbuick87]

If the car idles good, dont piss with anything. If it doesnt idle well your BLM's and IAC are a little high

 

[gnXfan]

Originally posted by blackbuick87
If the car idles good, dont piss with anything. If it doesnt idle well your BLM's and IAC are a little high

Ditto.

Do the runs and watch your knock. You may need to add some fuel and possilbly lower your iac (if your idle is poor).

 

[SpoolinGN]

The other night the car was running pretty rough, and the IAC were about 80. How can i lower them or does this mean my IAC is bad and need a new one?

Thanks for the help
Scott

 

[Fred 86 GN]

Assuming your car was in park...

AF is a measurement of air flow. The range given is 3-8. Most folks "properly" running cars are 4 or 5.

LV8 is high (should be less than 40)...this is engine load...not sure why.

BLM -- block learn modifier -- is high. 128 is average. 118-138 is OK. 150 is maxed out for most chips. Anything above 128 means the engine *thinks* it is lean and is trying to add fuel. Reasons for thinking it is lean -- vacuum leak, bad spark plug, bad injector...

ATS is intake air temperature. 128 is pretty hot. Underhood K&N filter? One degree temperature less equals about one more hp. Cold air induction is a good thing.

"Search" this board's postings for "IAC" and you will find the way to adjust it to less than 40, where it should be for good control of the idle air flow.

HTH

 

[SpoolinGN]

I set the IAC to around 20. and got the TPS to .4 Car seems alot better now, but the seems to load up on fuel at idle. Is it the chip doing it? I have the fuel set to 36 line off.


Thanks for the help
Scott

 

[Fred 86 GN]

What are your BLMs and MAF numbers. Doubt the chip is to blame...more than likely a vacuum leak.

 

[WarpSpeed]

Yeah, that MAF reading is a little high, probably not right either, and, the computer is fueling for 8g/sec, when it's probably closer to 5g/sec. That'd make it load up.
However, the LV8 is high too, maybe because the car wasn't fully warmed up?
What MAF reading do you get at WOT going through the gears?
Oh, do you have an AC Delco O2 sensor?