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View Full Version : Cant get it to Lean out (Help Please)


jallen100
10-04-2011, 03:31 PM
Ok all bare with me here because I am new to tuning LT1's and if I missed any info then tell me what you need and I will post it up.
Mods are:
95 LT1 M6
Injectors appear to be stock
I think it has a larger than stock fuel pump in it but I am not 100% sure as I have not been in the tank.
Centerforce clutch,
Ported and polished factory heads
Lunati .540 cam
Comp 1.6 rockers, double springs and push rods
Hooker long tubes, 3 inch exhaust with no cats, flowmaster muffler
MSD cap & rotor, coil and wires
CAI
4.11 gears

So we have been tuning on my 95 LT1 and it is rich and we can seem to get it to lean out.
Here are the A/F reading's that I am getting right now at WOT on the Dyno.
@3600 12.8
@4100 12.4
@4600 12.3
@5000 11.5
@6000 11.8
@6400 12.2
95ImpySS
10-04-2011, 04:01 PM
What is your fuel pressure?

Stock Displacement?

If your using C.A.T.S. to tune you need to pull some fuel out of the tables Volumetric Efficiency vs RPM vs MAP and the extended table at the corresponding MAP and RPM tables. Hope this helps.
LSWHO
10-04-2011, 05:34 PM
You have not said what you've tried.

These two tables:

%change to afr @ WOT vs coolant temp
%change to afr @ WOT vs RPM

Have you changed either of these? You can change it via these or through the MAF tables in the correct AFGS for wot/rpm.
jallen100
10-04-2011, 06:28 PM
What is your fuel pressure?

Stock Displacement?

If your using C.A.T.S. to tune you need to pull some fuel out of the tables Volumetric Efficiency vs RPM vs MAP and the extended table at the corresponding MAP and RPM tables. Hope this helps.

Using CATS, stock displacement and 45# of FP.
jallen100
10-04-2011, 06:28 PM
I am relaying all of this from the person dynoing the car. I will ask him.

He said he has tried all of the above and it is still Fat.
chile
10-04-2011, 11:00 PM
How much more leaner do you want to go. Those number seem fine to me.
Z28pr0jekt
10-05-2011, 12:11 AM
Did you check the IAC valve? (As in, unhook the valve from the TB and make sure the valve is actually working). I had a similar condition on my car where the datalog read that the IAC valve was moving however the car would continue to run rich no matter the fuel adjustments.

When I finally removed the valve I found that the spring was caked in gunk and completely stuck compressed. This caused the pcm to dump fuel.
jallen100
10-05-2011, 10:17 AM
How much more leaner do you want to go. Those number seem fine to me.

Just a tad more.
jallen100
10-05-2011, 10:20 AM
Did you check the IAC valve? (As in, unhook the valve from the TB and make sure the valve is actually working). I had a similar condition on my car where the datalog read that the IAC valve was moving however the car would continue to run rich no matter the fuel adjustments.

When I finally removed the valve I found that the spring was caked in gunk and completely stuck compressed. This caused the pcm to dump fuel.

I will check that out.
jallen100
10-06-2011, 03:03 PM
Got everything in line now. Thanks for the help everyone.
Z28pr0jekt
10-06-2011, 04:27 PM
Mind posting what the problem was?
steveh
10-09-2011, 10:34 AM
Plase post the details of how it was solved
jallen100
10-10-2011, 10:39 PM
The guy tuning it was not real specific. He just said he found something in one of the tables. I will ask him tomorrow as I did not have much time to talk with him this weekend. I was in a hurry when I picked up the car and I have been busy all weekend. I did see the A/F and he has it at 12.9 all the way across now.