LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Cant get it to Lean out (Help Please)

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Old 10-04-2011, 03:33 PM
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Default Cant get it to Lean out (Help Please)

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

Car made 384 rwhp @6400 on a mustang dyno as it is right now.
Old 10-04-2011, 05:34 PM
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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.
Old 10-04-2011, 05:47 PM
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At those Reno numbers the stock injectors would not be enough to keep up with fuel needs. Might be your problem
Old 10-04-2011, 06:27 PM
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Originally Posted by 96TransAmboosted
At those Reno numbers the stock injectors would not be enough to keep up with fuel needs. Might be your problem
That would make it fat?
Old 10-04-2011, 06:59 PM
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Originally Posted by jallen100
That would make it fat?
Don't see any new info on what you've tried to do so far. If you actually want help, at least try to provide the necessary info for others TO help.
Old 10-04-2011, 07:50 PM
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Originally Posted by LSWHO
Don't see any new info on what you've tried to do so far. If you actually want help, at least try to provide the necessary info for others TO help.
Sorry I responded to you on the other forum.

Using CATS, stock displacement and 45# of FP.

My tuner said he has tried both
Old 10-05-2011, 02:59 AM
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Your tuner needs to zero the % change to WOT vs RPM table, and use the % change to WOT vs coolant temp to set the base AFR.

In my experience the % change vs RPM table responds very slowly to changes.

Zero out the RPM table completely and make a pull, then start dialing the AFR in on the % change to coolant temp.

Your tuner realizes that he has to FLASH the calibration that he is changing right? Lol

If that for some reason does not work, or you have having to go to some huge wacky values, the injector flow rate value is probably off.

If you start manipulating the IFR value there WILL be a change in AFR.
Old 10-05-2011, 09:05 AM
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Your FP is high it should be 43.5. Also if the stock injectors are in the car I don't see you achieving those rwhp numbers. And if so then there duty cycle must be maxed out and could be dumping to much fuel. But I doubt it. If they were the stockers you would be running out of fuel.
Old 10-05-2011, 10:26 AM
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Originally Posted by 96TransAmboosted
Your FP is high it should be 43.5. Also if the stock injectors are in the car I don't see you achieving those rwhp numbers. And if so then there duty cycle must be maxed out and could be dumping to much fuel. But I doubt it. If they were the stockers you would be running out of fuel.
Stock LT1s show 45 to 47 psi @ WOT on my fuel pressure gauges. Not 43.5.

And, no damn way the P.E. Vs RPM table should be zeroed out. Something else is wrong.
Old 10-05-2011, 10:27 AM
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Originally Posted by gregrob
Your tuner needs to zero the % change to WOT vs RPM table, and use the % change to WOT vs coolant temp to set the base AFR.

In my experience the % change vs RPM table responds very slowly to changes.

Zero out the RPM table completely and make a pull, then start dialing the AFR in on the % change to coolant temp.

Your tuner realizes that he has to FLASH the calibration that he is changing right? Lol

If that for some reason does not work, or you have having to go to some huge wacky values, the injector flow rate value is probably off.

If you start manipulating the IFR value there WILL be a change in AFR.

I will ask him about this and see how he was going about it.

Originally Posted by 96TransAmboosted
Your FP is high it should be 43.5. Also if the stock injectors are in the car I don't see you achieving those rwhp numbers. And if so then there duty cycle must be maxed out and could be dumping to much fuel. But I doubt it. If they were the stockers you would be running out of fuel.
I am assuming they are stock injectors as they do not look aftermarket. Unfortunately I bought this car from someone who did not knpow a whole lot about the mods on the car. I am gonna have my guy dig in to it a little deeper. I can tell you that the rwhp was still going up when we shut it down on the dyno at 6400 rpm so it doesnt appear to be running out of fuel.
Old 10-05-2011, 10:45 AM
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Originally Posted by gregrob
Your tuner needs to zero the % change to WOT vs RPM table, and use the % change to WOT vs coolant temp to set the base AFR.

In my experience the % change vs RPM table responds very slowly to changes.

Zero out the RPM table completely and make a pull, then start dialing the AFR in on the % change to coolant temp.

Your tuner realizes that he has to FLASH the calibration that he is changing right? Lol

If that for some reason does not work, or you have having to go to some huge wacky values, the injector flow rate value is probably off.

If you start manipulating the IFR value there WILL be a change in AFR.
I just talked to him and he said this is how he has been tuning it. He said that he got the A/F numbers above by doing this. It was a lot richer before these numbers. He said that where the A/F dips and gets fatter, that he made some changes and it did not improve the numbers. He said he wants to see 12.9 all the way across and more consistant since we are planning on spraying it.
Old 10-05-2011, 11:32 AM
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What MAF is on the car?
Old 10-05-2011, 12:17 PM
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I ment to put 45.5 for FP. And I just dont see how the stock injectors would ever active over 350 rwhp. Im sure there aftermarket of some type.
Old 10-05-2011, 12:20 PM
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Originally Posted by 96TransAmboosted
Your FP is high it should be 43.5. Also if the stock injectors are in the car I don't see you achieving those rwhp numbers. And if so then there duty cycle must be maxed out and could be dumping to much fuel. But I doubt it. If they were the stockers you would be running out of fuel.
So your saying the stock injectors can't supply enough fuel so they are making the car run excessively rich?
Old 10-05-2011, 12:38 PM
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Are the BLMs locked? It could cause screwy AFR if not.
Old 10-05-2011, 02:06 PM
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Are you paying this guy to tune your car? I would run the other way if he can't figure out how to lean out the A:F and claims to be a professional.
Old 10-05-2011, 03:23 PM
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If the part throttle was tuned properly first, like it should be, blocking the BLMs won't make any difference. Any decent scan tool will show positive fuel trims in P.E., so that problem would be obvious.
Old 10-05-2011, 04:00 PM
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Originally Posted by Ed Wright
If the part throttle was tuned properly first, like it should be, blocking the BLMs won't make any difference. Any decent scan tool will show positive fuel trims in P.E., so that problem would be obvious.
Dude's getting a dyno tune. Don't know too many people that do partial throttle tuning on the dyno. Clearly not self tuned, so locking BLMs WILL make a difference here.
Old 10-05-2011, 04:28 PM
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Part throttle tuning IS part of decent, correctly done, dyno tune. Anybody that actually knows how to use a dyno can do the part throttle tuning right there on the dyno. Many don't buy the variable load add-on for Dynojets, but the brake can be used to get them close enough the fuel trims won't cause P.E. Fueling problems. Used to do it every day.
Old 10-05-2011, 04:32 PM
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Originally Posted by Ed Wright
Part throttle tuning IS part of decent, correctly done, dyno tune. Anybody that actually knows how to use a dyno can do the part throttle tuning right there on the dyno. Nagy don't buy the variable load add-on for Dynojets, but the brake can be used to get them close enough the fuel trims won't cause P.E. Fueling problems. Used to do it every day.
Ed, we are talking about a correctly done dyno tune, when clearly the OP isn't getting one. Yes, locking BLMs shouldn't need to be done on a proper dyno tune, but a proper dyno tune would also not have an issue altering AFR. You dig?


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