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Trying to learn and trying to reduce hardware, I disabled the fuel management system and removed the T-Rex booster pump. I need some help on tweecering in my A/F ratio.

I have a Summit MAF meter that does NOT have calibration documentation. I was told to multiply stock times 1.579 to get the base curve, so I moved the stock MAF transfer curve in the right direction with the Tweecer by 57.9 percent.

I set the injectors to match my 30 lb injectors. It is too rich and at 5300 RPM goes into "limp home".

I get:
2500 9.6
3000 9.1
3500 9.3
4000 9.4
4500 9.0
5000 9.0
5300 9.2
Shut off into limp home.

When I use the stock EEC IV A9L settings for everything, including 19 lb injectors and factory MAF transfer curve (this is still with 30 lb injectors and Summit MAF calibrated for 30 lb injectors), I get:

3000 10
3500 10
4000 10
4500 9.0
5000 9.0
5500 11
6000 12.5
6500 12

It seems no matter what I do nothing works better than stock, although loading a 2003 Lightning MAF curve and using the 30 lb injector settings starts to work. It pulls to 6500 RPM without going into limp home with A/F between 8 at low RPM end and 13 at 6500 RPM. I get about .15 or more G force better with the stock EEC settings!!

Can someone spend a little time helping me with this so I can learn what normal behavior is? I have this going on plus a little other odd behavior. I did better with the FMU in line and larger injector size dialed in.

Tom
 

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When I use the stock EEC IV A9L settings for everything, including 19 lb injectors and factory MAF transfer curve (this is still with 30 lb injectors and Summit MAF calibrated for 30 lb injectors), I get:
This isn't something you want to do...
What you need to do is start with the RIGHT injector settings, and a MAF Transfer that will get the car to run.
If the car runs rich, then lean out the MAF Transfer.

Because you don't have a Transfer you can download, you will have to create it yourself.
Not a big deal...


What Editor are you using?
Can you datalog?
What about the rest of the engine setup? Boost?


I'll help as best I can, but it's been a while...
jason
 

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Discussion Starter #3
Jason,

Thanks for the reply!!! I'll try not to consume your time but I'm stuck.

This isn't something you want to do...
What you need to do is start with the RIGHT injector settings, and a MAF Transfer that will get the car to run.
If the car runs rich, then lean out the MAF Transfer.

Because you don't have a Transfer you can download, you will have to create it yourself.
Not a big deal...
Here is where I am at now. I had this all working with a fuel regulator but I'm trying to trim in the system.

If I use the 30 lb calibrated MAF with my stock 19 lb injector settings and stock MAF transfer curves, I run richer than I want (A/F around 10) at low RPM climbing to 12 or so at full RPM.

3000 10
3500 10
4000 10
4500 9.0
5000 9.0
5500 11
6000 12.5
6500 12

The problem is idle quality plus the timing isn't quite right because the computer thinks it has 19lb injectors and is flowing a lot less air than it really is....but it works. I'm making about 450-500 RWHP or so according to my estimates using weight and acceleration.

The problem comes in when I change to 30lb injectors and recalibrate the MAF transfer by adding 57.9% to the air in the transfer. As I understand this the 30 lb injector makes it (30/19) * 100 = 158% of original air, or I adjust MAF transfer richer by 58%.

In theory the injectors got leaner (with no changes) because the computer now knows they are bigger by 158%, so I adjust the MAF transfer to compensate for the calibration change when it was calibrated to make it indicate the true air flow. This pulls it back rich by the same amount the injector size change in the computer made it leaner.


This seems to work because idle quality is greatly improved and the mixture is only a tad richer at lower RPM except I get a total shut off at 5300 RPM for some odd reason and the EEC goes into limp home mode.

Does the EEC shut off when injector duty called for is past 100% of the allowable time?

Do I need to run my laptop and do a pull and record the eec data?

What Editor are you using?
caledit v1.30 from tweecer.

Can you datalog?
Now that's a good question. I have the Tweecer RT which I think should datalog and a laptop but I don't know how to data log yet. I assume I have to run my laptop in the car to log?? I've read dozens of pages on the tweecer and hundreds on the EEC IV system but have not gotten up to the data logging stuff yet.

What about the rest of the engine setup? Boost?
It's a 302 engine. TFS heads and intake, headers, F cam, 8 lbs or so of boost. No intercooler. Good fuel pump and pressure. Still has A/C and all the luxuries but went almost 120 in the 1/4 mile and that was into fuel cutoff at 7000 RPM maybe 100 ft or so before I hit the lights, so power is very good with the stock program even if it is rich.

I'm monitoring A/F with a LM-2 that logs acceleration (I have a old aerospace accelerometer from a past project) and RPM when the LM-2 does not crash. :)

Tom
 

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Jason is good with the tuning also, he is another guy I forgot to mention earlier.
 

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Use the 30Lb injector Slopes in CalEdit.
Then change the MAF Transfer to get the AFR you want.

Think of 57% as a starting point.... you will have to make changes to that.
Lean it out until you get where you want to be.

Look into 'load scaling' to account for the boost increasing you VE. This is something I won't be much help with though...
EECTuning.org is a great resource. Run a search there using 'load scaling' and you will get some very good information.
 

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Discussion Starter #6
Look into 'load scaling' to account for the boost increasing you VE. This is something I won't be much help with though...
EECTuning.org is a great resource. Run a search there using 'load scaling' and you will get some very good information.

Thanks!!


This is where I think things are going bad and the computer is shutting off. I probably need to use some load scaling because with the blower it looks like VE is going through the roof. Maybe with the computer thinking the MAF volume is smaller the VE doesn't look like it is off scale.

I read the tweecer manual further and I can log multiple parameters with the laptop connected to the Tweecer so hopefully I will see what is happening at flame out.

I'll check the other forums for archived messages that may apply.

Tom
 

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Joe, you're too kind... really, I'm just making it up as I go :laugh:

I read the tweecer manual further and I can log multiple parameters with the laptop connected to the Tweecer so hopefully I will see what is happening at flame out.
Tom,
When you hit eectuning you are going to see tons of recommendations to use a software called BinaryEditor (BE for short).

BE is about 50000000000002% better than CalEdit, which is kinda buggy..... at least the time I used it.........
 
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