I am failry new to using Tuner from CATS and was wondering if someone could tell me about Injector Flow Rate Settings in the Constant table. I am currently set at 25.38 with 32 pound injectors. This was a mail order tune and am now tweaking it in, or at least trying to understand things a bit better.

 

Are you saying it was tuned with smaller injectors, and now you want to go up to 32's? Or are you saying it was tuned for 32# injectors, but for some reason has the constant set at 25.38?

In any case, you want a constant closer to 32, with corrections made for your actual fuel pressure setting, vs. the pressure at which the injectors were flow rated. You will also need to revise the "offsets" for the specific brand/size injector you are using.

Or did I miss the point of your question?

 

Right on the point. I had a tune done for the 32's and other mods and that is the current setting. The tuner might not think i would / could look but I want to make the tweak settings myself based on a couple other things that were "missed". I recently got Tuner from CATS and it seems pretty easy to use I just dont know what everything means. Already changed the idle as the tuner had it at 800 at the higher temps the lower temps was 900 with my cam, once it warmed up the idle was sh** so i bought Tuner to correct. Thanks for the attention. So you thinking i should be set like at 30 +? I am a noob so advice is appreciated.

 

The injector constant field should contain the flow rating of the injectors, based on their size and the pressure your fuel system operates at. I do not know the specifics of TunerCat displays or inputs, but I know the stock program uses a value of 24.896 #/HR (3.14 grams/sec) for the stock "24#" injectors. That's why it seems odd that someone set yours at 25.38 for a 32# injector.

What do the long term fuel corrections (BLM's) look like? With that injector constant, you should see them bottomed out at 108, and it should be running pig rich.

It just seems confusing, or maybe its some feature of TunerCat that I'm not familiar with.

One intersting possibility.... someone tuned your PCM for 24# SVO injectors, which will flow 25.30 #/HR when operated at 43.5psi.

 

Thanks for the pointed responce. Again i am a bit green with PCM tuning and i can do a log and check the BLM's. I have both DataMaster (full version) and FreeScan. I will take a look and again thank you for the attention. What should the BLM's look like number wise?

 

Injuneer;
I did a befor and after on BLM the before with the small setting was 118. The after was 136. Mind you the 118 Tune had about 500 miles on it and the 136 hads only about 20. I will try to drive it a bit more tomorrow and see what happens. I can send you the FreeScan screen shots if you like. OR can i post pictures here?
Thanks again BTW i Programmed to 30.03. Baby steps you know the deal! If the BLMs look better i will go to the full 32 next.

 

I can review you data log files. If you use DataMaster, you have to do the "export as .csv" so that I can open the file with Excel. If you don't do the .csv file, DataMaster is a .uni file, and I can't open it because I don't have DataMaster.

I don't know is this will help, but you might want to look over the "Air/Fuel Management" section in my online scanner writeup. That will explain how the long term fuel correction (BLM) cells are set up. You will need to get Bank 1 and Bank 2 BLM's for as many of those 18 cells as possible.

http://members.aol.com/InjuneerZZ/ScanMast.htm

 

Would a .csv file from Freescan be ok? Thanks again

 

Injuneer, what would be a good amount of time / miles for the blm's to be stable?

 

Injuneer, I got about 120 miles on the tune and logged a small .csv file for you. BLM's are in the 140 range. If bigger number is better looks like it is much improved. Let me know where i can send you the .csv
Thanks again

 

A .csv from FreeScan is fine. E-mal address in in my posts. Please identify the attachment in the e-mail subject, and include your screen name.... I really don't like to open attachments.

The PCM learns very quickly. But it only learns if you operate the engine in a wide variety of combinations of RPM and MAP, so as to stabilize as many of the cells as possible. I would think that driving it for a few hours would be more than enough.

You don't want a "bigger number" for the BLM's. You wnt them as close to 128 as possible. Maybe even slightly under 128. The BLM stands for Block Learn Multiplier. It is a term in the calculation of the required fuel mass that is BLM / 128. If your BLM is 128, you multiplier is 1.00 which means all the data and tables in the program are producing the correct fuel mass calculation. If the BLM deviates from 128, it means the data or the tables in the PCM is not correct.

Your results seem to indicate that you do not have as large an injector as youy think you have. When you tell it you have a large injector, it reduces the pulse width, compared to the smaller flow constant. But the reduced pulse width is producing low voltage (lean) reading on the O2 sensors, and starts increasing the multiplier to get more fuel.

Have you verified that your injectors are really 32#/HR? It sounds like they are more like 28#/HR. If they are really 32's, then the fuel pressure would be too low.... maybe only 34psi instead of the "normal" 43.5psi.

 

Injuneer, Definately 32's bought and installed them myself. BTW i am a bit green to this whole deal so my readings i was talking at idle. I will make a 10 mile or so data log run with all throttle positions. In any case the larger injector setting seems to help the car run better and sound better at idle.