So since my MAF was never scaled properly, I put in my stock injectors, changed my injector scaling numbers back to stock, did some logging and used a tool I found in another thread to scale my MAF. Once my fuel trims were close to 0 I figured that should mean my MAF is properly scaled. Well, now when I do some WOT pulls and log my AFR it is all over the place. Starts out lean, then goes really rich, then goes lean again. I have had to adjust my Fuel maps accordingly, and they look pretty crazy now. Can anyone tell me why this would be happening? I attached a log an my current tune.

 

Unless you also dial in your map table your a/f will never match what your requesting I had 9's in some spots to hit an 11.5 a/f even now with a lot of work on my map table I'm still close to a full point off

 

Some people will use the fuel cal table to help dial the fuel in

 

Replaced that ol' fuel pump full voltage relay?

Rich

 

They shouldn't be matching anyways. Those values do not reflect targeted AFRs. If you must, think of the units in the Fuel Map as different units of measurements.
You can calculate the differences between your actual and value you have in your fuel map, THEN use an equation to input the targeted values to acquire your desired AFR.

All calculations must take the current load/boost into affect as well, not just the raw value to compare.

 

While adjusting my map table I was able to get the values to be a lot closer (+- 1 af point)

But then I ran in to other problems lol this was with. The fuel cal table set to 100 and maf scaled appropriately

 

A picture is worth a thousand words. Here's his graph...



Fuel map...





Rich

 

So to answer a few questions, yes I have replaced the fuel pump relay, and I have tried modifying my MAP tables. I read on another thread that if you data log and then try to match the values in your MAP tables to what your actual load is it will bring you closer to getting your AFR's in your maps to match your actual. Well, since my actual load values were higher then what was in the MAP tables, I had to increase all the load values accordingly. When I did this, my actual load values ended up just increasing. For example, at 4000 rpm and 15.73 psi the original setting in the MAP table is 187.8. But when I datalog, my actual load is around 191. So, I change the MAP table to mach my actual by setting it to 191. The next time I log my actual load jumps even higher to lets say195. So maybe I am not understanding the correct way to adjust my MAP table. Maybe someone could enlighten me.

 

Are logging MAFcalcs and MAPcalcs? or just load?

 

Just load, but I can log MAF and MAPcalcs. What would I be trying to do by logging them? Am I trying to get them to look the same?

 

Use RAX Fast Logging. That's got it all set up for you.

You're simply trying to get MAPCalcs and MAFCalcs closer together. On mine, at WOT, MAPCalcs gets used during spool-up. Once boost peaks, MAFCalcs is a hair lower, so MAFCalcs gets used until redline.

Rich

 

How do you get them closer together? For example, if MAF logs lower the MAP, do you lower the number in the MAP table? If so, by how much?

 

Yep, if MAPCalcs is higher, lower that region of the 3 x MAP tables. Smooth it out. Be gentle.

I just made fairly minor changes at a time, logged, reviewed, repeated.

I wasn't all obsessive about getting it exact. I'll watch the logs for a while, let some different atmospherics come and go, then fine-tune some more.


Also, in the past, I "smoothed out" those peaks and troughs in the 3 x MAP tables. After working in this area some more, though, I'd actually recommend against a mass flattening. It's pretty apparent that some areas of the engine's operation really do bump and dip when it comes to MAP... if you watch MAP really closely.

Like, on mine, there's a definite transient rise in airflow at 4000rpm, right from load 140 up to my 230 max. I can see a MAFCalcs "bump"... and in the factory MAPCalcs there was a ridge built in at 4000rpm too. So I preserved it. If you're paying attention to AFRMAP and wideband at that point, you can see the fuelling calc likes to have the bump preserved (if your load is tracking MAPCalcs at that point).

Yes, if you stare at this stuff for long enough, you do go completely mad.

Rich

 

Yea I was trying to do this as well ... I started to have very strange things happen ... for some reason it knocked more had to lower timing by like 4 degrees a/f was a lot closer but didn't do me a lot of good since I couldn't run the timing I was running (logged advance)

 

If you're dropping 3 X MAP tables, then at the points it's actually running on MAP you'll be looking up lower load areas of the fuel/timing/everything.

But 4 degrees does sound awfully extreme if you're talking WOT areas...

Rich