I'm working on a car right now that I finally have running well enough to tune. I started going through what is available to me- I have never tuned before so I'm a little apprehensive.

It is a boosted car which I'm not sure makes a difference.

My first objective will be to get a/f in order. There is no MAF on this car so I think I would need to create several variations to have on hand for weather- does that sound right.

My questions are, if anyone out there is familiar enough to help me out:

There are 3 options for viewing and modifying fuel tables. I have pulse width, duty cycle, and Raw.

I modified the table for Duty cycle to top out near 100 at the highest rpm and boost. I now started modifying the Raw table as the primary fuel adjustments are made. I am thinking pulse width should be used for fine tuning since my range is more narrow.

Does the above sound right? I have also bypassed using the boost vs fuel trim and load vs fuel trim correction tables since they seem like ways to tune without getting into the fuel tables. Should I be tuning with the tables or the fuel trim charts- The charts don't seem very detailed as a tool and seem like coarse adjustments.

I have also noticed that in low gear the car leans out much more quickly than in higher gears with the same fuel map- I came across 1 of the fuel tables that adjusts fuel by load and another that adjusts by boost. There are a few others that adjust by throttle.

If the load (displayed as boost) is the same and the rpm and the fuel are the same, why would it be so likely to lean out in lower gears? The fuel to Load table (I assume the load would be greater at a higher gear) however the load vs fuel table is flat and makes no corrections based on load so I am confused.


I'm using an AEM EMS if that can help at all.

 

Is load registering the same in the lower gears? Are you logging the parameters that show you log for each gear?

 

I don't have a way to show a log per gear, but I can run a log through a few gears and then compare the boost to rpm to a/f and see what is happening. It's being street tuned so it is a little difficult to get a full run through all of 1st, 2nd, and 3rd.

I think I've got the fuel pressure up to cover the fuel at the top end and I just increased the duty cycles up at the higher rpms in case they were leaning me out up top.

I'm not sure, but increasing the duty cycle means the injector is open longer so I have a bigger window with which to make adjustments. If it is too low, unless the fuel pressure is higher, I will only be able to get x amount of fuel through. Once I do my runs tomorrow I will see if that helped.

The load may be changing due to a boost leak (Log was showing fluctuating boost about 1.5psi) so that may cause the differences between the runs.