Hey guys, weird problem. My car was running great, everything worked. I had these as my Inj PW vs Battery voltage:



RBob gave me these for my injectors and the car definitely liked it:

Offset Compensation versus Battery Voltage:
6.4 Volts: 3193 usec
8.0 Volts: 2163 usec
9.6 Volts: 1618 usec
11.2 Volts: 1278 usec
12.8 Volts: 1031 usec
14.4 Volts: 821 usec
15.0 Volts: 784 usec*

But when I use the offsets he gave me, my decel enlean stops working. I datalogged the car. When I let off the throttle at 50mph, my short term and long term C counts (using datamaster) lock in at 128 and do not move unless I hit the throttle or the car drops down to idle. The car is in closed loop the whole time.

If I put the old offsets back in, the decel enlean works fine. Any suggestions? Thanks!

 

Decel enleanment (DE) is a temporary shortening of the injector PW on a full or partial throttle lift.

Decel fuel cutoff (DFCO) is a zeroing of the injector PW on a closed throttle while the vehicle speed and engine RPM is high enough that the engine won't stall.

As far as I know the injector correction values won't affect either of these functions.

Are you using $32 or $6E?

RBob.

 

I'm using 6E. When I put the old values in. When I let off. My wideband hits 17s. With the new values it sits at mid 14s.

 

That makes sense, off the throttle the injector PW is going to be small. The ECM may even be in single fire mode.

Look at the offset values at 14.4 volts: 488 uSec versus 821 uSec

If the fueling calculation sets the PW to 1 mSec (1000 uSec), then the offset is added. There is going to be a considerable difference in the PW programmed to the injector.

1.488 mSec versus 1.821 mSec.

RBob.

 

So pretty much there's nothing I can do to make the lean decel work? The car for sure liked the offsets you gave me better than the old ones. What you posted makes sense though.

 

Can work with the MAF tables, they are used to create the initial fuel PW.

RBob.

 

As usual, you are a huge help. Thanks for the fast replies.