all,

i need some help here. i do have a DL and also a wideband..
but i have some tuning problem here that might need some enlightenment.

this happens on deceleration....during deceleration,
the RPM drop down from let's say 4000 RPM...
when it hits a certain low RPM the engine will defenitely bog.. normally it should be a little less than 1K RPM..

my case is.... when i decelerate... when it drop less than 2K RPM.. the engine is starting to bog already.. when i give it a little throttle...back.. the engine pushes and bogs even bigger.. when i give even more throttle....the engine will move back up the RPM without any bogging... is this situation too lean or too rich ?

normally people will say it's too lean... but based on below scenario.. i might be too rich as well

when normally i decelerate.... before the engine starts to bog... i give it a more bootst and petrol to push up the RPM... during that throttle movement.. i normally got a back fire... just one sound pop....then the RPM will go back up again normally and steadily...

based on the 2 scenario on the same car... is my afr during that low RPM deceleration too rich or too lean.. ?

btw, my WB reads AFR 13 to 14 range during that time...

or it's my ignition giving me problem ? or even the plugs ?

 

When you let off the accelerator, the injectors are turned off until the revs drop to your fuel cut point, or you give it more accelerator.

As soon as you give it accelerator again, it should be smooth.

From your history of problems with this engine, it is difficult to say what the problem is.

 

like chuck said. when you let off throttle the wb reads extremely lean then when you dial in again it must the back to normal as per tune.

 

actually.. it's not that lean as well.. it's around AFR 14.... my WB reads 16 for the leanest....

 

"From your history of problems with this engine, it is difficult to say what the problem is"

What kind of problems do you have with this engine? perhaps if you give more information we can have better insight in what to try.

 

?

 

Such as;
(1) original high knock with timing that was not aggressive but poor split
(2) running richer when water temps went high on the track

 

ohhh okay... i believe that you mentioned before my engine has a noisy drive train...nowadays... on WOT.. it doesn't go more than 40...

oh yeah.. and the very rich situation that i mentioned before... i found the problem it was a connection loose on my wideband to DL... the issue happened again but it was on the town road.. so... re-tightening the wirings... solved my issue.