Cruising and from a stop.

Hit it hard to jump striahg to PE and the wideband goes from 14.5-14.7 down to 12.X and then jumps to 15-16 and then settles down to the commanded PE of high 11 low 12.

What would be the best way to handle this?

Was intially going to attempt to play with the A/E but I can be going heavy throttle and then stomp it into PE and get the same result..............

Just wondering what some others experiences are.

Car runs great and pulls like a freight train once it gets past its initial lean spike....

later
Jeremy

 

AE lag filter?

 

Maybe up the VE table at the 90-100kPa levels?

 

That lean spike is where all my knock is coming from.

It starts there and continues of course becuase u have your foot to the floor.

Its great once it beaks thru the barrier and pulls.


Going to try and work it out by going back to stock AE tables for the Delta TPS and Delta MAP tables and retuning them for my combo again. Then playing with dropping my PE enable TPS% to see if I can cover it one way or another.

This is on an SD 383 app running $8D code.

later
Jeremy

 

Mine too....

But the could the instantaneous spike be where the AE hasn't kicked in yet?

 

Nope(least almost sure)

I did this test repeatedly so I knew it wasnt lying to me.

A/E comes on and it drops to like 12.XXX for a split second and then it has the lean spike to 15.6-1 then goes back to what the commanded PE should be.

Just trying to paint a picture in my head but im getting all greys :-)

later
Jeremy

 

BE CAREFUL ! !!
You may have tip-in preignition also going on, and that can be extremely life threatening to an engine.

Work up gradually rather, then worring about throttle stomps..

You'll probably see, that adding some in the VE table would help.

Not to mention, not getting caught in the too much timing scenario.

 

On top of Grumpy's input, don't forget to keep an eye on the injector duty cycle. The delta TPS% AE is added as async injections. This is because it is required as an immediate fuel adder. This won't show up in the injector DC.

OTOH, delta MAP AE is added to the sync PW. And will show up in the normal DC. Just double check that it isn't exceeding 100%.

There are ways to extend both the delta TPS% and MAP AE contributors. Tough part is figuring out which one needs to be touched.

RBob.

 

Got a bin and datalog to go with it?

 

Rbob, Bruce, Vern, everything is duly noted.

Going to start over on the A/E and go from there.

Wish I had easy ways of moving info anymore(anyone got a spare usb mem card/stick they dont want:-))

I'll find a way to shoot my bin and a datalog up later.

I dont believe it to be a timing issue at all.

WOT I am only at 28 degree and when i get there cleanly I get zero knock, except a degree or two on shifts.

In the main tables I am a high of 35-36 at cruise and tapers(rather quickly) into the 20deg range and then 80kpa and higher rpm's back to 28.

I took it for a drive last nite just to watch the wideband and the A/E just may need to be gone thru again. I could leave like just hard enought to squeak the tires(just load the converter) but I could get a lean splke repeatedly when I tried.

Will go thru the A/E delta TPS and rework.

thanks and later
Jeremy

 

In trying to get a longer duration of AE there are a couple of things that can bite ya. One is the minimum async PW (at $83EF). Once the TPS AE PW is less then that, TPS AE stops. Done.

With the larger injectors (Am I correct in thinking that there are larger injectors?), the correction vs. battery values may need to be increased. Also, the low PW offset's may also need to be increased. This is because a large injector tends to take a hair more time to open.

If not accounted for then small PW's don't do anything, and the AE stops before it should. On a PFI system AE is small amounts of fuel. So it can be tough to make sure that it does get injected.

To extend the actual commanded AE, the TPS AE is limited to a count of DRP's. Once that many DRPs have occured AE stops. Check the value at $8530, probably 12, or 3 engine revolutions.

There is some other stuff involved but I haven't had enough time to figure it all out. Fuel limiters, MAP AE, decay factors, MAP enable vs TPS%, just way complicated.

Maybe try the TPS filter coef vs RPM table at $856B. A small number should increase the AE and extend it.

There is some sort of MAP AE decay table at $8590. Looks like a smaller number will cause MAP AE to decay more slowly.

RBob.

 

Partial update :

Looks like playing with the delta TPS and delta MAP AE got rid of the spike under hard throttle jabs. I can romp it and it drops to 12.2-12.5 or so and then to high 11 , low 12 like the PE is commanded to.

Does appear that I may have gone a little to rich with the AE and at times I believe lessening the actual AE, but extending the time on will prove fruitful as well.(like the liter thottle jabs as below)

Still have some wavering of going rich and spiking lean(although less so) under normal throttle conditions here and there.

It did seem to help out quite a bit when I jabbed it to the floor and sent the rear out at about 40mph though :-)

I cheated and used my AE settings from my old 350 hotcam combo.

Also brought down my PE vs TPS settings into the low 30's-30% in any of the higher rpm ranges.

Making progress, now to get time to play with the wideband and romulator with a driver :-)

Will update as I get time to play.

later
Jeremy