I recently got a cable and winaldl software to get a better handle on what is happening with part throttle tuning.(8746 ecm) I thought, Ok, If I see a cell that is lean or rich , all I got to do is change it and that cell will be corrected. WRONG!! at least for me. I have gathered a lot of samples on various runs so I think I have reasonable data. But If I am lean say @1200 rpm @30 kpa (132.8) and I add fuel between 2 to 4 %, It also makes other cells rich like 1200 rpm @ 40 and 50 kpa and rich values at 1600 and 2000 rpm (ie 119-122) that prior to the change were in the 129 range. I have made other changes and I can't seem to establish a pattern as to what is going to change besides the cell I have actually modified.

I just read that you are supposed to clear the ecm between each chip. I have NOT done so cause I didn't know about that. IS that causing me to get bad data? can anyone suggest what I might be doing wrong?? My eyes are shot and my brain is gone from reading reading reading. Thanks for any help........old carb guy bob

 

Don't worry about 30 K/Pa at 1,200 rpm. About the only time you'll see it is in transistions, or so light of conditions it's not at all critical. It's kind of a gray area, the advance is making huge changes, and the filtering at that low of engine speed isn't going to be too good. ie half of what your seeing is timing related.

You'll probably so better leaving it a little lean, and getting the AE right just to get the off idle transistion nice.

BTW, is the drivibility suffering, or are you going for 128s?.

 

Grumpy, thanks for taking the time to resond.

The drivability is excellent the way it is now, I am just trying to refine the table to get the values between 126 and 130, hopefully closer than that so I can improve performance and" build horsepower" like you said in another post.

Some of my blm's are in the 126 to 130 range now but there are a number of 132's and 122's I am trying to adjust. For instantance, at 20 kpa 1600 to 3200rpm are rich in the 121,122 area. At 30, 40, 50 and 60 kpa I am rich between 2000 and 2800 rpm with blm's from 119 to 122. But there are also scattered cells that show 131, 132 at the higher kpa and rpm levels. so far I have only been trying to adjust the lower rpm's and kpa's and work up but maybe I should be adjusting in the higher rpm and kpa ranges. What do you think?

I have not been able to get many samples over 60 kpa cause I cannot achieve that load at higher rpms for very long. How do people do this?

I have very little knock, I get a few counts here and there . I was going to deal with that after i got the ve table right.

Any other suggestions would be appreciated but for now I am going to try adjusting higher rpm and kpa levels and see what happens.

Thanks again for your help....................bob

 

128's are nice.
But, they aren't the end all to tuning.
Especially in the limits of the calibration.

The lowest K/Pa I've ever seen was 38.
So I generally consider the 40 column as the limit to what I'm going to worry about. 35 and less I consider only to be found in over run conditions. Thou there is a small area where you might transistion thru that at low throttle openings.

Generally I set the PE enables at 60% TPS when roughing out a cal.. Then when I get as much as the VE done as possible, compare that to the oem values, and extend the table based on that. In most of the car stuff 70+ K/Pa is just really transistional stuff, as compared to say a H/D truck application. While the 100 K/Pa entry is used for the PE AFR, when your get to that stage you should be reading plugs to make sure your where you want to be.

FWIW, once you find the best pulse width for peak torque, an ecm bench gets really handy since then you can develope a fuel curve based on that. It won't be perfect but you can add a lil to it, and then just do a final trim to it once in car.
Might just for grins read the 9.4 with a stock ecm thread about what an ecm bench can mean.

 

Grumpy, thats a BIG help. So now I got a plan to keep me busy for awhile. Then I may read up on the ecm bench to see weather I can handle it. Thanks again...............bob

 

My setup runs reasonably close to 128's most of the time except for the idle (cell 4) stuff. There the BLM's slam right to 108 and there they lay. I was preparing to adjust the tables for that, but now I wonder if I should leave well enough alone.

Steve

 

Bob, if I read this rightly, you're having problems with the light load settings and you've got bigger injectors off a BB motor.

I wonder if the injector pulsewidth bias is selected to suit the BB injectors in the .BIN you're using? How about posting these if you're not sure and seeing what Bruce has to say?

John

 

Idle is almost really a special case, and in some codes they even allow for an open loop idle.

If 108 is the min the BLs go to in your cal, then I'd say do some work to it.

Timing will move the K/Pa readings a fair amount in some applications. And since it is so far retarded, it can in some applications give a slightly false indication of AFR. So in some cars you have to dither things more then you might expect.

While often 20-22d at idle is a typical setting some like 26.
HTH

 

Good idea cause I have not touched the BPW constant.

I am runing two 65# injectors from the SEO cop car
LO5 350 engine. I believe the BB injectors are 80# + but when I did the swap there was a lot of contrversy with the TBI guys as to weather the BB injectors were necessary. The original BPW constant for the COP 350 BIN was 135. I have not changed the constant but If I need to start there rather than the ve tables,
I would appreciate a quick note and I will read up on BPW's.
I gotta get new ******* glasses!!!!

Thanks to all......................bob

Ps, maybey I am just too old for this and need to get my 55 chevy back LOL