had the AE "uber rich" on WB last fall. this spring removed about 20% globally TPS/MAP AE. went over the edge and lean yesterday/today in easy daily driving per WB logs. did one WOT blast in rolling 2nd gear/ 3rd gear of 5 to 5000 rpms. some hesitation, but not too bad considering the petal slapped down to create a bog)and then takes off nicely in 2nd thru gears. i used stock GM tables for AE and then took equal % out of each value. may be under stock GM for 350 cid CF bin? now i am thinking of trading off some AE. adding to TPS values and leaving MAP where it is for now. i believe it is apparent that the AE is lacking initially as the sudden air flow is occuring b4 the map sensor can respond. anyway to equate the relationship of AE TPS grams injected vs the AE MAP grams injected? think they should be about equal as far as amount of fuel injected during each episode of AE? PE set at about 40-50% TPS if i recall. i am aware of trasition of AE MAP to PE. PE showed lean BTW last year(13.3/1). i plan on upping FP from 13 to 16 as well. need new gauge.

77747/tunercatl

 

ttt

 

Only as far as what makes you engine, and your right foot happy.

It's as much driving style, as engine demand.

Just to toss some numbers out, on my GN I cruise at ~55-60 K/Pa, and with my truck, 45-50. With the GN I use alot more TPS AE, compared to the truck since the delta MAP is so much less.

Generally, around town is primarily TPS, and then light hills on the freeway MAP, for the way I drive.

 

AE is so hard to tune with TBI, I still haven't come up with a plan that I stick with. I've tried everything, even removed a bunch of MAP AE and stuck it into the VE table, that seemed to help a LOT. Also, with the TBI ecm's the AE is pulse width so if you increase the fuel pressure and even if you change the bpw you'll still have increased your AE. This is why with my 65# injectors at 28psi I run a tad less AE than the stock tables! Some guys have pointed that out to me and asked and I just tell them that's what it likes and how AE is done with these ecms.
Using the VE table has helped a lot with keeping the motor from getting too much AE under free reving. Also, never put a zero in the 1st cells of either the MAP or TPS tables! Other than that just look at the setup vs stock. Big plenum means more AE, bigger motor, more AE, bigger TBI, more AE, more fuel pressure or larger injectors, less AE .

 

when i first used the WB i was off the chart rich on AE. yesterday i logged some AE sessions and find i am 10.0/1 to 10.5/1 for AE. is that about right for A/F? i did not look at PE as i am fearful i am too lean. need to find a safe place to take a quick look at PE(3rd gear of 5). FP is 13 lbs so i will bump that B4 i look at PE.

 

You need, well, at least IMO, to get the light load AFRs, correct, then the PE AFRs in line, and THEN start on fine tuning the AE.

The TPS PE enable setting, will have alot to do with how much AE you need.

Don't expect to do one thing, and then go off to do others, and think the first item was taken care of. Not to mention the effects of timing, on fuel demand. It's the constant refinement of a tune that gets to where it's correct.....

 

VE tables were done last fall. did not look at 4000/4400 rpm VE yet as need to disable PE and run a level stretch of xway near home to populate those cells. i will be carefull ! however i am starting over on VE as i suspect i will be lean in PE from what i have seen as one PE log was 13.3/1 on WB. well aware you walk before you run. drivability is so/so just lean i feel at AE TPS(slight bog) so will add some usec there and i am confident it wil come together. dont think 13 lbs FP will be adequate so upping FP tomorrow to 16 or so and again back to VE tables.

 

PS. PE enable at about 50% throttle if i recall. was like 75% early last year.

 

Ron,

Having gone through a similar exercise as you are now doing, I would suggest you first find if your 13 psi is good enough to support the WOT AFR you are looking for. Over the last 10 months I have gone from running 10.5psi now at 20psi. My BPW is set for 86 with 80lb injectors. I can also tell you that bumping your FP will reek havoc on your idle tune. The PW gets pretty small. I think I finally have it worked out but its taken a lot of tuning and help from guys like RBob, JPrevost and Grumpy(who started it all with his WB). Its now to the point where my commanded WOT AFR is pretty close to what I actually get on the ZT-2. I'm going to also suggest that the VE table resoultion for the 7747 may not be granular enough to really do the idle right.
All this work however has paid off with an extended rpm range and a much flatter torque curve. I'm hoping to get to the track and dyno this spring.

 

10:1 is definatly too rich. Something like 12:1 to 13:1, depending on where the motor is load-wise, would be better

 

Not to through a curve ball here and get off topic but to show you how much AE is really driver preference check this out. I don't run much AE at all on low throttle open and delta map. The WB shows even a lean spike when it shifts into OD and the TCC locks, but this is ALL below my stall speed of the TC so it's not like it matters. If anything it feels better to have it slightly lean below the stall. Too lean and you feel it slow down, a little and it's crisp, too rich and it bogs or lugs up to speed. Some people like the lugging, it's really always a refinement. And like Grumpy said, change one thing, go onto the next, but you'll be back at that first thing again soon enough because that's just how this whole thing meshes together.
Also, like Dom said, set your fuel pressure so you have enough fuel at WOT, then get your idle figured out. Do a little guess work on the part throttle stuff using the knowledge that 32 degrees WOT is good for a n/a sbc iron heads, 34 for aluminum, then slope your SA to like 5-10 degrees at 100kpa and 400-800rpm, slop your WOT SA all in at about 2800rpm and the rest is a blend. Then get your part throttle stuff figured out. Your INT is a good indicator of AE direction if your MAP is in a transient, but I don't think the 160baud is fast enough to help .

 

Ron,

To Jon's point, I found that if you had the VE table pretty well set at one pressure, then by changing the BPWC, your tune will be "close enough" at the higher pressure to get you started.
It will definitely be rich but you won't be melting any pistons if you take it slow. As for the baud rate, the WB has been invaluable there. On WOT runs, I'll have the scantool and the WB going and its just amazing how much of the WOT run is simply not there in the ALDL stream when compared to the WB output.
Its the same when you have a faster acting cam. The valve timing events just aren't documented at the rate you need to properly tune.