New here, questions and answers?

I have myself a 1995 Chevy C2500 Suburban, 5.7 TBI, 4L80-E. It has the 427 ECU with BNKM bin in it, $31 mask apparently. I haven't confirmed the bin as compared to the BNKM bins I've found here yet, my APU1, G1 adapter and MTX-L should be here tomorrow or Tuesday.

Currently the Burb has an open air intake, Ultimate TBI mod and a fresh tuneup with Accel parts. Soon to come are Hooker long tube headers with Hooker 2 1/4" full dual and Hooker Comp mufflers... no cats. Later this year the replacement engine I'm currently building for it will be going in. It is a Chevy 207 block .030" over, new pistons, pistons, oil pump, Edelbrock 3702 cam and timing parts. Stock 193 Swirl port heads, port matched and polished, unshrouded intake valves and smoothed chambers. Port matched and polish stock TBI intake manifold. 1.52 Comp roller tip rocker arms, Edelbrock valve springs and retainers. The exhaust and TBI, of course, carry over.

I figure this gives me plenty of time to learn and tweak my bin file with a basically stock setup, and customize some features along the way.

I've been researching and reading for about a week and this is what I 'think' I've learned, along with some questions.

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Fuel (for the coming soon engine)

- I need to increase MAX RPM to 5300 RPM, so I'll be changing 'RPM to Enter Fuel Cutoff' from 4800 to 5300. I'll adjust as necessary one the engine is in if needed. I'll also be changing MAX MPH to 110.
- Updating Culinder Volume from 43.73 to 44.41

..Questions about fuel.

Will I need to tweak the AE tables for TPS and MAP only if I see a drop in AFR or BLM while initially 'dropping the hammer'? I seem to understand the for about the first .1 second the TPS table is in control, then after that for about 2.5 seconds the MAP table kicks in. I imagine the end of the TPS table and the beginning of the MAP table should be close, and that the MAP table should fade as it reaches the end of the table.

The Open Throttle VE vs MAP vs RPM table seems to be my main fuel table. Adjust here as needed across the board?

For PE, there only seems to be one table for fuel, the PE AFR vs RPM, which listed AFR's in the 12's. Does this mean I simply adjust the Open throttle VE table, even for full throttle operations?

After all is said and done, I should adjust the idle screw on the TBI to keep idle counts in P/N to under 5. Right?

I see there are MAT tables in bin, but the Burb has the MAT or IAT sensor. Can this be added for more precise fuel/spark control?

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Spark -

- Looks like I need to adjust the Main Spark Table vs MAP vs RPM (Open throttle) for all my spark control. Yes?
- There is a PE Spark vs RPM table, but it is all 0's, so I assume it relies mostly on the Open Throttle table?

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Transmission (4L80-E)

The only shift timing table I can find is the Desired Shift Time Altitude Gain vs TPS vs Shift. I assume this is the main shift timing table and I should make my adjustments here for a quicker shift.

I also would like to be able to make 3rd gear hold while on a dyno. Should I change the value in the Upshift/Downshift MPH vs TPS in the 3->2 column to 127 mph?

Kickdown Mode looks like its the 'floor it' mode for the transmission, checking parameters to see if it should drop a gear or increase line pressure, etc. True?

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Air conditioning

It seems pretty straight forward that I need to change the Idle Speed vs Temp (A/C On, P/N) table to increase RPM so the A/C gets colder quicker when I hit the remote starter in the summer. I wouldnt increase more than 150 RPM, just enough to help the compressor.

In the bin I see that A/C Clutch Control is disabled, and there is an entire collection of Parameters/Tables for controlling the A/C for various throttle/RPM conditions. However, they are all 0's. I assume if I wanted to use these tables I would need to switch them on, then populate all the tables with proper values.

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Shift RPM/MPH

It looks like the ECU is set to shift based on MPH only. the RPM shift tables are all at 0. As far as I can tell, I would simply need to set the proper RPM in those values to increase shift RPM when the new engine goes in.

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Sorry, I know its a lot of questions, but I think I'm getting a decent idea of what needs to be done, without having the equipment to experiment yet.

Thanks for looking

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Will I need to tweak the AE tables for TPS and MAP only if I see a drop in AFR or BLM while initially 'dropping the hammer'?

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BLM and INT do not generally respond fast enough to provide useful input for adjusting AE. O2 (AFR) can be useful. Sometimes you just have to get everything else right and finish off by feel.

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The Open Throttle VE vs MAP vs RPM table seems to be my main fuel table. Adjust here as needed across the board?

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Be sure the transition points from open throttle to closed throttle are fairly close and don't ignore closed throttle table as BLM and INT driven to an extreme by incorrect idle settings will affect consistency of rapid transition to open throttle.

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- Looks like I need to adjust the Main Spark Table vs MAP vs RPM (Open throttle) for all my spark control. Yes?
- There is a PE Spark vs RPM table, but it is all 0's, so I assume it relies mostly on the Open Throttle table?

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There are multiple tables for tuning spark. While the open throttle table you see may appear to be easiest to change, do not fail to take advantage of other tables designed to better dial in spark for specific conditions. PE spark vs RPM can be used to add or subtract timing if the engine experiences knock in certain, specific cases that the main spark table cannot be programed around.

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I also would like to be able to make 3rd gear hold while on a dyno. Should I change the value in the Upshift/Downshift MPH vs TPS in the 3->2 column to 127 mph?

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Force 3rd by keeping shifter in D position. Trans will not upshift to 4th.

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Originally Posted by 1project2many

Force 3rd by keeping shifter in D position. Trans will not upshift to 4th.

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Yeah, I know that, I want to keep it from downshifting into 2nd gear so I can get a reading on the dyno as low an RPM as possible.

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Originally Posted by Scrufdog

Yeah, I know that, I want to keep it from downshifting into 2nd gear so I can get a reading on the dyno as low an RPM as possible.

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Easiest way to get 2nd/3rd gear only, would be unplug the 12/13 pin connector. This will default the transmission to max line pressure and 2nd (4L80E) or 3rd (4L60E)gear.

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Originally Posted by Fast355

Easiest way to get 2nd/3rd gear only, would be unplug the 12/13 pin connector. This will default the transmission to max line pressure and 2nd (4L80E) or 3rd (4L60E)gear.

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I've been reading a lot of your posts lately Fast355, especially on porting the 193 heads I'll be putting on the 'new' engine.

Having not been to a dyno in ages, I assume most dyno operators want the transmission to stay in 3rd gear for a 1:1 gear ratio. Since I have a 4L80-E would they just change a setting in their software to adjust for the 1:48 ratio?

Also, does it seem that most of my assumptions make sense? Besides what 1project2many has adjusted me on?

Inertial chassis dyno will compare engine speed to drum speed to auto-calculate "drivetrain ratio." IMO second gear runs are acceptable, especially if vehicle has larger than stock tires to provide additional load. TCC not applied will give erroneous readings anyway as torque produced at wheels is not equal to torque produced at engine times drivetrain gear ratios. As RPM increases and converter load decreases, torque multiplication from engine through converter decreases so accuracy improves.

Got my moates stuff yesterday. Dumped the stock bin with a homemade header adapter, uploaded it to the Autoprom, and put everything back together, works great. Installed APU on top of the PCM and ran the ALDL and USB cable to the glovebox. Ran a datalog and once in closed loop mode, has a BLM of 90-95 at idle. Seems that just the ultimate TBI and CAI were enough to require tuning. Will start on that within the next week.

Before deciding to go the tuner route, I was going to advance my distributor 4 degrees. Instead of doing that, I should just advance my Main table 4 degrees and tweak from there... correct?

Yes, why turn the distributor when you have tuning tools?

Adding 4* across the board is not a good way to make a spark table, there's no reason to add spark to certain areas like Decel or if your going to need spark at at startup there's probably another table. If you look around here there's been plenty of good spark tables posted you could use. Also have to be careful to watch for your adders for PE as well. Then always watch the knock counts and retard.

I wasnt going to add 4 degrees on every table, just the one main table, since thats what advancing the distributor would do anyway, thenstart tweaking that table, then follow with the other tables.

I will definately look around though for some guidance.