Very unusual '7747 .bin ~ 7.4 liter / 700R4

**RobertISaar** · 09-04-2012

since VE1 and VE2 are combined to form a single 8 bit value, there is no difference in resolution if you place the values in either one, so long as it adds up the same.

if you want the most possible resolution using stock code.... you would setup the BPC so that the lowest VE cell has correct fueling at 0% and the highest VE cell has correct fueling at 100%. that's VE1 and VE2 combined.

as you can imagine, this scenario is kind of unrealistic, since 0% VE would be a BPW of 0.

so, in a real-world situation, best resolution would be achieved with allowing the highest VE cell to touch 100% while retaining a correct AFR.

**EagleMark** · 09-04-2012

Dave, I noticed Async fueling at idle in your log? Also INJ - Async Transition Lo and INJ - Async Transition Hi are not stock 7.4L settings? Also not 5.7l settings?

The Async flag goes off when Off Idle. Not sure why your getting Async Fueling at idle? Most of my time has been in SB and Async only comes in WOT high load situations... and doing a recent six cylinder conversion using a V6 bin to start was always Async? Don't have my files from dead laptop so can't look at any old BB logs...

**dave w** · 09-04-2012

Originally Posted by EagleMark

Dave, I noticed Async fueling at idle in your log? Also INJ - Async Transition Lo and INJ - Async Transition Hi are not stock 7.4L settings? Also not 5.7l settings?

The Async flag goes off when Off Idle. Not sure why your getting Async Fueling at idle? Most of my time has been in SB and Async only comes in WOT high load situations... and doing a recent six cylinder conversion using a V6 bin to start was always Async? Don't have my files from dead laptop so can't look at any old BB logs...

I noticed the Async also. I've been thinking the tune is not close enough yet to be concerned about the just Async yet.

Thanks for thinking about the IAC wiring, as you suspected it is not correct. I also suspect the IAC is faulty. I don't think a faulty IAC circuit will trigger Async, but it's best to fix the IAC and see what happens.

I'll get back to tuning on this Suburban in a day or so, need to fix the IAC.

dave w

**1project2many** · 09-04-2012

Async Transition Lo and INJ - Async Transition Hi are not stock 7.4L settings? Also not 5.7l settings?

They are stock ASDU according to the comparison tool. When min PW gets below transition values asynch is enabled. Ugh... hard to make that smooth sometimes.

Out of curiousity, why not start with a BBC cal?

The xdf I have here doesn't have the injector voltage corrections defined. They are different for the larger injectors. Maybe I'm using the wrong definition?

**EagleMark** · 09-04-2012

I'm not seeing same Async Hi and Lo in last bin uploaded?

INJ - Injector Correction Multiplier is the parameter in TunerPro XDF.

He's starting with a BB engine cals imported to 700R4 bin/ASDU.

**dave w** · 09-04-2012

Originally Posted by EagleMark

I'm not seeing same Async Hi and Lo in last bin uploaded?

INJ - Injector Correction Multiplier is the parameter in TunerPro XDF.

He's starting with a BB engine cals imported to 700R4 bin/ASDU.

I really appreciate the help and information!

Here is the latest .xdf / .bin I'm using.

dave w

**jameslleary** · 09-05-2012

Originally Posted by dave w

I really appreciate the help and information!

Here is the latest .xdf / .bin I'm using.

dave w

Dunno if this helps, i just skimmed the thread.
94-95 454 TBI's used 4.3 injectors, with the TPI in tank pump, running at 30 PSI.
Also, the IAC for the BB was wired differently.

**dave w** · 09-05-2012

An update. Rewiring the IAC did not fix the high IAC counts at idle. The IAC was cross wired (high coils to low coils / low coils to high coils). Apparently it doesn't matters if the coils pairs are crossed wired, as long as the coils are paired together? I did an ohm measurement on the IAC coils, 52.6 ohms one pair coils vs 53.4 ohms on the other pair of coils. I measured another IAC I have as a spare, one coil pair measured 54.6 ohms the other coil pair measured 54.4. I don't think there is a problem with the IAC that I can measure. The engine seems to idle better and hot restart better now that the IAC coils are wired correctly.

The Async is a problem, but I'll deal with that later on. I think it's better to fix Async when the tune is better than it currently is.

The attached is this mornings .xdl, and .bin. I've made several changes to the .bin, trying to lower the BPW. I've increased the Injector offset volt to stock 350 injector settings, and lowered the BPW. Overall, the data log shows most cells are rich, which is the desired goal with this .bin. The upper RPM's and high Kpa's did not go as rich as hoped. The plus side of this .bin is the upper RPM's and high Kpa's did not go lean. As far as tuning options, I could increase the injector offset voltage and lower the BPW and lean the rich cells in the VE table. I could leave the injector offset and BPW as is, and correct the rich cells in the VE table.

I've got 32 hours to finish this tune, and a full time job that gets 1/2 of those hours. A lean tune will damage an engine, so I'm safe at this point.

dave w

**PJG1173** · 09-05-2012

Dave, while messing with my BB TB I noticed high IAC counts at idle even after I straightened out the wires too. I did notice though after a quick drive at operating temp the IAC counts would be in the normal expected range. IDK maybe its just a BB IAC thing.

**EagleMark** · 09-05-2012

Originally Posted by PJG1173

Dave, while messing with my BB TB I noticed high IAC counts at idle even after I straightened out the wires too. I did notice though after a quick drive at operating temp the IAC counts would be in the normal expected range. IDK maybe its just a BB IAC thing.

Should always look at IAC and all adjustments after warmed up and driven a little! TBI is a wet intake manifold so it needs to be warmed up and cleaned out (with a drive or WOT) before you look at data!

Dave, still can't see spark in data but looking at your log and spark table I think it is causing some of the BLM fluctuation.

But your going Async even more now then before?

Think I found Injector Async differences. That bin has Manual Trans Async settings from AKUP. AZFT is for Auto. They are differant between Auto and Manual! Here is a bin with a timing table I built and Injector Async settings ONLY! I have no idea what this bin is... Compare them and look at spark table in wireframe view when comparing and do the copy over to your bin.

If you compare the spark table to AKUP you will see how it is built. It is a much betterr timing table to start with then AZFT.

**dave w** · 09-05-2012

Mark,
The timing table I'm using is one of my "Skunk Works" creations. With the huge tires, I elected to go with a "Towing" type timing table. The Suburban can merge with freeway speed traffic (70 MPH in my area)! My test drive loop can generate a good spread of data, including a 2 mile 6% grade @ 40 mph speed limit. I'll come to a dead stop on the %6 grade and then accelerate Suburban without going into PE. So far, so good on the %6 grade test. The Suburban feels like it's accelerating on a level grade, when I accelrated from the dead stop on the 6% grade. The return trip down the 6% grade provides data for low RPM / low Kpa (20 ~ 30). Not always, but sometimes the data log will not show overall drive-ability.

I'll look at the Async settings from AKUP vs. AZFT. The IAC seems fine with stop and go driving in the 80ish afternoon temperatures. I don't like the IAC numbers at all, but the Suburban seems very drive-able with the numbers I'm seeing.

I wish you could have driven this Suburban when I picked it up, and then drive it now. It's night and day difference! I'll admit, the tune could be better, but it's a time factor I'm up against.

Thanks again to everyone for the input, help, and suggestions!

dave w

**EagleMark** · 09-06-2012

Open throttle blades to lower IAC counts. If they don't go down the IAC is stuck.

**dave w** · 09-06-2012

Originally Posted by EagleMark

Open throttle blades to lower IAC counts. If they don't go down the IAC is stuck.

That was the first thing I tried. Odd thing, when I jumpered the ALDL to close the IAC ... then started the engine the IAC counts were about 20 then climed back up to about 80 ~ 90. Another odd thing, when I had the IAC unplugged (after jumpering the ALDL to close the IAC) then started the engine the RPM's were about 1200 ~ 1400. I'll try a different IAC just to see if that changes anything. I don't know if the other IAC I have is any good.

dave w