So im still working on learning to tune and I need some help. Im running lean as my plugs are very white. I have a log and copy of my bin if some one could please take a look at it. I changed the pw to 130 and have 18psi with a modded tbi. now that the weather is been warming up here (70,s this week!) I am losing power after the engine warms up. untill then it runs better when cold (35-40's). Im looking for some help to get me going on this. for instance how would i add fuel in the 1000-2000rpm range? Im just not grasping how you calculate what changes to make.

400 800 1200 1600 2400 2800 3000 3200

20 1.95 3.91 5.86 9.77 14.06 17.97 25.78 29.30
30 14.06 24.61 30.86 37.50 41.80 42.58 41.41 35.16
40 14.06 25.00 35.16 40.23 43.75 44.53 46.09 45.31
50 17.58 25.39 37.89 42.58 45.70 47.66 48.83 49.61
60 30.86 35.94 41.02 45.31 48.44 49.61 52.73 53.52
70 37.89 39.06 42.19 46.88 49.22 53.13 54.69 53.52
80 40.23 41.41 44.14 48.05 51.17 52.73 54.69 55.08
90 42.97 44.92 47.66 48.83 51.95 55.86 56.25 59.38
100 46.88 46.88 48.44 49.61 50.00 57.81 62.11 62.50

what does the left colum stand for?

 

The numbers on top are RPM numbers down left side are MAP KPA (vacuum) 20 is high vacuum and 100 is WOT.

Increase numbers in cells that are lean.

 

It is normal for the plugs to be bone white when running a closed loop tune. To adjust the VE use the BLM values, they are the long term fuel trims. In closed loop the ECM targets an AFR around stoich and uses the fuel trims to achieve this.

See the Tuning Guide Book sticky, Chapter 5, 8746/8063/7747 ECM section. There is a ton of good info on tuning the C3 TBI ECMs there. Be sure to read the ones concerning VE1 & VE2.

The numbers in the left column is MAP, which is intake manifold pressure in KPa. The ECM uses manifold pressure and engine RPM to know which cells to use in the table.

RBob.

 

ok so what does the numbers in the cells mean... are they a percentage of maximum fuel? in other words the largest # in cell 100kpa and 3200 is 62.50 does that mean 62.50% of fuel being used out of 100%? I upped the numbers in some cells and see an improvement in drivability so that is good!

 

VE is the volumetric efficiency of the engine. Basically, it is the mass of air that enters the cylinder versus the mass of air that is available.

Note that the '7747 ($42) uses two VE tables that are added together.

RBob.

 

so adjusting the table is adjusting what? Its not adjusting air so its more like how much fuel is mixed with the mass of air entering cylinders. the cells represent an afr sort of?

 

There is also an issue with the 2 tables adding up to over 100 which is a mistake from GM from factory. I was sure I had added VE to table one before and got results but since the thread below I did some testing and you can add up to 99.xx in TunerPro to VE1 but it will not show any difference in data log as it get's truncated back to 100. Which is still to high. should never really use more than 95 as injectors will go static. From factory they are this way. There is also a VE1 corrected fuel table in this thread.
https://www.thirdgen.org/forums/diy-...ge-7747-a.html

What many people have done is add VE2 to VE1 and only use one table. But since VE2 goes to higher RPM than VE1 I don't know if those numbers should be left in RPM columns higher than VE1.

Bottom line is if you have an engine with mods and need more fuel you will likely need more fuel pressure.

My testing with raising BPW was only successful to about 150 from 135 stock. After that things went wacky. There must be some other adjustment needed in bin if BPW is increased beyond a certain range? Maybe Injector bias?

 

The VE table is used in part to calculate the desired pulse width to deliver the correct amout of fuel to provide stoich in closed loop. It is also used in open loop to provide the air/fuel ratio commanded in table.

the VE table is adjusted based upon the datalogs you create showing BLM data. If the BLM is not as desired(128) you change those values in the VE table. When all the stars align you might see all the cells rpm /map at 128. Realistically it will be close + or - 6. When temps humidity baro press change the BLM will swing accordingly.

Lots on info in stickies above.

 

ok well im running 18psi and set the pw to 130. this eliminated the poping going on when enigine very cold (30* or less)... didnt try increasing beyond 135 cause i thought more pressure allows a smaller pw which allows higher rpms. Im picken up a wideband o2 and guage this afternoon. can I just replace the current o2 with wideband to feed the gauge and ecu which is located at the y-pipe merge instead of on the header. still get some pinging under load. dizzy still set 8* advanced as setting to 0* makes it almost undrivable. got 2 months left to fix this so i can tow a camper.

 

The BPC is a set it and forget it. I dont believe it is meant to tune with it. same on fuel pressure. Set FP high enough to allow a DC < 85%. A patch too show DC may be available

7747 does not allow use of a IAT so < 30d F you will need manifold heat. a patch may be available to allow IAT. Not sure.

Initial Spark what ever you chose needs to be same as physical with ESC connector disconnected. Set it and .......... Not used to tune.

wideband can be used in place of NB just check with MFG of WB. Not sure how the def file for 7747 would need to be changed. may need a patch. Not sure. Search may show something

 

ya I dont see dc in tunerpro. I set dizzy to 8d so i could drive it befor i got the autoprom. I could add another bung for wideband easy enough. been wondering how to tell what the dc is so i guess thats next

 

If you have insufficient fueling capacity at 95-100%DC it may appear as overly rich on WB at WOT as injector is open and ECU has no control. If you can hit that 85% or less ECU can control nicely. I believe there is a patch for DC on 7747 def file.

POI if the VE tables are accurrate and fueling sufficient WOT-PE will be as commanded in bin

 

I've been working on a few patches in TunerPro XDF by changing a few numbers and have TPS% working as it does not come out in data stream but now does. I had built an ADX value for TPS% calculated from TPS voltage which was close, but from ECM is accurate!

Also got BPW done but can't seem to get conversion right for Duty Cycle... then while reading this thread did a search and of course RBob already has it done...

https://www.thirdgen.org/forums/post...16-post31.html

 

thats great info. I saw that post befor but didnt realize what it was. After reading so many posts i lose track of what i started searching for! I just finished installing wideband and guage. At idle im running 14.5 to 15.5. if i rev it in park it goes to 10.0 almost instantly. under cruse at 55mph and lite trottle it runs about 14.5 to 16.0. heavy accel causes it to goto 11.0 and it slowly creeps up to about 13. I suppose thats why if i set timing to 0d its just getting to much fuel. perhaps 18psi is to much fuel pressure. Ill work on figuring out the dc.

 

You should really use the injector sizing calculator first. There's a bunch of links and excel and Open Office spreadsheets in this thread below, one I use is one second page. It's the one that is linked to here from stickies but link is dead.
http://www.gearhead-efi.com/Fuel-Inj...re-math-needed

If you have 61lb injectors, turned up to 18 psi, 85% duty cycle and BSFC of .5 it shows a BPW of 121.3 to support 244HP. Get this right then tune!

I have a nice set of $42 XDF and ADX with dash boards monitors, data tracing and some hacks built in, but haven't tested the BPW hack yet, it was working on millseconds but duty cycle wasn't right. If you want to try it and send me back a data log so I can further test it eMail me or PM me your email. I don't want them floating around unfinished or tested, they will be available when done for everyone.

 

when should i see the bpw in the promid field? during datalogging? I made the changes in the bin with in the buffer hex editor. the regular hex editor in tunerpro didnt show the hex lines to make these changes

to get the sync PW on the ALDL line make these changes at the addresses shown:

Addr: Value:
$D4E7 $00
$D4E8 $AB
$D4E9 $00
$D4EA $AC

 

You don't have to use a hex editor, double click the **BPW Read Me Hac** and a box will pop up. In that box should be
Before D002D003
After 00AB00AC
While that box is open click on View, Parameter comments and I have notes in there.

We were working on this and came up with
Before D002D003
After BC0EBC0F
Which got some readings that looked correct for ms but I then found a thread from stickys here and RBob said it should be 00AB00AC but his picture shows 00AC00AB
https://www.thirdgen.org/forums/post...67-post93.html

That's why I said for testing I didn't want it floating around. When done it will be available for anyone.

You don't need to look at prom ID in ADX data side, I made a value called BPW from Hac** and it has the conversion in there. Item List, Sensor Data, bottom of first section BPW from hac**

But there is also a value in ADX data for injector flow, which was part of the first attempt in scaling it to percent 0 to 100 which may or may not work now but was used for the MPG history table and value output.

The other 2 hacs take place od OldPA3 for TPS% and O2 Cross Counts for Spark Advance. Same as above double click so box opens and read parameter comments.

HTH!

 

ok just tried it again... its shows dc at 5000-5500 just reving it in park... Ill take a log on the way home. at idle it shows 900 dc. tried changing b to c and it shows the same results

 

Sounds like it's working but have a math conversion issue? If you email me a data log I could work on the conversion/math end.... I should say ask my buddy to work on math end...

 

Now that's funny, I got all of the text explaining it correctly, then reversed the two when entering it in the hex editor. It happens.

RBob.

 

So you are human and not a robot?

It must be the conversion I put in the adx for BPW from that thread I got:
"(X * 0.015259 + .396) + 0.000000" adding the 0.00000 was a mistake from doing the spark hack at same time but should not affect it, right?

The .396 is INJ - Injector Bias of the bin I am using. His may be differant and that is noted in ADX...

Ooops, Range low and high should be 0 and 255, correct? With calculation from above! I have them wrong...

 

ya my injector bias is .396. ill send ya log in about an 1/2 hr.

 

eaglemark you have mail!

 

Never thought differently

RBob.

 

BTW I noticed on the autoprom that theres a 4 wire hook up point on it that im not using. would that be to hook wideband up to it for logging?

 

You know what's even stranger then that is the date on that post and time was exactly 4 years ago yesterday when we were talking of this!

 

Yes that's what it is for. 3 channels and one ground. There's a write up on Moates.

I'm looking at this now, you sure you got 00AB00AC in that box in BPW Read Me Hac**

Did you do the TPS% and Spark Advance Hac?

 

opps the c was a b so now its right. didnt do the spark hack or tps... all 3 are fixed now so ill do another log today and send it at 4:30. sHould i include my bin?

 

I played with this on my own truck today and got the BPW hack as well as spark advance and TPS% built into TunerPro XDF and ADX files.

The data log you sent me did not have the hacks applied properly, BPW, Spark advance and TPS% did not work in the data log you sent.

 

so what would be a target for bpw in milliseconds? thought i saw somewhere it was said 3.87ms would be 85% dutycycle

 

Depends on RPM. It was in the thread I referenced earlier, here's the post:
https://www.thirdgen.org/forums/post...07-post68.html

The ADX has a value BPW and of Injector Duty Cycle which is BPW X and tach RPM Y and math supplied in that thread. So it should be as accurate as a 160 baud ECM can be. It will put out DC for the RPM engine is at. Go by Duty Cycle and no reason to do math.

It was accurate on mine...

 

The calc and explanation is in the thread "free tune" in TBI stickies. I recall it to be 6.0? 85% x 7.0 msec = 5.95

 

I got tha calculation from the thread that is linked in stickes posted above. RBob had the math
BMmonteSS came up with this for allowed times depending on RPM.
Could not find anything differant skimming through the 9 pages of Free Tune sticky. Did they revise the formula?

 

EM, i take it the $42 mask is even more updated than last year? theres a few things goofed in mine and the ads i have is limited. just curious. S_AUJP spoiled me, i never want to go back to 160 baud lol.

 

Well it can't compare to S_AUJP or a 8192 baud ECM. But the XDF and ADX I have been working on for years is light years ahead of any ADS file you have.

I keep working on it because I have a sweet stock 2wd 1990 Suburban for about 8 years that came from factory with 1227747.

If you have a vehicle to test, PM me your email I will send you a set if you promise not to let them float around till testing is done on this BPW stuff?

When done they will be available to anyone as I like to share back the knowledge I gain from everyone. But I don't want these floating around if they are wrong!

V3 is here and will have V4 when done.
http://www.gearhead-efi.com/Fuel-Inj...Information-42

 

the files eaglemark shared with me are real nice...In fact I went through my files today and cleaned off all the extra xdf and adx i accumulated. Being new to tuning I was downloading everything i found! no need for them now.

 

Thanks Hammer!

I got your log and you were worried about hitting 6.xx ms. But you had a couple places that went to almost 8.xx ms. But they were under 2000RPM and only hitting maybe 30% on duty cycle gauge. If you look above at what BMmonteSS posted that is well within the acceptable range for that RPM and about correct for Duty Cycle %. Don't get hung up on a certain ms reading as they change through RPM range.

Look at his times per RPM. Notice how much more time you have available at lower RPM then higher RPM?

Use one of the dash boards and right click on whatever gauge you want to use and choose Injector Duty Cycle %. Don't worry about BPW ms.

Right now you look like you have plenty of fuel. What you need to do is find somewhere you can do a 1/4 mile run WOT at your high RPM shift points and record data. Higher RPM and load is where will will find if you have an issue.

 

pm'd mark

im also going to do a cleanout on some $42 stuff i currently have too lol

 

Well it's seems to be accurate and working well on all fronts so here you go.

Both the XDF and ADX is in there. I finished up some notes and comments along with thanks to people and links to threads where RBob had done the hard work years ago.

 

WOW! great job putting this stuff together! E-Beer for you

 

I haven't even looked at it yet, but I also agree with the E-Beer! The 7747 has been in need of updated ADX.