Got my Autoprom, now I have a few questions

[Mr.350]

First off I have done all my reading and everything. I have like 3 instances of firefox open now with about 12 tabs in each one. My first question is simply how do I get the bin from the memcal I am using. It is a mail order tune that still uses the UV chip. Will the autoprom read this, and if so will TunerPro RT V5? It seems like I was able to write it to my hard drive, but I cannot get it to copy back to the emulator or onto a chip for that matter. No matter what I do it goes into Limp mode, unless remove all adapters and put the memcal by itself in the PCM.

I bought the Autoprom, HDR1, G1, extra 27SF512 chips...

PCM: 7427
Bin: Custom
XDF: 0D_TP5_v250
ADX: A217_0D_v250

383 TBI, with 4L60E

[Eagle-Mark]

with your AutoProm plugged into the laptop then open TunerPro. Did it detect the hardware?

If it did good, if not you still have to go to Tools, then Preferences, then Data Aquis. and set it up there.

then you can Tools, Initialize Emulation Hardware and get the bin loaded in the AutoProm.

Make sure you have your comm ports set right. If you think everything is correct and still no go. Close the program, leave the AutoProm plugged in and restart the computer, then open TunerPro again.

[Mr.350]

with your AutoProm plugged into the laptop then open TunerPro. Did it detect the hardware?

If it did good, if not you still have to go to Tools, then Preferences, then Data Aquis. and set it up there.

then you can Tools, Initialize Emulation Hardware and get the bin loaded in the AutoProm.

Make sure you have your comm ports set right. If you think everything is correct and still no go. Close the program, leave the AutoProm plugged in and restart the computer, then open TunerPro again.

Well I can get TunerPro and the Autoprom to see each other, but my first question is how do I extract the bin that is in the mail order chip I got. I got the header so that it can sit in the autoprom, but I dont know what settings to use to read the bin from the UV chip.

[Eagle-Mark]

Reading the chip is way easy compared to the settings to burn one.

Hook up the AutoProm to laptop. Open TunerPro and it should detect hardware. Then click on Tools, then Moates PROM I/O. This will open the window with chip reading and writing stuff. Pick the chip type your going to read, then click Read Chip. You don't have to worry about all that other stuff to just read a chip. It will say reading chip into buffer, then Prom I/O succeeded. Then click save buffer to file! Your done!

[Mr.350]

Reading the chip is way easy compared to the settings to burn one.

Hook up the AutoProm to laptop. Open TunerPro and it should detect hardware. Then click on Tools, then Moates PROM I/O. This will open the window with chip reading and writing stuff. Pick the chip type your going to read, then click Read Chip. You don't have to worry about all that other stuff to just read a chip. It will say reading chip into buffer, then Prom I/O succeeded. Then click save buffer to file! Your done!

Hmmm, well when I did that it looked like all the data was right but it would not work to start the truck. Anyway I did get it to work by just copying all those settings into a stock bin so that now I have my custom tune that actually works.

[Eagle-Mark]

But all we did so far was read the chip and save the file. Burning the chip is another whole story but you seem to have got it! :-)

[Mr.350]

Actaully I did manage to get all the data off my mail order bin saved to another bin, burned to a chip and then run in the truck successfully. I just got the datalogging working now too, and I am working on an excel sheet that I can copy my datalogged BLMs into as well as current VE setting in the bin and it will spit out adjusted VE values to copy into a new bin.

Once I figure how to post a pdf on here I will show it for yall to comment on.

[Eagle-Mark]

You don't have to do a bunch of work on a spread sheet before hand. Just open your logged file in excel or others and answer a few questions and it comes out all lined up for you. HTH!

[Mr.350]

You don't have to do a bunch of work on a spread sheet before hand. Just open your logged file in excel or others and answer a few questions and it comes out all lined up for you. HTH!


Well its no big deal, now I can copy and paste my VE table and my datalog running average BLM and it will spit out a corrected VE table to use. I did that and then applied a smoothing with .8 factor to the end result in TunerPro. Seems to remove all the "jumpiness" in the graph without affecting values too much. So am I correct in doing this as my first step to tuning, getting the VE tables in order? Once I can get BLMs around 128 plus or minus 5 or so what do I work on next? In what order do the AE and PE tables come?

[Mr.350]

Also was looking over my starting bin, which was my second chip from TBIchips.com and noticed that the injector flow rate is set at 61 lb/hr. This would be great if I were running stock injectors and fuel pressure, but I bought the kit from TBIchips that came with a high flow/volume fuel pump and an 18 psi spring that I put in. So shouldnt my injector flow rate be set at about 74.7 lb/hr according to the stick pasted below? Will this change anything too drastically or is it only used for like MPG simulation or something?

http://www.fullsizechevy.com/forum/general-discussion/performance/200226-tutorial-you-getting-enough-fuel-support-your-performance-upgrades.html

[Eagle-Mark]

I don't have much time tuning the newer TBI ECM 16197427 but my understanding is the TBI Injector flow rate will effect everything, it has to be set right first. Maybe you could ask TBIChips if he has a differant stratagy for fuel presure, injector rate and tuning?

[907 Chevy]

The injector flow rate needs to be corrected.If the pcm still believes the injectors are 61 lb/hr then it's gonna run rich as fvck.

You are correct that 18 psi fuel pressure would yield a flow rate of 74.7 lb/hr,though this should be verified with an inline pressure gauge.

Edit:How much fwhp is your engine producing?With that fuel pressure those injectors will quickly go static at WOT.~150 lb/hr of fuel will only feed 270 fwhp @ 80%DC.

[Mr.350]

The injector flow rate needs to be corrected.If the pcm still believes the injectors are 61 lb/hr then it's gonna run rich as fvck.

You are correct that 18 psi fuel pressure would yield a flow rate of 74.7 lb/hr,though this should be verified with an inline pressure gauge.

Edit:How much fwhp is your engine producing?With that fuel pressure those injectors will quickly go static at WOT.~150 lb/hr of fuel will only feed 270 fwhp @ 80%DC.

I emailed Brian to see if he can update the injector flow rate in his bin and correct all other tables that go with it since I have already paid him for this. Then I can go back and tweak it on my own.

You make a valid point that I may have overlooked, but no worries if I need larger injectors I will grab some. I guess I estimated my setup in my sig to make around 315 fwhp so I guess I need around 100 lb/hr of fuel injector capability huh? Well that will help me find my way to properly tuning this thing.

I went back and looked through TunerPro and the datalog with the highest RPM recorded was 4448 RPM @ 52.95 inj DC but I will try and grab a log to redline to see what happens.

[907 Chevy]

Assuming 0.5 pound of fuel per horsepower and 80%DC you'd need the injectors to flow 95 lb/hr to support 315 fwhp.
Putting around 29psi to the 61 lb/hr injectors would yield the required flow rate.
There's no need to buy new injectors,you could mod your stock regulator or buy an aftermarket TBI regulator that's adjustable to up the fuel pressure.

I have an afpr from xtremefi for $50 that's adjustable up to 40 psi.

[whitelightnin92]

you will find that he left the flow rate at 61.1 lbs/hr to keep from maxing out the ve table. its fine like that. my injectors flow about 95 lbs/hr but to keep from maxing out the VE i run my flow rate at about 75 lbs/hr. this will give you more head room. it just means you will have to scale down your ve to avoid running rich

[Mr.350]

Assuming 0.5 pound of fuel per horsepower and 80%DC you'd need the injectors to flow 95 lb/hr to support 315 fwhp.
Putting around 29psi to the 61 lb/hr injectors would yield the required flow rate.
There's no need to buy new injectors,you could mod your stock regulator or buy an aftermarket TBI regulator that's adjustable to up the fuel pressure.

I have an afpr from xtremefi for $50 that's adjustable up to 40 psi.

Ok I checked them out and it looks like I need that inline fuel fitting and the gauge as well so I will order all that.


you will find that he left the flow rate at 61.1 lbs/hr to keep from maxing out the ve table. its fine like that. my injectors flow about 95 lbs/hr but to keep from maxing out the VE i run my flow rate at about 75 lbs/hr. this will give you more head room. it just means you will have to scale down your ve to avoid running rich

Thats what I figured. Does this software only let you run a VE of 100%? I have been tuning a 4 cyl turbo car and my VE went over 100%, but I guess TunerPro isnt designed for boosted stuff.

[Mr.350]

On second thought, I will just buy the regulator and rent the tool below to set it up and make sure it holds pressure. I love autozone and their loan tools...

http://www.autozone.com/autozone/accessories/Actron-Fuel-Pump-Diagnostic-Kit/_/N-26vs?counter=1&itemIdentifier=913437_0_0_&target=shelf

[Eagle-Mark]

On my one rig I had problems at WOT. I bit the bullet and bought an adapter that puts the presure gauge inline at the throttle body for reference on fuel presure. Then I made up a fule line with fittings so I could watch the presure while driving, it was run through the cowl and up through the vent under the windsheild. What I notoced is my fuel pressure was driopping at WOT after 4000 rpm. I would have never known that with a stock fuel pressure gauge.

Also remember for any one reading this DO NOT ever run fuel line into the passenger compartment. They do make fuel presurres gauges for passenger compartment that have sending unit to gauge, but never a line in like a oil presuure gauge does. Gas in passenger compartment is not good/safe/sane/legal...

[Mr.350]

Yea Im thinking with that 40" of hose that is on the gauge of the tool I pasted, I should be able to tape it to the windshield to watch while I drive. To make it simple I am thinking I will set it at 30 psi. Then at an 85% DC using the 61#/hr injectors at 30 psi should support 327 hp which I would be happy to make, but realistically dont quite think I am. Thanks guys for the help.

Also, I was thinking about keeping this thread going as I go through tuning my engine since in the next month or two I plan on getting a WBO2 also (already welded a bung in!). This seems like it could be yet another good thread to help others tune their engines, since yall have provided a lot of help so far.

[907 Chevy]

you will find that he left the flow rate at 61.1 lbs/hr to keep from maxing out the ve table. its fine like that. my injectors flow about 95 lbs/hr but to keep from maxing out the VE i run my flow rate at about 75 lbs/hr. this will give you more head room. it just means you will have to scale down your ve to avoid running rich

Hmm,why would injector flow rate affect the ve table?


Thats what I figured. Does this software only let you run a VE of 100%? I have been tuning a 4 cyl turbo car and my VE went over 100%, but I guess TunerPro isnt designed for boosted stuff.

I'm sure that would depend on the bin not the editor.Tunerpro can edit sy/ty,turbo grand prix bins,etc. all of which are boosted apps.

Happy tuning.Keep us posted...

[whitelightnin92]

it isnt really the software that limits the ve its the code. and flowrate directly affects the fueling. its no different than changing the fuel pressire

[HaulnA$$]

you will find that he left the flow rate at 61.1 lbs/hr to keep from maxing out the ve table. its fine like that. my injectors flow about 95 lbs/hr but to keep from maxing out the VE i run my flow rate at about 75 lbs/hr. this will give you more head room. it just means you will have to scale down your ve to avoid running rich

If you have to lie to the ECM to get the tune "right" then the ECM will lie to you, hence the beginnings of a vicious cycle that ends badly every time. BTDT.

I did'nt mean to jack the thread but bad advice begets bad results. JMHO.

[Mr.350]

If you have to lie to the ECM to get the tune "right" then the ECM will lie to you, hence the beginnings of a vicious cycle that ends badly every time. BTDT.

I did'nt mean to jack the thread but bad advice begets bad results. JMHO.

Thank you for the advice. I am just trying to get a "driveable" tune from TBIchips so that I can go on to work on my own bin, but have the old one handy just in case. So you think that could be one of the reasons I am having issues with cold idle surging and terrible take off while cold? Also I am being told by Brian that the 61#/hr injectors at 18 psi will support 300 hp, and he says that after 20 psi on them, they start to misfire and run worse under heavy throttle. Its getting hard to figure out what exactly to do to make this thing run well....

[HaulnA$$]

Thank you for the advice. I am just trying to get a "driveable" tune from TBIchips so that I can go on to work on my own bin, but have the old one handy just in case. So you think that could be one of the reasons I am having issues with cold idle surging and terrible take off while cold? Also I am being told by Brian that the 61#/hr injectors at 18 psi will support 300 hp, and he says that after 20 psi on them, they start to misfire and run worse under heavy throttle. Its getting hard to figure out what exactly to do to make this thing run well....

What Brian is telling you is BS. GM ran the mid 90's 454 TBI trucks with 4.3 TBI injectors which flow around 47 lb./hr at 12 psi but flow around 75 lb./hr when the the fuel pressure is up at 30 psi which is what GM did. There were no reports of injector problems with these trucks. Fuel pump problems, yes, but not injector issues.

I'll just say this. If you look at injector specifications, fuel pressure and voltage play a big role in how much injectors flow as well as other mechanical properties. For example, a 4.3 TBI injector might flow 47 lb./hr at 12 psi fp and 13.8V but will flow 75 lb./hr at 30 psi fp and 13,8V, however the offset times will be much different as the injector will take longer to open and close at the higher pressure for the commanded pulse width. This must be taken into account in the tune for fueling to be correct. If the offset times are too short, the engine will lean out at WOT. Too long and you blow black smoke at idle. HTH

[Mr.350]

Ok I just ran some datalogs with tts datamasters and did a WOT run through first and second and noticed that up around 4300 to 4400 the Inj BPW doesnt seem to go over 7.55 and it reports this as a 56% duty cycle. I think the way it calculates this is incorrect. Also at the end of both gears around 4400 or so there is a datapoint where the Inj BPW is 253 and the DC is like 1920%. To me this seems like injector issues right? Is this the data equivalent of them running static?

[HaulnA$$]

Ok I just ran some datalogs with tts datamasters and did a WOT run through first and second and noticed that up around 4300 to 4400 the Inj BPW doesnt seem to go over 7.55 and it reports this as a 56% duty cycle. I think the way it calculates this is incorrect. Also at the end of both gears around 4400 or so there is a datapoint where the Inj BPW is 253 and the DC is like 1920%. To me this seems like injector issues right? Is this the data equivalent of them running static?

You would be correct, Datamaster does not calculate injector duty cycle correctly for TBI. Take what is reports and double it. Thie answers your second point about the injectors going static. If you do the math, at 4400rpm and each injector firing every other DRP, that only allows for a 6.81mS total pulse width. 7.55 is not possible. Check your O2 sensor voltage at WOT. If it is less than 900mV, you're running lean. You need more injector. Are you're getting a bad bog when you lay into it hard?

[907 Chevy]

http://www.fullsizechevy.com/forum/general-discussion/performance/tbi-tuning-87-95-obd-i-ecm-pcm/316227-what-pw-max-80-injectors.html

Good thread on the subject.

[Mr.350]

You would be correct, Datamaster does not calculate injector duty cycle correctly for TBI. Take what is reports and double it. Thie answers your second point about the injectors going static. If you do the math, at 4400rpm and each injector firing every other DRP, that only allows for a 6.81mS total pulse width. 7.55 is not possible. Check your O2 sensor voltage at WOT. If it is less than 900mV, you're running lean. You need more injector. Are you're getting a bad bog when you lay into it hard?

The thing is that Tuner Pro RT gives me the same results, ~7.5 ms BPW and ~50% DC using the ADX file in post #1. Also my O2 is always above 900mV during those runs. It is usually at 915 to 970. I do get a bad bog when I lay into it and I can tell once it downshifts to first it has power but that quickly dies off before 4500 rpm. I guess I should up my fuel pressure, correct the injector flow rate mentioned above, correct the VE, and go from there? Also Brian says "Duty cycle isn’t even close to max on the few wot pulls on those 2 logs and the motor looked rich at the level we had at full throttle" when I sent him my datalogs...???

[HaulnA$$]

The thing is that Tuner Pro RT gives me the same results, ~7.5 ms BPW and ~50% DC using the ADX file in post #1. Also my O2 is always above 900mV during those runs. It is usually at 915 to 970. I do get a bad bog when I lay into it and I can tell once it downshifts to first it has power but that quickly dies off before 4500 rpm. I guess I should up my fuel pressure, correct the injector flow rate mentioned above, correct the VE, and go from there? Also Brian says "Duty cycle isn’t even close to max on the few wot pulls on those 2 logs and the motor looked rich at the level we had at full throttle" when I sent him my datalogs...???

Then you must be running in asynchronous fueling mode at WOT. Not the best way to do it but was common in the '95 calibrations. That is one of the first things I turn off. Reconfigure Datamaster to display the "Asynch Fuel" bit and replay the logs to verify.

915mV O2 is o.k., 970mV is rich.

As for upping your FP fore more injector, it is easy to go too far and then have problems with an erratic idle. Your injectors should be flow enough to support max HP at 1:1 tranny gearing at 80-85% duty cycle and no more. HTH

[907 Chevy]

Hauln,what is the benefit of running synchronous fueling at WOT?

Are the benefits(or drawbacks) of async/sync fueling dependent at all on intake design,e.g. single plane vs. dual plane?

It seems that running synchronous fueling would be of much greater benefit with a single plane manifold rather than a dual plane with it's two separate plenums.

[HaulnA$$]

Hauln,what is the benefit of running synchronous fueling at WOT?

Are the benefits(or drawbacks) of async/sync fueling dependent at all on intake design,e.g. single plane vs. dual plane?

It seems that running synchronous fueling would be of much greater benefit with a single plane manifold rather than a dual plane with it's two separate plenums.

Intake configuration really has nothing to do with it. Synchronous fueling is always better as the injector pulse is timed with the DRP (Distributor Reference Pulse). Having said this, a single plane would in my opinion, work better than a dual plane with asynchronous fueling as it has a larger common plenum area. Synch. fueling would still be better either way though since you can play with injector timing either by mechanically advancing the dizzy or in the chip. HTH

[Mr.350]

OK I am going through this again starting with a stock BIN. I have upped my injector flow to the correct value, cylinder volume, disabled async mode by increasing rpm to switch from sync to async to like 6k and also increasing map to 104. Kept VE stock. Was running lean. So I will be increasing the Injector Offset vs. Battery Voltage table by multiplying by 1.5 across the board brings the 0V and 14.4V to 595 usec.

For rough tuning of my VE does it matter much that I want to use and have enabled CCP and EGR?

Also was looking through and it appears that the A217_0D_v250.adx needs the Inj DC% value corrected for a 2 injector TBI V8. It states (IPW)*(TACH)/60000*100. I seem to think that since each injector should be firing 2 times per rev that the adjusted formula should be 2*(IPW)*(TACH)/60000*100 . Correct?

[Mr.350]

OK I am going through this again starting with a stock BIN. I have upped my injector flow to the correct value, cylinder volume, disabled async mode by increasing rpm to switch from sync to async to like 6k and also increasing map to 104. Kept VE stock. Was running lean. So I will be increasing the Injector Offset vs. Battery Voltage table by multiplying by 1.5 across the board brings the 0V and 14.4V to 595 usec.

So I just did this and it seemed to bring my BLMs down so that I may not max out my VE table. I am kinda getting sick of all this guessing and will be ordering a wideband O2 today also just fyi. Also I noticed that I have been using E10 fuel for the last few years, and have never gone anywhere that had anything different. Should I change Stoich AFR to 14.2? Will anything else need to be adjusted because I would think that the BLMs and everything is based on 14.7.

Anybody have a good link on tuning the 7427 0D with a WBO2? Best I could find I pasted below.

http://www.fullsizechevy.com/forum/general-discussion/performance/tbi-tuning-87-95-obd-i-ecm-pcm/436297-7427-wb.html

[whitelightnin92]

you need to change stoich to 14.2 but once you get your tune close you will probably need to tweak your 02 thresholds to get your blms at 128 when your wideband reads 14.2 in closed loop. if your ordering a wideband then i reccomend you run one of your inputs to the pcm egr pintle position input so you can read AFR from the aldl. then use TPRTV5 to input that data into a table. you will need to turn off all emissions equipment and set all desired afr to 13.0:1 across the board. then tune the VE to get 13.0:1 . then turn everything back on. but since haulin is here im gonna let you listen to him. hes got a bit more experience than i do.
peace

[HaulnA$$]

you need to change stoich to 14.2 but once you get your tune close you will probably need to tweak your 02 thresholds to get your blms at 128 when your wideband reads 14.2 in closed loop. if your ordering a wideband then i reccomend you run one of your inputs to the pcm egr pintle position input so you can read AFR from the aldl. then use TPRTV5 to input that data into a table. you will need to turn off all emissions equipment and set all desired afr to 13.0:1 across the board. then tune the VE to get 13.0:1 . then turn everything back on. but since haulin is here im gonna let you listen to him. hes got a bit more experience than i do.
peace

Sounds like sound advice to me. The only thing I would add is that when adjusting anything in the chip, especially something as critical as injector offsets, it is best to not guess. Either have the injectors flow tested by someone who can plot offset times vs. voltage and presure up to the pressure you are running or if you look hard enough, you can probably find some info on the net. IIRC I ran across some good flow info on TBI injectors.

[helo]

however the offset times will be much different as the injector will take longer to open and close at the higher pressure for the commanded pulse width.
:aniteef:

I'll throw in my 2 cents on this, I just dealt with it. I run stock 5.7 injectors @30psi.

I suspected my offsets were wrong after I somehow stumbled on an old thread by 93v8s10 that mentioned the injector offset table, but I had no idea how to go about trying to tune the table even after reading EVERTHING I could find.

I tried 650usec instead of 400, but no matter what I did with OLAFR, VE, proportional gains, ec, I couldn't get it to stabalize under all condiitons. I still had problems in gear under 500rpm.

Eventually I got around to trying 800usec. much better, no idle oscillation any more. I'm using stock 5.7 injectors @30psi. 750 or so might be more appropriate, but it's impossible to guess/verify injector offsets unless you're way off. For all I know, maybe I should run 900usec with slightly lower VE values for low rpm...
:shrug:

As for exceeding 100 on the VE table, x2 disable async fueling and you'll be fine. I wish this thread would have existed a few weeks ago... *sigh*.

[907 Chevy]

From rbob at tgo...

One way to find out what values to use vs battery voltage is to disconnect the alternator. Then drive around data logging. If the BLMs fall then the offset is too high at that battery voltage. And vice versa.

[Mr.350]

:aniteef:

I'll throw in my 2 cents on this, I just dealt with it. I run stock 5.7 injectors @30psi.

I suspected my offsets were wrong after I somehow stumbled on an old thread by 93v8s10 that mentioned the injector offset table, but I had no idea how to go about trying to tune the table even after reading EVERTHING I could find.

I tried 650usec instead of 400, but no matter what I did with OLAFR, VE, proportional gains, ec, I couldn't get it to stabalize under all condiitons. I still had problems in gear under 500rpm.

Eventually I got around to trying 800usec. much better, no idle oscillation any more. I'm using stock 5.7 injectors @30psi. 750 or so might be more appropriate, but it's impossible to guess/verify injector offsets unless you're way off. For all I know, maybe I should run 900usec with slightly lower VE values for low rpm...

Ok well taking that info as working good for you if the relationship between the 5.7L injector offset vs volts value and increased FP is linear (which I kind of doubt) then I could extrapolate that into an equation as a good approximation. 22.22*(FP) + 133.33 would be the batt volts offset. This gives stock presssure at about 400 and 30 psi at about 800, and me (18 psi) at about 533 which I will try.

Now Helo let me ask you this. How did you adjust the table for all voltage values. Offset the entire table + 400 or did you multiply the entire table by 2 or what??

Haulin, what do you think about my post #32 regarding inj DC%??

Also I have ordered my LC-1 with DB gauge kit so once that comes in I will be a pro!! (joking). Thanks everyone for the help though. I try to do as much reading as I can but sometimes ya just got to ask for help.

[HaulnA$$]

O.K., I think everyone is getting a little ahead of themselves. The goal here is to tune the vehicle not adjust a table. There is a whole lot more to it than getting one table right. Mechanical properties affect the tune and one table affects another. Everything must be considered as a system or you are just going round in circles. I know, this is a lot of doublespeak. I'll explain.

Since we are talking fuel systems here we'll go with that. Most everyone upgrades all the major components in their fuel system to support all the other go fast goodies they did to increase power. Fuel pump, fuel pressure, injector size are all changed or some combination thereof. Since all these things affect one table or another in the chip, you must calibrate ALL tables and constants involved. Instead of taking what some other scmuck and did and doing a monkey see monkey do bit, take a thoughtful and logical aproach. First off, "Injector Offset vs. Battery Volts" table. With higher fuel pressure, offset times change. As stated above, one way to adjust this table is to disconnect the alt. and adjust for steady BLM as voltage changes. Great, but what about the "BPW vs. Fuel Pump Volts" table, If this is not right, you just messed up what you just tuned. What about your minimum Synch and Asynch pulse width constants. If your offsets change, your minimum PW cannot be less than the offset or no fuel will flow. What about making flexible lines for your injectors so you can extend the pod and run fuel into a graduated cylinder. Turn the FP on for exacxtly one min. Measure the fuel in the cylinder and convert cc/min. to lb./hr and now you know exactly what your injectors flow. No guessing.

Did I get you thinking? Good, that is the point. Is this stuff harder then it looks? You betcha! Can it be done the right way? Sure, if you just use that thing on your shoulders with all the holes in it. :think::soapbox:

[helo]

My advice is that you need to work on your OLAFR table, it's probably causing most of your issues. Getting VE in the neighborhood is equally critical, and it sounds like you haven't spent very much time with that yet. Async fueling is just bad news (but has nothing to do with idle or low rpm running)

You can't really look at the tables mathematically like you're trying to do. To answer your question on inj offsets, your truck will only ever see about 7v-16v (and 0v should match 14v in case teh PCM pin breaks or whatever). Graph the factory values adn you'll see it's not linear at all. Without precision test equipment, any changes you make are purely WILD GUESSES. It's like adjusting SA, there's no way to do it using math no matter how much you analyze it. (and I was a math major).

I was running just fine before I found the injector offset table, with the exception of some semi-sporatic idle issues (but I had no stalling whatsoever). I spent a lot of time looking through my logs and searching google before I committed to fudging the injector offset. I reached my conclusion because I had wildly fluctuating BPW at idle (.4msec - 2msec). I had EVERYTHING else stable (I ruled out everything, and I confirmed the root of MY problem was too short of commanded injector opening.

[whitelightnin92]

Sounds like sound advice to me. The only thing I would add is that when adjusting anything in the chip, especially something as critical as injector offsets, it is best to not guess. Either have the injectors flow tested by someone who can plot offset times vs. voltage and presure up to the pressure you are running or if you look hard enough, you can probably find some info on the net. IIRC I ran across some good flow info on TBI injectors.

where exactly can i get this info you speak of? never been able to find anything on the net

[whitelightnin92]

if you really wanna learn about injectors read this. http://sz0031.wc.mail.comcast.net/service/home/~/Injector%20Dynamics.zip?auth=co&loc=en_US&id=2260&part=2

[HaulnA$$]

where exactly can i get this info you speak of? never been able to find anything on the net

Don't know. That is why I posted with the caveat of IIRC (if I remember correctly). If I had a link I would have posted it. The whole point is to get creative and figure out how to test these things for yourself. I'm not ever going to spell it out like do A, then B and C and get the result you want. I built my own injector flow setup at one time so I could figure stuff out but there is more than one way to do it. Even if you find info on the net, how do you know it is accurate for your setup. DIY is more than just a catchy phrase.

[Mr.350]

Alright, point taken guys. I guess I am just in a hurry to let the beast out, but it cant be done quickly, least not by me. So I will be waiting for the WB to come in before I do anymore real changes, other than adjusting VE to get BLM's close. Correct me if I am wrong, but this is my understanding of what to do when my wideband comes in.
1. Set Wideband Stoich to 14.2 and install into datastream
2. Enable Open Loop AFR Flag, Max temp for AFR Lookup in Closed Loop is already 149.8 C so leave as is, Min Temp for Closed Loop is -1.8 C leave as is
3. Set Open Loop AFR vs. Temp vs. Vacuum to 13.0 across the board (what about Open Loop Idle Lean Limit vs. Temp?)
4. Disable ccp, egr, (anything else?)
5. Go for a drive
6. Check the running average of the WBO2 AFR history table for datapoints with 10 or more samples. Adjust open throttle and idle VE cells by (WBO2)/13.0)*VE
7. Repeat 5 and 6 until no adjustment is necessary.
8. Undo steps 2,3, and 4
Anything else??

[whitelightnin92]

set pe to 13.0:1 aswell. disable cat overheat protection. theres some more but i cant think of everything off the top my head

[xch3no2]

WhiteL wazzup w/ that link?

Edit: I've only found offset info for MPFI injectors online...no tbi stuff tho...I run mine stock x2 (1400usec) at running volts and 50-60psi.

[Eagle-Mark]

OK I am going through this again starting with a stock BIN. I have upped my injector flow to the correct value, cylinder volume, disabled async mode by increasing rpm to switch from sync to async to like 6k and also increasing map to 104. Kept VE stock. Was running lean. So I will be increasing the Injector Offset vs. Battery Voltage table by multiplying by 1.5 across the board brings the 0V and 14.4V to 595 usec.

For rough tuning of my VE does it matter much that I want to use and have enabled CCP and EGR?

Also was looking through and it appears that the A217_0D_v250.adx needs the Inj DC% value corrected for a 2 injector TBI V8. It states (IPW)*(TACH)/60000*100. I seem to think that since each injector should be firing 2 times per rev that the adjusted formula should be 2*(IPW)*(TACH)/60000*100 . Correct?Injector offset vs batterey voltage is there to compensate for voltage fluctuations. I have read from several other tuners that this should not be messed with. GM knew better then we could guess/figure out what to do with it. Now this was a conversation on a 7747 so... a better adjustment for injector flow to compensate for higher presuure was Injector bias and BPW Constant for EGR off as the 7747 has a table for BPW for EGR on which changes the values for the VE there to compensate for EGR gas entering the combustion chamber. But once these put your BLM close then do the Main VE table. Getting the main VE table very close needs to be done before other adjustments because everything is based off the VE Main table. Just trying to put this into perspective for tuning this newer427 PCM.

[xch3no2]

It is entirely reasonable to use voltage offset tables to lean on the injectors for pressure compensation.

[whitelightnin92]

WhiteL wazzup w/ that link?

Edit: I've only found offset info for MPFI injectors online...no tbi stuff tho...I run mine stock x2 (1400usec) at running volts and 50-60psi.

crap i will try to fix it

[helo]

It is entirely reasonable to use voltage offset tables to lean on the injectors for pressure compensation.

:word:

The 7747/$42 equivalent for the $0d "injector offset vs voltage" is:

0x03E9 (table) "Injector Compensation vs Battery Voltage"
0x02DA (constant) "Injector Bias"
(both are defined in 42-7747-87-91tbi5.0.xdf, hit/miss with other $42 xdf's)

In $0D:
(0x4AFB) Injector Offset vs Battery Voltage
(0x497E) BPW Multiplier vs Fuel Pump Voltage



Injector offset vs batterey voltage is there to compensate for voltage fluctuations. I have read from several other tuners that this should not be messed with. GM knew better then we could guess/figure out what to do with it.

They're wrong, and I bet they've never successfully tuned a tbi setup running double/triple the stock fuel pressure.

There comes a point where you run out of variables to play with, and only then might it be time to start fudging the injector offset in pursuit of a stable injector PW at idle.

[whitelightnin92]

i never had a problem with idle

[helo]

Yea, my traffic light idling is slightly rich now because my offset table is now too high. Trial&error, I suppose.

Here's a link for OP & future readers,

Idle spark advance (http://www.fullsizechevy.com/forum/general-discussion/performance/tbi-tuning-87-95-obd-i-ecm-pcm/321564-idle-spark-advance.html)

I think this is what I've been missing. I tried reducing the allowed timing swings a while back to stabalize idle (no change), but I didn't think to try increasing the tables.

[whitelightnin92]

yea you definately want to increase timing around idle some if you have a larger cam. if it lopes alittle too much at idle thats a good indication. tune for lowest map at idle

[Eagle-Mark]

They're wrong, and I bet they've never successfully tuned a tbi setup running double/triple the stock fuel pressure.

There comes a point where you run out of variables to play with, and only then might it be time to start fudging the injector offset in pursuit of a stable injector PW at idle.This could be true! That is a big jump in pressure and something GM probably never even thought of, or the tuners ever thought of.

It may be a true statement up until a certain point but obviously at 2 to 3 times the presure all basic rules of tuning are out the door.