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FYI: TBI DIY performance and PROM tuning

Discussion in 'The Garage' started by BigBurban350, Aug 2, 2005.

  1. BigBurban350

    BigBurban350 1/2 ton status

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    TBI Stuff here

    PROM tuning here

    PROM tuning hardware here

    Info on your PCM here

    Learn how to build a data cable and download free datalogging software here

    I have learned so much about tuning the TBI computers its amazing what you can do. I posted this here because I know a lot of you guys have TBI on your truck and this is really helpful, especially for a TBI engine that isn't stock anymore (even just headers and k&n). I know my truck ran very bad and it was because of my stock computer on a modified engine. The chips you see in magazines are a RIP OFF!!! They aren't even slightly tuned to your setup. I spent about $100 on the hardware and $120 for a used laptop. The Software is FREE!

    An EPROM programmer that works and is inexpensive can be found on eBay for $50 (willem dual powered) and comes with the software. Another thing you will have to do is solder on a much better eprom chip or flash chip called 29C256 because the stock eprom is what cavemen use (example, you have to erase via UV rays in a little window on the eprom, wtf?!?). It is really easy and moates has real good service and even a guide to do the soldering. The adapter for the 7747 PCM is called a G2 (most likely w/ .6 spacing), it is also recommended to get a ZIF (zero insertion force) socket called the S2 (or get the S4 low profile) for the new prom chips. All this is found at moates.net for about $55 w/ 2 new 29C256 chips. Hes even got a new thing that allows you to switch to different bins (you'll figure it out) with one chip! I also recommend TunerPro RT for editing the bins because its free :) and its windows based with cool graphs for fuel maps and spark tables.

    If you don't think your engine needs tuning or just don't have the money to program(fuel pressure adjustment is free) than do this. Build a simple cable (or buy one for $20) to log data from your computer using the FREE winaldl software (DB9 connector here for pennies). You can then see all the parameters of your engine and see if you need tuning. BLMs are the main concern for fueling a TBI, 128 is the key number. Lower than 128 you are to rich, higher than 128 you are to lean. You can also monitor stuff like your knock counts.


    ---------------------------------------------------
    How I tune the fuel:

    Software used...Winaldl and TunerProRT
    ECM...8746 or 7747 (similar to 8746)

    My friend is winaldl, it logs data. I don't really use the data logging feature but I always record just in case. If you are doing WOT tuning, then use the datalogging feature to check your O2 status and when you start knockin. (Hint, the log is in text file form and you will have to adjust the top row to correlate with the columns, just do it you'll see).

    Still in winaldl, I use the BLM chart for fueling, once your car gets into closed loop the BLM chart will start to log. I use the wide average feature to see where I am at while driving. Wide average will give you a broader realm of your driving style, narrow will toss the outliers. Get in a nice long drive while running winaldl and when you are done your BLM chart will be filled with numbers. The best number, the one you aim for, is 128 (+/- 4 ok). At 128 your vehicle is running at perfect A/F ratio for the conditions. If your BLMs at a certain MAP are below 128, then you are running rich, if they are above you are lean.

    BLM vs. Integrator. The INT is just like a mini BLM, lets say you run lean. Your INT will raise trying to add fuel, once the INT reaches above 150, the BLM raises one digit to 129. Still lean? The INT raises until it reaches above 150, then the BLM raises one digit to 130...AND SO ON. Same with if you are rich, the BLMs just goes down.

    How you adjust your BLMs: After you drive your car for a while and get some good BLM numbers in, go ahead and save the table, click okay for the name (has date and time as the digits). Open up the BLM text file (be sure to delete /map so the maps values line up with the columns). Scroll down to the bottom and you will see correction factors. You use these numbers to multiply with the Main VE fuel table in TunerProRT (TPRT).

    So you are now in TPRT, you will have to load an .XDF file for the 7747 ECM (if you have that ECM). You can download these off the net, like at moates.net and diy-efi.org. The xdf file is like a template for the bin. A bin is what is programmed on the actual EPROM. Once your xdf is loaded, load your bin. I have found very small differences with "stock" bins downloaded off the net, but this is due to different engines, axle ratios, etc. I recommend using your EPROM programmer to read and save the bin from your stock chip (2732 chip). If you open the spark table (SA) and the main VE table the graphs should be relatively conforming (no right angles and crazy jumps).

    Back to tuning, do not touch the SA table until your fueling is done. Take the correction factor values from the winaldl BLM chart and just simply multiply that number to the correlating value in the Main VE table in TPRT. EXAMPLE: if you are running rich, then at 1800 rpms/60 map, its value on the winaldl chart is .865. You multiply .865 to the value on the Main VE table plus Adder VE table value in TPRT at 1800 rpms/60 map (Main Table and Adder table work together so you need to incorporate the adder table). Lets say that value is 60 on the main ve table at 1800 rpms/60 map and at 1800 rpms its 15 on the adder table, so, (60+15)x.865 = 64.9, then 64.9 - 15 = 49.9 <- new value. Easy huh? Go out again driving and make more adjustments until you are close to 128 all over.

    This is what I did to my two VE tables. I took the adder table and made all of the values 20. You aren't supposed to zero out the adder because of some compensation the computer does. For example, the adder table at 800 RPMs the value is 14.57, you make that 20, since you added fuel you must subtract 4.43 that from the whole 800 row of the Main VE table. Lets say at 1600 RPMs the value is 26.30 and you make it 20, you would have to then add 6.30 to the whole 1600 row in the main table because you took fuel away from the Adder. The adder table values are always added to the main. Other people have done this too.

    Now SA tables, I am about to start on that so I don't really have a lot of experience. If you are getting knocks at a certain area, then you should definatly drop a couple degrees around that area. By getting knocks doesn't mean 5 or 6, like 30-100. You do get false knocks. Like at 400 RPMs and 100 MAP i can get over 300 knocks, but that is probably from the starter or the headers. So tuning the SA tables is really the most SA before knockin.

    Edit: I don't know much about the spark bias factors, and basically I just eliminated the main, coolant, and TCC bias by zeroing them out. Surprisingly my car ran a lot better. My spark table is basically a mechanical table (like weights and vacuum advancing). At lower RPMs and low loads the engine has over 40 degrees of advance. At idle I made it around 12 degrees, and it seems to like that. For the WOT you want all of your advance in at 3200 (32 degrees give or take depends on engine). It is also recommended that at lower rpms the advance raises quickly and tapers almost flat from like 1500-3200. There is also slope SA, this is just a degree adder for when you get past 3200. You should make it 0 or play around with it (1-2) for higher RPM advance if your engine likes it.

    Another note, using TunerProRT. When you program your upgraded chips (29C256), you will have to program it so it thinks its the old style chip with less memory. It is called stacking. So after you have saved your bin, you will then hit F5 in TPRT. This will bring up the stacking tool. Your bin is 4k, and the chips are 16k I believe. Click browse on the lower input file and pick your bin. Edit the output file with the same name but OFFSET infront of it so you know thats the one you will program. Note you cannot reopen an offset file in TPRT (or I don't know how) so I save both bins.

    Don't be afraid of playing with stuff, just be sure to keep track of the good bins.

    Also, buy a new 02, since the fueling is all based on the O2. An A/F guage is handy to watch the O2 pinging and also for WOT tuning so you can get off the gas if you're lean.

    If you removed EGR, then make sure you change the on temps and speed to real high numbers so it will never turn on.

    Thanks JPrevost for help w/ this (Thirdgen.org)
     
    Last edited: Dec 1, 2005
  2. y5mgisi

    y5mgisi 1 ton status

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    WOW, thats some rely good info there man.consider this one bookmarked :bow: :eek1:
     
  3. uglyangelracing

    uglyangelracing 1/2 ton status

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    Thanks for the info. Just what I was looking for.
     
  4. ProJunkRacing

    ProJunkRacing 1/2 ton status

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    thanks man i am in tbi process now and i was looking for thanks thanks a million times over
     
  5. Emmettology 101

    Emmettology 101 3/4 ton status

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    Sweet!!! Very good info!!! THis one needs a sticky!!! :thumb:
     
  6. jmd4x4

    jmd4x4 1/2 ton status

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    Yes thanks for all the great info you found. cudos to you my friend.

    thanks
    jmd
     
  7. 91GMCSuburban

    91GMCSuburban 1/2 ton status

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    thanks for the compile.
     
  8. BigBurban350

    BigBurban350 1/2 ton status

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    I love my TBI. I picked up a 454 TBI unit which was going on my suburban. Now that my truck is rusted to hell, I built a Firebird and stuffed my suburbans engine into it. I bought new heads (Dart Platinums) which are worth twice as much as I paid for the car :rolleyes:

    I found that 3rd gen sight and I was amazed at what you can do for so cheap. My wheeling truck is definatly going to run TBI, I love it and its so reliable.
     
  9. TrcksR4ME

    TrcksR4ME 1/2 ton status

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    Good info, will have to save this for when I do my TBI swap :cool:
     
  10. ProJunkRacing

    ProJunkRacing 1/2 ton status

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    any ideas where to get an aldl to usb cable my painless harness is on the way so i wanna be able to tune it via aldl and my laptop has no serial port
     
  11. BigBurban350

    BigBurban350 1/2 ton status

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    Newegg is awsome!

    Adapter

    I have ordered a ton of stuff from newegg and never any problems and always real fast shipping.
     
  12. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    I get to learn all about this stuff. I'll need to do a whole lotta tuning on my TPI truck pretty quick, lol

    Thanks for the links. Hopefully it isn't too hard to learn how to re-program a prom...
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    I suggest going and checking up on the serial/USB adapters and what not over on thirdgen.org.

    IIRC some people have had problems with the adapters and ALDL, but since I have serial ports, I didn't pay attention. I just know there are some issues that I'd check into before purchasing any adapter.
     
  14. BigBurban350

    BigBurban350 1/2 ton status

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    I am into computers, but all this stuff was over my head. I just did it, bought all the stuff and asked questions. Now I burn chips everytime I got out and fine tune everything, its so cool. Tuning is key, good luck bro.
     
  15. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Yeah, I know a fair bit about computers as well, but I have no clue where to even start with this stuff. I don't understand the data structure, nor do I understand how I need to modify the chip to make things work the way I want. However, I am very willing to learn, and usually pick up on stuff pretty quick. I plan to buy one of those EEPROM chips that can be edited without the UV eraser, and start at step one and start going :) I got Brian Harris of TBIChips.com to get me set up with a custom prom right off the start, so the truck will run pretty decently already, but I will want to do a fair bit of fine tuning to get the most power and mileage outta the engine as possible.

    If you don't mind, can I work together with you to kinda get started with this stuff? Definitely seems a bit over my head at a first look, lol
     
  16. dirtwarrior17

    dirtwarrior17 Banned

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    More info...

    found this on yahoo...http://www.elmnet.net/~lange_c/TBI_INFORMATION.html

    Don't forget about this thing...http://misterbill.homeip.net/aboutprominator.asp

    The prominator is more expensive but you don't have to pull the ecm everytime you want to make a change, like you would with the eeprom... you solder the prominator in your ecm(or let bill do it) and hook a cable up to it and your done. With the "PRO" version prominator you can make changes on the fly or while your driving down the road. It also can save 6 maps at a time and switch from map to map using a switch that bill sells.
     
  17. dyeager535

    dyeager535 1 ton status Premium Member

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    Just go download tunerpro RT 4, get the ECU file for the 1227747, a .bin for a truck TBI application close to your year (the link dirtwarrior posted shows "ARJT" as a 1991 truck .bin) and then just use tunerpro to browse through it.

    Tunerpro will allow you to do most anything you want, and it lays the stuff out in a pretty easy to understand way. Once you find the things you want to change, it's a simple matter of having the actual hardware to change your stuff.

    I do like the idea of the Prominator and what not over the PROM burning stuff.
     
  18. dirtwarrior17

    dirtwarrior17 Banned

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    I thought you were goin with the prominator....

    Yeah its more expensive but IMHO its worth it. instead of burning all your maps on different chips you just save them and download them... its the same exact thing except you don't have to pull the ecm everytime you want to change the map and you can do it on the fly.
     
  19. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    Since my TPI was a custom install, I put the ECM in an easy to access spot right beside my steering column behind the instrument cluster :) Its about as easy as pulling a fuse to get my chips out :)
     
  20. BigBurban350

    BigBurban350 1/2 ton status

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    There are emulators where you can actually change stuff while the vehicle is driving. The only downsides are you need a friend to drive and its expensive.
     
    Last edited: Aug 12, 2005

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