now im a tbi guy!

[steveo]

i'll be honest, i've never liked tbi, but i guess i will now since i'll be daily driving one.

has a gm 305 crate longblock of some description with the original tbi stuff stuck on it.

have tons of crap in the engine bay i'll be stripping out (ac, air, whatever) just 'cause a cluttered engine bay pisses me off, then i'll start tuning.

[dave w]

Seems to me like there would be room in the engine bay to convert to a LT1 engine?

BTW, the '7427 TBI PCM is an excellent upgrade for the $$!:thumbsup:

dave w

[brian617]

Let me know if you need larger injectors, I have a clean set of 350 injectors i'd swap for a good pair of 305 injectors.

[buddrow]

Welcome to the world of TBI Steveo lol. After all the work you've put into the LT1 and you're having to "slum it" with a tbi, such a shame. :)

Buddrow

[steveo]

Seems to me like there would be room in the engine bay to convert to a LT1 engine?

sure would be, but i dont think i'll do that...one lt1 is enough lt1

[RobertISaar]

TRAITOR!

at least it's not a carb..... or e-carb. :laugh:

i would probably start collecting TPI parts in your situation(or the LT1 top end if it bolts onto the existing heads?), i just can't stand the thought of anything that doesn't have one injector(or more) per cylinder.

[steveo]

im with ya robert, if i ever see a cheap tpi setup ill be all over it. im actually a big lb9 fan too, i've had several. but i've never actually played with a tbi unit, so i kinda want to do it for the experience.

i havent even had a chance to dig back in my memory and remember what mask it's running, and i'll have to hit moates for some kit.

i think one problem with this car is that the stock lo3 tbi & computer was plunked on SOME sort of '305 ho' crate longblock, which i figure has a different VE

i have no bloody idea, but i can tell without it even being on a scanner, it's trimming a hell of a lot (the transition into closed loop is very obvious, and once it catches up, part throttle goes from odd to PERFECT)

it's catless right now, but the engine bay is cluttered with AIR junk, i think removing that will be my first order of business so i can actually work on the thing. then i'll hack myself up an open air cleaner.

[Fast355]

im with ya robert, if i ever see a cheap tpi setup ill be all over it. im actually a big lb9 fan too, i've had several. but i've never actually played with a tbi unit, so i kinda want to do it for the experience.

i havent even had a chance to dig back in my memory and remember what mask it's running, and i'll have to hit moates for some kit.

i think one problem with this car is that the stock lo3 tbi & computer was plunked on SOME sort of '305 ho' crate longblock, which i figure has a different VE

i have no bloody idea, but i can tell without it even being on a scanner, it's trimming a hell of a lot (the transition into closed loop is very obvious, and once it catches up, part throttle goes from odd to PERFECT)

it's catless right now, but the engine bay is cluttered with AIR junk, i think removing that will be my first order of business so i can actually work on the thing. then i'll hack myself up an open air cleaner.

First thing those cars need is headers and full exhaust, followed by a decent fuel pump and afpr. Then followed up with a great tune. I had a LT4 cammed TBI 305 put down 181 rwhp/282 tq on a Mustang dyno through a fullsize G-Van drivetrain. On a dynojet it would have been ~200 hp, in a car I could have thrown more timing and a leaner afr at it and combined with that and the removal of a engine driven fan and the extra u-joint, 9.5" corporate 14 bolt, and carrier bearing would have put down 220+ all day long.

[steveo]

really? even just full exhaust requires a fuel pump upgrade and a bump in pressure

were they really built so close to the limit?

[Fast355]

really? even just full exhaust requires a fuel pump upgrade and a bump in pressure

were they really built so close to the limit?

Yes they were! Most stock TBI engines are out of fuel at 3,600 rpm.

[steveo]

i don't get it, how would an engine with a 6k redline make it out of the factory if they leaned out at 3600 rpm?

[Fast355]

i don't get it, how would an engine with a 6k redline make it out of the factory if they leaned out at 3600 rpm?

Factory fuel shut off on most TBI engines is 4,800. I think the redband on my brothers factory 91 bird was 4,500.

That being said the math is fairly simple. The TBI F-car regulators only put out 9-10 psi most of the time. Injectors are rated 55 lb/hr @ 11 psi. At 10 psi they only flow 52 lb/r. Good for 185 hp at .45 bsfc and 80% dc. The L03 is net rated 170 hp, fuel requirements should be off a gross hp number. Most stock calibrations hit 100% dc by 4,500 rpm.

We had a worn out old L03 in that 91, nothing done but a magnaflow high flow cat and single 3" exhaust and an open element. At 3,500 the injectors went static and at 4,000 the o2 voltage would drop into the double digits range....17 mv...etc

[steveo]

i see my error, my head is still in multiport territory. i guess 8 cylinders with ~50lb/hr injection is pretty pathetic.

so the stock pump takes a shit on flow if you get an adjustable regulator and bump it up a couple pounds, and retune?

my plans for modifying this junker are exhaust and an open element air filter, that's about it for the next while (except i really have to paint it...)

[steveo]

... or would the stock pump be ok if i threw bigger injectors in there?

[tamperedchevy]

a stock tbi pump is only good for around 14 psi, but not sure how it would hold up with bigger injectors if you kept the pressure down. should work i would think.

I went with a gta trans am tpi pump from Oreillyauto $80. it holds my 18-19 psi flawlessly.(figured if it could power 8 injectors at 42lbs or whatever that it could hold up to two injectors @18 psi)

[steveo]

a bit of schooling here since this plumbing is a bit foreign to me....

the air pump can go without any ill effects since its mechanical, right?

the stupid heater thingie that runs from the exhaust manifold can go byebye without any ill effects too?

[RobertISaar]

i want to say the calibration is setup for the exhaust manifold intake heater and that removing it will cause issues due to no IAT(or perhaps i'm thinking of the trucks?).

[dave w]

The Camaro should have IAT. I've tuned without the heat riser (heater thingie), and without the air pump (smog pump).

dave w

[buddrow]

So Steveo, is this an automatic car or a stick?:idea:

[steveo]

it's a stick

it's pretty limp too, and has hot start issues, an intermittent idle miss, and is lacking power even for an lo3. something definitely needs help.

anyway i dont want to buy the necessary tuning gear yet but i want to ditch the stupid snorkel and heater thing, and all the AIR plumbing, i think i'll chance it and see how it goes..

i cant even clean the engine bay up with all the air pump stuff in the way. it's all gotta go.

this car has had the ecm and prom replaced at some point too, havent' had the chance to dig it out and see what's in there..

[steveo]

man oh man, this late 80s emissions loaded tbi crap is just brutal!

i dont like wrenching on it, and i dont like its design.

makes me want to run screaming back to carbville pretty quick

just out of curiosity, if i just basically chopped the injectors out, would i hit limp mode? or would the ECM still provide spark from the ordinary spark table (while bitching with check engine light obviously)

[steveo]

8063 $4D btw

[steveo]

finally got under there to do some rewiring (had an aftermarket alarm that was half working and screwing stuff up; so i had to rewire a lot of the chassis harness)

pulled the ecm at the same time...

AMYB.

is there a calibration list that'll tell me what the hell that is?

there's evidence of this ECM being opened multiple times...

[RobertISaar]

AMYB
88 F-body
L03 5.0TBI
M39 T5 2.95 trans
3.08 final gear
federal emissions
1228063 ECM
16120674 MEMCAL(PROM?)

[steveo]

i actually just found the bin for it in the old archives. man oh man tuning tbi is going to be weird.

the cal has a really gimpy looking ve table that ends at 3200rpm

i have NO idea where the rest of it is calibrated

is this typical VE for tbi?

[RobertISaar]

that looks slightly odd......

and anywhere above 3200 is taken care of in a VE adder table..... 2D.

[steveo]

what a shitty system.

anyway, it's a stock cal. i need me a chip programmer. and pull valve covers. this thing has had a longblock swapped and i dont think they're tbi swirl ports. it's missing a lot of power. needs ve tuning bad...

[RobertISaar]

yeah, i'm not a fan of 3D + 2D either.... being a C3, i don't really know what you could do about it, short of making it a EBL unit.

[steveo]

yeah i'd sooner repin it for a different tbi ecm.

i think i'll work with what i have.

[steveo]

last night, car was running like crap all of a sudden, bucking, surging, stalling, broke the trans mount and blew a chunk of rusty exhaust pipe off it was running so rough

checked everything basic... egr moved ok.. vac lines ok.. plug wires not burned.. base timing advanced just slightly..

figured i'd break it or fix it for cheap

unplugged the fan so it'd get nice and hot

then dumped 'bout a gallon of a seafoam-like substance down it (which got really frothy, since the injectors were spraying gas everywhere) then redlined it in 1st for a few minutes, hoping it'd either fix it or blow it up so i could convince myself to do an engine swap for something with more balls

it fixed it, runs great now

still a tbi guy

fml

[buddrow]

You don't have to be hatin' on tbi Steveo lol. It does serve the purpose. Not everything can be as glorious as your beloved LT1. :) Glad you got it lined out though. That VE map looks goofy like maybe the mask is different almost but not quite totally wrong.

Buddrow

[steveo]

yeah i dont know what the hell is going on there without that VE table.

mask ID byte in the bin is apparently at 0x04, and it's 4D. the 4D XDF im using seems fairly well developed.

there's no obvious reason why fuel would be added to a diagonal region across the table like that...? some of the spike is at common driving range too, 2400rpm @ 50kpa... 2800rpm @ 40kpa.. so if it's legit, its some pretty dumb VE..

but i suppose since this is a very wimpy cam with swirl port heads (very odd port velocity profile) and restrictive exhaust/intake; maybe there's a legit reason for extra fuel there?

[steveo]

interesting thing that i'd like to understand

i was chasing an exhaust leak.. you know, the usual TICKTICKTICK under load, but fairly quiet otherwise.

i found it in an interesting place, the o2 sensor ceramic was snapped in half, including the wire being slashed right open.

there was never a check engine light, but wow.

so since this thing was so stuck that my o2 socket broke in half. so i unplugged it while i went hunting for better tools.

it ran exactly the same with the sensor unplugged (never entering CL, obviously?) but oddly enough took about 2 hours of total driving before a check engine light was set.

why..?

when i finally removed the sensor i found that the element was also broken, just laying in the housing. i really doubt it broke from removal of the sensor.

how the hell did it run like this without setting a CEL, obviously it hit closed loop, right? if so, how did it manage to trim without a noticeable difference in how the car runs?

this is important in my understanding of these ol' tbi ecms; every other ecm i've played with runs like crap if you so so much as foul the o2 sensor, and almost instantly throws a code for it..

[RobertISaar]

the O2 sensor circuit is a bit different than the other A/D circuits in that it doesn't have a pull-up or pull-down resistor that will bring the signal to the limits when the sensor is unplugged, because of this, the whole circuit acts like an antenna and voltage will go everywhere randomly. that may have happened long enough to where you don't get a code set and the ECM was in closed loop, based on non-real sensor readings.

[ony]

steveo, what flaver ecm are you running?

[steveo]

8063 4D

no tuning gear or even serial cable yet, being lazy.

[steveo]

even before I get that stuff, I can tell, tbi is like running a friggn trs-80 when everyone else has quad core 3d accelerated supercomputers. I'm getting a tpi rig ASAP, when I find one that isn't four digits in price.

[RobertISaar]

these days, most people would call TPI ancient too....

i'm not one of those people, i feel it certainly still has valid applications.

[EagleMark]

Serial cable? What did you datalog the LT1 with? It should work on this as well.

Don't underestimate the old ECM, it does it's job quite well. The worst part is the old EPROM, do yourself a favor and eithwer get an Ostrich to Emulate and some day burn a final chip... yeah I know, no such thing as a final chip... or the G2 adapter and solder it in so you can run a newer EEPROM 27FS512 flavor works well with the Moates Burn 2.

I also have a GQ-4x programmer so I can burn the old 2732a chips. Gets old erasing them with UV light but it works. You can still buy the 2732a chip in ST brand and I found them to be very forgiving when it comes to multiple erasings and burnings compared to the stock GM chips... AMD IIRC...

There's a few old TBI ECM that would be a lot better off in tuning if someone put the time into the mask/XDF. When I started with $42 there were several of them floating around and even the best one just did not cut it. Luckily there was a great dissasembly and after combining them all and double checking the dissasembly along with adding things it tunes very well! Then of course you can add all the tricks, data tracing to ADX as well as history tables. I enjoy tuning $42 now with all the work done to XDF and ADX.

[buddrow]

We can give you a huge THANK YOU Mark for putting the $42 stuff.

Steveo, i had run into similar situations with totally inop o2 sensors not setting a code in the past but I just figured the early systems were more "forgiving" compared to the newer ecm/pcms.

Buddrow

[EagleMark]

steveo knows the work that goes into them as he's a member of the 100 hour club in $EE. I'm feeling better so if he plans on keeping the $4D I'll give a hand on the XDF and ADX to make them more then useful!

[steveo]

Serial cable? What did you datalog the LT1 with? It should work on this as well.

it was so built into the car with the dash computer, i just sold it with the car. need a new one.


There's a few old TBI ECM that would be a lot better off in tuning if someone put the time into the mask/XDF.

even with $4D the parameters discovered so far put EE to shame, although as i've already discovered, some of that is weird stuff (like that VE table that wasn't quite right)


Then of course you can add all the tricks, data tracing to ADX as well as history tables.

as with EE, im not too interested in tunerpro for acquisition so i wont really be too into working on the ADX.

i tried to make time with the EE one, but if im not going to use it, its hard to motivate myself to work on it.

i still use the software i wrote for all that. it just spits out csv data all the same, but..

if i want to analyze something in particular i can just use gnuplot to graph stuff, or run a c function to build my own tables and do averaging.

with the lt1 i was doing stuff like this for narrowband tuning (pseudocode)



make an array of 15 cells, storing min/max/avg of lterm(left), lterm(right), maf afgs, rpm, map kpa
if(coolant temp > whatever) and (runtime > 120 seconds) and (closed loop = 1) and (blm enable = 1) and (pe enable = 0) and (blm cell < 15) {
update all averages, min, and max in that cells
}


that gives a cell-by-cell running average, which you can feed hundreds of logs into.



**** BLM CELL vs TRIM, MAF, MAP, RPM RANGE/AVG ****
(Igoring records with records < 30)

* Cell 0 (527 Hits)
BLM: 120 - 133 (Avg 124.5)
RPM: 850.0 - 1575.0 RPM (Avg 1242.1)
MAP: 21.4 - 34.3 KPA, (Avg 28.8)
MAF: 7.8 - 44.2 AFGS, (Avg 9.5)

* Cell 1 (3181 Hits)
BLM: 120 - 129 (Avg 124.3)
RPM: 1400.0 - 2200.0 RPM (Avg 1767.1)
MAP: 18.5 - 34.3 KPA, (Avg 27.8)
MAF: 8.1 - 72.3 AFGS, (Avg 14.9)

* Cell 2 (864 Hits)
BLM: 120 - 128 (Avg 122.5)
RPM: 2000.0 - 2775.0 RPM (Avg 2260.0)
MAP: 16.6 - 34.3 KPA, (Avg 26.4)
MAF: 9.4 - 36.8 AFGS, (Avg 19.9)


i know it's not data tracing, but i think it's better for me to read. i found not only does it give me a realistic view of whether cell boundaries are being used properly, but where it spends most of its time, and easily throws me thousands of records for averaging.

similar for fueling,



**** Wideband AFR (Average) vs RPM during PE ACTIVE ****

RPM 0 - 400 14.0 8 Counts
RPM 400 - 800 13.9 5828 Counts
RPM 800 - 1200 14.4 1293 Counts
RPM 1200 - 1600 14.5 163 Counts
RPM 1600 - 2000 14.8 5 Counts
RPM 2000 - 2400 0.0 0 Counts
RPM 2400 - 2800 13.0 15 Counts
...


and for maf table scaling:



**** Wideband AFR AVERAGE vs MAF AFGS ****

MAF 0 - 5 14.4 2654 Counts
MAF 5 - 10 0.0 0 Counts
MAF 10 - 15 14.5 2381 Counts
MAF 15 - 20 14.6 3477 Counts
MAF 20 - 25 14.6 1954 Counts
MAF 25 - 30 14.5 1237 Counts
MAF 30 - 35 14.4 891 Counts
MAF 35 - 40 14.4 495 Counts
MAF 40 - 45 14.4 436 Counts
MAF 45 - 50 14.5 285 Counts
MAF 50 - 55 14.3 234 Counts
MAF 55 - 60 14.3 185 Counts
MAF 60 - 65 14.4 162 Counts
MAF 65 - 70 14.3 138 Counts


i'll do the same thing with this car, so i probably wont even fire up tunerpro rt.


I'm feeling better so if he plans on keeping the $4D I'll give a hand on the XDF and ADX to make them more then useful!

thats a ton of motivation to get off my butt and get some chip burning gear and a cable.. honestly i dont even know where to start tuning this beast, i think you're the guy i need to talk to. i still haven't gotten around to popping a valve cover and figure out what kinda heads i have.

[EagleMark]

Looking at the titles of the TunerPro RT XDF and ADX I've already done a little work to them. Also found a good looking disassembly to work with and added it to the $4D thread. With that we have what we need to look at the VE table. Unless you have a better looking mask/XDF and dissasembly?

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?525-1228063-ECM-Information-4D

History tables work well for things like BLM, then use it and a spreadsheet to dial in the fuel VE tables, and can always export the data log file to CSV or... Excel format. The Data Tracing is more and advanced feature but can show you exactly where you are in bin file while playing back data, great for finding that spot giving you trouble.

Diddin't you find your bin file? Post it up! It'll give me something to start working on...

[EagleMark]

Fueling looks the same as $42...


;~~~~~~~~~~~~~~~~
;-Main %VE table
;~~~~~~~~~~~~~~~~
;
LD278 FCB 0 ;row offset
FCB 16 ;Col offset
FCB 8 ;# of cols

; RPM/1k .4 .8 1.2 1.6 2.0 2.4 2.8 3.2 ;kPa
;
FCB 50, 49, 54, 57, 60, 62, 63, 65 ; 30
FCB 51, 52, 55, 63, 69, 76, 86, 90 ; 40
FCB 53, 54, 61, 65, 79, 88, 99, 103 ; 50
FCB 55, 59, 75, 82, 86, 94, 101, 108 ; 60
FCB 65, 71, 88, 91, 93, 99, 110, 116 ; 70
FCB 95, 107, 112, 108, 103, 103, 111, 120 ; 80
FCB 98, 106, 121, 121, 119, 119, 122, 127 ; 90
FCB 99, 107, 121, 125, 124, 125, 125, 129 ;100
FCB 99, 106, 120, 127, 126, 124, 126, 130 ;110
;
;~~~~~~~~~~~~~~~~~~~~
;-%VE adder table
;~~~~~~~~~~~~~~~~~~~~
;
; %VE ;RPM/25
;
LD2C3 FCB 51 ; 0
FCB 51 ; 400
FCB 74 ; 800
FCB 102 ;1200
FCB 106 ;1600
FCB 110 ;2000
FCB 112 ;2400
FCB 111 ;2800
FCB 106 ;3200
FCB 102 ;3600
FCB 96 ;4000
FCB 108 ;4400
FCB 99 ;4800
FCB 72 ;5200
FCB 64 ;5600
FCB 57 ;6000
FCB 53 ;6400
;

[steveo]

heres what ive been dicking around with so far mark;

4D-steveo is a supposed 4D xdf from the old moates site that has some interesting stuff in it mapped out, but has that bunk VE table and who knows what other mistakes.

i started 'cleanup' on it, but stopped once i found that VE table error. i think i will continue on with it, but everything in there needs verification.

4D works is the one everyone seems to have been using, ve table displays correctly and seems the most...um..correct.

AMYB is a bin i tracked down from the old site that matches the sticker on my chip.

thanks a lot for that disassembly, im going to have a go at it!

[steveo]

actually i take that back, that other XDF has the VE table looking more like a VE table, but it's backwards or something!?

[steveo]

man oh man that assembly is so complete and the code is so primitive, it's actually readable. this is going to be a cakewalk!

[Fast355]

man oh man that assembly is so complete and the code is so primitive, it's actually readable. this is going to be a cakewalk!

Years ago I discovered the same thing with $99.

[steveo]

ok this disassembly lists the VE table @ 0x278. both XDF files list it at 0x278B.

disassembly lists the table as 30-110 map, both xdfs are 20-100 map

no matter which way i look at it, AMYB's VE table looks very strange.

[steveo]

never mind, dumb moment, forgot the three bytes at the top. 0x28b is right, but like i said neither looks right somehow....

[EagleMark]

It's because it is built properly in the XDF in the $4D thread. Most of the one's we are used to looking at have RPM and MAP swapped. You can swap them and it will look correct.

If you open $42 you'll see it has two Main Fuel VE1 tables, one is the one we are all used to and the other is corrected... read the notes... but corrected one would not work with what everyone had already built as spreadsheets. Numbers in each cell are correct, just the shape of VE table your used to working with is different, RPM and MAP are backwards..

[steveo]

i see my mistake. the xdf i was working on was set to row order instead of column so it was gimpy, switching that fixed 'er up. yes the one in that thread is correct.

the VE curve looked backwards as far as VE looked like it was dropping as RPM increased....... but then i forgot that there's a VE multiplier table. once that is applied it looks a bit more like engine VE.

theres lots of cool stuff in that disassembly, but not finding much useful thats missing from the xdf.

[steveo]

my dumb question of the day.

HW mode? wuzzat

[RobertISaar]

highway.

highway fuel or highway spark

[steveo]

ahhh makes sense thankyou

[steveo]

good progress on xdf cleanup, put some hours into it, categorization and renaming to 'human readable' is mostly done, now for some comments and documentation (which should take a while since i dont know what half the stuff does yet), then the research into new stuff starts

[steveo]

version 1.0 attached! not completely finished but it's a good start

as usual with my stuff view in --category view-- or it'll look like crap.

[steveo]

lots more, comments cleanup on important stuff, added more from that dissasembly (anything i'm unsure of the code or how to interpret, labeled experimental).. error checking ae de etc etc.

im up in the air about even adding stuff like error checking thresholds, there's quite a bit, but since this thing barely sets a code no matter what you do anyway.... might not spend the time.

[steveo]

finally managed to insert a new chip into this thing, and i think i got it first try. (famous last words, right?)

http://resfilter.net/tmp/blmattempt1.png

i'm pretty happy with this anyway. i think my tuning skills are getting better, especially considering:

- first attempt at tuning TBI ever
- first VE i've ever done with a 'restricted from the factory' type engine
- low log diversity since this is a short distance car in a small town
- it took me 20+ tries to get VE right on my LT1

the big difference is that driveability is 1000x better. before it would die with gentle starts, you had to roast the clutch to get it moving. with a bit of added VE and pump shot in that transition, it barely needs throttle to get going. there used to be heavy surging at around 70-80kpa 2200-4000rpm in PE mode, that's gone too.

i did this with cheapass $40 ebay chinese chip burner. mark burned me these bins and mailed them to me, but apparently stuff gets from china to canada faster than USPS from the states does! crazy stuff. still looking forward to having backup copies so thanks again for doing that for me, mark

thanks again for all teh great info on this site, and all your advice that made it possible.

having the VE tables displayed with the 2d VE adder incorporated helped a lot. without that extra input, the ve table just looks warped and it's impossible to smooth or get a handle on transitions. more XDFs should try that. until i did it, i was really scratching my head...