11sORbust

No disrespect but you are wrong. Check back at sdi post at TGO. He was selling his engine and said it needed rebuilt . Do a general search on SDI it's in one of his last post....

RBob

iTrader: (1)

I would prefer that this thread stay on it's original track. I am sure that everyone understands why.

Thanks,

RBob.

88TPI406GTA

Also, I did find it a bit wierd how Ski had such a high dollar setup...and wouldn't buy a set of bigger injectors for an extra $300-$500...that really never did make sense...

He does go fast and did contribute to TGO...while he was here...but look at TRAXION...who has also gone fast...but with a more methodical approach.

Bottom Line: If I could buy either vehicle, I would buy TRAXION's...because it is for sure that he knows what he is doing...

ghost_man

11orbust...

No I don't think from his posts on the vette forum that it needed rebuilt. Corky's buyer only replaced the crank to go to a forged unit since he too changed out the heads with Ski and corky to get some extra power. And possibly to cover himself if he ever used nitrous.

Also Not sure why or what SDI means? What would be the purpose of doing a search on that?

I did not mean to get off the topic here, thought it was important to see what some others were doing with the MAF in the intake tract yet. Since it seemed that removing it here in the this thread and many others were to elimnate the restriction it imposed. But just like the injectors, if they can work it to get mid 10s out of it, then why can't we?

The one post that did come up with the SDI search post did have ski commenting that his intent was to show that you did NOT have to spend money on conversions and larger injectors to go fast. Maybe 88406 that was your answer to why he never upgraded. seems if he wanted larger injectors, he could have done so. I don't think that money is much a barrier.

But for me if I can save 200 dollars, and get something I really need it would be very helpful. Since grumpy's link, I have been totally unable to decide if its needed yet, then these guys keep going faster and faster with all the things we say here are not good.

More I read the more confused I become....

11sORbust

did somebody call ghost busters?.......

Back on topic!

could someone answer this..
And how whould I go about modifying the table. I was also thinking about jacking the tps to 1.0volts and see what happens. I'll switch to SD within a couple of weeks. Right now I'm just having fun and learning alot.

TPIgirl

LC217 = location where value is stored for RPM?
is this value in one or two bytes?

min(TPS%, LC213) .. do you mean the TPS% is found at the LC213 location? or is this a compare function to the value in LC213?

RBob

iTrader: (1)

The LC217[RPM] is a lookup table and index. Go to the table at location LC217 and using the engines current RPM do a lookup and use the value from that table location for the calculation.

The min(TPS%, LC213) means that the code will use either the TPS value, or the value at bin location LC213, whichever is smaller. It is a compare to find the lessor of the two values: the current TPS, or the value at bin location LC213.

The lessor of the two values is then used in the calculation.

This actually makes sense because of how a throttle body passes air. GM implemented the default equation to prevent over-flowing due to high TPS values. By the time a TB is 65% open in angular motion (which is what the TPS reports), the magnitude of possible airflow is near maximum.

RBob.

TPIgirl

Originally posted by RBob
airflow = LC217[RPM] * min(TPS%, LC213) + (IAC * LC214) + LC215

Okay, now where (location) does it get the value of TPS% in order to do the compare?

Thank you so far!


It does seem like you could make adjustments to this default fueling by just adjusting the TPS sensor so the input values get changed.

If you were going to make some adjustments in this default table which locations would you go for? gps?

RBob

iTrader: (1)

The TPS% value is stored in RAM, it is the TPS sensor value zero'd from idle and scaled. If at 5.1% TPS then 5.1 / .390 = 13. The 13 will be what is used in the calculation.

For both 11's and TPIgirl, I wouldn't mess with the physical setting of the TPS sensor. It auto zero's and, if it is adjusted too far and a TPS code gets tripped. . . Now the ECM is down another sensor.

So what to adjust: (note that I am going to use the cal locations from BUA, please change them if using $6E, both are posted above).

How the terms are used can be seen in the equation. The offset at LC215 is used to compensate for the throttle blade opening airflow from the idle screw setting. If the idle screw setting is changed it will change the airflow and the offset term will need to be changed.

The term at LC214 compensates for the IAC opening. If the IAC pintle shape and/or the opening is modified then that term will need to be changed.

The term at LC213 clips the TPS multiplier once past a set throttle opening. When to change this? Maybe with a larger TB? Dunno.

This leaves the airflow vs RPM/TPS table at LC217.

Easiest way to adjust this table would be from actual MAF data. If no MAF then by the BLM method as is done with the scalar tables. No real difference between them.

RBob.

11sORbust

What about the maf diag error. What do you think happens when that switch is turned off? My car didn't run hardly at all with that disabled.....

RBob

iTrader: (1)

I'd SWAG it as the ECM not knowing that the MAF was bad, it was still trying to use it. . .

RBob.

11sORbust

That's what I'm thinking. Wonder if I can try to adjust bpw vs load with maf diag turned off. It seemed like there was no load calculation though.

The reason I thought to jack the tps was to "match" the resolution of the code. Maybe 4 volts is too wide of range. The tps diag can be turned off.

On a sidenote the cold starting is good. IAC works fine. I do have to pump the gas a few times while cranking(only on first start of the day if below 60*f). I have not tried to change anything in the chip. Just taking notes at this point.

11sORbust

I just though of something else to do. Disable maf diagnostic and use the bad maf. It might just have a flat spot or the lower voltage might get hairy. Maybe it's possible to tune around the problem, just for fun.

TPIgirl

What would happen if you disable the maf diag and then hook up a map in it's place? Would it still get the 0-5v input and use the maf tables for fueling?

11sORbust

It just depends on what is wrong with the maf. Grounded signal wire, forget it. If there is a flat spot or something like that then it might work. That's only with the maf in the intake tract. Otherwise the lv8 will be off big time...

11sORbust

I changed my mind. The car runs very, very well(after I fixed some stuff). So it's going to stay mafless untill the 305 dies. Or untill I install an ls1. There is flat spots in the cal. Very minor though. I have raced those 215hp 4.6l mustangs and the old t/a has won a few times. It'll go 100mph with no problem. Gas mileage is not the best. But since I'm in closed loop then maybe highway mode will work,hmmm.

Guess I need to get that tps/rpm default table addded to my tdf. Something else I need to learn how to do...

I have logged about 20000 miles on it mafless

11sORbust

Forgot to add the idle is so smooth you can't hear the engine running.

Guest

You could drive the car without the TPS (instead of without the MAF) too, but why? I guess I'm failing to see the point in yanking sensors one by one and trying to get the car to run 'close' to right without them.

11sORbust

I'm not trying to make any point........

Guest

Well you must have had some idea in your head for removing it and seeing what happens. Just for the hell of it?

dimented24x7

iTrader: (2)

There is some logic to running a car w/o a maf, just using the tps for fueling. On a super hot race motor this would be desirable as it removes the handicaps imposed by a maf (or a map).

JPrevost

Hmm... well I don't have a maf and I haven't unplugged my map sensor but I have unplugged other sensors. My reasons were to see how well the car would run if a sensor crapped out on me. I drive 540 miles one way so it's important to me to have the car run well no matter what goes wrong. I'm currently running the diag cts fail threshold as 220 degrees and I have it set to default to 240 to dump in extra fuel. The added benifit of setting this threshold low was to warn me with an SES if the engine is overheating.

11sORbust

The maf was bad when I bought the car. I initally planned on swapping to sd. Cost of SD conversion is about $100 less than a new sensor. Once I fixed the mechanical problems the car ran good. Then the f/p regulator went south and dumping fuel into intake. Ran like that for a few months(ecm still was controlling a/f ratio very well). Fixed that recently and the car runs great. So I started to wonder why it is running so good. Jumped into the code and it looks like I can tweek thing to run even better. So why should I run a maf if it's doing so good. This is a bone stock '86 t/a 305 tpi. I'm sure the default tables wouldn't work so good on a modified setup(mabe can tweek em to though). The car has 190,000 miles now. Never rebuilt. Great oil pressure. No detonation. Coolant temp is always at 180-190, never over that.


Sometime I just do things to learn .......

11sORbust

back from the dead.......

Figure it's about time I learn how to add tables. I plan on using the tunercat tdf editor. Maybe you can help me with this. I don't need someone to hand out stuff to me. I'm wanting to learn how to add tables. Enough BS, I'll tell you what I think I know...

This is the table I want to add.

11sORbust

This is what I have so far in the editor........

I think the y/x axis form # is the location of tps and rpm(in the ram). Is that even close?

Like my label?

11sORbust

on a sidenote,



;--------------------------------------------------
; LK UP Default air flow offset per pct TPS vs RPM
; P/O ERR 33/34
;
; Value = Gms/Sec * 100 pct, (Offset)
;
; TBL = Arg * 100
;-------------------------------------------------
LF7C1: LDAA L0056 ; RPM/25
LDX #$C217 ; Default air flow offset TBL
JSR LF2BF ; 2d Lk Up Routine

LDAB LC213 ; If TPS > 65.2%, use for MAF Default
CMPB L0082 ; TPS Ld Axis Var
BCS LF7D2 ; BR IF TPS LT THRESH
; ... else
LDAB L0082 ;
LF7D2: MUL ;
STD L00EA ; Gms/Sec Disp Value
;--------------------------------------------------
LDAA L002C ; IAC Present Posit
LDAB LC214 ; Gms/sec Scale factor
MUL ;
ADDD L00EA ; Gms/Sec Disp Value
BCS LF7E4 ;
; ... else
ADDD LC215 ; 4 Gms/Sec default air flow offset
BCC LF7E7 ;
LF7E4: LDD #$FFFF ; Max Val if Overflow
LF7E7: JMP LF86E ;
;--------------------------------------------------


How does that work with the table I'm wanting to add? (or at least) why was it in a different location?


Thanks for any help.

Tim

11sORbust

??anyone??

11sORbust

look right?

RBob

iTrader: (1)

Sure does. Do need a little work on the title of the table though. . .

RBob.

Grumpy

So your using a default MAF table at over 62% TPS?.

11sORbust

What do you mean??? Rbob told me that the table is the only default table for fuel calc. So you are suggesting there is another table getting used <62%tps ?





LDAB LC213 ; If TPS > 65.2%, use for MAF Default

Is that what you are talking about?

11sORbust

Sure, if it was for public consumption in a tdf. But I don't think anyone else will have access to that table(or want to). Really the name is a perfect discription


It was kind of funny bacause the first gr/sec value was 8 no matter what I did. Then I realized to use the actual start of table.

RBob

iTrader: (1)

The gms/sec vs RPM table value is multiplied by the TPS% value. If the TPS% is greater then the term at LC213 (65.2% TPS) then it is held to that value (65.2%).

The comment on this line: BCS LF7D2 ; BR IF TPS LT THRESH

. . . is incorrect. It will BRA if the TPS% value is greater then the value at LC213.

RBob.

11sORbust

What's does "BR" and "BRA" mean ? That is what you are correcting, right?

11sORbust

dimented24x7

iTrader: (2)

BR/BRA is short for branch. Since the value in accumulator B is being compaired to the TPS% (or whatever is stored at that ram location), a bra will only occur if the TPS% is greater then the value in accumulator B.



EDIT: server cut my origional post off...

11sORbust

Thank you!!!!

I really, really HATE when that happens.

11sORbust

I'm going to piggyback the tps signal wire to the maf input wire(to ecm). Then try to tune the maf tables. If anyone is interested....

onebinky

iTrader: (1)

wHEN YOU GO wot, WOULDN'T THAT FLOOD THE MOTOR OUT?

iF YOU CAN TUNE FOR IT, WHAT KIND OF BENIFITS DO YOU THINK YOU'LL SEE?

EDIT: sorry for the caps, I was watching TV while typing

11sORbust

I'm doing it to learn. So I'm not sure...yet.

JP84Z430HP

I've finally taken the time to read MOST of this post, and it is interesting to say the least. The one question I have is does it run any better than with the MAF operational? I ask because you stated that the MAF was bad when you got the car. I'm not guessing either way, it would just be interesting to know. Maybe all that you're doing would make things better if adding the MAF back into the loop? Go ahead and scream at me!!!

11sORbust

Yes it does, but not by a whole lot. THats is the main reason I want to tune mafless.

For some reason I think it's possible to tune mafless to run on par w/ maf. Most people think it's a waste of time

dimented24x7

iTrader: (2)

One thing to keep in mind is that the calcs. for the default airflow term take rpms into account in order to closely similate airflow. The ammount of air that an engine draws will be in part related to what the engine speed is.

A cleaner way to do it would be to do things more directly in terms of the tps, but that, among other things, requires that you know assembly.

dimented24x7

iTrader: (2)

I dont think that its necessarily a waste of time. If you like your motors extra spicey then using the throtte to determine load would be a good way to go.

11sORbust

I was thinking about using the bpw vs load table($32).But I'm not sure yet. The main thing about using the tps would be that I have to rescale the load...



thoughts?