im having a hard time with something on my syclone. i have been fighting with it for quite a while and still havnt really gotten very far. for those that dont know i have a fully built motor with extensive head work and intake work on a flowbench..... great pains were undured to get every thing with in 1% in the top end. intake, heads, valves..... everything. engine build can be seen here http://www.syty.net/forums/showthread.php?t=21568 the end result is a motor thats extreemly sensitive to change in load. its very jumpy when on and off the throttle. just a touch of the throttle, or quick change in MAP will give a lean spot, that varys depending on how much the MAP changes in a given time frame. i have tried adding fuel in each of the AE tables, as well as all of the AE tables. the result is really discouraging. what im finding is that a quick change in MAP will result in an instant lean condition, and adding fueling in the AE tables causes the lean condition to be followed by a rich condition. both options haveing a slight stumble if the change in fueling is over 1 point. its like the AE fueling in the ECU is responding slower than the motor is. i understand that this is not the normal "run of the mill" motor, but im really hoping that the stock ECU is capable of taming this beast. i tried looking thru the P4 and some of the chipping information provided on syty related sites, and from what i see im using the right tables, im just not having any luck with the on off throttle stuff, and the TC lockup. the truck runs wonderfully, and cruises around with no issues. the tune is incredibly close to perfect other than the AE issues. if anyone has any insight on this, id love to hear your suggestions. i have tried just about everything i can think of including increasing the VE fueling, but it doesnt seem to be a VE issue. would suck to come all this way with the tune, and have to dump the stock ECU for a BIGSTUFF system.

im running 75lb low impedance injectors, with the injector driver upgrade and a DIG patch on the code so i can datalog WB info directly thru datamaster.

a small spike is unnoticable while driving and totally acceptable......
the larger spikes can best be described by a "hesitation" from the engine.
the really large spikes (TC lockup at greater than 50% throttle) are great enough that in order to compensate i have to run my fueling pretty far on the rich side. it can also cause a stumble or a split second of knock retard if it goes really lean. i have been keeping it at least at 11:1 under boost to keep from going too lean under a rapid change in engine load. (like TC lockup, or a 3-4 shift) i can partially compensate by richening the VE mix, but that can take the throttle sensitivity down as well if its richer than it needs to be. im just wondering what everyone else is doing to remedy this. surely there are a few custom motors out here that have rather specific fueling requirements/ similar issues

e

 

after talking to some good tuners, iv found that the reaction time of the injectors im using is much less than a small stock injector, and that is at least half of my problem. BIGSTUFF and FAST systems have an adjustment for this...... im looking into the 7449 ECU to see if theres a table for this (crosses fingers)

e

 

Try dropping the TPS% enable for PE WAYYYY Down.

Have you tried using the MAP AE?.

With the AE/TPS/RPM wonders can be had.

You can cure, just takes some dinkin with.

The aftermarkets, just throw so much fuel atta motor, that it's almost hard to not have one overly rich in AE.

I spent some time working on something similiar to what your fighting on a car with a 4,500 stall converter, and it took some playing with to get it right.


If you resort to making a code change(s), then using a MAP based PE enable works wonders.

 

yeah the AE delta MAP table didnt help much, i just cant get it to respond fast enough. if i increase the value in this table the lean spike is just followed by a rich spike a split second after the event. (typically 1 to 2 frames of datamaster which is ~1/6th of a second) i can see the ECU applying the fuel as requested by the table changes, but its later than the event. the AE for TPS is already pretty low since we are running a 3600 9/11 hybrid lockup converter. like i said the drivability of the motor is really pretty great at light throttle and cruise, although its a hair richer than id like it in some of the VE..... but its like that intentionally because im trying to compensate for the ECU's inability to react fast enough to rapid changes in engine load. all the datamaster files i have look like the fuel is always trailing the event. is there an injector offset, or reaction time table to compensate for delay from large injectors?

e

 

this is the info i got from mark at turbotune in greensboro, and phillip long (another local syclone tuner)......


i talked to mark about your tuning problem
he says the larger injectors have a much slower reaction time
a 29# one might be .30 ms
and a 75# coulc be around .9ms
there is not a way in the 749 computer to compensate for injector timing
you have to lead em a little kinda like timing in a motor
if not mark said to do fast or bigstuff....there is a table in there that will cure it for sure
he is doing bigstuff on a mustang next week
he said he has that problem you have on hondas all the time..
can hardly drive it around
because they went from 140cc to 1000cc
said it spikes really lean

 

Nope.

What for fuel pump are you running?. I had to go to staged 340l/hr pumps. You might be out of fuel pump when in AE, and they go static for a moment. No it won't show on any fuel pressure guage.

And a bad TPS can be a PITB to find.

 

i went back to the stock TB (had a twin 58mm BBK) to slow down the tip in lean spike, without much success, but that rules out a TPS problem as they were complete (had different sensors in them).

the pump is a walbro 340, and its doing it at part throttle just off idle as well as on TC lockup and 3-4 shifts, on and off boost, so i doubt its a fuel delivery issue or it would get much worse as power increased.

guess ill dick with it for another week or so, till phillip gets his motor up and running (we built a duplicate of my motor for him) and see if either one of us is able to get this ironed out. just hate to give up and go BIGSTUFF, when the tune is so freaking close...... took at least 2 solid weeks of tuning to get where i am right now. if i could just speed up the AE function this tune would be dead on the money.

e

 

0x0619 F92_TABLE Fuel Bias - Injector Offset vs Battery Voltage

mSec.
0
1.6
3.2
4.8
6.4
8
9.6
11.2
12.8
14.4
16
17.6
19.2
20.8
22.4
24
25.5

(mSec)
0.519
0.519
0.519
0.946
0.946
0.946
0.732
0.641
0.58
0.519
0.519
0.519
0.519
0.519
0.519
0.519
0.519

i havnt tried it yet, but i think jim sloan just found the answer to my question....... ill post back after lowering the values in this table. if my math is right, i need to drop all the values in this table by about .333 ms to place my rich spike directly over my lean spike in datamaster. either way, i appreciate your help thinking thru this grumpy.

theres also this table, but it appears to be unused since its zero'd out. probably used in another application.

0x062A F94_TABLE Fuel Injector Offset vs Base Pulse Width

mSec.
0.488
0.732
0.977
1.221
1.465
1.709
1.953
2.197
2.441
2.686
2.93
3.174
3.418
3.662
3.906

(mSec)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0



e

 

Those are just PW adjustments to compensate for what's going on. ie as the battery voltage drops the injector takes longer for the plunger to move, so a small amount of injector on time is added.

 

Those tuners are waay off base if they think this problem is caused by injector response. Like Grumpy says, the response time is just the open/close time offset vs battery voltage.

This problem sounds exactly like dTPS AE. TPS is used to anticipate the transient in lay terms (what's actually going on is a bunch of different puddles and vaporization rates, and sensor lag, and actual air flow inaccuracies during transients with SD, and GM fudges it over with a few tables).

dTPS AE is for the first instant, dMAP for the following .3 seconds give or take.

Your modified intake and all that really should require what you are seeing. It's a much more efficient air mover now, and throttle openings cause more "transient" things to take place.

 

There is a AE Delta TPS multiplier in $8D, I don't know if there is a multiplier in that mask. would raising the multiplier add more fuel faster because of the accellerated delta TPS value that is calculated? for the initial "tip in" anyway.
Seems like that would help that issue if the calc is raised to indicate more transition.

Just to clarify, I mean a separate multiplier for the delta TPS that is multiplied with the BPW first. Then other calcs are done to add the "pump shot" table value.

 

http://www.sunflower.com/~leroy/P4/section9.htm

Says they have dTPS AE in here.

I've never tuned with that mask either, but that's the place I would focus on and keep focusing on and keep on focusing on with a problem like that.

 

while i really appreciate you guys offering tips on tuning, your getting kinda off topic.

the real issue as i see it, is this.
this is full race motor that responds to change in engine load and TPS faster than the usual "mushy" motors this ECU was originally setup to control. a change in TPS or MAP will send this motor into action like nothing else i have seen from a 4.3 the throttle is extreemly touchy.

larger injectors really do have a slower reaction time, but in this case its no where near a large enough change (32lb to 75lb) to show up in the tune to the extent im seeing (roughly 3 ms delay).

now for the good part.... what i did to fix the problems i was having.

0x033B threshhold for delta TPS

this value was originally set to 1.9 meaning that the TPS had to change 1.9% before the ECU would deliver any AE fueling based on change in TPS, and ultimately delaying the fuel delivery as it waited for this change to occur before responding. changing this value to 1.17 centered the AE TPS fuel delivery right over the lean tip in hesitation i was seeing. tip in is now perfect.

0x0338 threshhold for delta MAP

this value was originally set to 3.6 (but i believe theres another table that automatically doubles this number based on percent TPS) this was requiring the ECU to wait for a large change in MAP before delivering fuel. changing this value to roughly half of its original value centered the rich spike caused by the AE MAP value directly over the lean spike caused by the actual change in MAP. once the 2 spikes were centered over each other i went from having a 1.5 point AFR lean spike to a .5 point AFR lean spike. while this is still less than perfect, its acceptable for TC lockup, and 3/4 shifts under hard acceleration, and unnoticable without datamaster.

while i wont argue, if you guys claim that these tables have other functions than AE timing, i believe they work extreemly well for AE timing, and i have seen no negative affects from making these changes. the tune on this motor is tighter than ever, and its just gonna get even snappier as i lean it out a little more in the VE. preciate you guys helpin me think thru this, and listening to me babble.....

e

 

where you located ???

there are also tps and map Ae multipliers and filtering values . sometimes dinking with them a bit can net big rewards in throttle response. i got a 2.0 n/a 4cyl with a 75mm tb. yeah it was a pita to get tip in just right. also there is a Ae decay rate in there as well. if your leaning out starting decreasing the decay rate. belive me you dont want ot overcompensate with to much ve to clean up a tip in issue. get the motor into some steady state typ of operation refine you ve and spark then go after ae for throttle response.

 

Could not changing the sense resistors with the combination of low z injectors create a delay in reaction time.

Here's a post discussing the resistor change.

https://www.thirdgen.org/techbb2/sho...se+%2Bresistor


NON EE Alert

ED89

 

do you have an address for the AE decay rate? im not seeing it.

e

 

i doubt that your injectors are lagging behind the commands from the ecm. would be the first time id ever even heard of it. sure there is a delay buts its pretty constant. but if your running lowz injectors without the proper resistors yes the injectors will behave erradicaly. that will cuase all sort of tunning mayhem .

 

No they'd open just as fast, if not slightly faster, but we're talking in nanosecs..

HOWEVER, the longer you run them that way, and at higher RPM, you will weaken the injector drivers, due to excess heat. Once they start to fail, then they can do all sorts of odd things. Once they're not enough long enough, they won't fire an injector (so far I've only seen them fail, open).

 

Look for table F37, I believe that's the one you're looking for.

 

thanks

the fairchild low impedance drivers have been installed but that is all. this is the usual syty recipee that most people are having luck with. i read the post about the sense resisters several times and im unclear why they are needed. most tuners from syty.net typically replace the injector drivers and run the low Z injectors in the standard syty wiring configuration rather than the sunbird configuration. no one seems to be having any issues with this, other than having to use a slightly larger ECM fuse, although id really like to hear someone talk about the advantages of one option over the other. as iv gotten more involved with the 7449 ECU, its mainly been because i needed to tune a truck, rather than just loving electrical engineering and being fascinated with electronics. to be honest i kinda hate the electronics side of things, but i find myself being pushed more and more in that direction as my need for advanced tuning options increase to meet the demand our sport/group. although honestly the more i learn about this stuff adn how it works the less im afraid of it. so if there is a tech artical on peek and hold vs saturated, point me in the right direction. i wouldnt be against trying a peek and hold setup if theres gains to be had. especially if its soemthing that hasnt been done with 6 injectors, and you guys need some one to document any notable differences.

the reaction problems have been cured. it was all an AE fueling timing issue. the truck is running great. been driving it almost every day for a week now (it doesnt come out in the rain). the tune is so close to perfect if you werent the one tuning it, you would never notice the small imperfections left.

the break in miles are on the motor now, and its about time to get some good gas and see what the dyno has to say.

e

 

There are two advantages to running the Sunbird wiring when using P/H injectors. They are injector life and driver life due to overheating unnecessarily. By using SY/TY wiring and P/H injectors, the full battery voltage is applied to the injectors all the time drawing more current (5 amps or more) than even the high peak current (around 4 amps) and never allowed to go into low current (around 1.3 amps) hold. As Grumpy pointed out, this causes excessive heat to be introduced into the injector solenoid coil and driver transistor, especialy at higher pulse widths where the peak portion of the pulse is a very small percentage, not to mention what the extra current does to pintle action. This is also why the SY/TY guys need a bigger ECM fuse. This will drastically reduce injector and driver life. Heat kills. There is no advantage to running this setup, only potential problems. The proper way to run P/H injectors is to run Sunbird wiring and the proper size sense resistor. For a 4 cyl. setup, a .1 Ohm sense resistor is needed. For a V-6 setup, a .067 Ohm resistor is required (this can be achieved by paralleling three .2 Ohm 1W resistors). For a V-8 setup, .05 Ohm resistors are needed. HTH

 

Lots of people do lots of things wrong, and get by with it forra while. With the advent of 60PPH and larger saturated injectors, even using P+Hs is obsolete.

And it's not reaction problems, while using words close enough is fine for bench racing, if you want to speak the language you need to learn it. Not trying to hammer you with details, but if you can't pose the question in a way that's readily understoodable, you'll be chasing answers forever. If you'd originally said tip-in stumble, I'm sure you'd have heard about the dTPS, dMAP AEs in the first few replies.

BTW, I've actually tested several 749s to destruction using P+Hs.
The drivers get erratic, and then fail. Not always will you see or feel them going out, until the motor really leans over.

 

i both agree and disagree with this statment. i agree proper terminology does make things easier. there are sevral good article on the internet discussing terminology.

i also disagree that hammering the nube is fiar. he obviously doesnt know. so its our job to present fact then allow him to draw conclusions from them. i intially thought this was an AE problem. but until we got him away from (blame the injector conspiracy thoerists) we accomplished nothing. if anything this post should be included in the other posts a sticky resource. its got some good info in it.

but please dude we love new memebers but take some time to familerize yourself with the lingo. makes it easier on everybody. i knows its an intimidating process. but once you learn the lingo its gets alot easier for us to help you and for you to help yourself.

just my 2cents.

 

dTPS, dMAP, AE vs coolant temps WAS where i was looking, and i had tried them to death. with no success. the answer lied in the threshhold settings that i posted above. mabe someone here knew that, and mabe they didnt. the way i described what i was seeing in the WB data was what i wrote in the post/titled the post. im sorry if you have gooder ways of describing it and "insider lingo" that i havnt learned yet. seems like good information iv found that could help someone with similar tuning issues in the future, as the threshold tables are not typically looked at as timing tools for when AE fueling is dropped. good bad or ugly..... my writing skilz are probably more limited than most since im an engineer. feel free to change the title of the post if it bothers ya, or edit the post entirely.

for the good of the group.

now back to your regularly scheduled program of bashing the noob.

e

 

OK, ignore any replies I accidently make to you in the future, as I surely don't want to be mistaken for bashing you.

 

although the tune is REALLY smooth now, it may have all been in vane. we are seeing just above 70% duty cycle at a measly 17psi, and we are only spinning the motor to 5200 (going to 5800 and ~28psi) so its possible we have started with too small of an injector. not knowing exactly how much power the motor was gonna make, made it a little hard to size the injector. probably should have gone with an 84lb injector over the 75lbers.

i like your idea about large saturated injectors (will keep me from rewiring the ECU), but so far the biggest thing i have seen available is a 65lb motron. are there larger offereings i dont know about?

e

 

The mototron is a good high impedance injector, you can achieve ~85lbs per hr at ~85psi. I wouldn't run any higher static pressure than that though. Keep in mind at ~30 lbs of boost, your fuel pump needs to be capable of 115psi fuel pressure and still flow enough to make the power you need, start looking at Weldon pumps. Bruce is correct in telling you that you have a mismatched electrical situation. to verify it all you need to do is scope it while running it a while, duplicating the EXACT same transients and you will see that the injectors do NOT repeat because the drivers are not made to do what you are doing. Hindsight is great, but next time an attempt is made to work in the unknown, take what is known and build a benchtop model and produce repeatable transients on a bench, then make the change and see if you can "tune" the transients back into it via software changes... it can sure save some grief. Good Luck.

 

They make some bigger then the 60s.

 

there are bigger injectors in saturated. i think they stretch out to like 120pph. there not very stable however, id be looking at a disc style injector bigger then 60pph in saturation.

 

we leaned the motor out a little more, and upped the base fuel pressure, and have gotten up to 20psi at 75% duty cycle, so its looking like these fuel injectors are gonna work out ok after all. gonna be close up around 28psi of boost, but i think they will work.

now i just need to research the changes needed to convert to the sunbird wiring configuration. i think we are set on making these injectors work, since we ahve them installed and running in both race motors, but im curious......whats the largest injectors you guys have run in this ECU with decent idle and drivability?

threw in a picture just for fun


e

 

ive run 4 80pph injector P/H on a 2.0L 4cylinder. so its handle some big fuel injectors. but again these are properly driven p/h injectors.

 

yeah, the largest ones i have seen on this ECU are 84lb
just wondered if anyone had run anything larger.

e

 

I am not trying to push it on you e-rue but Nolan at campbell automotive here in canada (he has a white typhoon that goes ~10.70s) seems to be a good resource on this subject.

 

nolan is a great help, and even provided me with a startup file to tune from, for these projects......without his advise i probably wouldnt have gotten this far. the problem is that im trying to go farther than he has, and since hes the best resource in syty land i came here looking for help that doesnt hang out on www.syty.net.

at this point im glad i did, because i would have never known that i had the ECU wired incorrectly for a peek and hold setup.

this sunday phil ran a 6.83@100mph with only 20psi of boost with an 85% injector duty cycle (75lb injetors). im pretty sure we can just go to 84lb injectors and have plenty of fuel for this project. just curious if anyone has tried tuning 95lb injectors, or 180lb injectors?

e

 

I'm trying to find these tables in the $8D code. I'm thinking that the threshold for delta TPS is located at L852E. Is this correct? Does anyone know the threshold for delta MAP is located?

When I switched to the bigger cam that has more duration on the intake lobe, I get a slight stumble if I move the throttle slighty while in DFCO. There is a lag and a lean spot. Adding pump shot just makes it rich after the lean spot. It is a never ending battle.

 

At L852E my chip (based on a 90 Vette 6 speed) was set to 10. The 8D hac has a value of 3 that corresponds to 13.5% tps threshold before AE fuel kicks in. At least that is the way I understand the table. The 6 speeds are set up with a value of 10. Would this be 40% then if 3 = 13.5%?

Anyway I set this to 2 and there was a huge improvement. I now have to try and get it to stumble. In third gear and about 3500 RPM I leave off the throttle and wait until DFCO kicks in. At that point, I slightly increase the throttle and that is where the dead spot was. I can hear it slightly and by playing with the table a little more, I feel like I can remove it. It seems to me this is a huge discovery especially for the MR guys out there that still suffer from the intake backfire.

 

Typically TPS% values get multiplied by .39 (100/256) to get the TPS precentage. So a 3 would be 1.17% TPS and a 10 would be 3.9% TPS.

You mentioned DFCO. Upon exiting DFCO there is a pulse of fuel added that is intended to re-wet the manifold. Can play with this too, it's at $85EC and is a 2 byte value.

RBob.

 

Thank you for the clarification on how to calculate the values. I was not aware of that. Thank you also for the information on the DFCO pulse. If I disable the DFCO, then all stumbles and hesitations are gone. If I enable it and set the AE TPS to .78%, then most of it is gone and I have to try and find it.

As far as the pulse of fuel that wets the manifild after DFCO, what do you mean by it is a two byte value? My base AXCN bin (91 Vette manual) has a zero in that spot. I also checked the AXCR (91 Vette auto) since the auto's have more AE fuel and it to is set to zero.

Thanks

 

The value itself is 16 bits, or 2 bytes in length. Both $85EC and $85ED are used:
This is the value from AXCN. In this case $85EC will be 0 and $85ED will be 128 ($80). The math is to multiply the 16 bit value by .01526 for the actual pulse in milli-seconds. If you want to manually edit the bin with a 0 in $85EC and a 255 in $85ED, the fuel pulse will be 3.9 msec.

The math to include both bytes is:

msec PW = (value at $85EC * 256 + value at $85ED) * .01526

RBob.

 

Ahhhh I understand now. This is all great information. Way back when I had this problem with a Miniram intake. The hesitation after a DFCO was the least of my problems. The biggest one was a lean pop in the intake when under a heavy load. I finially got rid of the pop but had to add a huge amount of fuel to cover it up. All that fuel caused a very rich condition that caused the fuel trims to dive. When the AE fuel was burned up, the motor went lean like right now. I finially gave up and re-installed my Super Ram.

Last night I disabled the DFCO and all is fine. I get some small backfires in the exhaust when I decellerate but nothing bad. Adding more timing at 20 KPA helps the backfiring. I have read older posts that suggest retarding the timing. I assume by advancing the timing, more fuel is burned in the chamber than in the header.

Thanks again for the detailed clarificaiton.