66
9.2 FUEL DELIVERY MODES
The fuel logic delivers fuel in three modes, synchronous, quasi -asynchronous and asynchronous.
67
When both synchronous and asynchronous modes are operating simultaneously, the output to the
injector(s) is the logical OR of the delivery pulses delivered b-v the two modes.
9.2.1 Synchronous Fuel Delivery
9.2.1.1 Synchronous Fuel Enable Criteria
The synchronous fuel delivery mode will be enabled when ignition is ON, and any of the
following conditions:
1. Engine not running, or
2. Engine running and engine RPM greater than or equal to *KQASRPMD*, or
3. Engine running, engine RPM less than *KQASRPMD*, and base pulse width
greater than *KAPLH*, or if base pulse width is less than or equal to *KAPLH*,
then not in quasi-asynchronous mode and base pulse width greater than *KAPLL*.
Once synchronous fuel delivery mode is enabled, it will remain enabled until base pulse width
becomes less than or equal to *KAPLC*.
9.2.1.2 Synchronous Fuel Delivery Mode Function
When the synchronous fuel delivery mode is enabled, the fuel injector pulse width is calculated as
follows:
Pulse width = BPW + INJOFFST + BPWLIN
where BPW = Base pulse width.
INJOFFST a Injector offset term.
The injector bias is a tern which compensates the delivered pulse width for the delays associated
with opening and closing the injector. It is calculated as:
INJOFFST = *F92*
where the *F92* table is a function of battery voltage.
BPWLIN = Injector linearity term
The injector linearity term is calculated as:
BPWLIN = *F94*
where the *F94* table is a function of BPW (base pulse width) if BPW is less than 3.9 mSec.
Otherwise, BPWLIN is set to zero.
9.2.2 Quasi-Asynchronous Fuel Delivery
Quasi-Asynchronous fuel delivery is used when the synchronous fuel base pulse width becomes
so small that the fuel pulses cannot be accurately delivered.
Enabling quasi-asynchronous fuel mode will cause the fuel injectors to be energized every other
reference pulse but for twice the duration (of the normal synchronous base pulse width). This
results in the same amount of fuel being delivered, but with an accurately controllable injector
pulse width.
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9.2.2.1 Quasi-Asynchronous Fuel Enable
Quasi-Asynchronous fuel mode is enabled when the following conditions are present:
· Ignition ON
· Engine RUNNING
· Engine RPM less than *KQASRPMD*.
· Base pulse width less than or equal to *KAPLL*.
9.2.2.2 Quasi-Asynchronous Fuel Delivery Mode Calculation
When the quasi-asynchronous fuel delivery mode is enabled, the fuel algorithm energizes the fuel
injector as follows:
Once every other reference pulse for an amount of time as follows:
EFIPWD = (BPW * 2) + BPWLIN + INJOFFST
where EFIPWO = quasi-asynchronous pulse width to be delivered by the injector.
BPW = base pulse width calculated by the fuel algorithm.
BPWLIN = base pulse width linearity term.
The injector linearity term is calculated as:
BPWLIN = *F94*
where the *F94* table is a function of BPW (base pulse width) if BPW is less than 3.9 mSec.
Otherwise, BPWLIN is set to zero.
INJOFFST = Injector offset term.
The injector bias is a term which comoensates the delivered pulse width for the delays associated
with opening and closing the injector. It is calculated as:
INJOFFST = *F92*
where the *F92* table is a function of battery voltage.
9.2.2.3 Quasi-Asynchronous to Synchronous Transition Mode.
This mode is used to make the transition from quasi-asynchronous fuel delivery to synchronous
fuel delivery.
Once the base pulse width becomes larger than *KAPLH, a quasi-asynchronous to synchronous
transition mode is enabled for a time period based on a multiple of 12.5 mSec.
This period is calculated as follows.
when vehicle speed is greater than or equal to *KQSYNMPH* then transition time 3
(*KREFMAXH*) * 12.5 mSec when vehicle speed is less than *KQSYNMPH* then
transition time a (KREFMAXL*) * 12.5 mSec
Ouasi-Asynchronous fuel delivery will continue until the transition time elapses.
9.2.3 Asynchronous Fuel Delivery
Asynchronous fuel delivery mode is used to deliver fuel pulses for acceleration enrichment.
These acceleration enrichment fuel pulses may be due to transient increasing engine loads such
as vehicle acceleration, idle air control (IAC) transient air, and engine accessory load transients.
The fuel system provides two accumulators that contain the running sum of fuel required as a
result of asynchronous base fuel and transient fuel. Each time the fuel system performs a base
pulse width to asynchronous pulse width conversion, the result is added to the asynchronous base
fuel accumulator. Similarly, each time the transient fuel system requires fuel delivery, the length
of the required pulse is also added to the transient fuel accumulator.
9.2.3.1 Asynchronous Fuel Delivery Enable
When the sum of the asynchronous base fuel accumulator and the transient fuel accumulator is
greater than *KAPMIN*, an asynchronous fuel pulse is delivered. If the sum of the asynchronous
base and transient fuel accumulators is greater than *KAPMAX*, then a fuel pulse equal to
*KAPMAX* plus INJBIAS is issued. The *KAPMAX* is subtracted from the asynchronous
base fuel accumulator. If the result is less than zero, the remainder of *KAPMAX* is subtracted
from the transient fuel accumulator. This process continues until the sum of the asynchronous
base and transient
If the sum of the asynchronous and transient fuel accumulators is less than or equal to
*KAPMAX*, a fuel pulse equal to the sum of the two accumulators plus INJBIAS (per paragraph
2.4) is issued and the two accumulators cleared. fuel accumulators is less than *KAPMIN* If
the asynchronous base fuel delivery mode is disabled, the fuel logic will clear the asynchronous
base fuel accumulator.

 

if im reading the strategy right then the $6e code could be holding the time to deliver a PW until the right number of ref pulses sit on teh accumulator. that would explian Ski down its 12.5 msec at 5500 rpm.

this is from the $58 pdf but it should apply to all the GM ecms there all batch fire in this era.

 

Not to be a bad guy, but you shouldn't make that assumption until you can confirm the other ecms/calibrations. The $58 is strictly Syclone/Typhoon not F-body.

Until you can show the code of the $8D (7730) or $6E/$32B/$32 (165), you should not post assumptions. You know what they say about the word "***/u/me" ?

You need to find the same code in $8D and the others or nothing of what you just said applies to an F-body.

 

**SHOULD**,
Kiddin right?.

BTW, still waiting on the flag location you mentioned that allows for the Injector constant to function, on the 58 code.

The various codes were written by different groups of people, at different times, for different applications, with different EPA mandates, to ASSUME they all operate the same is a critical error.

In the 3rd Gens, they even branch a GENERATION of ecm design, to equate that all the code is the same is a grievous error.

BTW, is the 58.pdf you quote available on line?.
When you quote someone else's text it's usually considered proper to credit the author in full. And to recognise any copyrights.

 

The PDF is avaible at the diy-efi.org download area. the codes being written by people is a good point. but the operating instruction sets are libraried. they build almost everything from a library of code segments. if they didnt then every calibration team would have to be retrianed for each vehicle.

as for the ECM's they all use the same processor in the P4 series of which the 165 is a member. there only so many ways to skin the cat. with the hardware being mostly generic it mandates almost a generic cominality between the ECM's. theres only so many ways to do it. the fact that the ECM can be hacked at all is a testimony to the fact that they all operate in pretty much the same manner. there more alike then different.

 

Funstick, that doesn't mean "quasi" exists in the existing code. The GN's have SEFI, but that means nothing to other ECMs, as well as the $8D has Low Octane Routines and fuel correction for the MAT, but it means nothing to $6E or $32. Find "quasi" code in the $8D and show me. Better yet, do a keyword search on "quasi" and tell me how many hits you get.

But please don't make "blanket statements" and infer the code exists in other calibrations like $6E or $8D without demonstrating the code. Nor should you infer this for Ski's Duty Cycles. That is completely false because I doubt Ski dove into the code and added "quasi" code or invoked the code that no one has proven exists in $6E yet.

All your doing is "***/u/ming". At this point, there is no proof of quasi code in the $8D or $6E. As I know that code, all you have is 10ms @ 6,000 rpm to open your pintle, spray your fuel, and close the pintle....and that's all.

But, I am willing to stand corrected if you can show me the code...no explanations...just show the code in $8D and $6E.

 

glen you do understand that i cant do that.and just becuase you dont see it havent seen it doesnt mean its not there.also think about what you suggest. if it did fire every 4 ref pulses ( 1 crank revolution) then it would be out of pw pretty quickly. i think those old injector sizing formulas were made when nobody understood the factory strategys. and using fuel pressure was the key. the problem is that those old assumptions and methods have been infered and ingrained into the tunning culture. time to think outside the box. obviously all is not well. things dont work the way people thought they did. up until SKi posted his stuff i wa looking for a way to test this. the good news is ill be placing a scope and a Ref pulse on a bench this week and fine out exactly whats going on. i will post those results. but i cant get into code and you know why.

 

You do know that if I could find "quasi-code" in the $8D or $6E that I (nor Bruce) would disagree with you. But all the documented hacks I've checked on both the $8D and $6E show no signs of "quasi-code". A keyword search on "quasi" shows absolutely no hits either.

It's a lot like when I first told people that the MAT sensor didn't modify the fuel calibration on a $6E and many MAF owners disagreed with me. But I could not find anything in the $6E code to suggest anything different (the MAT does have effect, primarily with the engaging of the EGR but nothing directly for fueling). And to date, no one has shown anything in the $6E code to prove the MAT directly modifies the fueling based on the MAT like the $8D SD code does (other than affects to fueling based on the EGR's engagement).

But until someone can produce code to prove "quasi-code" exists, one cannot make a statement suggesting that it does...the onus is on the person claiming existance of something to provide proof.

 

OK, so where is it?.
Please refer to where it's mentioned in the 6E code.

 

i cant. if i could then i would. there more to why i cant answer then i would like to admit. my situation has changed. i will be hanging around offering tunning tips and whatever else i can but code explatnations i cant. it would be simpel to prove however. just rig up a ref pulse and watch the injector drivers. if they switch once every 4 ref pulses then you asycn. if they switch every 8 ref pulses your quasi. easy to see on a dual trace scope.


cant argue with that type of data.

 

So how do I engage it? And make sure that it is NOT a display issue (ie. 20 ms @ 2 revs vs. 10 ms @ 1 rev). You are only saving an opening/closing of the pintle every second rev (about a 1-2% decrease in the true duty cycle).

But you do have to be able to tell people how to invoke it - if not, then how can we test it?

 

run a dizzy upto around 3000rpm with a stock arap calibration with a 255 grm/sec reading at the MAF. those of you with ECM benchs should have no trouble with this. watch the scope. dont forget that the dizzy turns 50% of the speed of the crankshaft

 

Well, just as a double check, I fired up the ecm bench with the syclone ecm, and code in it.

It there was a halving of injector firing times, then there would have to be a sudden doubling of injector PWs.

Spun all the dials for temp MAP rpm and I couldn't see it.
Looks like one of the times, just because you don't see it, means it ain't there.

 

Last night I did another test of the AFR as I needed to do some stuff to it out at the dealership, or I wouldn't have even taken it out as it was raining and the roads were pretty wet.

I burned another chip with the WOT % AFR vs RPM increased ~10% across the boards to see if I could get a richer reading.

I took the car out and let it warm up a bit. About a mile from the dealership I stopped on an open straight stretch and got into. The car was all over the place, but I made sure my Rs got up in the 5000+ range. The car was everywhere, thank *** its a 4 lane. The AFR as much as I could watch did just as I suspected. It was down in the 12.2-3 range even as my shift light came on at 5600 and the tack climbed to 6000.

I know there wasn't a proper loading of the car, since it was spinning badly, but at WOT the ecm should be just commanding a given pulse width corresponding to PE parameters. I would like to if the weather would co-operate here, continue to increase the pulse width to see when the AFR quites dropping, but I suspect it will continue to dump fuel in till the guage reads a min of ~10 and pegs out.

Again I think funstick is just trying to point out the obvious that something is going on that is allowing me to run a rich AFR with these injectors, even though the formulas say different. Its pretty obvious with Corky and I both running these injectors that they can handle this kind of power. It may all come down to effieciency of the engines, but I suspect its more along the lines that the formulas are inaccurate and under estimate the injector sizing.

There is no way that my injectors are static at 4200 RPM (as said in previous postings) and we are able to maintain an AFR, and turn the times we are. Corky has been running his engine for 2 years now tuning near 10sec times countless time, yet he never has had a single issue and his FP is down in the 30s, and still running fat.

All I can tell you is what I see on the WB and report it to you guys, the rest of the story can be seen in the videos and testimony's of the other sceptical members here that saw the car run that day. The rest is history.

 

Also I was just talking to a friend that has a lingenfelter 383 build exclusively by them. It runs 11.7 in the 1/4, I believe on street tires if I am not mistaken and they built his engine with 22 # injectors.

Now a place like lingenfelters I'm sure knows from experience/dyno tesing of engines, what injectors work and don't.

Just thought it was interesting and since it came up, thought I would throw that out onto the table as well.

 

I didn't see where he said anything about your car.
The origins of this thread about injector firing strategies goes back some time ago.

I ran the code he mentioned and tested for what he mentioned, and wound up with results. There is no doubt about what's going on. The injectors fire synch, or asynch from what's actually been seen on a bench.
If anyone's seen anything other then that, I for one would really like to know the application.

Until you have some accurate PW readings from what you're doing, you will be just postulating on what's going on. And from that origin you can extrapolate to anyone of a number of answers. Some being accurate and some being eroneous.

Have you checked for any worn rear suspension bushings in your car?. They can allow for toe changes, and make a car rather unstable, when under power.

 

Ahhh unless I am mistaken here is one instance.......

Ahhh unless I am mistaken here is second instance.......

You see Grumpy you are soooo quick to jump all over everyone for voicing an opinion, perhaps you should keep yours to yourself more often. anything anyone says that goes against the grain with your thinking you jump all over them.

1/2 the time I doubt you even read the entire posts.

Sorry Funstick and Glen, I was trying to post some information that was was mentioned and what I have seen in my car, since our last discussion, but since it runs soooo crappy and I can hardly drive it on the street, it probably all irrelevant anyhow.

 

Well I have read the entire thread....

Lets see some PW's with your 406..

Until that.. your just assuming and guessing.

Data and testing determines answers, not speculation.

 

Go back and read the other posts. It was brought up by others saying that I was static and not able to maintain a sufficient AFR. I did provide pulse widths for the 12.8 AFR.

Some claim I am static and some say that I am not. I am reporting what I is going on. I gave a log of a 1/4 mile run. What more can I do?

You don't have to come running to your buddies rescue. If your not going to try to participate in a meaningful manner, then don't!

I love how others have to jump on the band wagon around here. Its sad

 

im not saying anything to either side really. im simply offering my opinion based on observations. in the end its the data the counts. i dont think the ECM has mode like we think they do. there are timmer chips. these timmer chips dicatate injector firing. the code might command a mode but there has to ba a point where the timmer chip has some input. keep looking theres and explanation in there somewhere.

 

Chill with the chest thumping... I've read those too....

and I stand by this...

"RPM BPW Time Difference
2200 11.67 27.3 +15.63
3475 14.31 17.3 + 2.99
4150 13.85 14.5 + .65
4525 13.43 13.3 - .13
4900 12.74 12.2 - .54
4975 12.67 12.1 - .57
5075 12.41 11.8 - .61
5125 12.52 11.6 - .92
5275 12.13 11.4 - .73
5300 11.87 11.3 - .57
5450 11.23 11.0 - .23
5825 11.03 10.3 - .73
5850 10.57 10.3 - .27
6075 10.42 9.9 - .52
6175 10.39 9.7 - .69
6300 10.24 9.5 - .74
6375 10.08 9.4 - .68


Okay.... my thoughts..

Since it appears the Ski is going static @ ~4200 RPM, I thought I would do a difference in time avail to PW.

Since the accepted opening of a SAT injector is ~ 1ms he is only short of fuel during the initial opening, after that since the injector is @ 100% the difference in time is under the "normal" time required for the injector to open. Hence he is making up for the "lost" time/fuel by being static. "

From "Bottom Line..."


Again.. the mathmatics are solid. And this is the same reguardless it is a 165 or 730.

This is the same arguement that Trax, myself and others disagreed with you about in prior threads..

 

the math is solid. only problem is is the formula actually right ?

 

Exactly. No one is disputing the fact that you can mathmatically prove that I am static, and if I couldn't increase the % AFR and achieve a richer tune or maintain the one that I am shooting for I would be the first to agree the injectors are undersized. And obviously be shopping for some larger ones. PLain and simple.

I just, as funstick is alluding to, think that something else might be happening to allow us to run these sucessfully.

I would not spend the time or money on a WB to see it go lean or waste my time building an engine to run it lean and burn though a head gasket. And I certainly wouldn't spend 2-3 hours every weekend driving one way to a track if I thought I wasn't able to run good. Come on give me a little credit in the common sense department.

I can't speek for corky, but he has built some killer cars, both carb and FI that run way better than these do. I think his exact words were this is the slowest car I ever ran. Now I think he too would up the injectors if he thought they were holding him back. Hell he just paid 600+ dollars for his manifold to get ported.

Here is his dyno sheet.....



That is last summer at the carlisle corvette get together....if you would like to confirm this with him, feel free. I am not making up stuff to confuse people. Just trying to offer some help in figuring it out.

This weekend come hell or high water I will get some full data logs of me runnign through the 1/4 mile. I drop my exhaust as I need to get a mandrel one bent and the nearest place is out in NJ ~7-8 hrs away. When I drop the exhaust I loose my WB02 port. So I can't log the AFR.

Also as soon as I get my car dynoed I will share that as well.

In addition you can check with JD about his lingenfelter 383 that runs in the mid 11s with 22# injectors. That car was sent to them and returned the way it runs now. I would have though in a 383 the 22# would have been too small, but I suspect that with as many performance cars lingenfelter builds they would have a pretty good handle on things.

I will ask JD if he has any dyno graphs.

 

You may wish to look at this post:

https://www.thirdgen.org/techbb2/sho...hreadid=179612

It discusses the differences between the 7749 which runs the $58 code that Funstick is referring to, and the 7730 which can run the $58 but only with the stock typ high impedence injectors used on TPI cars.

You will notice that the $58 can also run Peak/Hold injectors for the 4 cylinder Turbo Sunbirds. This probably the code Funstick is actually talking about when he is talking about "quasi", and it does not exist in the 7730s or 165s.

 

quasi basically accumulates alot of small pw's to have one large injector event. what ive been sugesting is that at a certian rpm the 165 drops the async 4 ref pulse firing mode for a idunnosync 8 ref pulse firing mode.