wouldn't the reading be more accurate when it as close to the chamber as possible? I was wondering about this- do you use the same math when you're dealing with IAT (dry) as opposed to MAT (saturated)?
if it's the gas law, I'm on it

 

The inside of the intake manifold after the throttle body on a TBI engine can run up to 60*F cooler than an air duct/filter mounted IAT. The MAT is a more direct reading of what is actually going on, shortly before the air/fuel mixture hits the cylinders.

 

Rbob, can you explain the TCC related option words for me? I'd like to make sure they are set correctly for my application.

Here's my problem and reason for asking: When I'm on the freeway in overdrive, if I let off, then get back on it, the transmission seems to free-rev for about two seconds before I get any resistance on the engine. It doesn't do this in any other gear other than overdrive, so I was wondering if it was TCC related???

I should probably jump on it once when this happens to make sure there's no resistance. I usually just baby the pedal until the RPM's drop.

Thanks

 

Mine does the exact same thing, I kinda like it in the truck. Gives the truck a little headstart going back in to OD in terms of TQ

 

One difference in the 700R4 between OD and the lower gears is the overrun clutches. They are only applied in the lower gears. In OD (4th) the overrun clutches are dis-engaged. This is one reason the car will just keep on rolling in OD. Even with the TCC locked.

In the lower gears, with the TCC locked, it feels like a stick car. You can keep the TCC locked during decel by setting the TPS% Coast Unlock settings to 0.

For the option words:

TCC - Enable TCC calculations (0 = stick trans), need to set to a 1 for TCC calculations

HiGrH - 4th gear switch polarity (auto trans), need to be set for the ECM to use the proper low gear or high gear tables. To check it leave trans in D (not OD), and see if it locks at the correct low gear MPH point.

DcTCC - Unlock TCC during DFCO, this over rides the coast unlock, and will force an unlock when in DFCO,

TccHi - Set TCC enable output polarity, leave this as a 0. A 1 will invert the output and the TCC will operate in the inverse manner.

RBob.

 

Help me out here.......
Does this not make the IAT then dependant on the fuel spray cooling it ?
It seems to me, that we want to control the fuel spray based on the temp ( density ) of the air prior to cooling it with fuel, so we know how much fuel is needed.

It seems to me ( correct me if I'm wrong ) that if the IAT is prior to the spray, it's measuring air temp as a product of air temp, and a bit of friction across the IAT. Primarily the ambient air temp entering the engine.
If it's after the spray, then it's measuring a dynamic product of the thermodynamics involved in ambient, evaporative cooling, friction, heat absorption properties of the fuel, or liquid cooling, thermonics of air density under vacuum and the specific absorption properties thereof, rate of cooling due to changes in velocity, and probably a few other things.
That all sounds a bit complex for my one still functional brain cell.

What am I missing ?

Mine is ty-wrapped to the pod roughly adjacent to the injector nozzels, and seems to work quite well there, though I've been surprised at how much the air is already heated by that point.
Easy enough to move, though.

 

Yes, the IAT (and air density) can be highly dependant on the fuel cooling it. This effect seems to go away when the ambient and intake air temps are real high due to the fact that the heat input totally overwhelms the heat taken up by the fuel flashing over to a vapor. At moderate temps, though, the manifold can get much cooler. My airgap actually sweats on warm days. This is the reason you want to run a semi-heated manifold and open element so you have consistant warm temps to keep the IATs from drifting all over the place and skewing the fueling.

 

Certainly seems to me that a temp that includes as many of the modifing factors as possible would be the best, as the MAP is subject to these same factors,it would make the most sense to me (not that I know) to take temp at the same location. Thanks for bringing this up, lots to consider, Val

 

Except, that the reason we're looking at this temp, is in part to determin fueling, so if fueling affects the reading, it seems we'd want that reading before we modify it......
It might seem that the temp affects MAP, but really it's more the other way around, and the temp is partly an effect of the MAP.

 

Now, to my aging and feeble mind, it seems you've introduced yet another variable :
that the temp reading will be non-linear, and a further departure from incoming air, in part as a result of what the incoming air was before it was altered, before the fuel was added to alter it further, before we can determin how much fuel we wish to add based on what the incoming air was before......

See, here is my problem :
If the air temp, modified by fueling, is skewing the fueling, which is skewing the air temp, which is skewing the fueling......
Then why is it *not* better to simply measure it before we've gotten caught in this never ending loop ?

If we know what the incoming air temp is, then we pretty much know the density, and can determin how much fuel to add.
Since AFR is by weight, it matters not if the temp/density of the air changes *after* the correct amount of fuel has been added, as the weight of both will remain constant.

It just seems to me that you've chosen a particularly difficult way to do the same thing.
What am I missing ?

 

The dimly glowing bulb above my head says "but isn't the object to deliver a charge of specified density?And if temp is taken at manifold vacuum with fuel added,varying fuel temp would be included,and maybe effects of changing fuel formulations (maybe a variable best left out). As to establishing a self feeding fueling problem ,,would the IAT vs CTS% control that.What does fast 355 use for that figure with the in manifold sensor? Thanks all, Val

 

I always thought that the idea was to estimate air density and its capacity to carry fuel. I would think the IAT at themanifold would ultimately yield a very narrow range of measurements that have little relation to outside air temp.

 

I just installed Flash EBL. Fired right up - a bit rich to begin with. Naturally did not read any README files or manuals. When for short 15 minute with enabled VE learn.

During this test run:
ambient temperature 28C, sunny and dry
street driving
4th gear and TCC circuits are still disabled.

Log file is over 6.7 MEG for 25 min ride

After playback and reading this thread:

1) Need to disable lean highway cruise to allow for VE learn with NBO.
2) Get WBO (ZT1) connected to EBL for proper VE learns.
3) Question, after analyzing log-file I noticed when coasting to a stop (TPS =1%), speed slowly decreasing from say 45 to 20 system in open loop, and no DE. Naturally, with NBO no VE learn. I can post log extract.

//RF

 

I still have too much AE when I hit it from a stop. here are my AE tables. Is my 50mm t-body to blame? Too much for the 350? It's not a show stopper, but when I floor it from a stop the engine shows signs of too much fuel (almost dying). whaddya think? running 90's at 15 psi, FLash EBL V22, GMPP 350HO, Denver, CO (5400ft)

-Thanks Rbob for the Flash EBL, great product! No issues
AE.BPC.JPG

 

The open loop decel option is set. This is to prevent surging from closed loop corrections. It is "Option Word 3 - BIt 5 - OpDcl"

Can try it unchecked and see how it decels. If no surge then it may be left that way.

RBob.

 

What you can do is to taper off the AE PW (MAP & TPS) as the delta's increase. The attached pic is an example.

RBob.

 

Cool, thanks Rbob.

 

Is the reduction of AE at the higher limits of table EBL specific?

Is the pracIice of incrementally increasing the values as one goes up the table causing AE overload?

Possibly due to the EBL tables are expanded 2X that of GM.bin ?

 

It may be better to show all AE values & tables for two completely different vehicles. One if for a stick the other an auto, one has cam, headers, etc., other is mostly stock, One has a 2" bores, the other 1-11/16" bores. They both run rather well.

Some subtle differences in the cal, and some not so subtle differences.

RBob.

 

RBob, that's a really interesting comparison there. May I ask what size that first engine was? That is a gigantic amount of TPS AE, I'm surprised. Also, I've always had trouble with AE in my stick shift car, just seems nearly impossible to get it perfect, because it is soo sensitive to the slightest of changes. That's the biggest thing I've noticed the manual trans brings with it. I noticed all those filter values, double MAP, and multipliers are all very different. Can you please explain which ones should be changed and for what reason based purely on a stick vs. auto? Basically, I'm curious which values are different because of the stick and not because of the obvious fact that it has a cam, headers and 2" bore TBI. Thanks for any insight.

Jim

 

Exactly. Me too ! My car is a stick. My values are so much smaller but I have 80 lbs inj at 20 lbs so that explains why. I needed to add so much more AE fuel at 2400-2800 rpms(RPM multiplier) as I went lean there. That seemed to help. I see neg % changes in both tables for RPM multipler%. Stock EBL.bin I believe was an adder there(+)?

 

The first engine (AE01) is a 331 (30 ovr 327) SBC. And is a stick shift vehicle. The second engine (AE02) is a 305 with an auto.

Speaking of the first engine (AE01) vs the second (AE02):

Even though there is a lot of dTPS PW, the filters are higher for a shorter duration

The CTS multiplier is lower (reduces AE)

The RPM multiplier is lower (reduces AE)

The dTPS threshold for AE is small, this provides TPS AE with less pedal change

The dMAP threshold for AE is larger, won't get MAP AE until the MAP changes more

The AE -> TPS% to double MAP AE is set to 100%. This prevents the doubling of MAP AE PW when the TPS% is above the threshold.


The single largest issue with a stick car is MAP AE. It is very easy to pull the RPM down and create a high dMAP. This is partially compensated for in the RPM Multiplier table. Engine idles at 850 RPM, with the 400 & 600 RPM areas of the multiplier table pulling a lot of AE. Otherwise it just loads up and dies.

A second item with a stick car is DE (decel enleanment). Each time one shifts DE comes into affect. Too little DE and the engine is rich with the AE. Too much DE and the engine is lean with the AE. The AE in this case is when the go--pedal is depressed after the shift.



One item to note is the CTS based tables (filters & multiplier). If the values are graphed the slope of the line is less for AE01. This engine runs a rather cold intake tract. Where the other engine (AE02) runs a full water jacketed stock TBI intake manifold (no heat riser on the air cleaner).

RBob.

 

Quick question, I'm looking at the analysis screen for a full throttle run and I notice it's choppy by about 25 RPM throughout the range. I thought this meant it was misfiring (can't feel it), but I got on dynamicefi and the sample looks the same way. Is this normal? Why does it show it the way it does?

 

This is normal. Unless heavily filtered all (most? need to stay away from all-encompassing statements) ECMs show this trait. It has to do with the calculation being done for every 25 RPM. A single bit change will cause a 25 RPM jump. By single bit it is the change from say the value 200 to 201. The value of 200 is 5000 RPM (200 * 25), and 201 is 5025 RPM.

RBob.

 

IAT: sensor still in the air cleaner snorkel, fuel table was good till the temp dropped. Then the lower areas went rich,the cruise areas went lean, Like 12% each way, shifting bias toward the IAT, away from CTS has helped somewhat, does anyone have ideas or a formula that would help to zero in on amounts of compensation.All suggestions appreciated. Thanks, Val

 

Is EBL only for tbi cars, if not will it work for tpi,
if so, where do I get the info to make the change

 

I can't give a direct answer for this. From my experience the fuel change that is made this time of year has some to do with it. It also depends upon how much pre-heat and manifold heat there is. If the driveablity is OK, then I don't worry about it.

To help tune in the IAT/CTS blend table, use the EBL dump log and observe the gms/sec value. That will define which area of the blend table to change.

RBob.

 

The EBL is available with a port modification. This is recommended when used with a port injected setup. This mod changes the injector firing rate along with setting up the injector drivers. And is inexpensive.

If currently using a '165 ECM will need to add a MAP sensor (MAF is no longer required), along with a few pin changes. Real easy, pin/wiring changes freely available by request.

If currently using a '7730 ECM the change over is a little more involved. How involved depends upon what is currently in place (assuming a retro-fit to the '75). VSS buffer, and knock sensor filtering is different.

Please see my sig for additonal information.

RBob.

 

Let's see if I have the basic drift here, if the learn is pulling fuel from an area(like16 gps) when ambient drops, this indicates that IAT influence should be decreased (CTS % lowered). If the learn is adding fuel when ambient drops,IAT bias should increased. I think the opposite would be true on ambient rise. Would it be best to start with an 80% table to allow movement either way? Please comment, Thanks , Val

 

If the AFR goes richer as the ambient temperature drops, then the blend of CTS% needs to be increased. This lessens the affect of the IAT.

RBob.

 

I'm gonna give the CTS a more control because I've noticed it running more rich with the colder temps outside...probably too much IAT comp like you guys are talking about. I have the IAT in the manifold, also (guess that's a MAT?). A little off the IAT thing...I'm running open loop in idle at about 13.0 AFR and I've tried to decrease VE by .5 in the idle areas, only to have the truck idle like hell and have AFR's at 16.0. All I did was a .5 reduction...WTH? Maybe that idle VE % (around 30) is the bottom limit for my 90 pph inj's at 15 psi? My current injector offset is 730 usec for operating voltages (12-15) and I have a stock quality idle (after raising INJ offset) with the slightly higher VE. I guess my question is what would cause such drastic changes to idle and AFR with only a .5 reduction in idle VE? here's a pic
THanks guys
-edit/update
ok, tried closed loop idle and BLM was 100 with INT at 125. AFR's were bouncing from 14.3 up to 16.0, idle was more rough and the exhaust sounded worse, as well as a 5 Kpa climb in MAP from 40 (open loop) to 45 (closed loop).
pw's were very low, .8/.9. I think I'm on the ragged bottom edge of the injectors opening and closing...
I went back to open loop idle for now, sync pw at 1.2. SA at idle is 19/20. ANy thoughts?
LSVE2.JPG

 

My engine prefers no leaner than 13.2 for idle, might try taking out 1% at a time, Val

 

I hear ya...I tried .5% reductions and all hell broke loose.

-maybe I'll try .10% changes

 

Try divide 1.01

 

Sorry for asking but what is EBL???

 

www.dynamicefi.com

 

What is used with it to tune for software..and I have searched...all over in here and I'm lost. This looks better than the PROM idea for my friends 90 L98..

 

I use Tunerpro v4.14

google tunerpro and download...good to go

 

I would start reading at the begining of this thread and also the sticky's above that privide all the info you need.

It is an emulator-upgraded ECU- datalogger and creates new .bin from the datalogs. and a few other features all described on the website.

 

Hello everyone, I just purchased my EBL kit from dynamic EFI. I am watching these threads closely as I am going to be gathering tons of information for my project. Has anyone here successfully been able to get that A.I.R. diverter valve to work with EBL?

 

What are the amp ratings for the relays required for fan control as listed on dynamicefi.com? 14103304 and 14089936? I

 

Say I picked up a vortec TPI baseplate and had all the parts, fuel system components, everything necessary to run port fuel with the EBL Flash in speed density mode. I get my BPC, start with the stock EBL port fuel bin, go from there. How do I wire up the injectors converting from TBI to TPI? The page at dynamic is over my head. I know I could wire it up, just wondering how it interfaces with the TBI injector wires

 

You put 4 injectors in parallel off of each injector driver.

 

Thanks Fast. I take it the drivers in the EBL are good to go with running 8 port fuel injectors

 

I have run them with LT1 injector on my 305, ran fine. Needed alot of chip work, had a little surge during DE, but was otherwise OK. If I had spent more time working on the chip, I could have eliminated the very light throttle and DE surging, but I had no desire to as I switched back to the PCM. It to had the light throttle surge thing, but I completely eliminated it through tuning. The thing I found difficult, using the TBI firing scheme is idle and very light throttle. The injectors flow around 100# and I only have 305 CID under them. The PW gets VERY SHORT @ 550 RPM and NO Load on the engine, causing the ECM to enter Asynch. Asynch and PFI = Rough Running

 

what's the equivalent in port fuel for tbi injector offset? That's how I got my 90's working right with my TBI 350HO...raised the offset by 350usec. Can you disable async in port fuel like you can in TBI?

I guess the pw's dropped so much the engine didn't need sync fuel anymore and just wanted async

 

Is there another link to the VAFPR BPC value file besides the one in the wavy VE thread? That one doesn't work.

I'm using 81# injectors and the instructions for my Aeromotive regulator say the pressure should drop 5 psi when connected to a vacuum port. There's another file in that thead, but it seems to calculate for more than a 5 psi difference. There is also no place to enter the psi that the injectors are rated at. For instance, if my injectors are rated 81#@9 psi or 81#@12 psi that kind of matters, right? Maybe I'm missing something.

 

Is that info from Aeromotive website? I have same Aero regulator and have written directions some where but it seems as though that 5 psi cannot be correct. I would believe if you use a higher FP the vac you engine produces would reduce it a set amount. I will give an example. Say you are at 25 lbs before vac applied and then you connect to vac port say it drops to 10 psi. that would be acceptable for idle TBI. If you are at 15 lbs and do same it might drop to 5 psi? I would think you can adjust the FP at idle to whatever you wish with vac line active. I have never used my Aero VAFPR. I am currently at 20 lbs FP with 80's and idle at 875 RPM OL at 1.3 or so msec synch PW.

Maybe someone that has run the Aero unit with VAFPR can offer better comments.

 

Nevermind, I'm an idiot. The 5 psi I "thought" I read in the instructions actually came from an example they used on their website in the FAQ section. Under boost, it's 1:1, and on vacuum, it's roughly 1psi for every 2 in. hg.

I've been installing my regulator going on two weeks now. First I ran out of hose, then I ordered the wrong fitting for the back of the TBI.

 

I saved a calculator I found on this site that will calc the BPC when the FP is vac referenced. variables are cylinder CID FP inj size and number of inj.

numbers for me are :
84 zero vacuum or 100 MAP
85
87
89
91
93
95
97
99
102
105
108
112
115
120
124
129 80 vacuum or MAP (20????)

I believe this is for EBL table -Standard BPC table: 'BPC - BPC vs VAC'
I dont know how to post it but i can email it to anyone.