Pull the TB off and check the IAC passages in both it, the gasket, and the intake manifold. I was looking at the last data logs and I just get the idea that the IAC is becoming less effective the further it opens.

It just may be that the passages are too small or that a gasket opening for the IAC airway is too small.

RBob.

 

I removed the TB, check all intake bolts and gasket. Took the TB apart cleaned everything and blew it out. Remove IAC and cleared the passages, which are very large btw. (Its a 94 corvette TB,52MM), removed the airfoil that was in there. I even went out and bought a brand new IAC for it. Put it back together and datalogged. (see below). Same exact thing is happening.

 

I may have some good news (fingers crossed!)
Made some changes to the IAC-Idle/Drive table
Here's my latest log and for the 3 min's I was in drive it didn't stall

 

Can you post up your bin file? Also when you create your datalog file just just click the dump log button without selecting the boxes and it will create a XXX.ebl file. Open it up in notepad or change it from xxx.ebl to xxx.txt and it's a bit easier to read.

 

Question about the vss signal with the EBL. Does the ECm send the spped signal to the speedometer, or is it calculated inside the speedometer?
I am trying to correct a speed discrepeancy due to a gear change and it would be nice not having to go under the car to change out the speedo gears!

thx

 

The EBL Flash does not affect the speedometer. You can change the VSS PPM in the EBL ECM to correct it, but not the speedo. IF your GTA has a magnetic VSS it is buffered via a separate 4-out buffer box.

If the speedo is cable driven there is an optical VSS pickup in the back of the dash cluster.

For the EBL P4 Flash, it does buffer, or can buffer, the VSS. And sends pulse streams to the speedo and cruise. However, it can't make fine adjustments to these data streams.

Either need to change the gears in the tranny or use a SGI-5 box.

RBob.

 

Hey RBob, I tore apart my instrument cluster today and seeing my (unused) shift light, I was wondering if a shift light for us auto guys could be incorporated. I don't wanna ditch my stock tach, and I don't really wanna add an aftermarket shift light either. Is there an output on the ECM, and a table in the EBL that could be used to turn the light on when the ECM reads 6000 rpm? NOS stuff maybe?

 

Yes, the EBL ECMs have a real shift light output. With your username being '88, etc,:

SHIFT - Shift Light RPM (8cyl)

The actual output pin varies and with the EBL Flash is user selectable.

RBob.

 

https://dl.dropbox.com/u/42321996/11aug2012.zip

Hey guys I'm looking for a gentle shove in the right direction with my tune. I exported my log to a .CSV, at the link above.

Motor is the low-end "260HP" Goodwrench 350 w/ about 8.5:1 compression. Only mods are EBL and some of those cheap f-body headers from Summit. 61 lb injectors. I've had the engine running for about 3000 miles now and I've been going easy on it because I don't have a wideband. AFAIK I have the fuel map in pretty good shape, at least for the areas I normally drive in around town or down the interstate occasionally lets say 3500 or less. At this point I can do long ve learns and there's really no changes.

This weekend I decided to log just a few WOT throttle bursts in 4th gear. I was a little surprised to see my duty cycle go as high as 168% under WOT i.e. around 8m54s. Does this mean my fuel delivery (I have a 40PSI pump into the stock 13psi regulator in the throttle body) can't quite keep up with the fuel demands of the engine? This kinda surprised me given the fact TBI 350s are all over the place so I'm guessing the answer is something I'm not aware of.

I know I have some spark retard going on too but I didn't think this had anything to do w/ the DC%, although it may be a symptom of that problem. I was running +4 across the stock EBL TB2 bin's SA table for a while but changed it to +6 just this weekend before this log. I already backed it down to +4 where I never had knock counts or retard w/ my normal driving style except a bit at shut-down.

So the spark issues aside, what's my next move with the fueling? Something like the Jet AFPR, maybe 18-20psi to start, w/ BPCs adjusted accordingly? Or step up to police 350 injectors, possibly in conjunction with a bit more fuel pressure? I know...I probably need to get a WB O2 too. If it matters driveability is more important to me than squeezing out the last 5% of performance.

TIA,
-Dave

 

55# injectors @ 13 psi supports roughly 208 HP @ 85% injector duty cycle. You are going to want to up the pressure to 20-22 psi to support the 260 HP of your crate engine. At this PSI you also want to consider a Vacuum AFPR. The Aeromotive 13301 is a popular choice. You will have to redo your VE tables, BPC, etc once you change your fuel pressure. Check out the tuning papers and TBI fueling written by rbob on his website, dynamicefi.com.

 

Sorry, I mistyped...I'm running 61 lb injectors, not 55s. I found RBob's TBI fueling calcs page but for 260HP it looks like I have a lot of room to spare w/ 61 lb injectors @ 13psi. I should even be able to barely get away w/ 55's if I'm reading that correctly but I did swap up to 61's when I was getting the motor running just to play it safe.

 

Still not enough fuel to support what you have. Use the EBL Utility to calculate what PSI you will need to run at (looks like 16-17 psi). You could probably get away with out the VAFPR, I think rbob has recommended it for 18 psi and up setups.

 

Seems the gears are no longer produced, and the aftermarket didnt continue either!
The drive gears are easy to find, but not the newer (cone) style driven. I have a few calls to some core business' in the area but I'm not optimistic. Good call on the sgi--5 box, considering i have to change the speed sensor due to the jump in gear size, it may prove to be cheaper and easier then messing with the gears.

thx

 

have you checked here ????? http://www.transmissioncenter.net/sp...n_______va.htm

 

I did actually, they told me that its not being made, and near impossible to find one.
Have one guy getting back to me today, if not, I will buy the digital box.

Thx

 

Up the fuel pressure and see how the DC% responds. you wanna be at 85%. topdown solutions sells a spring one step higher than stock. around $12 I hear.

 

I have found that small changes in AE and PE can have a more dramatic effect than expected on DC.

If there is any excess with these much is to be gained by trimming them down to proper level.

I also think you are likely to need a little more pressure in the end, no VRFPR will be necessary for you tho, just a regular one, mod your regulator to start with, it's pretty easy.

 

You guys are talking about dc% needing to be 85. Is that at WOT because im new to the ebl and mine is around 100% at WOT?

 

You do not want to go over 85% @ WOT. If you are above that you need to increase fuel pressure thus increasing the lb hour of the injector. Use the calculator supplied with the ebl to determine what fuel you need based on what HP the motor puts out.

 

Thanks guys. I have a spare TB so I was gonna mod the FPR on that one in case I screw it up and then swap it in this weekend. I'll keep you posted.

I think my confusion comes from all the different injector calculators I've used seem to have like 20% variance, so w/ some I'm fine w/ 61's @ 13psi and others show me pretty undersized.

 

I would say only use the EBL, RBob knows his shtuff, plus there's a thread on FullSizeChevy.com too (http://www.fullsizechevy.com/forum/g...-upgrades.html), it explains how all the calculations work. I think 18psi with 61lb.-ers will be safe for you.

 

Here's an update on my tune in case anyone is interested. I modified the stock FPR to be adjustable and adjusted up to 15psi, which seems to be the limit w/ that mod and the stock spring. DC has dropped to a max of 120% on heavy accel now so it looks like I'm about half way there. The extra fuel seems to have helped my timing too...I ran it back up to +6 across the stock table and I don't get any counts on heavy accel in the 3-5Krpm range like I was getting before. Oddly enough my mileage seems to have gone up 1mpg too on my trips to work down the interstate. I would never break past 11.9mpg before and now I'm getting almost 13.

Next step is an external FPR. I'll bump it to 18psi and see where I'm at after that.

 

You may have to get a different fuel pump. The stock pumps tend to stall out at about 15 psi. You might no be able to get 18 out of the stock pump.
Get a Walbro 190 or 255 liter pump. http://www.autoperformanceengineerin...ml/fpapps.html

 

What John said about the fuel pump, except, no to the 255 LPH pump unless you are going to run 30 psi of fuel pressure. The TBI unit and return line will be too much of a restriction for a 255 LPH pump unless the fuel pressure is high.

For a mild build a TPI pump is a good choice.

RBob.

 

I have a stock replacement Vortec pump in mine, seems to do well with 18psi, though I haven't gone below that (started at 25psi but that was more than I needed). The EP381 is rated at 60psi & 155lph from what I've found, and from the math I've found that's good for about 400hp.

 

I actually already have a 40psi pump installed so I'm covered there.

 

Has anyone experienced an incorrect wud readout for wide band afr? I find my WUD reading on average .5 richer than the actual wideband gauge. Its not a major issue because i can compensate for it but it would be nice to have an identical readout between the two. My WB unit is a innovate MTX-L .
Is there a way for me to fine tune the readout?

 

Yes, create a User Device for it. Also, the 0v=10:1 & 5V=20:1 for the WUD's built in Innovate device doesn't match the Innovate default set up.

RBob.

 

thx Rbob.

Yes, I already had a new device setup to match the innovate 0v=7.35; 5v=22.39 output. therein lays my issue. WUD readout at cold key on is equal to MTX-L of 22.4;1. From there the wud readout starts to read richer, and no where is it dead on.
Just for giggles, i switched the device to the WUD default innovate setting (10-20:1), and the darn thin reads bang on from 11.5:1 -20:1. I couldnt run the car since it was too late in day, but i gave it a quick start to fill the exhasut with fuel just to test the readout.
How can the default formula give me an accurate reading until it maxes out at 20:1? It should be off by a larege margin in the lower and upper AFR ranges.

 

Sounds like the MTX-L set up has been changed. Or, there is a grounding issue. Try running the gauge ground to the engine block (none to the EBL board). Can also change the user device set up to offset any ground issues. But it is better to run the gauge ground to the engine block.

RBob.

 

I have a problem... again..lol

My TCC settings are:
LoGR MPH to Unlock- 42
LoGR MPH to Lock-48
HiGR MPH to Unlock-44
HiGR MPH to Lock-52
TCC- Forced Lock - 100

Option Word 2 Bit 2- not checked
Option Word3 Bit 3- not checked
Option word 2 Bit 7 is Checked

A year ago while on a dyno in the Wud Display TCC light would turn on when I hit 50 mph- turn off at 66 and back on at 100 mph

I was asked the other day if my TCC was locking up and I said I believe so. I was told I could test this while I was at a steady speed above where the TCC locks up, and while keeping the steady speed just press the brake pedal enough as to get the brake lights to turn on and look at the RPM gauge and it should jump up a few hundred RPM's. So I did this several times and nothing happened.

At around 53 mph I do feel as if the tranny makes a shift.... thought it was the TCC but now believe its OD.

So I went back into my datalogs I've done in the last couple of weeks while highway driving... and I've looked thru several. Ranging speeds of 40 to 85 mph...and at no point did the WUD display the TCC light on, matter of fact it never turned on.

So
1) It appears its not locking up...what direction to I look in to resolve this?
2) what my goal is to do is to keep the TCC locked up all the time above 52 mph, can I just bring my force lock down to 52 mph?

 

Best thing to do is to open your current BIN in Tuner Pro. Then open a stock EBL BIN set up for the 700R4 as a compare BIN.

Check every "TCC - xxx" parameter and table of your BIN against the stock EBL BIN. The enable CTS value or the coast unlock TPS% thresholds can easily prevent TCC lockup. If any items differ just copy them over from the stock EBL BIN.

Also, make sure you didn't put the shift light on the TCC output as that will override it. So make sure that the "Shift Light Output" parameter is not 8.

That will work, but isn't ideal as you may want it to unlock at say 60 MPH for acceleration.

RBob.

 

Compared .bins every TCC parameter is identical to an orginal .bin using the 700r4

Shift Light Output parameter is set to 0

Been doing some searching in this thread and found a post in regards to HiGrh- Option word 2 bit 5.
When I had PeteK build my new trans he used a N/C switch for this. My HiGrh is checked according to the post I read you wrote
N/O- this would be checked
N/C- this would be unchecked
can you verify this?
This may be my problem

 

This makes no sense at all. Please email your BIN & the data log to me.

That only selects which set of parameters/tables to use. The high gear sets or the low gears sets of parameters/tables.

Do a key-on, engine-off, with the WUD connected. It should show P/N. Foot on brake and shifter in any position except P/N (use R, OD, D, 2, 1) and the WUD should show D.

If it shows OD, then flip the HiGrH flag (un-check it).

RBob.

 

Had to have some minor sheetmetal and paint work done... now back on the road and doing some tuning again, finally!
Question on the DFCO - Lower/Upper MAP Thres(hyst):
I noticed that the Rows "Lower" and "Upper" for the hyst are swapped here when compared to the MPH and RPM hyst. Is that correct or is that a mistake in the XDF? Just got me wondering, and i couldn't find it out by myself because i'm not sure what the MAP hysteresis is supposed to do for this one Thanks!

 

It is correct. The reason the table rows are reversed is that the RPM & MPH vaules, the actual needs to be higher to enter DFCO.

While the MAP values, the actual needs to be lower to enter DFCO.

DFCO - Lower/Upper MAP Thres(hyst)

Engine manifold pressure needs to be below the lower value to enter DFCO. Will exit DFCO once the engine manifold pressure rises above the upper value.

RBob.

 

I took a closer look at my SA table vs. the stock Vortec table, and for the most part it follows a similar curve. At upper rpms (3500+) mine is lower than the stock setup by 4-6º on the top end... does that sound like a fuel grade issue to anyone?

 

Doober: Not an expert or anything on this, but just one thing i realized: There's a separate PE SA table that will be added on PE based on rpm (and gear, on a manual) imho. Maybe that's the degrees you're looking for, but then again i'm not sure the stock calibrations also have a table like that to be added on PE...

RBob, on that DFCO:

I have realized why the rows are reversed in regard to RPM & MPH hyst. rows now, but I'm stiull wondering what the actual reason is for MAP to be say over 45 to exit and under 38 (off top my head that's the stock L03 vals) to enter. For exiting i would guess that with MAP indicating engine load, 45 MAP would be considered too high to stay in DFCO because it would maybe stall. I'm quite clueless tho concerning the enter condition.. Either i would think that it could be any arbitrary number (could be 90 or whatever) or that it would be the MAP value corresponding to a engine settling down pulling good vacuum (say in the 20's or therebouts). Care to explain that one to me?
Thanks
Also I'm not sure why you would exit DFCO based on a low MPH value.. Maybe that got something to do with DFCO kicking in and out when coming to a stop or when going at low speeds ('creeping')?

 

If you reduced the SA due to knock, then yes, a higher octane fuel will/should help.

RBob.

 

My understanding of DFCO is to protect the catalytic converter during long decel from higher speeds. I can see some gains occurring in mileage, although not sure how much of a gain.

With that in mind there isn't any reason to have DFCO active at lower speeds. Not to mention the driveability issues.

As for needing a low MAP value, in decel it will be low. There is one main priority in using DFCO, do not let the engine stall. This is very important as it is a safety issue.

Using the input of two sensors makes it that much safer. What if one of the two wasn't reading correctly and the code only used that one sensor.

Secondary is the driver/passenger feel when the ECM enters and exits DFCO. I have it disabled in one car as when it exited (fuel back on) it caused an uncomfortable jolt. Modified engine and a stick shift can/will do that.

Regarding ECU/XDF entries, we have found one the the DFCO parameters conversion incorrect. It is the MAP increase to exit:

DFCO - MAP Increase to Exit

The current value appears to be 23 KPa, but is really only 3 KPa. This can cause the ECM to exit DFCO shortly after entering it. You can correct the conversion itself by changing the:

"0.312500 * X + 20.000000"

-to-

"0.312500 * X + 0.000000".

(change the + 20.000 to + 0.000)

Or just add an additional 20 KPa in the parameter entry window. Making it 42 is then really 22 KPa increase. The conversion we used is for an absolute MAP value, not the required delta value.

RBob.

 

I remember reading this a lot about DFCO, but I'm still not sure how the cat is protected by temporarily shutting off the fuel injection.. or, IOW, I don't understand how the Cat would suffer from decelerating, given a stoichiometric AFR.

For me the reason to have DFCO at lower speeds is the consistency in driving behaviour. My expectancy concerning DFCO behaviour might be different because I'm used to stick cars, but somehow I would prefer to not have the DFCO based on vehicle speed but rather RPM and MAP only. I sometimes find myself a bit disturbed when I come to a complete stop and I feel DFCO exiting at 20kph or something like that.

I get what you're saying tho on the safety issue and the absolute necessity to keep the engine from stalling. But RPM and MAP is still two sensors I'm not sure my daily driver bases DFCO on vehicle speed.. Actually I'm pretty sure it doesn't, but no clue if this is a common practice, and it's stick as said. Driveability with DFCO at low speeds for sure is a factor, but as said for me the bump/jolt on DFCO exit is more acceptable if it happens more consistently. Might play around some more with it and lower the MPH drastically, and see how driveability is.

On that MAP Increase XDF mistake, so that +20 offset is assuming the typical MAP of 20 in DFCO/decelerating right? Thanks on the pointer.

Anyways i know this DFCO stuff is a minor issue. I just crossed my mind every other drive to and from work since this is all driving in city traffic, so I was thinking about it and tried to figure it out Thanks.

 

The way i got it Doober meant that his current SA curve at higher rpms is even lower than the stock Vortec table. pretty sure he reduced the SA due to knock, but imho not a fuel grade issue if a stock curve is hotter than the one he's using? unless GM is expecting higher octane with that stock SA curve you're referring to

 

It isn't always stoich. Some calibrations go open loop on decel to prevent surging. There is also the possibility of mis-firing, which will quickly kill a cat-con. Due to the small injector PW's and the low density of the mix in the chamber, it doesn't always get the correct amount of fuel or even light off.

You shouldn't feel it exit DFCO. Your regular car driver doesn't want to feel it. They want a smooth steady feel to the vehicle. Once you understand this and the need for no stalling the whole DFCO logic falls into place.

Note that we added a SA reduction on exiting DFCO to the EBL. This too was put into place to ease the 'jolt' from the engine running again. It helps, but on my one car wasn't enough to reduce the jolt to where it was acceptable.

There are others that have the same jolt with modified vehicles. I recall a thread or two here on this issue.

It may be that disabling DFCO is the right thing to do on your car.

And TPS makes three.

This parameter is an increase in MAP over time to force an exit. If the MAP increases too quickly that is a sign that the engine may be stalling. The +20 in the conversion is for a regular MAP value, not a delta or increase in time value.

In the DFCO parameters there is also a decrease in RPM delta (over time) that will cause an exit. Again to prevent a stall.

A pending stall exit from DFCO also adds a fuel pulse.

RBob.

 

He is running a 383. Likely the compression ratio, exhaust, and cam aren't stock.

RBob.

 

Totally amiss then on my end, sorry.

On the DFCO thing, need to do some rereading and rethinking first i guess ^^

 

It indeed isn't stock My thinking is cylinder pressures are higher because it's still a mild cam compared to other guys that run cams in excess of 230º on the intake, coupled with the small increase in static CR (~9.5:1 compared to... 9:1?).

From this site I got an estimate of around 7.5:1 DCR at about 2500' elevation. I'm in Oro Valley, AZ, stated elevation is more like 2600' but elevation varies widely depending on where you're driving. Calculated DCR for sea level is 8:1. Everything I've read on DCR is 7.5-8.5:1 is optimum for pump gas, with race engines being closer to 9:1.

I'm also wondering if underhood temps (running an open element cleaner right now) are also affecting it, because I still get knock on occasion at high engine loads after it's reached operating temperature - coupled with the hot AZ days it can get really hot under there. I went from a 4.3 to the 383 so I didn't reuse the air cleaner, I'm thinking sometime in the future I'll get one of those cheap 'cold air' kits off eBay, I'm not a huge fan of how the stock cleaner looks and the aftermarket setup would help clean up under the hood a little.

 

Phew, that sparked a lot of new questions. I was also looking at the info in EBL_Calibration.html but it didn't help me out enough..

Gotcha on that one.

That would be DFCO - Exit SA Multiplier, right? It's set to 37.65 in the EBL_F_2016 base. Does that mean it will only use 37.65%, or whatever value set there, of the actually commanded SA value during the DFCO exit transition? Also how long is that transition phase anyways?

Concerning DFCO - Enable TPS% Threshold, it says 'The minimum TPS% required to enable DFCO.'. I take it DFCO should be active on off-throttle conditions, so a setting of 1.57 here means it won't enter DFCO if the absolute TPS is > 1.57%?

Guessing DFCO - RPM Drop to Exit.. What sampling period is used to determine the delta value on these (or, in general, any delta values?) anyway?

DFCO - Fuel Pulse Upon Exit, would i want the AFR to jump right back into the stoich range, or slightly lean combined with a reduced SA, or something else.. to keep the jolt low?

edit: Another peripheral question: Can I indirectly use IAC - DFCO Steps to (marginally) adjust the engine brake torque during DFCO?

Thx

 

Imho a DCR of 7.5 or 8 prolly wouldn't cause a lot of knock, although when combined with high underhood / intake air temperatures things get different. If it were me I'd definitely plan on throwing out that open element and installing a CAI setup asap.

 

When exiting DFCO via the TPS% threshold the current SA is reduced to that percent. So if the SA is currently 20* BTDC it will become 20 * .37 = 7.4* BTDC. The SA is increased by the same rate as the transition from cranking to running SA:

SA - Startup Blend Filter

Yes, basically closed throttle.

It varies according to which delta is being referred to. For the RPM drop it is over a period of 50 milli-seconds. For the MAP delta it is the same one that is used for AE.

The fuel pulse on exit is an anti-stall technique. It isn't used if the driver depresses the go-pedal.

More then just marginally, can make quite a difference in roll-down.

RBob.

 

Thanks for answering all the questions! I really felt a boost in driveability on the way home after I trying to work out the ideas behind DFCO and doing some educated adjustments. I guess I had been playing with DFCO previously without really understanding it, making it worse to the point it was annoying in city driving. The hints you gave concerning the anti-stall exits (guessing that would mean any exits based on RPM, MPH and MAP?) and the difference to a TPS% based exit might be quite important too.
So just recapping to see if i got it right?
- anti-stall exit (RPM, MAP, MPH) uses the fuel pulse but no SA reduction
- TPS% exit uses the SA reduction but no fuel compensation
Thanks again Robert!

Btw - i really hate this silly mouse pointer device Windows thinks i plug in just about every time i'm using my laptop with the EBL grr ^^