Feedback on first ever tune for a 91 Speed Density TPI L98

[Blown WS6]

I am using the EBL P4 Flash ECM with What's Up? Display for VE learns and data logging (I haven't figured out how to data log yet). I have an AEM Wideband with 0-5V data input into the ECM for VE learns and logging.

The Engine is a 355ci SBC with 10.8:1 compression and stock L98 heads milled down 0.010". Comp cams Computer Cam grind number 266HR-14 (210/220 @ 0.050" Duration, 0.500"/0.510" Lift, 114 LSA). SLP 1 3/4" shorty headers with a custom built Y-Pipe (2 1/4" to single 3") and open exhaust at the end of the Y-pipe. Hand ported Plenum but stock TPI intake other than that. I have an AFPR running 48psi and I have the base timing set to 12 deg BTDC (which it ran best on before I had a programmable ECM and was just using a cheap scanner to look at Knock counts)

Using the supplied base BIN: EBL_P4_3005.BIN I did about 6 VE learns using the WBO2 as the input device to learn. (Figured it was better than using the BLM and the NBO2)

I got some choppy VE tables that I then learned how to smooth using information on this site. (I haven't ran this new table yet)

Spark retarding seems to happen the most at around 60 MAP/2000rpm and 2200rpm and around that area. (I had the base timing in the BIN set at 6 deg BTDC even though the dist was actually set at 12 deg). I then set the Base timing in the BIN at 10 degrees BTDC (distributor still set at 12) and had almost no spark retarding.

I'll post some pics of the What's Up? readings and the VE tables from TunerPro in a second from my phone.

Just looking for feedback on what I should do different. Sometimes my AFR goes really lean at light cruise (17-19) and I'll get off the throttle and come back and it then reads 14.7-ish. Is that lean ok for a lean highway cruise? Also, my stock ECM shut off the injectors on decel when I manually downshifted my ProBuilt Stage 3 700R4 and now it doesn't I'd like to enable that feature again.

Any feedback is appreciated. For reference on my technical ability: (might matter in your depth of answers) I'm a MOPAR dealership tech for over 15 years and also taught Engine Management Systems at WyoTech for 5 years. I was a Smog tech in California as well. I'm VERY good at fixing things back to OE specs but this is my first foray into tuning. I used to just bolt stuff on and try and work around the stock tune with other methods.

Thank you.

[Blown WS6]

Here are some pics of my data and tables:
This is the spark retarding with 6 extra deg of advance the ECM didn't know about.
17673
After pulling 4 degrees of timing
17674
Low speed VE tables before smoothing but after 6 VE learns
17675
17676
High speed VE tables which didn't change much on VE learns
17677
17678
Spark advance tables which i haven't touched
17679
17680

[Blown WS6]

Low speed VE tables after smoothing 17681

[ralmo94]

Just looking for feedback on what I should do different. Sometimes my AFR goes really lean at light cruise (17-19) and I'll get off the throttle and come back and it then reads 14.7-ish. Is that lean ok for a lean highway cruise? .
.
I don't have any experience with the EBL, but I don't think I would command a lean cruise until the VE is dialed in close.
As far as if that's too lean.... is the engine happy with it, no lean stumble? And is the commanded ratio the same as the wide band?

Threads I have read about Lean Cruise for carburetor guys, say to lean out until lean stumble, then richen back until it goes away. But that might NOT be the best for fuel Economy. AFR's around 15.5-16.5 MIGHT return better FE.

VE tables look nice, how high RPM have you had it too? Looks like you are richening your VE from original, you MIGHT copy the highest rpm cells you have hit to the higher rpm cells you have not hit, for a better starting point

[Blown WS6]

I don't have any experience with the EBL, but I don't think I would command a lean cruise until the VE is dialed in close.
As far as if that's too lean.... is the engine happy with it, no lean stumble? And is the commanded ratio the same as the wide band?

Threads I have read about Lean Cruise for carburetor guys, say to lean out until lean stumble, then richen back until it goes away. But that might NOT be the best for fuel Economy. AFR's around 15.5-16.5 MIGHT return better FE.

VE tables look nice, how high RPM have you had it too? Looks like you are richening your VE from original, you MIGHT copy the highest rpm cells you have hit to the higher rpm cells you have not hit, for a better starting point

I've had it to 5000rpm which is its normal redline (TPI runs out of power fast over that) and the AFRs are like in the low 13's. I need to figure out how to data log with the What's Up? interface so I can see it better.

Should I pull timing in the problem areas you think?

[ralmo94]

I've had it to 5000rpm which is its normal redline (TPI runs out of power fast over that) and the AFRs are like in the low 13's. I need to figure out how to data log with the What's Up? interface so I can see it better.

Should I pull timing in the problem areas you think?
Some tutorials say when dialing fueling in to reduce stock tables by about 2 or 3 deg to ensure knock doesn't mess with fueling.
If you do, you should probably also lower the cells you hit before knock occurs.

See following post from 1project2many about knock retard
http://www.gearhead-efi.com/Fuel-Injection/showthread.php?8868-What-should-I-do-about-my-main-spark-table



Knock is an audible event which indicates combustion pressure and temperature have risen too quickly and the energy which would be used to drive the piston is being converted into sound. Knocking can be caused by pre-igniton (before spark plug fires) or detonation (after spark plug fires). Triggers can include hot spots on the cylinder head or piston, lean air/fuel mixture, incorrect spark timing, incorrect octane rating, or a mix. During knocking the engine block, cylinder head, and piston top are heated above average temperature. As chamber temperature rises it becomes easier to light the air/fuel mix and the rate at which combustion occurs decreases. If knocking is allowed to continue there will almost always be damage.


Preventing engine damage using knock counts is really a dynamic process. Once knock begins the computer has to reduce spark advance below the value where it first occurred. Timing might be safe to 43 degrees, knock begins at 44 degrees, then the knock sensor activity causes timing to drop to 39 degrees before knock stops. This is because the combustion chamber and piston top require time to cool off. A stock timing table and ESC system are programmed to advance spark to table maximum, and if knock occurs ESC will reduce advance until knock stops. It will then increase advance toward table maximum. If knock occurs during this process ESC will begin the cycle again.

Tuning with knock counts imo requires time travel. Tuning with knock counts is not simply a matter of reducing spark advance at the RPM and MAP where knock is occurring. The goal is really to prevent knock by decreasing timing by the smallest amount necessary. Properly tuning with knock counts IMO requires reading datalogs from a point in time prior to the onset of knock to the point which indicates combustion chamber heating is causing or strongly contributing to knock. Changes such as afr increasing or rapid spark advance can begin a cycle of temp rise that results in abnormal combustion. I have seen cases where increasing fuel delivery at 2000 rpm prevents up to 6 degrees of spark reduction at 3000 rpm. I use the shape of the spark table as a guide. If I see a nice curve that generally seems to work, but requires a substantial change in shape (up to 4-5 degrees of timing reduction in one area) due to knock, I try to find a way to prevent knock in the first place.

In short: Drive the vehicle to obtain logs. Review logs for knock. Adjust timing tables to reduce advance and drive again. If you find you are reducing knock by more than three degrees in any three adjacent cells review the logs for changes that can be made elsewhere which could prevent heat in the combustion chamber from causing knock.

[ralmo94]

I need to figure out how to data log with the What's Up? interface so I can see it better.

Did you see this page from dynamic efi?
Scroll down to data logging
https://www.dynamicefi.com/Tune_Intro.php

[Blown WS6]

Did you see this page from dynamic efi?
Scroll down to data logging
https://www.dynamicefi.com/Tune_Intro.php

Yeah I reread it and noticed my issue was I was looking for a file that was already there because button says open and I am supposed to name a new file and create it with the Open button. Thank you!

[ralmo94]

Yeah I reread it and noticed my issue was I was looking for a file that was already there because button says open and I am supposed to name a new file and create it with the Open button. Thank you!

Great!


I've had it to 5000rpm which is its normal redline
You should copy the 4800 rpm row to the next rows down, because what it will do is, it will interpolate between 4800 and 5200 If you leave 5200 lean, you could end up chasing yourself

[Blown WS6]

Great!


You should copy the 4800 rpm row to the next rows down, because what it will do is, it will interpolate between 4800 and 5200 If you leave 5200 lean, you could end up chasing yourself

Ok I did that. Overall the car runs pretty well. I do feel it runs too lean at WOT however as it gets to the 14s. I am trying to look at the PE tables and figure out how to enrichen it there without moving the VE tables which are pretty accurate now.

Then I will schedule some dyno time and get some more data.

[ralmo94]

Ok I did that. Overall the car runs pretty well. I do feel it runs too lean at WOT however as it gets to the 14s. I am trying to look at the PE tables and figure out how to enrichen it there without moving the VE tables which are pretty accurate now.

Then I will schedule some dyno time and get some more data.

If the VE is correct when not commanding PE, yes PE should be adjusted, I imagine with the VE learn and wide band, it would get it close no matter what you have PE set at.
What are the current PE settings?

[Blown WS6]

If the VE is correct when not commanding PE, yes PE should be adjusted, I imagine with the VE learn and wide band, it would get it close no matter what you have PE set at.
What are the current PE settings?

This is everything I found related to PE
17701

[ralmo94]

This is everything I found related to PE
17701

If you are getting 14's afr WOT, are you sure you are getting PE? Maybe setup a histogram table of load vs tps vs rpm.

Also logg should show if Pe or not and Commanded AFR

[Blown WS6]

If you are getting 14's afr WOT, are you sure you are getting PE? Maybe setup a histogram table of load vs tps vs rpm.

Also logg should show if Pe or not and Commanded AFR

Ok so looking at the Data Dump: my AFR is showing 12.8 but my WB is showing low 14's. The top row is where I stabbed the throttle. Looks like my AE needs to get turned up too? So what here is going on? The ECM is just assuming the NB O2 is full rich and is 12.8 because its not using the WB O2 to actually control fuel? How do I fix this?

17702

[ralmo94]

Ok so looking at the Data Dump: my AFR is showing 12.8 but my WB is showing low 14's. The top row is where I stabbed the throttle. Looks like my AE needs to get turned up too? So what here is going on? The ECM is just assuming the NB O2 is full rich and is 12.8 because its not using the WB O2 to actually control fuel? How do I fix this?

17702

Could you post the bin you are using, along with the XDF?

[Blown WS6]

Could you post the bin you are using, along with the XDF?

Ok had to switch to my tuning computer:

[ralmo94]

Do you also have the original bin before you started tuning, so I can see the differences ?

[Blown WS6]

Do you also have the original bin before you started tuning, so I can see the differences ?

Yeah here is the original BIN supplied with the EBL P4 Flash I was told by RobR to use for a 91 Speed Density 350 TPI with an auto trans

[ralmo94]

Only real changes I see are

VE Tables 3
Idle Speed
EGR
Spark Advance

I would suggest setting so everything commanded is stoich
and dial the VE in there.

Open Loop AFR
Example Highway Mode
PE
Open Loop Max AFR

Either by Wide Band VE Learn, or blm tuning, Or just log the wide band open loop and tune from there.

I see the extended VE leans up as RPM increase and the original did not. I think I would copy 6k rpm to the end.

[Blown WS6]

Ok I'll try that. Thanks!