Big Blue's Transformation

[Gary Lewis]

I wrote the tune in with the "Base O/L Fuel Table Stabilized" in it that is shown above, which is basically Bill's, and then took the truck for a drive. And after studying the log, particularly the section shown below, I think I'm learning a few things.

First, the system is going from closed loop to open loop, and back, at some throttle position or load setting, or combination thereof. The reddish square wave indicates that, and when it is high it is in O/L and when it is low it is in C/L. And notice that the white LAMBSE2 trace, which is the AFR the system wants, goes flat when the system goes into open loop mode - there's no use of the O2 sensors to control the AFR.

Second, when it goes into open loop it does use the Base O/L Fuel Table Stabilized values, but not quite in the way I expected. As shown, when LOAD exceeded 65% the desired AFR went from 14.64 down eventually to 12.35. And as soon as LOAD drops below 65% the desired AFR comes back to 14.64. In other words, the percent row is the upper limit for that value, not the lower limit.

If I can figure out where that parameter or table is that is taking it into O/L I might change that point. However, the system really does a pretty good job of keeping the actual AFR at the desired level even in open loop. For instance, there are three places in this snippet where the desired AFR stays flat at 14.64 for some time. And actual AFRs are 14.46, 14.67, and 14.36 from left to right. So it isn't critical that I make it quit going into O/L, although as things like barometric pressure, air temp, etc change that may get more important.

Last, even when the actual AFR does come down to 12.4 to follow the commanded AFR I cannot feel a difference in power. In other words, keeping the AFR at 14.6 or a bit higher doesn't cause the power to drop off. And that tells me that I can change the table to run 14.64 at a higher load percentage, especially since I now know that the shown percentage is the upper limit rather than the lower limit.

Does this make sense?

Bill - The only thing I can see is the Engine Load Spark Adder table, and it is a table of all 0's. So it doesn't look like the spark is being changed based on load.

As for going from O/L to C/L, the table "Open Loop Base off RPM C" appears to be the one that determines that. And in this case the numbers on the left are mine, which are stock YER2, and the ones on the left are your Truck ECU 032614.

So here's my thinking: I want to be able to run a true 70 MPH in closed loop on most hills at 14.6:1 AFR. That's just shy of 2000 RPM and this engine seems to be able to do that - with ease. So I'll change 2000 RPM to 70% in the above table and drop down smoothly after that point. And I'll change the AFR table as shown below, which is your table with those two mods.

Thoughts?

 

[85lebaront2]

Bill - The only thing I can see is the Engine Load Spark Adder table, and it is a table of all 0's. So it doesn't look like the spark is being changed based on load.

As for going from O/L to C/L, the table "Open Loop Base off RPM C" appears to be the one that determines that. And in this case the numbers on the left are mine, which are stock YER2, and the ones on the left are your Truck ECU 032614.

So here's my thinking: I want to be able to run a true 70 MPH in closed loop on most hills at 14.6:1 AFR. That's just shy of 2000 RPM and this engine seems to be able to do that - with ease. So I'll change 2000 RPM to 70% in the above table and drop down smoothly after that point. And I'll change the AFR table as shown below, which is your table with those two mods.

Thoughts?

Should work, just keep your ears tuned for signs of detonation. Are you running regular or higher octane gas in BB? One of my goals is to be able to weigh the option of mid grade vs regular in Darth.

Essentially see if I have to back off on total advance using regular, and if so what effect on fuel consumption will it have. With the current prices, the percentage difference is a lot smaller than it used to be so it may end up being a non-issue.

Goal is to try to get Darth up around 14 highway which is what Matt gets with his V10 Excursion. Overall ratio between his 3.73 vs Darth's 3.55 and his larger OD tires is fairly close. Biggest difference is V10 is 413 ci vs Darth's will be 466 ci. V10 also does not have the low end "grunt" a 460 does, Matt was in 2nd towing a trailer with his 1986 F150 on it going over the Blue Ridge peak on US 17. Darth walked a similar load up the slopes of the CBBT in 3rd lockup at 54 mph.

[Gary Lewis]

Should work, just keep your ears tuned for signs of detonation. Are you running regular or higher octane gas in BB? One of my goals is to be able to weigh the option of mid grade vs regular in Darth.

Essentially see if I have to back off on total advance using regular, and if so what effect on fuel consumption will it have. With the current prices, the percentage difference is a lot smaller than it used to be so it may end up being a non-issue.

Goal is to try to get Darth up around 14 highway which is what Matt gets with his V10 Excursion. Overall ratio between his 3.73 vs Darth's 3.55 and his larger OD tires is fairly close. Biggest difference is V10 is 413 ci vs Darth's will be 466 ci. V10 also does not have the low end "grunt" a 460 does, Matt was in 2nd towing a trailer with his 1986 F150 on it going over the Blue Ridge peak on US 17. Darth walked a similar load up the slopes of the CBBT in 3rd lockup at 54 mph.

Thanks, Bill.

I'm running Regular, meaning 87 octane, and so far no pinging has been noticed - even by Janey and her ears are better than mine.

Yes, the 460 has grunt! And I think with the changes we are discussing 14 MPG is within reach.

[Gary Lewis]

Thanks, Bill.

I'm running Regular, meaning 87 octane, and so far no pinging has been noticed - even by Janey and her ears are better than mine.

Yes, the 460 has grunt! And I think with the changes we are discussing 14 MPG is within reach.

I think these changes worked, although there is still room for improvement.

The route I'm testing on, which is just west of Skiatook on HW20, has a very steep and long hill about a mile out of town. In fact, in profile it probably looks just like the yellow LOAD trace in the snippet below. You can see that we went O/L about 1/4 of the way across, but what is interesting is that this time the desired AFR doesn't just go down to 12.35 and stay there like it did before. Instead, as the load eases a bit it comes back into the 13's. In fact, actual AFR got to a high of 13.7 during that time.

So we are getting some tempering of the enrichment that should help in my quest for reasonable MPG.

[Gary Lewis]

I think these changes worked, although there is still room for improvement.

The route I'm testing on, which is just west of Skiatook on HW20, has a very steep and long hill about a mile out of town. In fact, in profile it probably looks just like the yellow LOAD trace in the snippet below. You can see that we went O/L about 1/4 of the way across, but what is interesting is that this time the desired AFR doesn't just go down to 12.35 and stay there like it did before. Instead, as the load eases a bit it comes back into the 13's. In fact, actual AFR got to a high of 13.7 during that time.

So we are getting some tempering of the enrichment that should help in my quest for reasonable MPG.

Bill - I was comparing your tune to mine again to see what I might have missed and ran across the table below - Spark ACT Retard. And in the comments you can see that it says to multiply the number shown by the value in the ACT Spark Retard Multiplier Table. However, they used that term rather loosely and it is actually the Spark Retard Multiplier For ACT, which I've included below.

In both tables my values are on top and yours on bottom. And you can see that neither of us have any retard for ACT temps up to 100F, but at that point things differ a bit. However, though the numbers in the first table differ a bit, they don't when you take into account the multiplier.

For instance, at 120F I have a -14 and you have a -20 in the first table. But if we assume we are running about 65 MPH on the highway in top gear my multiplier is .3 and yours is .2. So I'd have a subtraction of 4.2 and you have a subtraction of 4.0. So they come out pretty close.

Anyway, now I see why I'm insulating the inlet air system. And I wonder how many of the aftermarket EFI systems have this kind of detail?

[85lebaront2]

Bill - I was comparing your tune to mine again to see what I might have missed and ran across the table below - Spark ACT Retard. And in the comments you can see that it says to multiply the number shown by the value in the ACT Spark Retard Multiplier Table. However, they used that term rather loosely and it is actually the Spark Retard Multiplier For ACT, which I've included below.

In both tables my values are on top and yours on bottom. And you can see that neither of us have any retard for ACT temps up to 100F, but at that point things differ a bit. However, though the numbers in the first table differ a bit, they don't when you take into account the multiplier.

For instance, at 120F I have a -14 and you have a -20 in the first table. But if we assume we are running about 65 MPH on the highway in top gear my multiplier is .3 and yours is .2. So I'd have a subtraction of 4.2 and you have a subtraction of 4.0. So they come out pretty close.

Anyway, now I see why I'm insulating the inlet air system. And I wonder how many of the aftermarket EFI systems have this kind of detail?

Insulating will help sitting with low air flow. One of my datalogs actually shows what happens once the truck is moving, the ACT pretty quickly comes down to ambient. This was before I installed the baffles around the radiator which separates the incoming air to the air filter from the radiator heat.

Only time I ever had a problem was creeping on the approach to the Downtown Tunnel from Portsmouth into Norfolk, Darth got hot enough that the computer shut off the AC compressor and raised the idle. As a result I was putting him in Park every time traffic stopped. Ambient was over 100° with Rh around 90%.

[Gary Lewis]

Insulating will help sitting with low air flow. One of my datalogs actually shows what happens once the truck is moving, the ACT pretty quickly comes down to ambient. This was before I installed the baffles around the radiator which separates the incoming air to the air filter from the radiator heat.

Only time I ever had a problem was creeping on the approach to the Downtown Tunnel from Portsmouth into Norfolk, Darth got hot enough that the computer shut off the AC compressor and raised the idle. As a result I was putting him in Park every time traffic stopped. Ambient was over 100° with Rh around 90%.

I know it gets really hot under the hood. And since some of the stuff I plan to do is at low speeds, I think having the inlet tract insulated has got to help.

[Gary Lewis]

I know it gets really hot under the hood. And since some of the stuff I plan to do is at low speeds, I think having the inlet tract insulated has got to help.

Ok, I think I now have a good handle on the AFR tables and have a tune that, hopefully, will work well in that area. And I have gotten the check engine light off. So at this point I have two more things to tackle:

Idle RPM: I have the high surge when the engine is started cold, and then it never gets down to the 648 RPM that I've dialed in for idle when the engine is fully warm. But I've taken another stab at that by reducing the #'s in the Idle Air Adder For ECT table and we'll see how that goes later today.

Timing: I really don't think that there's enough timing dialed in. I had the initial set at 13 degrees but Ben asked me to set it back to the stock 10 so that all the numbers in the tables work as they are supposed to work. But that left me down 3 degrees from when we got the 13.6 MPG, and Ben only added back 1 degree at light load/low RPM and 1/2 degree at heavy load/high RPM via the Spark Borderline Knock Threshold table.

So last night I sent Scotty a note and asked what he thought. He quickly responded with "I assume your WOT tables go to max of about 36 degrees at 3000 ish?" as well as "Each vehicle is going to be a bit different based on weight, gearing and tire size. Tune based on your O2 sensor reading vs the engine telling you it is happy. Not some arbitrary final numbers."

But, in BE there's no such thing as a "WOT table" for spark. There's the MBT (Max Brake Torque) Spark table, and mine is shown on top and Bill's below in the screen shot. So I'm down 3 degrees across the board from Bill - according to that table.

HOWEVER, BE says:

Table is utilized to determine where engine makes maximum engine brake torque.

MBT = Spark Max Brake Torque

+ MBT Spark Retard Multiplier for ECT

+ Adder for EGR To Spark Torque Max * EGR Percentage

+ MBT Spark Modifier For AFR/Lambda

+ MBT Spark Adder for IMRC

And, on one of my WOT pulls total timing, known as SAFTOT, was at 27.5 degrees at 3000 RPM with 84% load and 12.28 AFR on the wide-band, while the ECU was calling for 12.35:1. So the other tables are apparently being used in the calculation. And I'm sure that Bill's other tables are different than mine, so it is really difficult to figure out who is doing what to whom.

Given that, I'm going to see if I can create a spreadsheet that will have a place for each of the many Spark tables and then do the calculation to see if I can figure out what #'s to change to get good timing.

[Gary Lewis]

Ok, I think I now have a good handle on the AFR tables and have a tune that, hopefully, will work well in that area. And I have gotten the check engine light off. So at this point I have two more things to tackle:

Idle RPM: I have the high surge when the engine is started cold, and then it never gets down to the 648 RPM that I've dialed in for idle when the engine is fully warm. But I've taken another stab at that by reducing the #'s in the Idle Air Adder For ECT table and we'll see how that goes later today.

Timing: I really don't think that there's enough timing dialed in. I had the initial set at 13 degrees but Ben asked me to set it back to the stock 10 so that all the numbers in the tables work as they are supposed to work. But that left me down 3 degrees from when we got the 13.6 MPG, and Ben only added back 1 degree at light load/low RPM and 1/2 degree at heavy load/high RPM via the Spark Borderline Knock Threshold table.

So last night I sent Scotty a note and asked what he thought. He quickly responded with "I assume your WOT tables go to max of about 36 degrees at 3000 ish?" as well as "Each vehicle is going to be a bit different based on weight, gearing and tire size. Tune based on your O2 sensor reading vs the engine telling you it is happy. Not some arbitrary final numbers."

But, in BE there's no such thing as a "WOT table" for spark. There's the MBT (Max Brake Torque) Spark table, and mine is shown on top and Bill's below in the screen shot. So I'm down 3 degrees across the board from Bill - according to that table.

HOWEVER, BE says:

Table is utilized to determine where engine makes maximum engine brake torque.

MBT = Spark Max Brake Torque

+ MBT Spark Retard Multiplier for ECT

+ Adder for EGR To Spark Torque Max * EGR Percentage

+ MBT Spark Modifier For AFR/Lambda

+ MBT Spark Adder for IMRC

And, on one of my WOT pulls total timing, known as SAFTOT, was at 27.5 degrees at 3000 RPM with 84% load and 12.28 AFR on the wide-band, while the ECU was calling for 12.35:1. So the other tables are apparently being used in the calculation. And I'm sure that Bill's other tables are different than mine, so it is really difficult to figure out who is doing what to whom.

Given that, I'm going to see if I can create a spreadsheet that will have a place for each of the many Spark tables and then do the calculation to see if I can figure out what #'s to change to get good timing.

This is an exercise in futility! And there are several reasons I say that. One of the reasons is that what BE calls the parameters in the comments isn't what they call it in the tables, so it is hard to find things.

Another is that the calcs use live parameters, like AFR, RPM, LOAD, and even barometric pressure, so you can't just run a calc from the tables. You have to go to a data log and find the live data and then go to the tables and use that data to interpolate between values. For instance, my RPM was 3066 but the table shows 2800 and 3500, so I had to find the what the advance would be there. And the AFR had to be calculated as well. But then I realized that I didn't even log barometric pressure.

Last, there are tables after tables after tables. But it looks like there are two main sets - the ones base on altitude and those based on max brake torque. And I don't know which is used when.

So here's the plan, Stan. I have a tune I created that leans the AFR a bit, both in closed loop awa open loop. So I'm going to write it in and go for a run. Then I'm going to use Bill's MBT Spark table, which has 3 degrees more advance across the board, and write it in and go for another run. Hopefully I won't have any pinging. And I'll check the logs to see that I do have 3 degrees more advance, which will tell me I'm on the right trail. So if I want more I'll know what table to use.

[1986F150Six]

This is an exercise in futility! And there are several reasons I say that. One of the reasons is that what BE calls the parameters in the comments isn't what they call it in the tables, so it is hard to find things.

Another is that the calcs use live parameters, like AFR, RPM, LOAD, and even barometric pressure, so you can't just run a calc from the tables. You have to go to a data log and find the live data and then go to the tables and use that data to interpolate between values. For instance, my RPM was 3066 but the table shows 2800 and 3500, so I had to find the what the advance would be there. And the AFR had to be calculated as well. But then I realized that I didn't even log barometric pressure.

Last, there are tables after tables after tables. But it looks like there are two main sets - the ones base on altitude and those based on max brake torque. And I don't know which is used when.

So here's the plan, Stan. I have a tune I created that leans the AFR a bit, both in closed loop awa open loop. So I'm going to write it in and go for a run. Then I'm going to use Bill's MBT Spark table, which has 3 degrees more advance across the board, and write it in and go for another run. Hopefully I won't have any pinging. And I'll check the logs to see that I do have 3 degrees more advance, which will tell me I'm on the right trail. So if I want more I'll know what table to use.

You are very diligent, Gary!