Accel DFI gen 7 tuning....

[Jim Nilsen]

I am tuning my DFI tonight and decided to start a place to share tuning strategies and programs.

I really like the 3d ve table function and am wondering how many of you use it to see the holes and peaks to smooth it all out?

I am also wanting to know what most of you might be running for A/F ratios for a hot cam? I know all engines vary but there has to be a better way to get started than just guessing.

I hope this thread turns into a place we can share files and get better at programming .

If anyone knows of any sites that have people who share info here would be the thread to put hem in.

I am going to keep adding as I learn and hope it may help some others in the future.

[camcojb]

well, you picked a system that's a bit tougher to tune than most, but very capable once you get it correct. For a naturally aspirated setup shoot for 12.8-13.2:1 a/f at wot; I'd probably start with the 12.8 to 13:1 range initially for wot just to be safe.

Jody

[Jim Nilsen]

well, you picked a system that's a bit tougher to tune than most, but very capable once you get it correct. For a naturally aspirated setup shoot for 12.8-13.2:1 a/f at wot; I'd probably start with the 12.8 to 13:1 range initially for wot just to be safe.

Jody

Thanks Jody, it is a bit harder but hey it is what was the best when I bought it and now things have progressed to EZ EFI and self tuning.
I am getting my wideband today and will get it installed this weekend and I will be ableto really know where I am at and have control of it. If you have any tips on going from HEGO to UEGO let me know? I am getting excited about the whole thing again after the problems that have held me back and disappointed me.

Now if mother nature would cooperate and give us an early rainfall instead of more snow I can get it out on the road and do some tuning under a load.

Thanks again, Jim

[camcojb]

Thanks Jody, it is a bit harder but hey it is what was the best when I bought it and now things have progressed to EZ EFI and self tuning.
I am getting my wideband today and will get it installed this weekend and I will be ableto really know where I am at and have control of it. If you have any tips on going from HEGO to UEGO let me know? I am getting excited about the whole thing again after the problems that have held me back and disappointed me.

Now if mother nature would cooperate and give us an early rainfall instead of more snow I can get it out on the road and do some tuning under a load.

Thanks again, Jim

Not sure what you're asking on the O2's. You ideally want the wideband O2 (uego) for tuning to get real a/f numbers away from stoich, which the Gen VII uses. To me the a/f number they provide makes sense, and the narrow band (hego) units confuse me with their voltage readings instead of an actual a/f ratio..........

Jody

[Jim Nilsen]

Not sure what you're asking on the O2's. You ideally want the wideband O2 (uego) for tuning to get real a/f numbers away from stoich, which the Gen VII uses. To me the a/f number they provide makes sense, and the narrow band (hego) units confuse me with their voltage readings instead of an actual a/f ratio..........

Jody

That sort of answers my question. I too feel a bit confused with the hego reading because when I started to go where I thought I should it would go out of range and do the prompt of being out of closed loop. I have to run so rich to keep running and adjust the other areas like bringing my injector timing down from 1.5 back to the 0.80 where everyone says I should be able to be. Don Bailey told me to raise it up to get started and that having it high will affect everything else for the fuel and will make it harder to run 14.5 at idle if I under stand him correctly.

The wideband will I think as you say ,stop confusing me and give the numbers I can really work with and the ecu will be able to correctly work with it until everything comes together.

Thanks again, It is just a few more steps of learning to manipulate the program to make the logic I know come together and then I will be able to tune it for how I want it to run.

How common is it for people to have one tune for the street and another for the track and running hard with the accel? I am told you can have both but it seems like that would take a lot longer to achieve and having 2 programs to start with for safety of the engine and the possibility of error on my part as a beginner tuner would make sense.

Thanks again.

[MrForce]

How common is it for people to have one tune for the street and another for the track and running hard with the accel? I am told you can have both but it seems like that would take a lot longer to achieve and having 2 programs to start with for safety of the engine and the possibility of error on my part as a beginner tuner would make sense.

There should be no need for two tunes. The whole point of the VE table is that at lower RPMs and lighter loads (higher vacuum) you will have less of a fuel demand and at WOT High RPM, high load) you will need and supply more fuel. The only time a second tune is called for is if your changing something else such as going to race fuel, etc. Some drag racers will have a different timing curve for traction conditions at the strip.

[Jim Nilsen]

How common is it for people to have one tune for the street and another for the track and running hard with the accel? I am told you can have both but it seems like that would take a lot longer to achieve and having 2 programs to start with for safety of the engine and the possibility of error on my part as a beginner tuner would make sense.

There should be no need for two tunes. The whole point of the VE table is that at lower RPMs and lighter loads (higher vacuum) you will have less of a fuel demand and at WOT High RPM, high load) you will need and supply more fuel. The only time a second tune is called for is if your changing something else such as going to race fuel, etc. Some drag racers will have a different timing curve for traction conditions at the strip.

Thanks, you answered the question well from how it was phrased.

I was thinking about the timing table being different for the gas they have at the track. After being at Gingerman and running out of fuel and learning that they only have high octane fuel, it would make sense to be able to get the most out of it with the change of a program. That race fuel is too expensive to buy and not get more out of it.
Afterall, it is a drag race from corner to corner !

[Hammered]

I use the 3D map to find anomalies, but I also avoid causing them to start with. After getting well within the range of the ECM's control (+/- 20%) I did a bunch of logs at steady conditions and then sat down with a calculator and used the AF corrections to calculate a close VE. Because the computer interpolates between the cells, you need to adjust them in blocks to bring the table up or down smoothly. Once I got the VE real close, I bumped the timing up until it was too much and then backed off 2-4 degrees depending on where I was in the table. Then I did the VE table again, followed by a check of the timing. Last was the AF table followed by more timing and VE fine tuning. This was for idle, cruise and mid acceleration.

[Jim Nilsen]

I use the 3D map to find anomalies, but I also avoid causing them to start with. After getting well within the range of the ECM's control (+/- 20%) I did a bunch of logs at steady conditions and then sat down with a calculator and used the AF corrections to calculate a close VE. Because the computer interpolates between the cells, you need to adjust them in blocks to bring the table up or down smoothly. Once I got the VE real close, I bumped the timing up until it was too much and then backed off 2-4 degrees depending on where I was in the table. Then I did the VE table again, followed by a check of the timing. Last was the AF table followed by more timing and VE fine tuning. This was for idle, cruise and mid acceleration.

That is what I was doing yesterday and it seemed to be going well for progress. I have a bunch more timing to add in the low end since the PNP program was on the conservative side starting the timing out at around 20 for most of the map. I bumped it up to 28 and found my kpa to come down considerably and then started to change the A/F ratios up from 12.5 to 13 on the lower end. This seemed to really smooth everything out more but still didn't seem to be enough.

I really need to bring my injector timing down from 1.5 to .80 I have been told but when I bring it down it doesn't seem as crisp for throttle response. I think as I progress in the other areas I will be able to bring it down? Is this good thinking or is there a better way to lower the injector timing that I am missing?

Thanks for letting me know your strategy to progress. The worst thing about the accel intructions are there are no instructions that tell you what you just told me. I am just going on the basic logic of tuning and that is what they tell you to do but it is a bit concerning to know you are changing things that can make a drastic change so quickly and when it works you are sure of what you are doing and when it doesn't you have to think more like a computer to know what to do next ,especially when you are going in the direction that normally works without efi.

Thanks again ,that was a great help and look forward to more

[Hammered]

Do mean injector pulse width when you say timing? The VE and PW are directly related and you are better served working the VE table.

I couldn't agree more about the Gen7 instructions. The instruction book (if you can call it that) is akin to putting a turd on top of a wedding cake. I read everything I could and consulted a bunch of tuners, the best being an EFI developer for an OEM.

I would suggest taking care of all your steady state, full operating temperature points first. Then, take care of start-up, warm-up enrichment and acceleration once you have those dialed in. I would also forget AF until you have the timing and VE correct. Then dial in AF and go back adn fine tune VE and timing again.

Another trick to speed things up is to program in a known good vacuum/mechanical distributor profile for your combo. For my Pontiac combo, there are some tight ranges for initial, full mechanical, total at cruise and WOT. I took the conservative end of the ranges and interpolated in between to create a timing map that was a whole lot closer than the super conservative Accel generated one.

[Jim Nilsen]

Do mean injector pulse width when you say timing? The VE and PW are directly related and you are better served working the VE table.

I couldn't agree more about the Gen7 instructions. The instruction book (if you can call it that) is akin to putting a turd on top of a wedding cake. I read everything I could and consulted a bunch of tuners, the best being an EFI developer for an OEM.

I would suggest taking care of all your steady state, full operating temperature points first. Then, take care of start-up, warm-up enrichment and acceleration once you have those dialed in. I would also forget AF until you have the timing and VE correct. Then dial in AF and go back adn fine tune VE and timing again

Another trick to speed things up is to program in a known good vacuum/mechanical distributor profile for your combo. For my Pontiac combo, there are some tight ranges for initial, full mechanical, total at cruise and WOT. I took the conservative end of the ranges and interpolated in between to create a timing map that was a whole lot closer than the super conservative Accel generated one.

I meant ot say injector offset, it is found in the engine configuration editor. you go to configutation and then systems to get there. It measures in milliseconds and I do believe it is the duty cycle of the injector. I was told that a larger number would increase the time the injector works and will add more fuel with a higher number. 0.80 is the normal setting and I moved mine up as instructed by Don Bailey to get the car running and then keep going down with the number until it has problems, hopefully getting back to the 0.80.

The engine really seems to like a lot of fuel. It has a lot of duration and I did take some of it out at idle with the help of the Rhoads X lifters. They really made a big difference in the amount of vacuum I have at idle. They also made the engine require a lot less fuel to run.

With the amount of duration I have I do believe it will tolerate more initial timing than I think. I am up to 28 degrees after warm up at 1000 rpm and it seems to really like it a lot more than the conservative 20 the predictor had it at. I wish I could put it under a load to know for sure but it will be awhile before the snow melts where I live to do that.

I am going to install the wideband and pick up the tune from where I am since it will all change what it has for control of the A/F ratio. Having a reading that is more real as Jody stated will hopefuly make it easier all around.

Thanks for the helpful instructions and I will get back to the thread as soon as I get the wideband installed. I hope it goes easy and the laptop I am borrowing can handle the extra load of another program without it slowing down


Thanks again,Jim

[Hammered]

I had to wait through winter on mine too and couldn't stand it. You should be able to dial in the idle, no load mid-rpm and start-up while sitting in your garage though.

Something still doesn't make sense. Injector offset is measured in crank degrees and is generally the angle at which the intake valve closes. With a long duration cam, this is probably around 590-600*

Maybe you're referring to the VE versus ECT coefficient. You could force the whole table lean or rich at any temperature with this correction factor. Ideally, it should be 1 at your normal operating temperature.

[Jim Nilsen]

I had to wait through winter on mine too and couldn't stand it. You should be able to dial in the idle, no load mid-rpm and start-up while sitting in your garage though.

Something still doesn't make sense. Injector offset is measured in crank degrees and is generally the angle at which the intake valve closes. With a long duration cam, this is probably around 590-600*

Maybe you're referring to the VE versus ECT coefficient. You could force the whole table lean or rich at any temperature with this correction factor. Ideally, it should be 1 at your normal operating temperature.

What you are refering to is intake valve closing angle. it is the point at which the injector fires.It is found in the VE predictor section. The number I was told to input there by Don Bailey was 360 , he says that he uses it on all tunes and it really is most important at idle and warmup and it is only used in sequential mode. I calculated from the info from accel the it would be 330.To get this number you add the degrees before tdc that the intake valve opens at .050 lift and add 90 degrees to it to ensure the injector is getting fuel right before the valve opens or as it is opening.Which makes no sense as to why they call it the closing angle on the screen. I just know that Don knows what he is doing no matter how it is calculated.

The number I am talking about called injector offset(ms)is in the engine configuration editor that you go to configuration and then systems to get to. It is on the same screen as your compression ,cubic in., injector size. map configuration, firing order etc.

I have found that the screens from one version don't seem to be the same as earlier versions or at least that is how it seems when talking about this to others. I am positive about what I am saying because I am refering back to the screens as I type this so I am not confused by the terms.

When talking to both Don and Jeff Jasiek they are on the same terms and the same page.

It would be nice if the parameters were more easily found and not set with defaults that are way out of line with the numbers needed to be input. The default number for the intake valve closing angle is 41 and that is way too late, the stroke is defaulted 3.00 and that is way to short and other numbers are way off too. even when you read the instruction they give you examples that have numbers that are better than the defualts. The instructions for the intake valve closing angle have an example of 280 for a cam that is milder than mine, so 330 would have been a good number but Don uses 360 as a norm.

I am writing the info above to use as a reference for other who may be trying to configure the system some day.

It never ceases to amaze me that they ask you pick a system for your engine and then give you generic numbers parts that aren't in your kit or that don't work.

You have to find an EMIC to get your system running is what I believe they want you to do.

I am still figuring out where to put another box in the car and have it narrowed down to 2 places now.

My head hurts from this stuff sometimes when you try to figure out what they are telling you in the instructions. But when it is all in it does make some sense as to how they confused you..

Thanks again for being there and we will have a thread to address the issues someday that will have good answers.

[Hammered]

I see what the problem is now. Injector offset was a firmware 4.0 addition and I'm still running a 3.X firmware. From Accel's website:

:Programmable Fuel Injector Offset Time:
The “dead time” for a fuel injector is now programmable. This is the time that the
fuel injector is held open until fuel just begins to flow from the injector."

Do you know if this adds a fixed amount of open time or does it begin the open time sooner in the cam cycle?

Why can't Accel spend a little more time to tell the user what these parameters mean? Oh yeah, I forgot we covered that earlier

[Jim Nilsen]

I see what the problem is now. Injector offset was a firmware 4.0 addition and I'm still running a 3.X firmware. From Accel's website:

:Programmable Fuel Injector Offset Time:
The “dead time” for a fuel injector is now programmable. This is the time that the
fuel injector is held open until fuel just begins to flow from the injector."

Do you know if this adds a fixed amount of open time or does it begin the open time sooner in the cam cycle?

Why can't Accel spend a little more time to tell the user what these parameters mean? Oh yeah, I forgot we covered that earlier

It's my understanding that it holds the injector open longer to allow for more fuel flow but that probably relates to opening sooner too, which is a crutch to make up for too lean of a condition and will plague the whole system for running rich no matter what you do elsewhere. But it sure did help me get the car fired up. When I finally got to twice the time it really woke up. Now I have to go back and time it down as I want to lean the whole thing up. I know that I am not going to go lean anytime soon, that's for certain.

I am so glad that I paid to upgrade the board in the ECU as it seems I would be maxed out to where you are now with the program. I went from 2.1.3 to 6.1.5 and man what a difference in the screens and tables. Some things are more automatic and others need more info to get going.

When talking with Jeff Jasiek he said that some guys who had good tunes with their 4.0 versions had to start completely over when they upgraded to 6.0 versions.

Tuning is still basically the same for most of it though.

I mashed the pedal to the floor for the first time today and saw the tach go so fast to 6 grand I couldn't pull my foot back fast enough, I am almost certain it hit the rev limiter in the program. I can almost feel the rear wheels spinning in 1st the next time out.

What was really amazing was how much advancing the timing changed the auto cal reading in the ve table. It went from .400 to around .275 in a few places. Which I think if I change the injector offset now to less it will lean things up at the sensor and still be good at .400 in the ve table.

The more I play the more I see how to manipulate it.

Thanks for the help.

[MrForce]

Injector offset is nothing more than a compensation for the mechanical delay in injector opening time. As an example, if you had a commanded pulse width of 2.2 ms and the injector took 1 ms to get off its seat, you would have a net opening time of 1.2 ms. The required offset varies by injector brand and size. 0.80 is a good default starting point.

By adding to that value you effectively richened up the entire curve.

[Hammered]

I'm pretty happy with my 3.X firmware. I haven't had a need for anything different.

One thing I wish they would allow, is copying a table into a spreadsheet program. I have some smoothing software I could apply to the table if this was possible.

Timing can make a huge difference to VE. That's why you have to tune fuel, then timing, then repeat. Then throw in AF and do it again.

Maybe I don't know what I'm missing when it comes to the new software. Let's see: 1) get the upgrade and possibly have to do everything over or 2) leave well enough alone? ummm

[Jim Nilsen]

Injector offset is nothing more than a compensation for the mechanical delay in injector opening time. As an example, if you had a commanded pulse width of 2.2 ms and the injector took 1 ms to get off its seat, you would have a net opening time of 1.2 ms. The required offset varies by injector brand and size. 0.80 is a good default starting point.

By adding to that value you effectively richened up the entire curve.

Thanks for totally clearing that up. Richening it up across the whole curve is exactly what Don told me it would do.

I tried last night to bring it down and it really slowed the revs time to go up down and it just seems to like it around 1.5.

What will I have to do to the other tables to bring it down? I have tried some changes to see how the engine reacts but each time it never seems to be enough by doing one table. What would be the amounts across the spectrum to bring the time down to .080 and still be rich enough?

[Hammered]

This should work: go to your VE table and click the PW (if I recall correctly) button on the lower right of the screen. Take a look at your pulse width values, highlight the whole screen and press the "]" key until you add 0.7ms (the difference between 1.5 and .8). I don't believe you'll be able to add exactly 0.7ms because the program picks a predetermined increment, but you should be able to get very close. There's also a box on the lower left (if I recall correctly) of the screen where you should be able to enter +7 or +0.007 (I believe it's the former) to get the same result. Then go back to your Config screen and dial back the offset by 0.7ms.

I found that the best way to richen the whole table is to go to the VE screen, highlight everything and then multiply by 1.1 for example to richen it by 10%.

[MrForce]

I am wondering if you could post up a VE table and a timing table for a normally aspirated big cammed SBC. I know it would not be exactly the same as what I need but I am just trying to see if I am anywhere near the right track on things.

I have gotten a few places of my program to finally go a bit to the lean side to learn what it takes to get there but I am still wondering what a really well done 3D map looks like and a timing table too.

I am looking more for how I need to adjust it with the kpa's and the rpm. Without putting it under a load I think it is leading me in a direction that I will have to change a lot later when wide open throttle at lower rpm is happening.

I moved this back to your thread.

Send me your latest .ecm file and any of your thoughts on where it is good and bad. I will mod it and send it back. Email is [email protected].

Rob