Dynojet help please!

[jtonga]

When I bought my Spyder (2014 RSS) a few months back it came with the Dynojet Commander 5, O2 Optimizer, and Two Brothers exhaust. For the second time now, the check engine light came on and coding for LEAN condition. The first time it happened, it went away on its own. But this time it has stayed on for 3 weeks now. I've tried connecting it to the computer and resetting the map but still no luck. I’ve called a few motorcycle shops that are "certified Dynojet tuners" but they all want $300 to create a customized map... I know close to squat about this stuff but from what I've researched, I can buy a Dynojet Auto-Tuner for that price that will automatically create a custom map, and make continuous adjustments as needed. Also, I'm not even sure a map adjustment will fix the LEAN code. I asked my dealer if it could be a bad O2 sensor, but he doesn't think that the check engine light would have went away on it's own the first time if it was... Bike only has 1,200 miles and is still under warranty (B.E.S.T.) until April but unfortunately mods like these interfere with warranty work. The pipes look great and bike sounds awesome, but if it was up to me I would have left these things stock. I can't speak on how it has enhanced the bike's performance because this is my first Spyder and I don't know any different.

Any advise/suggestions would be greatly appreciated!

Thanks in advance, Joe

[Easy Rider]

but if it was up to me I would have left these things stock.

If it was me, I never would have bought a bike that has been "modified".

You CAN put it back stock, probably fairly easily and without a lot of expense.......and you probably NEED to do that if you want any warranty support at all.

Except maybe for the pipes.....but if the CAT has been removed and there are no baffles in the "mufflers", then that can contribute to a lean condition just by itself.

[Snowbelt Spyder]

Hey Joe. You didn't mention which cylinder, or both, threw the code, but I guess it doesn't matter. The code is set by the Spyder's fuel trim function trying to correct a lean condition but reaching it's limit of adjustment before it can do that. The PC5 makes it a little more difficult because you don't know if the situation is a PC issue or a vacuum leak or other type issue. Let's just focus on the PC part of it. In the closed loop area of the map, the values are probably still set for 8%. That means the PC is adding an additional 8% to the Spyders fuel mapping to help richen the mixture. When you look at the O2 Optimizer in the PC software, unless you've changed them, the values are probably still set at 0. Out of the box, the O2 Optimizer at that 0 setting, is trying to richen the mixture from 14.7 to around 13.6. The lean code would be set if the Spyder fuel trim, in conjunction with the 8% from the PC, cannot reach the mixture that the O2 Optimizer is asking for. So, what to do about all of that? Give the Spyder's fuel map a little bit more help. Edit the PC map and increase the settings in the PC map closed loop area from 8% to 9%. At the same time, go into your O2 Optimizer settings and set them both down to -2, which is asking it for a bit less richness. The inside of your pipes are probably a bit sooty. Then ride for a couple hundred miles. While you're in there check your vacuum hoses on the left side of your throttle bodies for cracks. Replace as required. And if that code was for the rear cylinder, don't rule out that you could have a purge valve issue. Now ultimately, if it doesn't clear up, you may have to disconnect and remove all of the PC and O2 Optimizer stuff and put it back to stock. That will eliminate that variable and you could get work done under warranty.

[Snowbelt Spyder]

Another thought comes to mind, too, Joe. There are some folks out there that have developed a method to flash the Spyder's own ECU, and except for not being user adjustable like the DynoJet stuff is, also achieves better performance over stock. Another alternative for you, then, would be to just go through the Power Commander installation instructions in reverse order and uninstall all of that DynoJet stuff. Except for the ground and throttle position wires, it's just a matter of unplugging and replugging connectors. No cost involved. With only exhaust modifications done to your Spyder, the ECU is capable of adjusting for that on its own. See then if your code situation corrects itself after riding for awhile, or have it repaired at the shop. After that, you may be happy with the stock performance anyway. If not, a forum search will bring up information about flashing the ECU. Good luck with it.

[jtonga]

Hey Joe. You didn't mention which cylinder, or both, threw the code, but I guess it doesn't matter. The code is set by the Spyder's fuel trim function trying to correct a lean condition but reaching it's limit of adjustment before it can do that. The PC5 makes it a little more difficult because you don't know if the situation is a PC issue or a vacuum leak or other type issue. Let's just focus on the PC part of it. In the closed loop area of the map, the values are probably still set for 8%. That means the PC is adding an additional 8% to the Spyders fuel mapping to help richen the mixture. When you look at the O2 Optimizer in the PC software, unless you've changed them, the values are probably still set at 0. Out of the box, the O2 Optimizer at that 0 setting, is trying to richen the mixture from 14.7 to around 13.6. The lean code would be set if the Spyder fuel trim, in conjunction with the 8% from the PC, cannot reach the mixture that the O2 Optimizer is asking for. So, what to do about all of that? Give the Spyder's fuel map a little bit more help. Edit the PC map and increase the settings in the PC map closed loop area from 8% to 9%. At the same time, go into your O2 Optimizer settings and set them both down to -2, which is asking it for a bit less richness. The inside of your pipes are probably a bit sooty. Then ride for a couple hundred miles. While you're in there check your vacuum hoses on the left side of your throttle bodies for cracks. Replace as required. And if that code was for the rear cylinder, don't rule out that you could have a purge valve issue. Now ultimately, if it doesn't clear up, you may have to disconnect and remove all of the PC and O2 Optimizer stuff and put it back to stock. That will eliminate that variable and you could get work done under warranty.

Thanks for the great info Doug! I should have mentioned it was Bank 1 (P1171). I did check the hoses, and they look good. Today I'm going to plug into the PCV and adjust the closed loop and Optimizer settings like you suggested. So do I need to adjust anything on the Optimizer box itself or can I make the -2 adjustment directly through the PC software? I haven't even touched the Optimizer box yet, is it something I plug a USB into or manually dial-in?

[jtonga]

Another thought comes to mind, too, Joe. There are some folks out there that have developed a method to flash the Spyder's own ECU, and except for not being user adjustable like the DynoJet stuff is, also achieves better performance over stock. Another alternative for you, then, would be to just go through the Power Commander installation instructions in reverse order and uninstall all of that DynoJet stuff. Except for the ground and throttle position wires, it's just a matter of unplugging and replugging connectors. No cost involved. With only exhaust modifications done to your Spyder, the ECU is capable of adjusting for that on its own. See then if your code situation corrects itself after riding for awhile, or have it repaired at the shop. After that, you may be happy with the stock performance anyway. If not, a forum search will bring up information about flashing the ECU. Good luck with it.

Thanks again Doug , much appreciated! If adjusting the PCV and Optimizer settings doesn't pan-out, I like your idea of uninstalling and seeing how the bike performs with just the Two Brothers exhaust. Just wondering... when installing the Dynojet system is there anything physically taken off/out of the bike (besides the exhaust) like stock connectors or stock O2 sensor? As you can tell, I have a lot of learning to do!

[Snowbelt Spyder]

Hi Joe. To adjust the O2 Optimizer, you plug into the optimizer module itself with the USB cable. It’s covered with that little rubber plug. Then start the PC software. The O2 Optimizer menu item will then appear in the menu bar. Click on that and you’ll get a graphic with the two little sliders on it. If you go to the Dynojet website and to the PC model for your machine, there should be a link so you can download the install instructions. In a nutshell, the PC module and O2 Optimizer module plug into the existing harnesses, so that they essentially intercept the O2 sensor, injector and ignition signals. And there’s probably just a posi-tap for the throttle position. I haven’t looked and yours specifically. To uninstall, you unplug the Dynojet modules and replug the OEM harness back together, and removing the throttle position tap. It would be a quick job.

[jtonga]

Hi Joe. To adjust the O2 Optimizer, you plug into the optimizer module itself with the USB cable. It’s covered with that little rubber plug. Then start the PC software. The O2 Optimizer menu item will then appear in the menu bar. Click on that and you’ll get a graphic with the two little sliders on it. If you go to the Dynojet website and to the PC model for your machine, there should be a link so you can download the install instructions. In a nutshell, the PC module and O2 Optimizer module plug into the existing harnesses, so that they essentially intercept the O2 sensor, injector and ignition signals. And there’s probably just a posi-tap for the throttle position. I haven’t looked and yours specifically. To uninstall, you unplug the Dynojet modules and replug the OEM harness back together, and removing the throttle position tap. It would be a quick job.

Okay great, I plugged into both the PC and O2 Optimizer and made your recommended adjustments. Much easier to use than I expected, especially with your guidance. You were right with the O2 settings, both sensors were set at zero (now at -2). I am using map #25-010-002, I've attached a pic of the newly modified map compared to the old. It rained all day today and forecast is looking pretty lousy for the next few...

Can't wait to take a nice ride, see what happens, and report back

Map8%.jpgMap9%.jpg

[Snowbelt Spyder]

Unfortunately I can’t find it right now, but a couple years ago a guy posted with your exact problem. It’s like this - when operating in closed loop, the Spyder ECU still controls and maintains the AFR. However, since the O2 Optimizer intercepts and spoofs the signal from the O2 sensor and sends it on, the O2 Optimizer is where you set what the operating AFR is going to be. The map in the PC is just helping the Spyder ECU to reach that. The default setting of 0 is a little too rich and causes a soot build up on the front O2 sensor. He pulled his and found that. That’s where I got the info to go to -2. He ended up replacing his front sensor to start out with a clean one. I ran mine at -4 all last year to try to clean it up. Come to think of it, it’s still set at -4 front and -2 rear. And so, it might help you to go to -4 on the front, too. That’s probably info I should have told you sooner, but we’re out of town and have some distractions. I apologize for that.

[jtonga]

Unfortunately I can’t find it right now, but a couple years ago a guy posted with your exact problem. It’s like this - when operating in closed loop, the Spyder ECU still controls and maintains the AFR. However, since the O2 Optimizer intercepts and spoofs the signal from the O2 sensor and sends it on, the O2 Optimizer is where you set what the operating AFR is going to be. The map in the PC is just helping the Spyder ECU to reach that. The default setting of 0 is a little too rich and causes a soot build up on the front O2 sensor. He pulled his and found that. That’s where I got the info to go to -2. He ended up replacing his front sensor to start out with a clean one. I ran mine at -4 all last year to try to clean it up. Come to think of it, it’s still set at -4 front and -2 rear. And so, it might help you to go to -4 on the front, too. That’s probably info I should have told you sooner, but we’re out of town and have some distractions. I apologize for that.

Doug, seriously you have nothing to apologize for.... your saving my butt $$$ . Again, I have little to no knowledge about this so please bare with me. I'm just trying to understand the manipulative science of AFR. If I started off too lean and I'm trying to richen the AFR, why set the sensors on the O2 Optimizer toward leaner levels? Instead of -2, shouldn't I be moving the sensors toward +2?

Thanks again, I hope your enjoying your trip & distractions!

[Snowbelt Spyder]

Hey Joe. Haven’t forgot about you and have an explanation for you. But I’ve been in Benton PA without a boat. I’ll get back to you soon.

https://m.youtube.com/watch?v=C18F-iw3vW8

[jtonga]

Hey Joe. Haven’t forgot about you and have an explanation for you. But I’ve been in Benton PA without a boat. I’ll get back to you soon.

https://m.youtube.com/watch?v=C18F-iw3vW8

You weren't kidding about distractions... . I really hope everyone made it out okay, and those affected receive as much help as they need with the aftermath. I was in PA just a few days ago with my family visiting Hershey Park. Thanks for keeping me posted Doug

[Snowbelt Spyder]

I had a feeling you would ask that question, so now is a good time to talk about this. Kinda long explanation, though, but I don’t know any other way to do this than give you the full download.

Modern day fuel injection systems have two modes - closed loop and open loop operation. If you understand the basics off how your cruise control works, then you understand closed loop operation. For example, you set a target speed, or a “set point”, for what you want the speed to be. You have a control system that controls a process to try to maintain that speed - in this case operates the throttle and thus rear wheel RPM, and you have a sensor to feedback to the controller whether it’s operating at, above, or below that set point. Same with electronic fuel injection. The target AFR , the set point, for the air-fuel ratio (AFR) is provided to us already programed into the ECU. It’s fixed at 14.7:1. 14.7 pounds of air to 1 pound of fuel. The process we’re controlling is exhaust gas O2 by controlling fuel flow; and our O2 sensor feeds back to the ECU whether we are at, above, or below set point. At 14.7:1 the O2 sensor output voltage is around .45 volts. Leaner and the voltage goes down, richer and the voltage goes up. The ECU is programmed to automatically maintain that .45 volts.

Programed into the ECU is a baseline fuel map looking very much like the Power Commander (PC) Map. It’s called a lookup table and contains values that correspond to the turn on duration time of the fuel injectors. The ECU interpolates between the squares so that there is a smooth transition across the operating range. The baseline map is OK for the perfect engine on the perfect day. In the real world, ambient conditions change, filters slowly get clogged, fuel pressure changes, the purge valve opens and closes, etc. So, the ECU needs a way to fine adjust the fuel delivery from the fuel map in order to maintain the AFR at set point. That function is called fuel trim, and it operates continuously making little adjustments based on feedback from the O2 sensor. So, like your cruise control is constantly making little adjustments to the throttle to maintain rear wheel RPM using that signal from the speed sensor, the ECU is constantly making little adjustments with fuel trim to try to maintain .45 volts coming from the O2 sensor.

So, let’s say we get a small crack in a vacuum hose or we install a free flowing air filter, or exhaust. This results in higher airflow through the motor and thus a leaner AFR - let’s say it becomes 14.8:1 - meaning that there will be more O2 in the exhaust, Sensing this, the output voltage of the O2 sensor goes down. The ECU sees that decrease in voltage and increases the fuel trim amount, adding slightly more fuel which compensates for the additional air, thus restoring the AFR back to set point as sensed by the O2 sensor. The end result is that the AFR has been restored back to 14.7:1, the fuel trim value is slightly more positive than it was before, and it’s all completely invisible to the operator. If we get a real large vacuum leak for example, the same thing happens except that the fuel trim function may reach the limit of it’s range. Around 10% for the Spyder. If the fuel trim reaches it’s limit and still has been unable to return AFR back to set point as sensed by the O2 sensor voltage, it’s then that we get the lean code tripped. Because it’s then that we have a lean condition that can’t be corrected.

The main take away is that the lean code is not tripped unless the fuel trim function CANNOT restore the actual AFR back to our target AFR - our set point - before it reaches the limit of it’s range. So, what’s all this have to do with a Power Commander? We’re getting to that. So far, we just need to get an understanding of how closed loop operation occurs during a change.

[Snowbelt Spyder]

So, why add a PC at all? Well, an AFR of 14.7:1 is wonderful for emissions and for the operation of the standard 3-way catalytic convertor, but it’s not ideal for obtaining the best power. The more oxygen that’s used in the combustion process, the more power produced. There are charts and graphs out the wazoo showing this. A more ideal AFR for power is mid to upper 13’s. But BRP made it impossible for us to just hook up a computer to the Spyder and change the set point in the ECU from 14.7 to 13.6. So, at the time, the industry came up with a piggy-back style of fuel controller to try to accomplish that.

For example, let’s take just a simple fuel controller and add it to a closed loop system. It has controls on it, or a map in it. It taps into the harness going to the fuel injectors and adds additional fuel on top of what the Spyder ECU is already delivering. Sounds simple. But if you understand closed loop operation, you understand why this won’t work to try to operate at a different AFR. The reverse happens of what we went over before. Adding additional fuel from the fuel controller causes the AFR to become richer and reduces the amount of O2 in the exhaust. The O2 sensor responds to this and it’s output voltage increases above .45 volts. The ECU sees that increase in voltage and reduces fuel trim in order to cut back on fuel and restore the AFR back to set point. So after a few miles, the ECU has un-done the setting from the simple fuel controller automatically. This type of controller may be used to correct a lean condition after a lot of mods have been made, but it can’t be used to force the ECU to allow operation at a richer AFR in order to get more power output. So, in order to allow operation at a richer AFR without the ECU fighting back against it and un-doing the change we want to make, we have to intercept and and modify that O2 sensor feedback signal. And that’s the job of the O2 Optimizer.

In essence, the O2 Optimizer gives us control of the AFR set point. When it’s set for “0”, it is modifying the O2 sensor output voltage such that the Spyder ECU will now attempt to maintain an AFR of 13.6, even though it’s programed set point is still 14.7. It essentially sends a false signal on to the ECU. I call it spoofing. When you first start up after installation, the ECU will think it is running too lean, and start increasing fuel trim. However, there’s not enough range built into the ECU to allow for fuel trim alone to achieve that new target AFR value of 13.6. That’s where the map that’s in the PC module comes in. It “helps” the fuel trim function by adding an additional amount of fuel over the closed loop operating range. And since we’re now spoofing that signal from the O2 sensor, the ECU doesn’t try to un-do that. Instead, the ECU and the PC map work together to try to attain our new AFR set point coming from the O2 Optimizer.

[Snowbelt Spyder]

So, we started out by getting 8% help from the PC module across the closed loop operating range. What’s going to happen if - along with that 8% - the fuel trim setting reaches it’s adjustment limit and we’ve only attained an AFR of say 13.7 - falling short of reaching our richer set point of 13.6? Right - we get the lean code. It’s a lean code because our ACTUAL air fuel ratio is LEANER than our set point, or targeted air fuel ratio, and we’ve reached the limit of adjustment.

So, how do we fix this? Two ways - we give the ECU fuel trim function a little more “help” from the PC map and increase those settings from 8% to 9%. Small changes first. DynoJet wants us to stay between 8% and 10%. And we also adjust the O2 Optimizer in the leaner direction - that is asking for a leaner set point - or to put it another way, a “less rich” set point. For example, going from “0” to “-2” may change the demanded AFR set point from 13.6 to 13.7. That would now put the set point we’re shooting for within the adjustment range of the fuel trim, and hopefully, after a few miles and a few operating cycles, the lean code will reset because the fuel trim setting will have backed off from its adjustment limit. Ending up with an AFR of 13.7:1 now being maintained, and the automatic closed loop control function still working normally as before. If this happens, then life is good.

In summary then, in the closed loop operating mode, the map in the PC module only “helps” the ECU fuel trim function attain and maintain set point. The O2 Optimizer is where we ask for a richer or leaner AFR as our set point or target AFR. Adjusting from “0” to “-2” is asking for a target AFR that is “less rich” than before, thus allowing the ECU to attain and maintain that.

Now, the issue that other guy faced was soot build up on the front O2 sensor during the time he was running at the “0” setting. That’s the second reason to set the O2 Optimizer to a “less rich” set point. Less soot production. That could be at play with you, too, know ing that your system initially was running ok. Perhaps a replacement O2 sensor might be required. They are not that expensive. Ride it for a week or so and see how it goes. And as I mentioned, you could set the front cylinder to “-4” in the O2 Optimizer asking the front cylinder to run even a little “less rich” in an attempt to clean it off. Or, as a Plan B, uninstall everything and restore full operation to the ECU only. It’s only a matter of unplugging those modules from the Spyder connectors, and plugging the Spyder connectors back together. And removing the throttle position pickup wire. Then see if you need to try to fix anything under warranty.

[Snowbelt Spyder]

So what about open loop operation. You may have noticed those 3 columns in your PC map where there are a lot of negative values. That’s the open loop area of operation. In open loop, the feedback loop from the O2 sensor is not used, that is - it is an open circuit. Thus the name, open loop. The ECU delivers fuel based on the settings in the ECU map without any feedback. I asked DynoJet why the settings in the PC map had such large negative values. I thought there must be some typos. But he said no, that the stock AFR in open loop is very rich and so those PC map values are there in order to subtract out some of that fuel flow - thus leaning out the AFR a bit. Because I have a completely different air intake - JT’s air filter - I chose to edit my PC map and just put “0” in all of those squares. Thus, running stock settings in open loop. We don’t want any detonation now, do we.

Even if you went to an Autotune system, DynoJet tells you that you will still retain your stock O2 sensors and still operate in closed loop just as we discussed. When you decide to accept the fuel trims from the Autotune, you don’t accept fuel trims in the closed loop area, only the open loop area. To me, the advantage of Autotune, then, is that you can see the actual number of what your AFR is, and you can more accurately set your O2 Optimizer setting and more accurately set your open loop AFR to a very specific target AFR set point. All of that was just something I didn’t need. Rather than the additional expense of removing the exhaust, adding two more bungs in the exhaust, two more wide band O2 Sensors and the Autotune system, I’ve stuck with the basic PC and O2 Optimizer package. For 5 years now, it’s been working flawlessly.

Hopefully, this long winded explanation helps with an understanding of how it all fits together. They call this area I live in the snow belt. And this is what I did during the winter of 2013 - I read up on stuff and watched a lot of youtube videos. You can Google a lot of what we’ve gone over here. Spyders, cars, trucks, it’s all the same. Especially helpful are those troubleshooting videos. Scanner Danner has a number of them which provide some real good knowledge of fuel trim, closed and open loop operations, and how to diagnose and troubleshoot different codes. But, now that a couple of folks have figured out how to flash the Spyder ECU, the days of needing a piggy-back style system might be coming to an end.

Good luck with the thing and be safe.

[Easy Rider]

Hopefully, this long winded explanation helps with an understanding of how it all fits together.

And now you all know how to build a watch.
Don't EVER ask what time it is again.




Sorry couldn't resist.
How many current "mechanics" do you think understand even a part of all that ??
I bet pretty close to none.

[Snowbelt Spyder]

Gee, and I was so hoping to make it easy to understand.

[jtonga]

Gee, and I was so hoping to make it easy to understand.

Excellent job explaining ! If your aren’t a teacher, you’d make a great one. I believe this thread will help a ton of people, especially those as clueless as me

[Bob Denman]

Soooooo… How is your bike running now?

[jtonga]

Soooooo… How is your bike running now?

It seemed to be running fine before, but keeps hitting me with a lean code (bank 1). Last time check engine light went away on it's own, but has now stayed on for almost a month. With the great guidance of Snowbelt Spyder, I've made adjustments to the closed loop and O2 Optimizer sensors.

So basically it's now just a ride-and-see... hope to do the riding part tomorrow. Finally free for a few days and heading into some real nice weather, so definitely will report back soon!

[jtonga]

Extremely grateful for this site, and hereby declare Snowbelt Ryder AFR-Master! The check engine light disappeared after turning the bike on and left idling for 10 minutes. Talk about a quick response time! Thank you sir for providing me with the perfect AFR recipe. Took it for a 60 mile ride and bike runs great, best it has yet! So for anyone with the same Dynojet equipment (PCV & O2 Optimizer) and the same problem (P1171/Lean condition), change the 8's to 9's in the closed loop AND adjust both Optimizer sensors to -2.

Once again, Spyderlovers to the rescue ! You guys are

[STSScreaminDemon]

This thread is a few years old but recently purchased/installed the PCV though having trouble finding the o2 optimizer. Seems to be running fine, but this thread seems to suggest the PCV is worthless without the optimizer since the ECU is constantly trying to counteract the PCV settings. Maybe I'm over simplifying, but why can't the stock o2 sensor leads be capped with something that provides the .45 V to the ECU so it doesn't try to adjust? Wouldn't it then just supply fuel based on the stock map. Then use Autotune Dual Channel option and replace the narrow band sensors with the supplied wide band sensors to get an accurate reading for AFR and get PCV map trims based on that. If this is possible, it would seem to be the ideal option. Please correct me if I'm missing something.

[Snowbelt Spyder]

The short answer is that what you've described is a violation of the clean air act and nobody will make the O2 sensor mod that you want. But, you could make it yourself, I guess. Google Harley Davidson and EPA lawsuit. It all started in Aug of 2016, and shortly thereafter, the O2 Optimizer disappeared from the Dynojet product line. It took 4 years but Harley ended up paying 12 million. Now, you can still adjust the open loop area of the fuel map with the PC V. That's the last 3 columns on your map that already have values in them from Dynojet. In that region, the stock O2 sensors are not in control. But in the closed loop region, any changes you make in the map will be compensated for by the ECU because of the O2 sensor control loop. So, as far as aftermarket tuners go, they must leave the stock O2 sensors alone or face the wrath of the EPA. Even if a product was marketed as off road / racing use only, if it could be used on the road, as was the Screaming Eagle Pro tuner, it's a violation.

Doing all of the mods that you described would end up costing you more money than sending away your ECU for the flash, and you still would have no idea how well your tune is working without getting on a dyno. I see a very limited market for the PC V these days, especially without dyno time. That’s a lot of money for a limited or unknown amount of additional horsepower.

[STSScreaminDemon]

I was wondering what happened to the O2 Optimizer; makes sense. Thank you for the additional info. Unfortunately, my Spyder is my daily driver so don't have the opportunity to pull out the ECU for flashing. Luckily my main focus is in the open loop area of the map to take advantage of my exhaust and air intake mods. I just liked the idea of being able to set a specific AFR throughout the map and not having to guess what's happening. My ride is pulls strong but like you said, I'm not sure I accomplished anything without a dyno run.