Hondata

The subject vehicle is an FK8 with a host of bolt ons. I have been running the standard Hondata Fuel System for several years, but recently upgraded to the Hondata Fuel System Plus by adding the cam and 1425cc injectors. In testing I have noticed a definite improvement in fuel system capacity. In fact, since I'm currently testing with a stock turbo (I normally run an RV6 R660) I am actually seeing that at higher RPMs the ECU seems to be losing control of the HPFP and it's overshooting the DIFPcmd by up to 60 bar, with the fuel pump duty cycle oscillating out of control. I tried some mild tweaking of the HPFP PID tables but nothing really seems to improve the situation. I was unable to find any documentation on those tables, either, so I was making small tweaks here and there to try to gauge any changes. On a WOT pull it's not all too noticeable unless you're checking the logs closely, but during the time I was trying to tune this behavior out, I was using part throttle, low boost pulls in 2nd gear to slow the rpm ramp and you can see from this plot that the system really loses control of the pump in this type of scenario, to the point where the engine sputters and pops a bit at upper rpms. Granted, this is not a very likely scenario that any driver will encounter, as at part throttle you would be upshifting rather than winding the revs out to 6000+ rpms, but this is only for illustrative purposes. When I reinstall the updated R660 turbo in the coming weeks I want to make sure that I have the fuel pump system fully under control so I can properly tune everything for repeatable and reliable power.
to gather these logfiles, I flashed my car back to an OTS calibration and added the Fuel System Plus mod plus a few other minor tweaks, just to get any variables out of the way. That calibration is attached as well as a few snippets from the log file.

Thank you for your attention to this matter.

Your post shows exactly what I've seen with the new fuel system, but I assure you that with adjustment of the fuel pump settings, you can fix that (provided there's no install errors of the components, that is).

D-Rob wrote: Wed Mar 06, 2024 1:58 pm Your post shows exactly what I've seen with the new fuel system, but I assure you that with adjustment of the fuel pump settings, you can fix that (provided there's no install errors of the components, that is).

Thanks, do you have any hints or tips to share with me on how these tables should be adjusted? The documentation that I've managed to locate in the help file doesn't really provide much information.

just a quick update. After seeing how much fuel trimming the ECU was commanding (total trims were hitting as much as -15%) I decided to try increasing the injector size and that seems to have cleaned things up a lot, as well as pushing my trims closer to 0%. At 1525cc i'm seeing roughly -2% to -3% long term trims, with it trimming out to overall trims at WOT of around -1% -2% on a 3rd gear pull. I have made a few other tweaks to help the fuel system out (such as flattening the lambda in the 4000-7000rpm cells of the last 2 columns. I forgot how much movement there was there in the stock lambda curves (recall I reverted to an OTS tune to try to get to the bottom of this). a 0.15 change at 5000 was causing a huge swing in trim. I'm next going to try 1550 to see how the long term trims settle out. Also, I am testing on a ~53% ethanol blend, where I was previously testing with pump 93 at E10.

So it seems that these "1425cc" injectors seem to flow a fair bit more than 1425cc. I am curious to hear of others' experiences with these.

1550cc might be the magic number. this was a 4th gear pull up to 6000rpms (with boost limited to about 21ps via the boost by gear by tune table - awesome feature!) and the AFRs tracked almost perfectly at 0% trim.

I'm about to file a request to make the injector size cell live tunable. I could've gotten to the bottom of this within like 20 minutes instead of 4 hours.

How is the car running since you last posted the magic number? I just recently installed the Hondata Fuel System Plus and I am waiting to get scheduled for a tune. I selected the recommended tune from Hondata and drove my car around the block for a bit to clear the codes, but I am a little cautious driving my car since I know I need a tune. I am okay to drive the car on the recommended tune from Hondata before I get my tune? Thanks, your insight would greatly be appreciated.

FLO_FK8 wrote: Tue May 28, 2024 8:46 am How is the car running since you last posted the magic number? I just recently installed the Hondata Fuel System Plus and I am waiting to get scheduled for a tune. I selected the recommended tune from Hondata and drove my car around the block for a bit to clear the codes, but I am a little cautious driving my car since I know I need a tune. I am okay to drive the car on the recommended tune from Hondata before I get my tune? Thanks, your insight would greatly be appreciated.

You can drive around on the street but just keep an eye on your logs and ease it into any big boost events until you're comfortable that the fuel system is behaving as desired. It seems like the HFS+ mods that change the HPFP Feed Forward Offset table causes issues on my car. The standard values for the normal HPFP seem to work better, but they are still not perfect. And I have not yet figured out how to dial them in. I had some trim issues and I was able to sort those by adjusting the fuel injector size. If you notice that your fuel trims are way off (ie, lots of negative trims indicating it's overfueling) with the standard 1425cc HFS+ injector size, try increasing it to something like 1500 or 1525cc.

The main issue I'm still having is keeping the fuel pump under control at all rpms. I dynoed my car last week with the new RV6 turbo but I saw some stuff on the dyno that shows that I just can't seem to fully get rid of the fuel pump oscillations everywhere. I have improved the oscillations a bit but there are some remaining situations which bring about some annoying pump control issues. I don't know if it's a problem that's specific to my car or if it's related to the longer stroke of the fuel cam causing some weirdness at higher rpms. I have been trying to get it under control at 4000rpms as everything below that seems pretty clean, but after lots of live tuning and logging on the street I seem to have made some strides but I just can't seem to get the situation fully smoothed out.

If I had access to a dynapack where I could control load, rpm, and rpm ramp and live tune in real time, I feel like I could get this sorted much more quickly than trying to log and tune on the street.

Good luck, and hopefully someone else will chime in here with advice for both of us.

Here's an example of one of the oscillations I'm trying to smooth out. I was seeing some fuel pump weirdness from time to time in some pulls so I started logging at different rpm intervals and found things starting to get messy at 4000rpms so I started working on that. I've tried a lot of different things and it still looks like this: I want to see my fuel pump duty looking much smoother than that and would also like to see my DIFP more closely tracking the DIFPCMD especially at steady state.

Thank you for the information Jeffx. This is very helpful. I have my tuned scheduled for June 10th and will keep you posted on how it goes and if my Tuner runs into similar issues or finds a way to smooth out the system. I'm planning to go in on 93 and then add the E85 once my tuner runs some baselines. For your trial runs, what is your ethanol %? Based on the Hondata information, we're supposedly able to run full e85 with the HFS+ but not sure if we can fully utilize the full e85 content. I'm hoping my tuner can smooth things out and I can just run e85 so I don't have to mix anymore fuel. Thanks.

You should have no problem running full e85 as long as the pump doesn’t lose control.

These injectors flow 1530cc. The rating of 1425cc was incorrect. Calibrations and modifications will be revised for the next release.

Thank you for the update regarding the injector size.

I've also been getting cold start issues after installing the HFS+ or essentially rough starting. I've had a few misfire codes and then recently, I got the P050B code for the Cold Start Ignition Timing Control System Performance. However, once the car does start after a minute the car is fine. I am able to drive it and then shut off and turn on the car. It fires up fine, it's only when the car has sat for a long time, and I start the car from a cold start.

I did notify my tuner and would've thought getting a tune would fix it. My tuner did ask me to reach out to Hondata since it doesn't look like he has access to touch the cold start information that's related to the P050B code.

FLO_FK8 wrote: Tue Jun 18, 2024 11:06 am Thank you for the update regarding the injector size.

I've also been getting cold start issues after installing the HFS+ or essentially rough starting. I've had a few misfire codes and then recently, I got the P050B code for the Cold Start Ignition Timing Control System Performance. However, once the car does start after a minute the car is fine. I am able to drive it and then shut off and turn on the car. It fires up fine, it's only when the car has sat for a long time, and I start the car from a cold start.

I did notify my tuner and would've thought getting a tune would fix it. My tuner did ask me to reach out to Hondata since it doesn't look like he has access to touch the cold start information that's related to the P050B code.

As I recall the cold start issue went away after I increased the injector size during my early testing. Try it with the 1530cc value and see if that eliminates it.

Just a quick update. I managed to alleviate much* of this oscillation by trimming the feed forward gains by a lot. On order of 50% or more. This also alleviated the runaway fuel pressure situation I was seeing.

It took me awhile to get to this point since I was unable to find any information on how to properly approach this. In prior testing I experimented with the feed forward gain figures but I had only dropped them by ~10-15% and didn't see any improvement so I decided to shift my attention elsewhere and no matter what I tried, I seemed to find dead ends after many test miles.

I still have some work to do to fine tune these feed forward gain figures and also to try to understand if the Feed Forward Offset tables still need to be addressed or if the tables that Hondata has for those are good. Hopefully Hondata will test the feed forward gain tables and we can get some "golden" numbers to use as starting points.

For reference these numbers are close to what I'm currently using but not the exact numbers, so YMMV. To clarify, this is with the Hondata Fuel System HPFP, 1530cc injectors, and camshaft.


*To get to this stage of progress I relaxed the PI control tables in order to fine tune the feed forward gain so I could see how far off the gains were without the correction of the PI feedback loop. I haven't done any testing yet with these PI tables restored to their normal values but once I am satisfied with the fine tuning of my Feed Forward Gain tables, I am hoping they are able to clean up any remaining errors in DIFP once I restore their values.

Hi All,

It's been a while since I've got my tuned and what I'm noticing is that my car has a hard time on cold start when I'm on full E85 on the HFS+. If I'm on strictly 91 or 93 no cold start issues. I wonder if that's normal or if anyone has similar experience? I did change my spark plugs when I got my tune and check my ignition coils. Any info would greatly be appreciated. Thanks.