2x0 wrote: Mon Apr 02, 2018 4:33 am
If 185 ECT and 135 IAT are your normal warm engine conditions then both compensations should remain at 0% for those values. Post up your compensation parameters. It could be that your cold ECT and IAT fuel compensation is a bit high, which makes it start up cold and run well but once it is warmed up it actually needs more fuel in the fuel tables.
Also, running in closed loop would help adjust for whatever factors are throwing this off. This is the purpose of closed loop, because your table and parameter values will never be perfect for all conditions. Let the O2 sensor feedback do it's job under normal driving and idling.
Hi 2x0,
I really appreciate your help man! My normal warm engine conditions are 185* ect and about 85-100* iat, the compensation for these parameters is in fact 0.
I only have this issue during hot restarts when the iat exceeds 125+ degrees.
My calibration and datalog is attached on a few posts above if you would be kind enough to take a look at them.
Did you ever find a fix for this? i’m running into the same issue and cannot seem to get enough fuel after hot restarts. Sure i can run closed loop but it still barely starts and runs rough for 30 seconds if IAT is over 130
mukduk wrote: Sun Sep 08, 2024 6:03 pm
Did you ever find a fix for this? i’m running into the same issue and cannot seem to get enough fuel after hot restarts. Sure i can run closed loop but it still barely starts and runs rough for 30 seconds if IAT is over 130
The only thing I found that “sort of” helps is to add fuel in the low load IAT corrections around that temperature (I start adding 1-2 percent per degree above 125 so that by 130 degree IAT I would be adding ~10% extra fuel and then change the closed loop delay down to like 5 seconds so it starts compensating sooner and adding the additional fuel needed right away. The normal setting for the closed loop delay is 30 seconds so by changing it to 5 seconds it will start correcting a lot faster after restart along with the extra fuel from the IAT correction. Still chugs and runs lean for ~5-10 seconds but that’s better than 30+ seconds of shit running after hot restart. Surprised Hondata hasn’t come up with a way to read the IAT sensor and ONLY apply extra fuel after restart when IAT is above say 110 (thus confirming it is a hot restart). That way we don’t have to mess with the air temp compensation which will start adding fuel if you get stuck in traffic for example I was stuck at a train one time and my IAT went to 134 and I was adding like 15% more fuel due to the IAT correction and I was idling at like 13.2 afr because of it while waiting for it to pass, once I started moving the intake temp came down and the correction goes away below 125 degrees the way I have it set up, but still it is annoying to have to “hack” it like this and it doesn’t even totally solve the issue.
Another note, some of the reading I’ve done about this is that the injectors actually get heat soaked causing the injector to need to be held open longer to provide the same amount of fuel (rather than being caused by the IAT temp itself it is really just due to the large injectors like 1000+cc which causes a much bigger change in fuel delivery compared to like a 440cc dsm injector). But I wish Hondata gave us a “hot restart fuel adjustment” similar to the post restart fuel adjustment but ONLY apply it after hot restarts for some set duration (or allow us to pick a duration for that fuel to be applied after hot restart so we can tune it to provide the fuel we need on hot restart). I tried messing with the rate of decay and post start fuel stuff (for cold starts) but that causes even more issues and makes cold start pig rich.
thank you for that info! i’m somewhat glad to hear i’m not the only one who is struggling with this issue. It’d be nice if they had that setting but i’m sure they’re more worried about developing new features for the new vehicles /: i honestly debating switching to smaller injectors and retune. daily driving this car now and don’t want to deal with this every time i run errands lol
mukduk wrote: Fri Nov 01, 2024 12:03 pm
thank you for that info! i’m somewhat glad to hear i’m not the only one who is struggling with this issue. It’d be nice if they had that setting but i’m sure they’re more worried about developing new features for the new vehicles /: i honestly debating switching to smaller injectors and retune. daily driving this car now and don’t want to deal with this every time i run errands lol
No problem, I wanted to come back and mention my brother came up with a clever idea of wiring in a second coolant temp sensor (zip tied up in the cabin) on a switch that reads close to ambient air temp and then when I do a hot-restart I can flip the switch before starting it to have it read from the cabin-coolant sensor which will read around ambient air temp and will cause the water temp fuel compensation table to kick in. That way it adds however much fuel compensation is in that water temp table until I flip the switch back to the regular coolant temp sensor which will remove that extra fuel. Totally eliminates the problem but feels very hacky and requires me to have an extra switch wired in the car that I have to remember to flip on hot restart (and flip back after the o2 sensor and closed loop starts adjusting).
It's a pretty cool idea though but again feels very hacky when I feel like it should be something where you can just program the hondata to give it some more fuel on hot restart and allow us to change that hot-restart fueling for some kind of duration maybe 15-30 seconds until the o2 sensor can kick in and closed loop starts compensating.
