380Km per tank on my DC5 Lux, running rich?

[tinkerbell]

12:1 at idle is fine. probably most influenced by the coolant temp at the time.

do you have an aftermarket thermostat?

[Mattski]

12:1 at idle is fine. probably most influenced by the coolant temp at the time.

do you have an aftermarket thermostat?

sweet, currently the thermostat is standard, from what i can gather in the data log the A/F at idle moves between mid 12's and mid 13's varying slightly on ECT (between 84c when cruising to 95c max when sitting in traffic)

Also the A/F leans right out when i appear to be backing off the throttle (compression breaking) in the low to high 20's??? is this also normal?
(again this is what i can gather)

And again thanks for all the help guys, learning more every day

[tinkerbell]

yes, it is normal to swing a bit at idle as the engine ECU will be in "closed loop" trying to keep a 14.7:1 AFR (stoich) - normally.

BUT a low ECT reading will keep it richer (which is why i suggested your 12:1 was due to ECT), so if it stays at 12:1 when the car is HOT, you may have an issue...

but is *should* get to over 14:1 at idle when it is at operating temp - this may indicate a problem with the idle strategy?

yes, normal (fuel saving strategy that exists in more EFI cars) when you back off, and close the throttle plate, the ECU is supposed to sense the TPS is at 0v and shuts off the injectors...

going to 20:1 proves it is working this way, which is good...

can you log the actual voltage readings from ths O2 sensor?

[mugsee]

12:1 works fine but I'd imagine that something closer to stoic would be better for fuel ecconomy. By default, idle is set to ~14.5-7ish on the DC5R.

RE: lean spikes on throttle off. This is taken from CRSX:
According to HELMS the ecm cuts off fuel under deceleration and 0 throttle for the sake of economy. So, the high AFR is normal. If you shift to neutral and let the engine go to idle then you'll see the AFR come back down when the ecm reintroduces fuel to keep the engine running.

Edit: beaten by tinkerbell

Btw, any idea if your running in open loop?

[Mattski]

yes, it is normal to swing a bit at idle as the engine ECU will be in "closed loop" trying to keep a 14.7:1 AFR (stoich) - normally.

BUT a low ECT reading will keep it richer (which is why i suggested your 12:1 was due to ECT), so if it stays at 12:1 when the car is HOT, you may have an issue...

but is *should* get to over 14:1 at idle when it is at operating temp - this may indicate a problem with the idle strategy?

yes, normal (fuel saving strategy that exists in more EFI cars) when you back off, and close the throttle plate, the ECU is supposed to sense the TPS is at 0v and shuts off the injectors...

going to 20:1 proves it is working this way, which is good...

can you log the actual voltage readings from ths O2 sensor?

Ok i understand what you mean, well with the ECT around 85/90 it gets a minimum of 12.74 and a maximum of 13.75 while idling. so its running a little richer than optimum

And yep the kpro datalogger shows me current and volts of the primary O2 sensor, although i'm not sure what to be looking for

[Mattski]

12:1 works fine but I'd imagine that something closer to stoic would be better for fuel ecconomy. By default, idle is set to ~14.5-7ish on the DC5R.

RE: lean spikes on throttle off. This is taken from CRSX:
According to HELMS the ecm cuts off fuel under deceleration and 0 throttle for the sake of economy. So, the high AFR is normal. If you shift to neutral and let the engine go to idle then you'll see the AFR come back down when the ecm reintroduces fuel to keep the engine running.

Edit: beaten by tinkerbell

Btw, any idea if your running in open loop?

Cool well that explains the lean spikes when off throttle, and my not so great fuel economy when sitting in traffic,
as for running in open loop i'm not sure, is there an easy way to tell?
If it helps the car was tuned my Dyno Dave over 12 months ago.. (not here to bash anyone etc) just giving the info in case it helps..

[EK4R]

just scored 600+ on a tank with IHE and Hondata and 17" rims. w00t

ithink your luxury has some problems. better get it checked it. my friend dc5 lost 50km a tank with just a catback which was strange

[Kyo]

hm... yeh, i never thought change exhaust will decrease fuel economy :/

can i datalog the stock ecu? do i have to go to a honda dealer for this?

[endymiony2k]

Ek4R, you are getting 600+ on a tank? Thats impressive.
my usual fuel eco is 180km per half tank. My mod is IHE + hondata + 17" rims too, and should be highly similar to your mods.

I think the driving style makes a big difference on the fuel eco

[EK4R]

na thats was one off. usually 520 when the light comes . 600 was when fuel light came on and i fill it up with 42.7 litres . it was 450 freeway driving