Closed loop Lean cruise and idle and cruise timing

General Tuning Questions And Discussions
vp304
Posts: 451
Joined: Wed May 19, 2010 2:21 pm

Closed loop Lean cruise and idle and cruise timing

Post by vp304 »

So my daily driver l67 ute on 11p does a lot of cold start short trips. My drive to work also is only 7-8km each way.
Winter time now 180deg thermostat and i noticed my fuel economy has gotten a bit worse. Like 300km to a tank all city driving short trips.
Car is 91 fuel only
standard boost pulley
Not driven hard etc. Bit of a work tow horse

Couple of questions i have been doing some googling on some usa pages and they say because of the low compression ratio of the l67 you can add a fair bit of timing in the cruise area some guys running up to 40deg of cruise timing and saying it has improvements of 1-2l per hundred km fuel economy ?

Also i am guessing these are the main closed loop and lean cruise tables below how do they all look on my tune ?

Any reason why on the A/f ratio - Idle A/F ratio vs Coolant temp, Once the car is warmed up at 92 deg c coolant temp it asks for 14.5 idle af ratio?

Air fuel ratios are good in open loop i spent a lot of time to get them pretty spot on.
Have wideband also my cold starts from stone cold and they are decent
Fuel filter not that old same as spark plugs and air filter
Closed loop set to come on at 40deg c also in the tune
and at 44deg c for idle
leads are good condition etc etc.
Car runs pretty good all round.

Just trying to get a bit better fuel econ out of it
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'quipt4it
Posts: 675
Joined: Sun Oct 28, 2012 12:57 pm

Re: Closed loop Lean cruise and idle and cruise timing

Post by 'quipt4it »

vp304 wrote:...Any reason why on the A/f ratio - Idle A/F ratio vs Coolant temp, Once the car is warmed up at 92 deg c coolant temp it asks for 14.5 idle af ratio?...
The idle table setting is set to that figure.
Can you post your timing table.
When you said you were fussy you weren't kiddin' :lol:
vp304
Posts: 451
Joined: Wed May 19, 2010 2:21 pm

Re: Closed loop Lean cruise and idle and cruise timing

Post by vp304 »

Hey quipt4it :)
This thing has to go like a sports car
But be as fuel efficient as a toyota prius lol :)
Last edited by vp304 on Sun Jun 06, 2021 1:17 am, edited 1 time in total.
'quipt4it
Posts: 675
Joined: Sun Oct 28, 2012 12:57 pm

Re: Closed loop Lean cruise and idle and cruise timing

Post by 'quipt4it »

vp304 wrote:...This thing has to go like a sports car
But be as fuel efficient as a toyota prius lol :)...
lol
The general rule is that added timing helps part throttle feel and economy.
Add some in, maybe 0.5 degs. at a time (from 70 KPA), but keep an eye on the spark plugs for signs of detonation.
Those cruise figures look high enough. Extra timing may not help much. Won't hurt to try, as you say, off boost would have low cylinder pressure.
vp304
Posts: 451
Joined: Wed May 19, 2010 2:21 pm

Re: Closed loop Lean cruise and idle and cruise timing

Post by vp304 »

The 85 onwards map
400rpm to 3200 rpm area has low timing as on 91 fuel and even sometimes on e10 (i tried) down low i would get knock just as coming onto boost up to around 1-3 psi when the Intake air temps were up high exp after being stuck in traffic. I noticed it in 2nd gear. Thats why that is that way.
But that should not affect cruise much.
I have done 4000 plus km on the street now with this timing map and run on a friends dyno around 3500km ago. I also check the plugs here and there at the start before and after the dyno.

Could i add a little in at cruise areas timing wise. Watch knock sensor while driving and also check plugs after some road time.
'quipt4it
Posts: 675
Joined: Sun Oct 28, 2012 12:57 pm

Re: Closed loop Lean cruise and idle and cruise timing

Post by 'quipt4it »

vp304 wrote:Could i add a little in at cruise areas timing wise. Watch knock sensor while driving and also check plugs after some road time.
If it were mine I would try it.
Gee, a 7-8 km trip is barely warming it up (in Winter).That's where you're fuel is going. Extra richness in the Cold A/F R tables. See if you can sneak a lil' of those numbers.
I know we spent a lot of time on those, but maybe juggle AE with that Cold A/F R table if you're that concerned about getting 50 mpg lol.
vp304
Posts: 451
Joined: Wed May 19, 2010 2:21 pm

Re: Closed loop Lean cruise and idle and cruise timing

Post by vp304 »

Yeah i know those dam short trips are killing me, and by what i read on google search cold starts can use up to 20% more fuel i think thats were its all going.
I trimmed those cold start settings a fair chunk already also :(
May have to put a bit of cardboard infront of radiator to block half of it over winter lollll
'quipt4it
Posts: 675
Joined: Sun Oct 28, 2012 12:57 pm

Re: Closed loop Lean cruise and idle and cruise timing

Post by 'quipt4it »

vp304 wrote:...Yeah i know those dam short trips are killing me...
Not to mention what it's doing to the poor engine...
vp304
Posts: 451
Joined: Wed May 19, 2010 2:21 pm

Re: Closed loop Lean cruise and idle and cruise timing

Post by vp304 »

Yeah that also :(
Charlescrown
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Re: Closed loop Lean cruise and idle and cruise timing

Post by Charlescrown »

No use blocking the radiator when your got a thermostat doing it's job.
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