Factory tune for VY S/C V6..

[lowandslow]

Hi all,

Just wondering if anyone can help me out. I'm chasing a random stalling/cut out issue with our Calais. Looking at the data logs and sensor info the only thing that i can think of that will be making it do it would be lean cruise.

I've just had the fuel pump and filter changed and at times while at freeway speeds on flat ground you can see the AFR trace ramp up into the 18.5 mark. A touch of the throttle will bring it back to normal then it goes back up. If you leave it it will sit at this AFR for about 20 seconds then return to normal then go lean again. If this is lean cruise then no wonder it gets outrages economy.

Anyway back to the point of this thread. Can anyone help me out with getting a memcal sorted out for a 2003 VY S/C V6 with the lean cruise function disabled or at least dumbed down by say 50%.. (If thats possible??)

Thanks,
Brendan.

[Jayme]

I think you may be barking up the wrong tree... lean cruise wont suddenly turn on and cause this issue. it didnt stall with this tune at the factory, therefore trying to solve the problem by playing with the tune is just hiding a mechanical issue. lean cruise only enabled > 80km/h anyway. when exactly is it stalling?

[lowandslow]

99% of the time at freeway speeds. ie 80kph and up.

This is usually the scenario. Happens with cruise on or off.

Cruising along the freeway. 100kph in top gear at about 1800rpm or whatever they sit at. Everything upto temp and your using very little to no throttle. Car will go into open loop, o2's zero and the AFR climbs to around 18.4 and it will sit there for about 15-20 seconds then open loop turns off and normality resumes and after 20-30 seconds if throttle inputs haven't changed it will repeat.

Car won't stall or play up if you drive it like you stole it tho.

If you have any ideas as to why open loop suddenly turns on please help me! I can send you a log file of it playing up if it helps.

Cheers.

[Jayme]

That will help. Post up a log and the adx you took the logbwith.

[lowandslow]

Heres one of the first logs i managed to catch. Took ages for it to do it when i had the laptop plugged in.

Some history on items replaced thus far -

sprak plugs
DFI
CAS
Fuel pump/filter
Checked the magnet on the cam sensor hasn't broken
Cleaned MAF, TB, IAC
Fuel pump controller

It hasn't died since the fuel pump went in Yesterday but it hasn't been driven far. Heres a screen grab of what it looks like on the log. Stalls appear to be totally random and come when it's lean.

[vs ss]

Has it got a thermostat in it? I say lean cruise is dropping off because it's dropping under the enable temp threshold.

Edit : mods feel free to move this topic if needed.

[lowandslow]

It has an 82* thermostat in it. Has been in for well over 18 months.

[lowandslow]

Has it got a thermostat in it? I say lean cruise is dropping off because it's dropping under the enable temp threshold.

Edit : mods feel free to move this topic if needed.

Yes, please move it to where it's most suited. I didn't know it would get this much help. Thanks all!

About the temp issue and lean cruise. There does appear to be a direct relation to lean cruise's minimum enable temp and the coolant temp at the time.
But in the log when it stalls, its only at 81 degrees when something makes it shutdown. Possibly lack of fuel flow/pressure? Question is, do they run this lean in lean cruise?

[Dylan]

Might be worth getting a memcal done with lean cruise enabled at say 75deg or even disabled to try.
Have a spare memcal?

[lowandslow]

Hi Dylan.

One with lean cruise disabled would be ideal really. Fuel consumption isn't much of an issue and the car has only a limited time remaining before it's updated. Just need it to be a reliable shopping trolley for a few more months until after the wedding. Apart from this issue I've hardly spent a cent on it 4 years besides routine and general maintenance.

No i don't have a spare. I'm hoping someone could help us out. Compensation will be provided of course.

Cheers.