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vs 5l running rich

Posted: Fri Sep 06, 2013 6:09 pm
by phear
hi i have a vs 5l 304 and its been running rich for a while now, i replaced the o2 sensor about 6-12 months ago its a ngk 2 wire.

ive taken a log as attached i started logging when cold until it was hot then let it idle once hot im running a 80C thermostat.

any info would be appreciated or anything else you notice in the log.

i have attached the adx in case you need it.

thanks jamie

Re: vs 5l running rich

Posted: Fri Sep 06, 2013 7:07 pm
by antus
i havnt had a chance to look at the log, but 80 degrees seems too cold. Have a read of this thread regarding genuine thermostats and the difference being too cold makes to fuel consumption. http://pcmhacking.net/forums/viewtopic. ... 67&p=33053

Re: vs 5l running rich

Posted: Fri Sep 06, 2013 11:00 pm
by phear
Ill have a read but it always stinks of fuel which I dont think the thermostat would cause. I did notice the o2 sensor reading was red but didnt throw a code so im guessing it may not be working properly but need someone who knows what there looking at to check the log for me.

Re: vs 5l running rich

Posted: Sat Sep 07, 2013 7:12 am
by VK_3800
82 degree thermostat is factory for a V8, even if that's not what you meant 80 is close enough for that not to be an issue (I've had them side by side with more than 5 degrees difference in the same rated thermostat anyway)

Re: vs 5l running rich

Posted: Sat Sep 07, 2013 8:43 am
by antus
Ive had a look and can see what you mean, def. rich at idle. but other than it looks ok. Is the engine stock? Is the tune stock?

Re: vs 5l running rich

Posted: Sat Sep 07, 2013 11:22 am
by yoda69
If stock with stock tune check for leaking injector or fuel leaking into the engine vacuum hose from the regulator.

Re: vs 5l running rich

Posted: Sat Sep 07, 2013 1:32 pm
by phear
engine is stock (besides cai, k&n air filter panel, exhaust, about to put extractors in) and i have not put a tune in it yet but dont know if anyone in the past has but i doubt it.

i have not long ago within 6 months had the injectors cleaned and new caps and seals put on them.

i did the old carby cleaner trick and sprayed all the vac hoses and injectors to check for any vac leaks but none showed up.

ill look into the regulator vac hose.

is there any possibility it could be the o2 sensor playing up? (i have a s/h o2 sensor but dont know if its any good as it came with the extractors i bought, that i could try)
or fuel pump?
or could it even be something silly like the pcv valve?
thanks for the input guys!

Re: vs 5l running rich

Posted: Sat Sep 07, 2013 5:21 pm
by phear
just checked the regulator vac hose and theres no fuel in it so thats not the issue.

Re: vs 5l running rich

Posted: Sat Sep 07, 2013 5:53 pm
by Charlescrown
I am not a specialist at looking at these logs but I am concerned that it takes 15 minutes to reach operating temp. Have a look at the coolant temp sensor. Maybe remove it and clean off the bulb end to make sure the coolant can get to it. I do know that 3mm of scale is equivalent to 25mm of cast iron in it's ability to transfer heat.

Re: vs 5l running rich

Posted: Sat Sep 07, 2013 6:06 pm
by phear
ok ill do that thanks, im guessing its the one in the inlet manifold on the passenger side as the one on the front is where i have my aftermarket gauge sender.
i have got a heavy duty radiator in it due to using it for towing. (could be why it takes longer to heat up)
also could be because i drilled a small hole (1-2mm) in the thermostat for bleeding it when replacing coolant as theres no bleed valve on the 5l.
virtually replaced the whole cooling system all hoses, thermostat, heater tap, radiator, coolant about a year ago.