Knock Sensor readings - What is a normal ? V6 3.8L

[delcowizzid]

The o2s should swing regular and quite rapid in closed loop the stft shouldn't if you are just rolling along at one throttle opening

['quipt4it]

There is 8mm difference between the intake and exhaust valve.
I would like to know how someone fitted two intakes in that small confine

[JohnDee68]

There is 8mm difference between the intake and exhaust valve.
I would like to know how someone fitted two intakes in that small confine

Not sure of the exact measurements, but the heads that were on the current motor in my car were the one with larger inlet valves. Almost identical size to the exhaust. Comparably larger than the inlet ones on the VT.
here is a pic of the head upon its removal from the new to be refurbished motor. Later to be the same head which i had the Vt inlet valve as comparison in the picture previously. I don't understand it either, but it was what it is.

[JohnDee68]

The o2s should swing regular and quite rapid in closed loop the stft shouldn't if you are just rolling along at one throttle opening

delcowizard, can you dumb that down a little please for me? What should a STFT act like at idle/drive/1800rpm? As I am trying to diagnose an economy issue and it might give me some other path to check in the process to resolve my issue (with the car i mean )

[JohnDee68]

Guys,
I am going through log files of TunerPro that I have done over time with my car.
I wonder if anyone can shed some light on something for me.
I am learning and understand the "closed loop" and "open loop" being that closed loop uses the O2 sensor readings to keep fuel trims ideal. What causes the closed loop to go back to open loop at times ? I question this as it seems mine cycles between the two very often weather at idle or at near 2000rpm ?
My O2 sensors also seem to swing erratically I think. Could poor injectors spray patterns or even fuel pressure supply, or AFR settings be a cause of such readings?
Also, can knock detection be caused by poor injectors ?

[vlad01]

What's the actual economy figures like? My Nephew averages 13L/100 on his VS manual. I get at the moment as it's winter about 10L/100 on my VP manual, usually does about 8.5L/100 in summer.

[Charlescrown]

O2 sensors must swing around quickly. It's the ECU responding to the output. They get lazy as they die and that is a major cause of high fuel consumption.

['quipt4it]

... Poor fuel. (E10) currently in use. Though previously with regular unleaded I would get even worse (nearly 200km) less per tank when not using E10...

Dang that is a wide spread between those two fuels.
Regular ULP is rated at 91 RON (Research Octane Number), E10 is 94 RON. Research has shown E10, as of it's lower energy (lower calorific value), usually returns less mileage than non Ethanol blended fuels.
You would expect to return slightly higher mileage from the 'Regular' fuel, even though it is lower in octane than the E10.
I wonder if your situation is knock (and retard) related more than anything else suggested.
Your engine is disassembled now?
A good comparison would be to try a higher octane 'Premium' fuel.
On a different note, you aren't confusing intake with exhaust valves are you?

[JohnDee68]

What's the actual economy figures like? My Nephew averages 13L/100 on his VS manual. I get at the moment as it's winter about 10L/100 on my VP manual, usually does about 8.5L/100 in summer.

Yeah, this motor is getting more around the 13-15 L/100. With my style driving (usually very good for fuel saving) I expect and have in the past, got more of the 7-8L/100 on average. I usually calculate old school of mpg, so it shows a more significant variant, which allows me a more noticeable change in the running of the engine fuel use. Anything below 28mpg for usual driving of mine, is a sign of something a miss. I should be getting more around the 35mpg, where I struggle to get 25mpg at the moment.

[vlad01]

It's hard to know what it actually is or if it's a multitude of things all contributing. My old VP vacationer used to get about 7L/100 but as the engine got a lot of Ks on it it increased to about 10-11L/100 by the time it had 400K on the clock. Interestingly that was even with perfect tune and knock retard disabled.

But one thing I did notice was severe lifter rattle at certain rpms, they were bleeding down so perhaps I was loosing valve lift and timing. The engine was a little down on power from 90K on the clock when I first installed it but not a massive amount, maybe 10-20%?

My new VP auto with 120k stock gets way better economy than my old shitbox VP with perfect tune, knock disabled and manual, with lean cruise, but the engine had a very hard life. Overheated badly by my nephew, drove it 40km with no coolant and seized it 6 times on the way home and the valve springs are weak I think as it struggles to get power over 4k rpm, rolls over a lot compared to my other cars. Now it's consuming coolant so it's on it's last legs. The economy has deteriorated to about 12L/100 at the moment.