Consult shows a differential of 50% between L & R sensors. L reads say between .4-.6v Right .2-.4 when you blip the throttle. When holding the throttle steady at 3000 rpm the L needle swings correctly (lean rich lean rich) with a reading fluctuating quickly between .4 and .6v. What effect would one O2 sensor reading half of its opposite create?
Good call. Hadn't considered that given the readings were so different, range is usually between .1 and say 1 v. These seem lazy. I don't have the specs for an OEM O2 sensor. I could make a joke here about 3 mechanics as there were 3 off us using Consult and experience trying to get the TPS set correctly, reduce the idle speed, CAS timing check again for vacuum leaks and trouble shoot and repair prior to RWC. This is a freshly re-coed engine done around 100k's, car has been off the road 3 years. Basically there are 2 types of O2 sensors Zirconia, produces voltage signal and Titania, produces ECU powered voltage then measures resistance. Short story both measure oxygen content in exhaust gases for AFM etc. The two different types cannot be used together. I intend to replace the sensors as their correct functioning is imperative for achieving initial basic set up. Should have done it when engine was out.
The OEM O2 sensors are..... ......the Zirconia type. Specified voltage output is 0V to 1V, however you're more likely to see a 0.2V to 0.8V range. The voltage you see on the meter is the output of the sensors reacting to the O2 present in the exhaust gas. If the sensors are faulty, you'll get an incorrect signal. What if they aren't faulty? What would that indicate?
Hopefully you are referring to the AFM. We have already swapped this and TPS out with the same readings on screen. If not? What are you proposing? Still going to swap O2 sensors and have swapped back AFM to original unit so not too many changes are made before the O2 swap and see what the readings are after that.
Eventually after much stuffing around the O2 sensors have been replaced. What a difference these have made. Car runs sweet as can be BUT the ECUTalk readout has the sensors up around 1 and staying steady and not fluctuating. Is this correct
they should be at operating temp, 2k rpm and above to work correctly they don't work at idle, take it for a drive and set a constant speed say 80kph and watch ecu talk if they are fluctuating then they are ok
No not correct. When there is less oxygen in the exhaust gas, the voltage output of the sensor will be high. When there is more oxygen, the voltage output will be low. When the O2 is perfect the voltage will be 0.5V. But it will never be perfect because the ECU is constantly adjusting the fuel to the injectors. That is why there should be a fluctuation in the readings. The fluctuation range should be between 0.0V & 1.0V with the average at 0.5V. If your O2 sensor is reading 1.0V there is very little O2 in the exhaust gas & it's telling the ECU "Too much fuel, take some out". However, if the reading is staying constant & doesn't fluctuate to below 0.5V, then there's something wrong.
Visual inspection of the old O2 sensors showed that they were wet with contaminates such as fuel which maybe the reason why the L sensor died so quick! The comment "then there is something wrong" What and where would you direct me to look? The ECU Talk shows the needle fluctuating after it is up to operating temp and run up to approx 2000 rpm but not by much. Still ranging at the upper range .5-1. Not a rapid movement quiet lazy. I'm happy with the rest of the displays on the ECU Talk.
Surprised you say you're happy with the rest of the displays on the ECU Talk. With the O2 sensors indicating there is not enough O2 in the exhaust gas, the ECU should be supplying less & less fuel to maintain stoich. However from your description, it isn't achieving the desired result. Try creating a decent vacuum leak & see if the O2 sensors respond.
Could be lots of things from leaky injector to poor valves - the sky's the limit Looking at too much fuel or not enough 02 but check the gauge and sensor first Something is not right - it should fluctuate quite rapidly
This is completely re-coed engine done less than 100k's. The injectors were cleaned and checked plus new seals including the rail to manifold seals. Which sensors are you referring to? and in respect of the guage are you referring to the fuel pressure?
02 sensors - as explained they should fluctuate quite a bit as the ECU tries to keep up Could be lots of things - was just citing examples - even the 02 sensors or the connection since you have been working on them?
Is the engine running in open or closed loop? When no signal is received from the O2 sensor, as is the case when a cold engine is first started (or the 02 sensor fails), the computer orders a fixed (unchanging) rich fuel mixture. This is referred to as "open loop" operation because no input is used from the O2 sensor to regulate the fuel mixture. If the engine fails to go into closed loop when the O2 sensor reaches operating temperature, or drops out of closed loop because the O2 sensor's signal is lost, the engine will run too rich causing an increase in fuel consumption and emissions. A bad coolant sensor can also prevent the system from going into closed loop because the computer also considers engine coolant temperature when deciding whether or not to go into closed loop.
To answer you mike I get the occasional hick up but generally idles fine. I will change out the coolant sensor, although when I checked the engine over with the temp gun and ECUTalk for a comparison they both read the same. I do have a feeling that the car may be running a little rich due to being idled and not driven. I think a good run as soon as she is registered may help.
Whoa! Don't just change the coolant sensor. It may be the problem, but you should test it first. Does the engine run in closed loop? What happens to the O2 sensor reading if you introduce a vacuum leak, such as removing the hose to the brake booster?
In my opinion we are going into closed loop. The following are the readouts from ECU Talk at idle and above 2000 rpm Idle 850-862 temp 83-90c Throttle V .42 Timing 15 at idle-35 above 2000 rpm AAC% 55% @ idle Duty cycle L 1 @ idle 3 @2000 Right the same L O2V .96v @ idle .16v-.93v @ 2000 R O2v .92v @ idle .16v-.94v @ 2000 Air Flow V idle 1.18 1.60 @ 2000 F/B O2 L & R flicking 0-1 on over run There is a small miss occasionally at idle when first started but smooths out when warmed up. Took the car for a drive and there is no pinging goes were well under throttle. O2 sensors are working but as expected not in unison when cruising at around 70-80kph. Instigated a BIG vacuum leak O2 needles drop almost to zero and car almost stalls. So wise one, what's your opinion? Isn't it fun diagnosing faults by remote control?
Did you have air con on? what ambient temps and how long/aggressive were you driving to get up to 90 C? In summer that's not a temperature to be worried about but if you just went around the block and it got to 90 you could have issues trying to drive much further. You could do with bringing the throttle position sensor up slightly to 0.44V, sometimes it causes issues having it lower. Your AAC (auxilliary air control, basically an electronic idle valve) is a bit high, you want it to be down between 15 and 25 when your air con is off and car is at operating temp. This info should help http://z32.wikispaces.com/Idle+Control Sounds like the O2 sensors are doing what they should.
