Took some co2 reading tonight.

 

No matter what I did, the left side was always twice the reading of the right!

 

e.g. Left read 3%co2 and the right read 1.5%co2.

 

When switching the sniffer, the change was almost instant and the difference always the same!

 

This may sound daft, but listening to the exhaust note up close, the left side sounded like.. puff puff puff and the right sounded like.. pop pop pop!

The difference was very noticeable. Any relationship do you think??

 

So! my question is.. What would be the key features to check, that would most likely cause this fault?

Cheers Steams,

Just charging my old IBM laptop, then I will see what data scan has to say.

 

Oh meant to say, I have checked resistance on the heater side of the sensors and both came back with 8.5 ohms.

I think the accepted range is between 3 and 1000. so a bit on the low side, what ever that may mean?

 

Also checked the supply voltage to them and that came out as 11.8 volts each side.

Edited March 9, 201312 yr by redwine300

A bit of an update.

Ran data scan for a good 20 minutes, engine temp' sat at around 78

Left Hand o2 gauge stuck at 32 flickering to 29 once in a while. (this is the side with the higher co2%)

Right hand did moved once round to 90 but once I blipped the throttle she just returned to 32 and did not move again.

Also, disconnected them both but still no change!! are they dead or am I missing something?

A bit of an update.

Ran data scan for a good 20 minutes, engine temp' sat at around 78

Left Hand o2 gauge stuck at 32 flickering to 29 once in a while. (this is the side with the higher co2%)

Right hand did moved once round to 90 but once I blipped the throttle she just returned to 32 and did not move again.

Also, disconnected them both but still no change!! are they dead or am I missing something?

 

I'd say they are both dead mate. I'm sure one of our experts will confirm or deny.

Cheers Steams, I am inclined to agree.

 

I do hope that some of the experts as you say will post their thoughts.

I really want to know for sure, as my MOT is due soon.

Come on guy's, please put me out of my misery, I need closure. lol

Cheers Steams, I am inclined to agree.

 

I do hope that some of the experts as you say will post their thoughts.

I really want to know for sure, as my MOT is due soon.

Come on guy's, please put me out of my misery, I need closure. lol

 

i gave you closure in post 2 http://www.300zx.co.uk/forums/showthread.php?168235-Two-different-CO2-readings&p=1717017&viewfull=1#post1717017 :D

i gave you closure in post 2 http://www.300zx.co.uk/forums/showthread.php?168235-Two-different-CO2-readings&p=1717017&viewfull=1#post1717017 :D

 

Looks like you we're right all along Znut

I think I was in denial.

Do these things make a big difference to performance or just mainly MPG?

Decided to try another route, so I read up about putting the ECU into diagnostic mode 2 and check the o2 sensors individually.

Never keen on messing with delicate electrical items but thought, what harm can I do.

Anyway, after stripping back the carpet and removing the ECU far enough to see it from all sides, I then got even more confused.

I found the red bulb sure enough, but there is just a gaping hole where I presume the setting screw should be!!

Is this normal? if so is there another way of activating diagnostic mode 2 on the ECU.

 

Please don't loose interest guys, I know this thread may becoming tedious but I really do need your help.

The screw is in the hole, it's mounted on the circuit board of the ECU. You'll need a smallish flat blade screwdriver. And don't worry about us losing interest, that's why were here bud :)

The screw is in the hole, it's mounted on the circuit board of the ECU. You'll need a smallish flat blade screwdriver. And don't worry about us losing interest, that's why were here bud :)

 

Cheers Steams.:thumbup1:

I guess I am going through the disheartened stage of problem solving at the moment. :confused1: Bl**dy Zeds, lol

Steams,

I know this may seem odd, but I have had a really close look at the ECU, and not only is there no screw, there is now switching unit in there either.

I remembered the car came to me with a second ECU in the boot, so I had a look at that one as a comparison, that has the screw and the switching unit intact.

Would it be worth swapping ECU's over, or is that asking for trouble?

Steams,

I know this may seem odd, but I have had a really close look at the ECU, and not only is there no screw, there is now switching unit in there either.

I remembered the car came to me with a second ECU in the boot, so I had a look at that one as a comparison, that has the screw and the switching unit intact.

Would it be worth swapping ECU's over, or is that asking for trouble?

 

I was hoping to try the swap over tomorrow night, what do we think?

Steams,

I know this may seem odd, but I have had a really close look at the ECU, and not only is there no screw, there is now switching unit in there either.

I remembered the car came to me with a second ECU in the boot, so I had a look at that one as a comparison, that has the screw and the switching unit intact.

Would it be worth swapping ECU's over, or is that asking for trouble?

 

I was hoping to try the swap over tomorrow night, what do we think?

Sorry mate, just noticed. You can try the other ECU but it's a bit of an unknown quantity so may just through up other problems. Won't hurt to try though. But you may be flogging a dead horse. The o2's are used by the ECU to adjust fuelling etc on the fly. If they fail the ECU will revert to it's basic map, so the car will still run but won't be as efficient as it could be.

Sorry mate, just noticed. You can try the other ECU but it's a bit of an unknown quantity so may just through up other problems. Won't hurt to try though. But you may be flogging a dead horse. The o2's are used by the ECU to adjust fuelling etc on the fly. If they fail the ECU will revert to it's basic map, so the car will still run but won't be as efficient as it could be.

Sorry mate, just noticed. You can try the other ECU but it's a bit of an unknown quantity so may just through up other problems. Won't hurt to try though. But you may be flogging a dead horse. The o2's are used by the ECU to adjust fuelling etc on the fly. If they fail the ECU will revert to it's basic map, so the car will still run but won't be as efficient as it could be.

 

No problem Steams, I just really appreciate the help and advice mate. :thumbup1:

The reason I suppose I am clutching at straws with regards to trying the ECU, is the forlorn hope that maybe the unit is at fault and not the 02 sensors.:whistling:

I've just priced some OEM ones up and fell off my chair!! :sad: Could not believe the price!:taz:

Still, will just have to bite the bullet and get them ordered. With a bit of luck I can get them fitted over the week end. That's if I can get the old ones out that is.

I am going to start soaking them in plus-gas every night this week.

Sorry mate, just noticed. You can try the other ECU but it's a bit of an unknown quantity so may just through up other problems. Won't hurt to try though. But you may be flogging a dead horse. The o2's are used by the ECU to adjust fuelling etc on the fly. If they fail the ECU will revert to it's basic map, so the car will still run but won't be as efficient as it could be.

 

No problem Steams, I just really appreciate the help and advice mate. :thumbup1:

The reason I suppose I am clutching at straws with regards to trying the ECU, is the forlorn hope that maybe the unit is at fault and not the 02 sensors.:whistling:

I've just priced some OEM ones up and fell off my chair!! :sad: Could not believe the price!:taz:

Still, will just have to bite the bullet and get them ordered. With a bit of luck I can get them fitted over the week end. That's if I can get the old ones out that is.

I am going to start soaking them in plus-gas every night this week.

No problem Steams, I just really appreciate the help and advice mate. :thumbup1:

The reason I suppose I am clutching at straws with regards to trying the ECU, is the forlorn hope that maybe the unit is at fault and not the 02 sensors.:whistling:

I've just priced some OEM ones up and fell off my chair!! :sad: Could not believe the price!:taz:

Still, will just have to bite the bullet and get them ordered. With a bit of luck I can get them fitted over the week end. That's if I can get the old ones out that is.

I am going to start soaking them in plus-gas every night this week.

 

Yeah the oem lambda's are a bit dear, the pattern ones Mike does are good though. I've got them on mine and had no problems.

 

Help and advice is waht makes the forum go round bud. lol

No problem Steams, I just really appreciate the help and advice mate. :thumbup1:

The reason I suppose I am clutching at straws with regards to trying the ECU, is the forlorn hope that maybe the unit is at fault and not the 02 sensors.:whistling:

I've just priced some OEM ones up and fell off my chair!! :sad: Could not believe the price!:taz:

Still, will just have to bite the bullet and get them ordered. With a bit of luck I can get them fitted over the week end. That's if I can get the old ones out that is.

I am going to start soaking them in plus-gas every night this week.

 

Yeah the oem lambda's are a bit dear, the pattern ones Mike does are good though. I've got them on mine and had no problems.

 

Help and advice is waht makes the forum go round bud. lol

Yeah the oem lambda's are a bit dear, the pattern ones Mike does are good though. I've got them on mine and had no problems.

 

Help and advice is what makes the forum go round bud. lol

 

Nice one Steams.

 

Thought I might share this.

Having ordered my replacement 02 sensors, a couple of deep impact sockets and a long 1/2" extension,

I thought about soaking the little bliters in Plus Gas.

how do I get the stuff to the base of the sensor I thought? so, after scratting around my shed, I found a 2 foot length of copper brake pipe left over from my recent repairs.

I straightened it out and flattened off one end so as to get the fluid right where I needed it. worked a treat!!

I will do this each night this week, mind you, getting to them with a socket will no doubt be a different matter.

Yeah the oem lambda's are a bit dear, the pattern ones Mike does are good though. I've got them on mine and had no problems.

 

Help and advice is what makes the forum go round bud. lol

 

Nice one Steams.

 

Thought I might share this.

Having ordered my replacement 02 sensors, a couple of deep impact sockets and a long 1/2" extension,

I thought about soaking the little bliters in Plus Gas.

how do I get the stuff to the base of the sensor I thought? so, after scratting around my shed, I found a 2 foot length of copper brake pipe left over from my recent repairs.

I straightened it out and flattened off one end so as to get the fluid right where I needed it. worked a treat!!

I will do this each night this week, mind you, getting to them with a socket will no doubt be a different matter.

No problem Steams, I just really appreciate the help and advice mate. :thumbup1:

The reason I suppose I am clutching at straws with regards to trying the ECU, is the forlorn hope that maybe the unit is at fault and not the 02 sensors.:whistling:

I've just priced some OEM ones up and fell off my chair!! :sad: Could not believe the price!:taz:

Still, will just have to bite the bullet and get them ordered. With a bit of luck I can get them fitted over the week end. That's if I can get the old ones out that is.

I am going to start soaking them in plus-gas every night this week.

 

How much were they?

 

When the nearside lambda sensor went down on mine, I did away with them totally and ran open loop 100% of the time. I've found that I can get a more stable AFR than using O2 feedback every time, plus it lets me achieve close to 30mpg on a run, running at a leaner 16+:1 AFR with the appropriate timing :)

How much were they?

 

When the nearside lambda sensor went down on mine, I did away with them totally and ran open loop 100% of the time. I've found that I can get a more stable AFR than using O2 feedback every time, plus it lets me achieve close to 30mpg on a run, running at a leaner 16+:1 AFR with the appropriate timing :)

 

Now you tell me! :lol: :lol: :lol: :lol:

 

As for price, I paid £60 each plus £20 shipping. Ouch!

 

Still, after a couple of hours and a few layers of skin, I managed to get both of the little b*ggers out without too much drama!!

Well relieved to say the least!!!

Now you tell me! :lol: :lol: :lol: :lol:

 

As for price, I paid £60 each plus £20 shipping. Ouch!

 

Still, after a couple of hours and a few layers of skin, I managed to get both of the little b*ggers out without too much drama!!

Well relieved to say the least!!!

 

Haha, needed plenty of mapping though!