I'm currently driving with my O2's unplugged. Only driven it a few times and not very far. I'm curious what damage this could cause if any

As far as I have read the only damage you are doing is to the environment. But I will wait fir the expert's to post :)

In that case the ECU uses a default value and calculates everything else based upon the ECU default value. So you're not getting 100% correct running but it's not far off

 

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You'll likely just be running rich, and maybe a tad lumpy at points.

 

To be honest all your doing is burning more fuel/money.

You'll likely just be running rich, and maybe a tad lumpy at points.

 

To be honest all your doing is burning more fuel/money.

 

I would agree with that, I changed both of mine a little while back.

Made a significant difference to me fuel economy also.

Went from 160 miles to the tank to just over 200 miles to the tank. (around town.)

Plugs look a lot healthier and she now purrs like a kitten. (well worth the hassle if you ask me.)

I'm currently running mine without the O2 sensors connected and it seems happy enough in general. Fuel consumption isn't noticeably up.

Why are you disconnected?

I unplugged mine because when connected the car runs badly especially during the warm up, behaves like its misfiring, but couldn't isolate to a single cylinder. Unplugged them and now it runs fine.

I used DataScan which confirmed the driver side sensor to have gone bad, the output being stationary whilst the other side sweeps correctly.

Need to get round to replacing them both really for optimum running, but can't see them coming out without a big fight!

In short, when the engine was out I swapped the O2 sensors but the new ones don't work right (only one I believe) but I don't think they're proper nissan ones. There's nothing wrong with the old ones so thinking of getting those put back in. But thinking, is it worth getting done ASAP or is there no real hurry

I'm currently driving with my O2's unplugged. Only driven it a few times and not very far. I'm curious what damage this could cause if any

 

I wouldn't have suggested unplugging them and leaving them unplugged if it would cause any damage to your car's engine :wack: It's always better to have functioning O2 sensors than not, though. Myself, I like to run a lean cruise (AFR >14.7:1) so do away with O2 feedback altogether.

 

Unplugged O2 sensors: ECU sees a constant voltage of 0.31v as opposed to a fluctuating voltage between 0 & 1.5v. This pegs the AFR slightly rich, but O2 feedback is still functional when the car is up to temp. As is the case with fully-working O2 sensors, the only section of the map that is affected is the closed-loop section (idle & light load up to around 4800 RPM on stock cars). Cars I've mapped have a very different closed-loop area compared to standard. Closed loop area in top gear is different to the other gears on stock cars.

Edited September 15, 201411 yr by Noz

I wouldn't have suggested unplugging them and leaving them unplugged if it would cause any damage to your car's engine :wack: It's always better to have functioning O2 sensors than not, though. Myself, I like to run a lean cruise (AFR >14.7:1) so do away with O2 feedback altogether.

 

Unplugged O2 sensors: ECU sees a constant voltage of 0.31v as opposed to a fluctuating voltage between 0 & 5v. This pegs the AFR slightly rich, but O2 feedback is still functional when the car is up to temp. As is the case with fully-working O2 sensors, the only section of the map that is affected is the closed-loop section (idle & light load up to around 4800 RPM on stock cars). Cars I've mapped have a very different closed-loop area compared to standard. Closed loop area in top gear is different to the other gears on stock cars.

 

Very interesting! When connected, my car behaved like a pig under light load, you could drive through it with more throttle. Makes sense with a dead (lazy output) o2 sensor confirmed with DataScan.

So what your saying Noz, is that the car can be mapped to run properly without O2 sensor feedback, the sensors can then just be snipped off?

How will the car fuel correctly during warm up or will the map mostly compensate for that too?

Cheers.

My car doesn't have any 02 sensors, as Jim said they help with economy and engine running. Noel has mapped my car without them and its' very smooth.

I have just 'de-catted' my 300TT and fitted new O2 sensors. The aftermarket ones (OEM connections advertised) did n't have the right connectors! Bought propoer Nissan ones and the fuel economy has improved by about 3 mpg. The hot idle is much better (smoother).

Ran mine for donkeys years with none connected , never had an issue !

Very interesting! When connected, my car behaved like a pig under light load, you could drive through it with more throttle. Makes sense with a dead (lazy output) o2 sensor confirmed with DataScan.

So what your saying Noz, is that the car can be mapped to run properly without O2 sensor feedback, the sensors can then just be snipped off?

How will the car fuel correctly during warm up or will the map mostly compensate for that too?

Cheers.

 

Sorry, missed this.

 

With no O2 feedback, it is quite time-consuming mapping an engine for a required AFR at all light load (cruise) sites. Other than that, it's not a problem to do in the slightest. With a lean cruise set up, timing adjustments also need to be taken into consideration as flame propagation (combustion) occurs at a slower rate.

 

With regards to warm-up, O2 feedback is only operational above engine temps of 25°C for UK & US cars and 50°C for JDM TT cars. This is generally-speaking, there are a couple of OEM maps that use O2 feedback from 10°C. There are warm up correction tables for both fuelling & timing. Again, all aspects can be modified & controlled fully during the mapping process. The standard ECU is very versatile.