Oxy sensor and mapping questions...

[ChefAngus]

Yes another boring mpg question. My apologies.

I replaced my oxy-sensor 2 years ago.
Since then the car has been sat untill recently when I replaced the engine due to big end failure.
With this replacement engine the mpg seems a little low! Is it possible I may have damaged the sensor while removing/re-fitting it? It passed emissions fine on mot! If I post the results can anyone tell me if all is as should be...i.e. The sensor is working.
Also I heard re-mapping helps, can anyone shed some light on this procedure for me pls.will it Help economy, Is it expensive, where is best to get it done etc!
I have a 2ltr 3s ge, 91/92. I live near Norwich.
Thanx for your time ppl

[toxo]

On your MOT emissions sheet you should have a figure for lambda value. This should be around 1. If it's wildly different (I forget the MOT threshold) then your o2 sensor is bu88ered. If not then look elsewhere.

If you have an osciliscope you can check the sensor for correct operation yourself, the procedure is in the BGB

[ChefAngus]

Thank you, that Is some solid usefull advice.
I just got 250 miles out of my thirst tank of fuel. Used bog standard unleded.
Is this about right for my engine?
Driving flat back roads...only beaned it half a dozen times for a few seconds, other wize grany style driving!

Your help here Is greatly apprichated

[bobhatton]

That is not too bad at all. On a motorway at no more than 70 and never going into boost you should get 300 miles per tank full at best.

Bob

[toxo]

300mpg eh Bob? I reckon you mean 300 per tank

Most I've ever got is 360 I think, but that was an entire tank of motorway through France. Least I've got is 175

[bobhatton]

300mpg eh Bob? I reckon you mean 300 per tank

Most I've ever got is 360 I think, but that was an entire tank of motorway through France. Least I've got is 175

Oh yes Thinking of too many things at the same time.
My Rev 1 is far better on fuel than my Rev 2, not sure why.

Bob

[ChefAngus]

That is good news, but my car is na! Assuming you realise this by mentioning not using boost.
Just wanna check my running temp now pls...should my temp needle be just below half way?
Just asking because not sure if thermastat needs changing.
Oh...will I get more mpg from shell ultimate? Have been using the bog standard stuff?

My oxy reading was 0.994
Thanx again for your time.

[ChefAngus]

I have a late 1992 k reg mr2!
Is it a rev1 or 2?
The car I took my engine from was a j reg...it didnt have a charcoal can and many bits looked different under the hood.
Could that have been a rev1?