hux309

Do these need to be reset or are they far more adaptable than the standard affair?

Ive just fitted a new lambda as the signal voltage didn't even register on the mot so the old sensor must have really been borked.

harvey

iTrader: (48)

You cannot reset a Simtek. It is mapped to a specific vehicle and comes with a base map for the mods on that car to allow the installer/mapper to start from a particular point and make map adjustments to suit that vehicle.

Checking the signal voltage on the lambda sensor is most certainly NOT part of any MOT so be careful someone is not having your trousers down. The car has to pass the emission test, subject to year and model. The lambda is used to control fuelling in closed loop which can affect emissions.

banny sti

iTrader: (68)

Does the simtek not run properly, if the lambda sensor is not working?

Banny

hux309

Yeah i realised that after a bit of snooping, it adapts pretty quickly from what i understand.

Ive fitted a new sensor and the car runs smoother on the overun, when putting my foot down it's the same as even but general gentle driving has certainly improved so something must have been amiss.

They can't have me with my trousers down as they're just an mot station, no garage work whatsoever which is the reason why i use them, so i know i won't be done over.

I think he may have done the test as a favour to show me if the lambda was borked or not, he also did me a favour as when i removed the decat i saw a small pinhole by the lambda boss, so that will be sorted and put back on soon as this test is out the way.

She didn't fail by that much just the co level was 7.52% so the again the lambda must have been faulty.

Cheers

harvey

iTrader: (48)

Hux, as long as you are happy you have it sorted that is fine but if you have a small hole in the D/P by the lambda boss, it may be drawing air anyway which will distort readings. You may wish to consider asking your mapper to check it out with the new lambda fitted, when the car is in final state, not for a full remap but just to look at the closed loop running.

Banny. Any ECU that runs closed loop needs an accurate lambda signal in closed loop operation so the ECU can adjust fueling to maintain 14.7:1 AFR. (Stoich) where most efficient combustion takes place. This is the function of the O/E cars narrow band lambda sensor. Obviously, if the lambda is U/S, the ECU does not have an accurate target point to work round. When the ECU is in closed loop lambda and achieving the target, you can see the AFR needle or digital read out (if you have an AFR guage), oscilating around stoich as the ECU adds and removes fuel to stay on target with slightly varying conditions.
For this to happen the fuel map has to be somewhere close to what is required.
Running out of closed loop and the ECU adds fuel per the fuel map regardless of the lambda. This is the case for many ECUs not just the Simtek.

hux309

Well i do plan to get some gt headers so i'll just have her in for a remap then.

The downpipe was fine when i had the simtek fitted so the map in itself is fine just the lambda buggering up the afr id imagine, car runs sweet all the time so the base map must be decent.

Next time i take her out i'll have a whiff of the exhaust fumes, last time it was stinking, it'll probably be much reduced with the new lambda in place.

Test will be next saturay, fingers crossed.