Help, overfuelling

Hello, have had some problems with my Supra long now.

The car has T88 turbo, HKS F-con V, 720 injectors, hks fuelrail, hks 280l fuelpump.

The problem is that it overfuels very much. like the car was set up when i bought it, it suddenly started to cut on 5500rpm.

Checked my AFR and was ok up to the turbo kicked in, but from then, it overfueled alot. up to 9.0 in AFR. Because of the overfuel ,the engine wouldnt take more than 5500rpm. turned the fuelpressure down, and can now drive it to 7000rpm, but have lost much hp in the mid range, and the turbo spools up later.

What can make the engine overfuel so much. dont think it has been mapped like this.

Any tips?

(excuse my english, im norwegian)

do you have the stock o2 sensor still in place?? if so any codes etc, check codes. how long has it done this for?

o2 sensor, that is the lamdasensor placed behind the turbo? i still have the original yes.

Picked up the car in uk in oktober 05. Drove it nice the way home to Norway, but when i started to use my right foot here home, it was like this.

But the car was dynoed in Uk before i bought it, so it was ok then.

But now the AFR goes more and more rich ,the higher rev i have.

may be the o2 sensor, yank it out and test voltage (not sure the what voltage they should read?), if voltage doesn't read as it should it would be that at a guess and you'll need to buy a new one, if it's ok voltage wise then give it a clean and put it back in and see how it feels and reads.

someone like nic on here can surply a new o2 sensor for £65 i think if you need one, this is my thoughts but someone else may have there thoughts on what else it may be.

shall check codes tonight

it should be somewhere behind turbo on downpipe.

what year is yours as some years need a scan tool, as opposed to the old paperclip trick on diagonistic port.

Surely if you're able to get acurate AFRs then you must have a wideband O2 sensor (+gauge), not the standard O2 sensor? or am I being thick?

If it overfuels when on boost but is OK otherwise, it's not the stock sensor. That's strictly narrowband closed-loop.

A 9:1 ratio will cause stuttering and a marked loss of power, to the point of not being able to accelerate. This could be a spurious increase in fuel pressure if it's suddenly started happening. If it's always been like this it'll possibly be the map in some fashion.

-Ian

Surely if you're able to get acurate AFRs then you must have a wideband O2 sensor (+gauge), not the standard O2 sensor? or am I being thick?

testing it with an wideband sensor, conected to a laptop. the sensor was put in the back of my exhaust.

have now taken the diagnostic check, and the code 42 shown. this is "no1 speed sensor signal circuit".

will this be shown if the car stands still?

shall i drive the car when taking the engine check?

cheers

Vebjorn

the 42 still shown when driving.

What does this sensor do, and what is the most common fault on this?