Thread: Tuning problem

Got a issue with tuning a car.

Sr20ve engine and ecu, stock ve maf and 333cc injectors. Has a Japanese daughter board.

Idle mixtures are high 14's to low 15's, full load is low 12's, and mixtures are good under acceleration.

The problem is at light load/cruise (around 3000rpm), it wants to run mid 12's, when i accerlerate it goes into mid 13's and then into the 12's for load like it should.

The narrowband o2 is saying its super rich too.

Ive tried adjusting the TP Scale, Vq map, cleaned the maf (voltage looks ok at all times)

Obviously ive tried taking fuel out of the maps, but that ended up giving the car a massive flat spot around all the points that it used to run rich under light load, and was still rich under light load.

Ive got the K value set at standard 333 value, and the TP scale is the same as stock as its a sr20ve bin file that has been modified.

I have used this tune on many other cars with no problems such as this, and have tried a couple of unrelated bin files and the problem is the same.

Anyone got any ideas?

Is that area of the map flagged for O2 feedback when maptracing and it still wants to run really rich?

Does the narroband value flip around correctly at idle and other areas?

Is the MAF voltage at that point not jumping up a large amount ? cleaned?

Yeah the maf voltage is ok, been data logging it and the numbers are ok.

Only thing i can think of atm, is if i disconnect the narrowband o2 from the ecu (i have a adaptor loom for tuning that i can unplug the wire) the ecu is still showing a o2 sensor voltage, where my car with the sensor unplugged shows 0v. Im wondering if the ecu has a fault and is adding a offset to the narrowband. Ive used the LM2 to output a narrowband reading to the ecu, and it seems to be trying to correct things, but not entirely managing it.

When i unplug my O2 sensor input (narroband simulation from my LC1), the voltage goes to ~0.32v which is the normal value that the ECU assumes during warmup stages and defaults to 'lean' so the ecu richens the mixtures up a little. I see 13 on partial throttle with no O2 sensor connected in cells that are closed loop and normally give 14-15:1

Learned a lesson today, dont tune while sick.

The whole problem was the K value, or it was fixed by changing it.

My sensor wasnt getting a good reading at idle at the tailpipe, and since i was using the stock k value and base map for a sr20ve, i didnt think to even consider that this was the problem. Ended up dropping the K from 270 to 235, this is for stock 333's, and now it cruises at 15.0ish, drops nicely rich to mid 13's with a light squeeze of gas, and mid to low 12's on full load.

Lesson learnt there lol.

isnt stock is 254?

Its 294 on the 'stock' sr20ve bin file i have, i dont know if someone has messed with the value in that bin tho. Is 254 the accepted value when using a sr20ve bin or a b13 style bin in a earlier ecu?

what ive seen is 254, 5g, 4g, and we ecu...