MoTeC Global Forum

i am having issues with the fueling and idle, have been for ages but finally made it to the dyno.

the injector data starts at 0.1 and i think this is a mistake and it should be 1.0

Does any know if this is actually the wrong calibration

Hi Steve,

I'll look into this for you.

Hi Steven,

I've looked at the raw data from the calibration and this low number is correct.

No other injector has this low value and the car doesn't run right at all at low rpm and load - flooding so it looks wrong to me - i am seeing .6 to.8 lamdda regardless of VE table values.

cant run it for longer than 2 mins like this as the plugs are no good after that....

Hi Steven,

I've gone over the data again and all of the checks that are done on the data have been passed, and I redid the calibration as well with the same numbers being generated from the data.

I would need to have another injector supplied to be able to retest the injector.

Hi SteveC,

Hypothetically lets say the value at this point is incorrect, and the time to inject 0.1 microlitres is wrong in the calibration. I would say that your injection quantity at idle would be somewhere in the region of 15 microlitres, and go up from there, so you wont even be operating in this point of the linearisation table.

Looking up this area of the table, it is saying you will have around a 1.3-1.6ms pulse width (at 3 bar differential pressure, depending if the batt voltage is 12-14V) for roughly what I would expect to be an idle fuel volume. That kind of pulse width when dead time is taken into consideration is completely reasonable.

Do you have a secondary stage of injectors? if you are trying to blend a second set of injectors in at too low a fuel demand this could cause overfuelling. Do you have engine displacement correct, fuel type correct and are all your sensors reading a reasonable value?

If you compare logging from when your previous injectors were fitted, to now, check the fuel volume. If the fuel volume is different, then something has changed to cause a change in requested fuel volume. Perhaps a trim has been changed, a sensor is not reading correctly, or if a large jump in firmware versions took place, make sure all the migration notes were followed. If the fuel volume at idle is the same, but the mixtures are completely wrong, there are several possibilities. I would start by carrying out an injector output test to ensure no injectors are stuck open. I would check with a mechanical gauge that your fuel pressure is accurate. If everything checks out, I would confirm the right injectors were supplied to you.

If your 100% adamant that the calibration is wrong, you can send the injectors to us VIA A DEALER to have them retested against our calibration.

Regardless, the Xpurt 1550 injectors are supposedly an unmodified Bosch injector, which would make them a 0 280 128 333 injector. You could try this calibration from the drop down list and see if behaviour changes.