missing while loading up on the dyno at 1800rpm

[The Alchemist]

Hi, Mike here again with another wee problem I discovered while tuning this Holden SS. When commencing a dynorun you would usually load the car up at low revs then release the dyno and do a run. This particular car had a miss once you reached about 80kpa at 1800rpm. IT felt like a ignition cut it was so abrupt yet at 2000rpm it was fine and could be loaded right up to 100kpa. During and right up to the "miss" the mixtures where fine with no lean misfire as can sometimes happen thats why I feel it was a limiter of some sort...

Does anyone know what this could be....once again I have been right thru the calibration file for this car and can find no limiter or similar that could be causing this.....

Cheers Mike

[dfe1]

In spite of what the manufacturers say, a lot of aftermarket MAFs aren't calibrated properly. As a result, the PCM isn't getting accurate information about actual air flow through the sensor. It's a good bet that if you installaed an original equipment sensor, most, if not all of your problems would be solved. I know a lot of people who chased problems they couldn't solve until they reinstalled the original MAF. Then everything worked as it should. A quick MAF swap might be worth a try just to see what changes occur with AFR and the miss problem.