Alot of customer are asking us how to check their own MAF sesnor with their Nanocom. So we decided to do a write up about it. We shall assume you know how to save logs and export to your computer.
Let us explain how we test to make sure it’s functioning, these values are the one displayed by the ECU.
First test is at idle – viewing on live data we expect to see a reading ranging from 55 – 61. If its “4.00 or 0” then the MAF is faulty and needs replacing, this also means that ECU is running on a default value and will not be working to its full potential to protect the engine from expiring.
Second Test is at approx 2000 rpm – with the car stationary and in “P” for autos or “N” manuals we hold the revs at 2000rpm and wait for the MAF reading to stabilise on the nanocom if all is well you would normally expect to see values ranging between 185 -200. Anything less would suggest the scaling factor of the MAF is faulty and needs to be replaced.
So onto some logs, in the first picture this is off a “functioning” MAF sensor which its origin is unknown we suspect it’s none Genuine/OEM part. You can cleary see that we applied the test above and it has failed we the figures below.
IDLE – average 80.00
2000 Rpm – Average 251.00
So yes this MAF works BUT its reading to high. The problem with this is that its sending higher values to the ECU so the ECU will think more air is being used by the engine trying to add the correct fuel to achieve the desired AFR (Air Fuel Ratio) making for smoke or in this case MAF cut at 3k Rpm (Note 1)
We decided to try a Britpart MAF sensor to see how it fairs. Again we performed the exact same test as above on the exact same car back to back. Here is the results and these are average values.
The readings from this sensor are acceptable, you can also see that there is no longer any MAF cut symptoms.
Let’s hope it lasts.
Scatter Plot for Damaged MAF
