Td5 MAF KG/Hr numbers

[justinc]

As the title suggests, thought I'd list a few useful benchmark figures for referencing your MAF readings.

At hot idle, settled after 2 minutes, should read minimum 48 to 55 Kg/hr. 30 to 40 is not acceptable. Cleaning MAY help, but after cleaning and no change replace MAF. Interestingly, the reason I say rest engine at steady idle for 2 minutes is that I have observed a few engines that after a rev or two will dip below 40 for about 30 seconds or so and then back up to 50 or 60. Some may even reach 65, which is the higher end of the idle readings I have observed.
Mid throttle, (No load, in neutral, 2500 to 3250 - odd rpm) 150 to 250 depending on mapping, the higher figure for advanced performance maps is quite usual.
You can spike the figures to 550+ under no load conditions with a build up to 3000rpm and then a quick rev to 4000rpm . This is a quick indication but ideally driving on the road will show AT LEAST this reading even under moderate throttle if climbing a hill with a healthy MAF output.

The inability to reach 550 to 650 under any conditions is a fail. Clean and try again, if no change replace MAF.

One thing is for sure, BEFORE mapping/ chipping, the MAF needs to be reading correctly or poor results will be evident. Unusual to show a fault code unless completely failed, and I have even seen an Airflow circuit fault come up on a perfectly functioning MAF, so it pays to understand the figures and then you can to a degree ignore what the 'fault codes' are saying.

I'll try to get some more definitive figures on pressures etc also as I can.

JC

[Redback]

I have just been through all this, testing the MAF flow, the readings for mine were 58 at idle and interestingly enough at 3000rpm (no load) 350 to 380, but under load 550 +,as it reaches 3000rpm.

Baz.

[discowhite]

and to add to this, i thought i had a dead OEM MAF so i swapped it out with a cheap one from the UK.
the idle figures for the cheap one are 48 and a max of 620 and the OEM one was 52 and 550.
now the differance between the to was massive...well to me anyway, the fuel consumption didnt change but the auto's shift points did! the cheap one showed slow hanging gear changes, almost like the auto didnt know what to do, but if driven sensibably (not a word i use:twisted:) it acted as it should. where as the OEM one every gear change was perfect and there was no way i could confuse the auto's ecu.

cheers phil

[justinc]

and to add to this, i thought i had a dead OEM MAF so i swapped it out with a cheap one from the UK.
the idle figures for the cheap one are 48 and a max of 620 and the OEM one was 52 and 550.
now the differance between the to was massive...well to me anyway, the fuel consumption didnt change but the auto's shift points did! the cheap one showed slow hanging gear changes, almost like the auto didnt know what to do, but if driven sensibably (not a word i use:twisted:) it acted as it should. where as the OEM one every gear change was perfect and there was no way i could confuse the auto's ecu.

cheers phil

Thanks for adding the auto trans bit Phil, I forgot all about mentioning the havoc a failing/ failed MAF makes on shift quality etc.

I know the aftermarket MAFs are quite cheap, but I use genuine only for the very reasons you just described.

JC

[justinc]

I have just been through all this, testing the MAF flow, the readings for mine were 58 at idle and interestingly enough at 3000rpm (no load) 350 to 380, but under load 550 +,as it reaches 3000rpm.

Baz.

Baz, is yours chipped? If so, I reckon your no load higher figures are at that point when extra fuelling happens in order to bring on more boost earlier.
I don't think it is a problem, as I said most aren't that high in no load conditions at the 2500 rpm mark, but jump hugely just before 3000, and even more so when under load / chipped.

JC

[Redback]

Baz, is yours chipped? If so, I reckon your no load higher figures are at that point when extra fuelling happens in order to bring on more boost earlier.
I don't think it is a problem, as I said most aren't that high in no load conditions at the 2500 rpm mark, but jump hugely just before 3000, and even more so when under load / chipped.

JC

Yes chipped, but having tested the flow on more than one occasion and having a different chip in 2 of those occasions, I can say that there was no difference between the chips in numbers recorded.

Baz.

[justinc]

The flashtune Tombie chips I have done I noticed a much earlier rise in MAF readings from standard,( I always do a before and after check) the word 'aggresive' springs to mind:twisted:

I agree that top end figures are similar, BUT definately seems to build up faster and at lower RPM with chipping, which is basically the reason we do it in the first place:twisted:

Have you got a BD or TRT chip?

JC

[Redback]

The flashtune Tombie chips I have done I noticed a much earlier rise in MAF readings from standard,( I always do a before and after check) the word 'aggresive' springs to mind:twisted:

I agree that top end figures are similar, BUT definately seems to build up faster and at lower RPM with chipping, which is basically the reason we do it in the first place:twisted:

Have you got a BD or TRT chip?

JC

Both, first time was a BD medium chip 2nd time TRT medium, that TRT medium is a far better chip than the BD chip.

Baz.