N46 MAF Reads 0

R

ryz4

Member
 Cumbria
Morning All,

Does anyone else have a 2.0L N46 that reads 0 g/s on airflow from the MAF?
I'm trying to hunt down bad throttle response issues and lumpy idle issues.

Yesterday I changed the throttle body and MAF but neither made any difference to either issue.
The new (to me) MAF also didn't output any data.

I've realised that below 3k revs, the car takes a long time to rev up and match what I'm asking for. To be honest, it responds like a diesel.

Over 3k, more in the realms of 4.5k it revs nicely and sounds a lot happier.
This makes me think the VVT system isn't actually working properly, but I've got no codes saying things aren't working, and unplugging the e.s.s doesn't improve anything either.

I'm at a loss at the moment. So I'm going down the 0% airflow trail... I should also say that i comfortably got 39mpg on a 60 mile run i did last night though.
 
It doesn't seem to run any differently, It starts as normal with it disconnected.

Plugging it back in whilst running makes no change either. Bare in mind this is a cold start though.
 
Both the replacement MAF and throttle body came from a car that was running perfectly. Though they have been in a box in my garage for a few months. But no reason to suspect either was faulty.
 
Yeah I don't suspect either of them are faulty.

I started it up with the vvt plugged in and unplugged it afterwards, it almost stalled then caught itself and carried on.

I can hear some lift tick coming from the vvt motor though.
 
My Maff as always read zero mate and ive replaced it with 3 doner known working ones. Gave up thinkin bout it in the end.
 
Hi matey,

Yeah thats sort of the conclusion i started to draw however i got a check engine light yesterday P0420, bank 1 efficiency.
So either the 02 sensors are going off, the cats clogged, the maf and 02 sensor are making the engine run rich or lean.
Or a small misfire so not all fuel is getting combusted and its being dumped into the exhaust messing up the rest of the ratios.

I'm going to change the coils from bank 1 to bank 2 tonight and see if i get the code appearing on the second bank 02 sensors.

Looking through RealOem theres 5 lambda sensors to look at which will be almost as pricy and new cats so hopefully i can solve the problems before then.

It could also be an air leak on the intake side causing the same issue so i've got to check what i can.

I'd love to see a 100% healthy N46 engine running and see if the lumpy idle and throttle response issue i thought i had are actually just characteristics of the engine.

As you mentioned the other day i've been giving a good thrashing and its definitely happier at 4k+RPM than it is south of that.
 
[ref]ryz4[/ref], check out your other thread on this. It seems I'm not the only one suspecting either the DME or the wiring to it from the MAF.
 
Have you put E10 fuel in mate, my P420 code stopped abruptly over 6 months ago after changing from Ultimum or super plus unleaded to this, after 10 years, and runs sweet with no more emission codes. :)
 
Alright. Well I'm sat here with a multimeter if you have things I should check.

Do you want me to check the loom connector or the maf itself?
 
I can't find a wiring diagram for the 2.0 in TIS. Does your MAF have a 5 wire connector?
 
Yeah it does.

Measuring its resistance its in the area of 3.6kOhms. Both of the MAFs i have read the same.
I also checked the pins of the connector on the loom-side and i had 12V at one pin, 4.9-5V on 2 pins and 0 V on the pin that i measured resistance over. Nothing seeming out of the ordinary on the ECU side IMO.
 
Ok try this. At the connector (disconnected) with the key on (may have to have the engine running) check:

Pin 2 Red wire with a White tracer for 12 volts (power for the MAF).
Pin 4 Red wire for 5 volts (reference voltage).

If you don't have 12V and 5V your DME is bad.
 
Forgot to ask what year your car is? It makes a difference on the pin outs and wire colors.
 
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