No airflow meter...

[Anonymous]

Hey, firstly i want to thank fast-guy & J-GTI-r for replying to my last post.. BIG-UP! My last post was last week and concerned my car peaking at 4800rpm. I have an sr20det with an aftermarket management and FMIC. When i bought the motor it came without an airflow meter. So, the boost pipe from the intercooler runs straight into the intake manifold. i thought that the management would compensate. Could this be why the motor peaks at 4800rpm and is burning very rich? What is the cost of an airflow meter, and what alternatives do i have if i can't get one... I'm in South Africa and SR20DET parts are scarce and expensive. Thanks.

 

[AJ4]

You must have an airflow meter ( AFM ) connected so that the engine knows how much air is going into the cylinders. The fuel must be mixed with air in the correct proportions or it wont burn properly. The AFM tells the ECU how much air is going in, and the ECU then works out how much fuel to put in to run correctly.

There are other ways of measuring the air going into the engine, but an AFM is the simplest and cheapest way.

A popular choice of AFM is one from a Z32 Nissan 300ZX engine, which is a bit bigger and less restrictive than the standard SR20 one. You should be able to find an SR20 one online somewhere though, lots of places that sell them will ship anywhere in the world so finding one shouldn't be a problem.

If I was you I would find an instruction manual for your ECU and see what type of air measuring system it uses, as there are a few different types. The standard SR20 one is definately an AFM system.

 

[sypher]

do you have an piggy back unit on your car or a complete engine management replacement such as a haltech or motec system as far as i know the later mentioned use '' Manafold Pressure Sensor '' this a sensor simillar to a potentiometer but is a weat stone bridge and the voltage signal (back to ecu) is proportional to air pressure in the manafold

if you are still using the stock Nissan ecu like me (kind of) the air flow meter should be right after the air filter on the left hand chassis leg, have a look at your ecu on the tunnel inside, behind the radio

either way as said above the ecu needs to know the quantity/density of air in the intake to calculate the amount of fuel required to be injected by the control unit

 

[Fast Guy]

If you have the full nissan engine wiring harness on the engine still, the connection for the maf is probably still there, in which case you need to get hold of a maf and bolt it in place. (Like Sypher says, after the filter and before the turbo.)

The air filter is bolted on to the maf in this picture

 

[geetee]

So, the boost pipe from the intercooler runs straight into the intake manifold.

Errm... that's how it usually is :?

The MAF or AFM (whatever) is usually placed just after the air filter... i.e. between the filter and the turbo intake.

Cheers
GeeTee 8)