Unstable Idling,New Air Intake

[stix]

Hi guys,

I own a 4B10 1.8 mivec powered car and have recently purchased an arospeed short ram intake.

Upon installing it together with a HKS SPF, the engine idles low at 500rpm and the engine would shake vigorously to the point where it would just die on its own. Power is there in the 1500rpm-4000rpm but when it hits the mivec activation point, the car loses power.kinda like getting a mild rev-cut.

I installed it as such:

1) Remove battery terminal.
2) Remove MAF from the stock piping.
3) Install the Arospeed SRI.
4) Install the MAF sensor.
5) reconnect wires and battery.

Pretty straightforward. I have made sure that the MAF is properly installed and facing the correct direction. The MAF sits flush in its mounting and not loose. The only difference i can find is that the arospeed pipe is a larger diameter than the original piping. The MAF fills the whole diameter of the pipe and on the arospeed, it is hanging the sensing element is not centered in the middle of the pipe.

Help anyone?

 

[R11]

Idle Speed Control Valve (ISCV)

I don't know whether your car equipped with this, located under the throttle body.

Its worth to check to make sure the connection to the ISCV is secure.

 

[teo1957]

My experience is last time when I own a 6A12 twin turbo, after I changed the stock filter to Blitz Sonic Power kit, the engine gave out black smoke (sign of reduced air to fuel ratio) and became not smooth when accelerating.

I changed back to original and problem resolved.

 

[stix]

i replaced it back to the original piping and everything is back to normal immediately.my only suspect is the maf sensor.its either the pipings maf sensor mounting mould is not perfect or its the design flaw. Returned it to the dealer to get a replacement so hopefully its just this particular unit.

 

[miriguy]

aiyahhhh, that dealer sell you faulty stuffs ahh

 

[teo1957]

i replaced it back to the original piping and everything is back to normal immediately.my only suspect is the maf sensor.its either the pipings maf sensor mounting mould is not perfect or its the design flaw. Returned it to the dealer to get a replacement so hopefully its just this particular unit.

Sometimes the humble stock unit is better than it's flashier 'upgrade'...

 

[teo1957]

A Kármán vortex sensor works by setting up a laminar air stream. The air stream is disrupted by a vertical bow in the sensor. This causes a wake in the air stream and subsequently the wake will collapse repeatedly and cause Kármán vortexes. The frequency of the resulting air pressure oscillation is proportional to the air velocity.

Mass flow sensor - Wikipedia, the free encyclopedia

Laminar air stream -> disrupted by vertical bow -> resulting in wake -> cause Karman vortexes.

Change the air stream before the sensor, and you'll disrupt the resulting wake and vortexes. The ram will probably benefit engine with MAP sensors, but owners with MAF/AFM sensor engines need to test for themselves to know which aftermarket modification will increase and not decrease performance.

 

[Dayline668]

FYI.. A MAF sensor need to be retune if u change to bigger diameter box then stock where the sensor is placed. If u did not rescale the only thing can settle is revert to stock or find the same diameter as the stock. Rescale can be done with opensourse tuning. Same hav been done on my subaru.

 

[stix]

Thank you for the info. yes, its now back with the dealer and will be getting a replacement unit. The thing is it has been installed in other similar vehicles with no problems. otherwise i'll just maintain the stock unit with a drop in.

 

[stix]

For those of you who has a 4B10, arospeed air intake ram is a NO-GO. Problems with the design.

 

[Dayline668]

As i say, go reflash n can be done.