Brand New Z32 Afm Problem

[silman]

Sent my RB25DET 180SX for a dyno run yesterday after having run the new engine in for over 5000km's. it was running the stock RB25DET AFM, but I couldn't install the Z32 plus tomei plug until it got tuned yesterday.

The GT30/40 turbo is installed and the car at 1.2bar is making 190kw but the Z32 is maxed out at 5 volts already. The car drives perfectly fine but the AFM is maxing out for some reason so early. The setup is using a Power FC with AVCR, and apexi air filter. 720cc nismo injectors and Tomei 270 fuel pump

Any suggestions as to what could be wrong? it's the usual orange stickered JECS item (22680 30POO A36000 N62).

[sinistaGTR]

.... pmed you lol

Edited April 19, 2007 by sinistagtst

[StockyMcStock]

RB25 with those mods should be making a lot more power than 190rwkw.

perhaps the dyno just reads very low, and the car is making much more, thus maxing out the AFM? how does it feel on the road using your high tech seat of the pants dyno?

[silman]

Yeah it can make a lot more power, but because the AFM is showing 5 volts it's maxed out and that is the point of this thread - to determine why it's maxed out so early.

The dyno is one of the lowest reading one's in Brisbane, a few people i know have taken the car for a power run at other shops straight after and read 30kw extra at the wheels. The car only feels fast to me because i've done a 5000km run in with no more than 4000rpm the entire time.

How many people have purchased a new Z32 AFM and found it to be faulty straight after install? I've done a search but haven't found any posts on this here.

[Cubes]

Big boost leak?

A mate of mine is hitting 4.7v at 275rwkw, gt35r @ 17psi.

[silman]

AVCR, Defi Gauge, and seperate external gauge all read 1.2 bar - no boost leaks evident.

[Cubes]

Doesn't mean there isn't a boost leak though.

[RRob]

Isn't there some dodgy china copy z32's getting sold now. I had first hand experiance with one and heard of another here in perth.

[silman]

Cubes - Correct me if i'm wrong, but should a boost leak have anything to do with the voltage of the afm? metered air being drawn through before the compressor is it not?

My mechanic also mentioned that this could be one of those copy AFM's, it was bought through a sponsor on this site, and looks identical to the ones pictured in just about every search result i found tonight.

[dontfeelcold]

don't non Z32 afm's max out earlier than 5v? Inlcuding the dodgy ones

Edited April 19, 2007 by dontfeelcold

[Cubes]

Cubes - Correct me if i'm wrong, but should a boost leak have anything to do with the voltage of the afm? metered air being drawn through before the compressor is it not?

My mechanic also mentioned that this could be one of those copy AFM's, it was bought through a sponsor on this site, and looks identical to the ones pictured in just about every search result i found tonight.

Of course it will... If you have a leak in the system the turbo's going to be sucking and compressing a lot more air than if there wasn't a boost leak. So the afm will read higher, not sure if its possible for it to read this much higher though. :S

[silman]

Isn't there some dodgy china copy z32's getting sold now. I had first hand experiance with one and heard of another here in perth.

Where abouts were these Z32's purchased from?

[paulr33]

whats AFM1 value at idle?

when you rev it a few times does it return to the same value?

have you checked for any piping leaks?

are u sure the car is dynoed correctly? not 3rd or auto or something obvious?

what rpm is it maxing at ?

[_8OO5TED_]

i purchased a dodgy "chinese" AFM. i will check the part number on the side of it tomorrow and let you know if it matches.

[Devils_Advocate21]

Dodgy afm i say or incorrect setting in tune used ie: set to use standard default afm, not set to z32 wouldnt this cause an issue aswell?

[Blitz]

Isn't there some dodgy china copy z32's getting sold now. I had first hand experiance with one and heard of another here in perth.

No, there are no "China copy" AFM's on the market - That really is a stupid rumour

As far as I can tell, there was an early batch of Bosch AFM's that had some problems. I bought a pair of them for my GTR and when I discovered that they were misbehaving during tuning I contacted the shop I purchased them from and they confirmed that the issue with their behaviour was a known problem and had been taken up with the company that supplies many dealers in Australia.

Both of them were promptly replaced under warranty without question

[Beer Baron]

it sounds like a dodgey afm to me. I know of a few people lately who have had new Z32 afms crap out. I'd say contact the place you bought it from.

[_8OO5TED_]

the part number on my "Z32 AFM" wasnt even a Nissan part number.

[Blitz]

the part number on my "Z32 AFM" wasnt even a Nissan part number.

Maybe because you purchased a Bosch Z32 AFM?

[paulr33]

Dodgy afm i say or incorrect setting in tune used ie: set to use standard default afm, not set to z32 wouldnt this cause an issue aswell?

selecting the wrong AFM or using the wrong AFM ramps will give screwy results on the load axis map and tuning but wont make it max out.

ie: if the afm is reaching 5v then its measuring as much air as it phyiscally can. what the ecu does with that value is upto the ecu.

the ecu logic for airflow ramp and control is done after the signal is read in