jccalzada

Hi everybody! So I have my SC 350Z but i've been having some issues with my maf sensor. Im running 2.87 pulley, and normally I have to change Maf about every 8 months or so, it just stops working....
I have been doing some research for a while now, and I found the PMAS HPX... is this a good solution? I see you have to do some tuning, anybody nows what kind of tuning you have to do?
The car has a AEM FIC computer also...is the tuning made through the FIC? Its been a bit hard to find information about this MAF....

Any help would be appreciated, im getting a bit frustrated with this maf issue

jccalzada

Also, very important, some of my mods:
- Vortech v2 SC 2.87"
- RC 550 injectors
- MD lower plenum and upper plenum spacer
- AEM FIC computer
- Injen catback
- kinetix racing high flow cats

...i think those are the most important....
help please...

djamps

iTrader: (1)

MAF just don't stop working..HPX PMAS is just a modified stock MAF so it isn't going to fail any more or less. Is it getting fouled up with oil or something?

jpc350

Check the blower outlet for any signs of oil..

ace32x

iTrader: (10)

that and uprev now makes a maf aswell thats suppose to be superior to the hpx

jccalzada

no oil anywhere....everything looks really clean, no dirt, etc.. you can see it on the picture, thats the MAF i took yesterday night, thats exactly how i found it.... however, let me explain a bit more... the car is running perfect, AFR looks great under boost and without boost....
however, when i said "it stops working" what i mean is...the first thing i notice is the afr level going way to rich (my AEM AFR gauge is in 10.0 that the richest it displays)...the car feels like stumbling, its almost impossible to drive it...and of course a check engine light....when we scan the car the error was in the maf...so yesterday night i replaced again the maf with a new one and now the car is perfect again...this is what happens every 8 months or so...
when i had the 3.33 pulley or the 3.12 pulley, this was not an issue...however when i changed to the 2.87" + 550cc injectors, this became an issue...

Anybody with this same problem?

Eno

iTrader: (1)

Sounds like the car is kicking into safe mode... I had that issue until I upgraded to the Uprev GT MAF.

It will do that when the stock MAF is tapped out- can be anywhere between 350-400hp (crank I'm told) and 5-6psi. Sounds very likely that this could be your intermittent problem. Especially as you went to the smaller pulley and presumably more boost?

Just wondering- does it happen when you hammer on it?

You can shut the car off for a few moments and turn it back on- it should be fine and driveable... until you hammer on it again. Even then sometimes you tip the scales... other times you don't. With my issue I tried bombing on it a few times and it was fine and other times not so much.

tonyzS/C03

iTrader: (3)

I would think maybe a grounding issue? voltage spike maybe? that or what ITNKICN said, possibly knocking the computer into some sort of limp mode almost...

Eno

iTrader: (1)

I learned a lot about this when I was going through my issues before too... basically the MAF measures airflow through voltage resistance. A certain amount of air generates a predictable and measurable amount of resistance and as was mentioned earlier that resistance maxes out at 5v. So let's say that a charged system flowing the air required to produce 6psi creates 5v of resistance- that is all the MAF can read. At 5.1v the system essentially fails because the ECU won't know how much air is coming in... and from there it looses track of how much fuel to send etc etc. It bucks into "safe" mode... once you restart the car it'd be okay.

Again, this is what I understood in very basic format... but I think that captures the general picture.

OldManZ350

iTrader: (23)

I have used the Stock MAF for over 40,000 Miles with no problems, my car is making 17+ PSI. Also the Stock MAF will read past 5.0v's, how much I don't know.......

djamps

iTrader: (1)

The stock MAF does not output more than 5V, nor does the ECU know how to read more than 5V. In fact, the ECU will go limp past 4.8V or so.

OldManZ350

iTrader: (23)

I've logged to 5.16v, and it is at 4.8v @ 66038rpm and above. ECU has not gone into limp mode after 100+ runs to 7100rpm.... Can you explain?

RMichael

there is some cross posting because the stock MAF apparently sends the car into limp mode at after around 5.0 and there are MAFs that can go to around 9?

there apparently isn't any evidence here though.

jccalzada

Thats exactly whats happening....it actually starts when you go full throttle, then it 'stumbles'...if you go on and on, eventually, it goes into safe mode, AFR goes absolutely rich (you can actually smell the gas out of the exhaust)...ignition off then on, and everything back to normal....days go by and eventually it just goes off again (it doesn't matter if you are @ WOT or not)....so again, i have to change MAF sensor...we are running aprox 10 psi of boost...output around 400whp... so i imagine the amount of air that is actually going through the intake is a bit more than the stock maf can support....
anyways, i already bought the PMAS HPX maf sensor, however, i don't really understand how am i supposed to "program it" ? any ideas? it comes with a CD which gives you a simple excel sheet with some voltage parameters...am i supposed to do something like this?

http://www.youtube.com/watch?v=9MwDfmGWJzw

has anybody bought this HPX MAF?

jccalzada

THIS IS THE TABLE ....

Indx X-value Y-value CALC 3
VOLTS FLOW KG/HR
1 0.88 4.9445458 6.502077727 6.502077727
2 0.89615686 5.4383812 7.151471278 7.151471278
3 0.91231373 5.9457754 7.818694651 7.818694651
4 0.92847059 6.4675395 8.5048144425 8.5048144425
5 0.94462745 7.004484 9.21089646 9.21089646
6 0.96078431 7.5574195 9.9380066425 9.9380066425
7 0.97694118 8.1271559 10.6872100085 10.6872100085
8 0.99309804 8.7145033 11.4595718395 11.4595718395
9 1.0092549 9.3202713 12.2561567595 12.2561567595
10 1.0254118 9.9452695 13.0780293925 13.0780293925
11 1.0415686 10.590307 13.926253705 13.926253705
12 1.0577255 11.256193 14.801893795 14.801893795
13 1.0738824 11.943737 15.706014155 15.706014155
14 1.0900392 12.653748 16.63967862 16.63967862
15 1.1061961 13.387034 17.60394971 17.60394971
16 1.1223529 14.144405 18.599892575 18.599892575
17 1.1385098 14.92667 19.62857105 19.62857105
18 1.1546667 15.734636 20.69104634 20.69104634
19 1.1708235 16.569114 21.78838491 21.78838491
20 1.1869804 17.430911 22.921647965 22.921647965
21 1.2031373 18.320838 24.09190197 24.09190197
22 1.2192941 19.239703 25.300209445 25.300209445
23 1.235451 20.188316 26.54763554 26.54763554
24 1.2516078 21.167485 27.835242775 27.835242775

.....AND SO ON

jccalzada

SORRY, LAST POST JUST DOESNT LOOKS RIGHT....



[img=http://img281.imagevenue.com/loc554/th_659748677_Screenshot_122_554lo.jpg]

lanceccs

I am troubleshooting mine, suspect MAF as well.

https://my350z.com/forum/forced-indu...me-events.html

Flo-ridaZ33

iTrader: (60)

I read 5.08v and my car hasn't gone into limp mode.

jccalzada

well, i already bought my PMAS HPX....however, someone just told me that this maf wont be useful for me, since i work with the AEM FIC piggyback and the only thing i can do with the FIC is clamp the MAF signal....

anybody with any experience with the pmas on AEM FIC?

Vince@R/TTuning

iTrader: (7)

^^^ the PMAS MAF on the FIC is going to be a waste. You will have a really hard time getting it to work in the percentage tables on the FIC(if its even possible). You best bet is to keep the stock MAF, clamp the voltage and modify your fuel tables off the pressure sensor. It should work pretty decent as it uses the same theory the the split second box and UTEC's use.