Z32 Maxed Out!

[Daboss]

Hey forum need expert opinions from you guys. My problem is my z32 is maxing out or so it would seem. I have a rb25det series 2 with gt35r and z32 with 3inch coupler going to a 4 to 3inch reducer to the intake of the turbo.

Now my problem is lately I have been noticing that my check engine light flashes everytime I get into boost, I also have a pfc and when I check readings with the pfc hand controller the only reading i see that looks like it could be a problem is the afm voltage at 4.5-5.1.

I found this strange as I figured 17psi should not be enough to cause a z32 to max out like that so I went over the wiring this weekend and noticed one of the grounds had came loose in the afm wiring. So i joined the two grounds of the z32 and connected them to the ground of the afm wiring and thought problem solved. Did not drive the car from then until just now and when going into boost the same check engne light flashed when going into boost in second gear and max boost was 16.5psi. Looked at the pfc hand controller and the afm voltage was showing 4.5 volts.

I never noticed this problem before and was wondering what it could be, cause as soon as I see the light I stop accelerating, so can not say for sure it is on continuosly when boosting. Does this seem normal to you guys or does afm seemd to be broken. I looked inside at the sensor wires and did not notice anything broken all seems normal. Can 16psi on a gt35r cause a z32 to max out?

Oh and when it happened for the first time and I checked the pfc hc at idle the voltage was jumping around from 0-5.1 . That is what prompted me to check the wiring and noticed one of the grounds were off.

Edited August 16, 2010 by Daboss

[Moodles2]

A Z32 AFM has resolution up to 500PS, which is a max theoretical of 373kw (in the real world is more like 350kw). Whenever you play with the AFM (cleaning, resoldering etc), it's a good idea to reset the ECU (don't know how it's done with PFCs) so it forgets everything it's learnt so far and starts from scratch.

[JonnoHR31]

pfc's dont learn so re setting wont do anything. whats the idle voltage like now that you fixed the wiring?

[Daboss]

A Z32 AFM has resolution up to 500PS, which is a max theoretical of 373kw (in the real world is more like 350kw). Whenever you play with the AFM (cleaning, resoldering etc), it's a good idea to reset the ECU (don't know how it's done with PFCs) so it forgets everything it's learnt so far and starts from scratch.

Reset the pfc? Don't know bout that, resetting the pfc will erase everything it will then require a retune. The pfc has a warn function for the afm and I figure it is just reaching this point, and wanted to know why, if that was possible with the setup I have and if my car is in any danger. Highest knock reading is in the 30's afr is in the high 11's to 12 on full boost.

No real sign of knock and no excessive lean out so could this just be the jump in voltage at the onset of boost casue it happens when boost comes on at around 4-4500rpm and when I see it i remove my foot instantly so can not say if it is consisitent throught the rev range.

On the pfc what is the afm warn volatge? Casue as I did it this morning the max voltage read on the ofc was around 4.4 -4.5v and the light flashed.

[Daboss]

pfc's dont learn so re setting wont do anything. whats the idle voltage like now that you fixed the wiring?

Since fixing the wiring at idle I am seeing around 1.3v but noticed when starting the car to move it out of the driveway this is before fixing the wiring it started with no afm voltage problems.

I then did the rewire after the startup and thats when I noticed the ground wire missing and reconnected it and didnt drive it from then until this morning cause I figured I had solved the problem. Which I didn't cause coming on to boost this morning it happened again.

[hypergear]

Mine Z32 AFM was maxed at 26psi. car made 344rwkws.

[GTScotT]

Can 16psi on a gt35r cause a z32 to max out?

To answer this simply, yes.

The 35R is more flow than the Z32 can read, which 16psi could be just enough with dense enough air. They are a fairly efficient turbo from what I know, dont need 30psi to make max power.

See your tuner about your issues, talk it over. You should be able to tinker with the values to give it a slightly broader spectrum (while making your points a little wider).

Or switch to MAP or Q45

[jarrod83]

i had my rb25 gt35r upto 27psi and wasnt maxing out the z32, i have also had my rb25/30 combo upto around 23psi without maxing it out either, i have heard of the cheaper fake z32 afms to max out at alot less power than the genuine ones.

[R31Nismoid]

Just a side point, the AFM is as far away from turbo intake as possible?

Funny stuff happens when its too close.

But ye, GT35, you'd be on/around the limits of the ole Z32.

And its nothing to do with boost pressure, its airflow.

[Daboss]

To answer this simply, yes.

The 35R is more flow than the Z32 can read, which 16psi could be just enough with dense enough air. They are a fairly efficient turbo from what I know, dont need 30psi to make max power.

See your tuner about your issues, talk it over. You should be able to tinker with the values to give it a slightly broader spectrum (while making your points a little wider).

Or switch to MAP or Q45

Yea wish I could but have no competent tuners here, had a q45 but sold it cause of the size and heard the z32 could support more. Plus it was ok before just happened this weekend was boosting fine with it before, noticed problem checked founfd a loose ground connection, reconnected it and still the same problem. Is there a way to switch to map sensor with pfc?.

i had my rb25 gt35r upto 27psi and wasnt maxing out the z32, i have also had my rb25/30 combo upto around 23psi without maxing it out either, i have heard of the cheaper fake z32 afms to max out at alot less power than the genuine ones.

How do you tell if it is fake?

Just a side point, the AFM is as far away from turbo intake as possible?

Funny stuff happens when its too close.

The airflow meter is in the corner were the stock intake box use to be and the turbo is in stock position.

[Daboss]

Mine Z32 AFM was maxed at 26psi. car made 344rwkws.

What size turbo is this?

[KiwiRS4T]

Yea wish I could but have no competent tuners here, had a q45 but sold it cause of the size and heard the z32 could support more. Plus it was ok before just happened this weekend was boosting fine with it before, noticed problem checked founfd a loose ground connection, reconnected it and still the same problem. Is there a way to switch to map sensor with pfc?.

How do you tell if it is fake?

Read this thread on how to tell a fake: http://www.skylinesaustralia.com/forums/Wr...ow-t332812.html

[nicr4wks]

Yea wish I could but have no competent tuners here

Don't PFC's also flash the engine light for knock?

when going into boost the same check engne light flashed when going into boost in second gear and max boost was 16.5psi. Looked at the pfc hand controller and the afm voltage was showing 4.5 volts.

So the light comes on as you start making boost, and continues to stay on until max boost? What are the boost and afm voltage readings when the light FIRST comes on.

[Adriano]

I doubt you are maxing the AFM out with a gt35r although it can max one out, if you are only running 17psi you would have to be revving th esnot out of it before there was enough airflow to max it out. 4.5v is a fair way for 5.1v, as the airflow-voltage curve is exponensional eg the extra .6v is probably 80rwkw. Can you peak hold the value. Could it be the injectors maxing out, that will trigger an engine light, or knock as you already know.

[GTScotT]

Very true re peak hold.

The PFC handjob should be able to press the right key to highlight max values.

Can the OP confirm the AFM is hitting max voltage?

[Nackerz]

the q45 can make more power then the z32 afm.

q45- has been known to goto 450rwkw

z32- should be good for around 350rwkw

have a look for yourself

http://www.paulr33.com/diagrams/airflow-meter-wiring.html

[paulr33]

hello

the Q45 specs are wrong and grossly miscalculated, even apexi caps them at 230rwkw from their powerfc documentation even though we all assume they are bigger and better (they arent). single z32 is good for around 360rwkw as per apexi specs and the powerfc will throw the engine light when you max it at 5.0v, not at 4.5v or anything less than 5v

as adriano said it wont be linear so unless you peak 5.1v on the AFM don't worry about maxing it out. and if you max it at 6500rpm its not a big deal, it just means you run out of load cells and stick on the same axis (map sensor style on full boost) so no loss

if you max a single Z32 your optoins are twin Z32 or map sensor dont bother with Q45 AFM, it is pointless and a waste of time and money

[Nackerz]

I have a q45 sitting there doing nothing that i got for next to nothing so dont bother me man!

[Daboss]

I doubt you are maxing the AFM out with a gt35r although it can max one out, if you are only running 17psi you would have to be revving th esnot out of it before there was enough airflow to max it out. 4.5v is a fair way for 5.1v, as the airflow-voltage curve is exponensional eg the extra .6v is probably 80rwkw. Can you peak hold the value. Could it be the injectors maxing out, that will trigger an engine light, or knock as you already know.

Nah it was the airflow meteras I did a peak hold and saw 5.1 plus when doing a sensor check the airflow value was going black and jumping around at idle from 0-5 volts.

Very true re peak hold.

The PFC handjob should be able to press the right key to highlight max values.

Can the OP confirm the AFM is hitting max voltage?

Yea I confirmed this with the handheld. With the peak hold and the sensor check.

the q45 can make more power then the z32 afm.

q45- has been known to goto 450rwkw

z32- should be good for around 350rwkw

have a look for yourself

http://www.paulr33.com/diagrams/airflow-meter-wiring.html

Ok will read thanks. I just read on this forum somewhere that the q45 would make less.

So far seems as if the problem has been solved a switched to a spare z32 I had and so far nomore warning light. Will monitor for the next few days and keep posted.

[JonnoHR31]

q45 has a much norrower range than the z32, as in 1v from both afm's will see the q45 flowing a lot more air, likewise 2v and probably 3v. but get closer to 4v and 5v and the z32 is flowing more air at the same voltage. z32 afm's support more peak power than q45s, just look at the standard pfc airflow maps for both and it becomes quiet obvious.