Possible Faulty Afm + Nismo Afm

[mick86]

Hi all,

I've spent a lot of time searching through the forums to find a solution to a problem i have with my R32 GTR. I have a few questions i'm hoping you could answer, which i couldn't easily find whilst searching.

Basically _i think_ my car is suffering from faulty AFM's. I have read that its quite common that the AFM's have dry solder cracks occuring from the old age. I disconnected them this morning and rev'd the car and it went in to the safe mode, which sounds/feels very similar to what happens quite often when i'm driving.

I want to try and fix the issue by following this tutorial: Fixing your RB26 Afm's

If this doesn't work, i was looking in to buying Nismo air flow meters (http://www.nengun.com/nismo/air-flow-meter). I want these purely because they appear to be a straight plug n play. My car has been in the work shop numerous times in the last year and its a real hassle getting it out there.

If i were to buy the nismo air flow meter and plug them in, would i require a re-tune? If the answer is yes then i would most likely get some Z32's as they are cheaper, and it would end up in the work shop anyway If it does require a re-tune, could someone tell me the reason why, and also what would happen if i didn't have a re-tune. I have a Mines ECU in case you need to know.

Thanks in advance for any help you can offer!

Mike

[Moodles2]

Short answer yes, retune needed.. but if you have Nistune you could just change the AFM in the Nistune software and it will do all the voltage corrections.

AFM lesson, volt range 0v = no airflow, 1v = approx idling, 5v = maximum airflow the MAF can handle. The stock RB26 AFMs handle 440hp (absolute max) as a pair. While the Nismo AFMs handle 775 hp (again absolute max) as a pair.

For the sake of argument, your stock AFMs are maxed out at 5v, which means your making up to 440hp, the ECU/current tune is mixing in the required fuel to make that power. If you put the Nismo AFMs in, and don't touch the tune, the engine will try to make that same power (440hp), but will only be reporting about 3-4v to the ECU, which the ECU is then mixing in the fuel to make about 200-300hp.. which means the engine will run super lean and destroy itself.

My advice, get rid of that Mine's chip, Nistune it, and get a full proper tune.

Z32's are cheaper, but they are a 80mm shell vs the stock/Nismo afm which is a 65mm shell. If you have pods, you will have to sell your current pods+elbows and buy 80mm compatible pods+elbows.. if you have the stock airbox, you'll have to get rid of it and go 80mm compatible pods+elbows.

[mick86]

My advice, get rid of that Mine's chip, Nistune it, and get a full proper tune.

Z32's are cheaper, but they are a 80mm shell vs the stock/Nismo afm which is a 65mm shell. If you have pods, you will have to sell your current pods+elbows and buy 80mm compatible pods+elbows.. if you have the stock airbox, you'll have to get rid of it and go 80mm compatible pods+elbows.

Hey there,

Thanks for the info, appreciate it

Is it possible to pick up new genuine oem air flow meters? I want to avoid going to the workshop again because it will mean new piping + Nistune chip + retune. If it comes to that, then obviously i will. I was having a quick look for genuine oem afm's and i couldn't find much that wasn't referring to the Z32 or the Nismo afm's. I found this: http://www.rhdjapan.com/nissan-oem-maf-mas...r-58012?nflag=1 which seems to be genuine oem. Do you forsee anything wrong with these parts? It is quite a bit more expensive than the Z32's, but in the end it will even out if i can just install the oem ones myself at home.

Cheers

[Moodles2]

Just remember that the stock RB26 AFMs only have resolution up to 328kw (and then again, in the real world about 290-310kw max), those genuine OEM ones will do as you want (at a expensive price), plug straight in and nothing will need to be done tune-wise, except for maybe a ECU reset.

If you ever want to go above that power level you will need Nismo AFMs or 80mm AFMs (Z32, RB25 etc) anyway. If you are willing to upgrade to 80mm piping, try a pair of 2nd hand RB25 AFMs, as a pair they support 400kw.

[mick86]

Just remember that the stock RB26 AFMs only have resolution up to 328kw (and then again, in the real world about 290-310kw max), those genuine OEM ones will do as you want (at a expensive price), plug straight in and nothing will need to be done tune-wise, except for maybe a ECU reset.

If you ever want to go above that power level you will need Nismo AFMs or 80mm AFMs (Z32, RB25 etc) anyway. If you are willing to upgrade to 80mm piping, try a pair of 2nd hand RB25 AFMs, as a pair they support 400kw.

Alrighty then, well i have a bit to think about then i guess. I've bought some CRC cleaner and will see if that clears up my problems. If not, i'll be going down the path of a new afm i guess. Thanks for the info! You've been a lot of help

[mick86]

Hi again, i've resoldered the joints in the AFM's and also given the sensors a good clean with a can of CRC contact cleaner. I've put the AFM's back in the car, however it seems to be running really rich. The engine gauge shows its warm (after about 15 mins idle), but when giving just a few revs to it, its spitting out a fair few dropplets of unburnt fuel.

I haven't really given this kind of thing much notice before, so i'm not sure if this is quite normal? Should i be worried? I haven't taken it out for a test drive yet, as i need to put the air filters back on. I also let it idle for 15 mins because the battery was flat and i had to jump start it. Any advice is welcome, thanks in advance

[Moodles2]

Did you reset the ECU? You need to disconnect the battery, and keep pumping the brake pedal to discharge what power is left in the system.

[mick86]

Did you reset the ECU? You need to disconnect the battery, and keep pumping the brake pedal to discharge what power is left in the system.

Hey there, no i haven't reset the ECU. I have a Mines ECU in there, will resetting it give the same results as a stock ECU? Btw, i checked my car yesterday and the battery is totally flat, had to unlock it with my key and everything. Not even the alarm went off when i did that. Would it be safe to say the there's no power in the system? I'll jump start it later today hopefully. Thanks

[Moodles2]

Mine's ECU is just a standard ECU with a piggyback inside. Functions just like a stock ECU, will self learn all the idle and timing settings again.

[mick86]

Mine's ECU is just a standard ECU with a piggyback inside. Functions just like a stock ECU, will self learn all the idle and timing settings again.

Hey again, so after another week of letting it sit in the garage, i put the air flow meters back in the car today, and jumped started the battery. Took it out for a spin, and i immediately noticed that it sounded different - it sounds like a wrx now. What could cause this to happen all of a sudden? It was fine 2 weeks ago (last time i started it), and now after starting it back up, it has the different sound. After letting it warm up a bit, there is very little power when i hit boost.

So far i have: cleaned the AFM's with a CRC contact cleaner, tried to resolder the joints within the AFM's. The battery was absolutely dead flat, so im assuming that the ECU would of reset. I also noticed its spitting out less unburnt fuel since last time.

Futher more, will driving the car in its current state cause damage to the engine? I'm planing to drop it in to unigroup at some point soon, but its quite a decent drive there, so i don't want to drive it there if its going to cause damage. What do you think? Thanks

Edit: Just had a look at the ECU diagnostic and it gave me a code 55 - no malfunction

Edited August 29, 2010 by mick86