Not the issue I'm having, its fine until the secondaries are supposed to come on then it goes lean. Additionally, I've already rewired the fuel pump and relocated the relay to the rear. Pump voltage has been verified along w/fuel pressure.

I'd like to get ahold of a wiring diagram for that as well, the cosmo and 20b afm have a slightly larger opening and the same size exit when compared to the s5 afm (which already flows better than the s4 flapper style) so....

...with all due respect I for one am interested in a better solution than the crap-tastic flapper door afm which in addition to not reading accurately at higher flow levels, are positron sensitive, and highly prone to failure.

The issue is not CAN, or SHOULD it be done (because it has, and successfully) the only question is how...?

 

FSM has the pinout

 

Got a N318 AFM! The flap spring tension feels higher than the N326. Going to fix my catch-can/evap/crank case vent routing to after the AFM and make sure nothing is getting sucked into the intake.

Just curious, does anyone have any information on Rebuilding Air Flow Meters? Would Denso be able to 'service one'?

Higher AFM Flow Readings here I come! I want to see +715!!! And More Boost!

 

I doubt there are many places rebuilding airflow meters. The flapper/vane type was an 80s thing, mostly Denso and Bosch versions. In the scheme of things there are very few cars still on the road which used that design. I'd be surprised if any parts from the actual OEMs are still around.

 

^Pretty much what I figured although I noticed rebuilt ones for sale for outrageous prices on the web...

FWIW: I emailed/contacted Denso, asking for any information on it & about servicing it. Who better to contact than the Manufacturer? Hope they supply me with some additional info on it!

 

I find that interesting and logical. Drop in a higher tension spring and increase the flow rate ceiling? I think so. Doing so and putting the meter (fully enclosed) in series between the turbo & TB also makes sense to me to not only improve responsiveness but also produce high end power more efficiently. A teamfc3s.org member's time slip showed 12.6 @ 116 mph @ 1 atm boost with this setup, stock ECU/AFM/ports, FCD, a T-61 (if I recall) and a Greddy AFC. I like the idea of having boosted air against the flapper vice sucking air @ atmosphere. Isn't that what the 2.1 allow to do anyways? Give you the ability to set the pulse width @ a given input signal? Now, do I plan on do in it? Only if I get bored w/my current 1.8 and a Haltech becomes out of the question.

 

Blowing through the AFM, while people have done it, has been discussed and is not recommended.

 

Neither Denso, or Mazda will give any info on the N318 AFM. Denso had me contact DensoUSA and they said that it was a Japanese Part Supplied to Mazda and to contact Mazda. Mazda says that it is still an available part from Mazda, they do not have any diagrams for it and recommended not to rebuild it.

VAF sensor info
http://www.aa1car.com/library/vaf_sensors.htm

Here are the testing procedures


It has a variable resistor for temp, contact closes when flap opens & has variable resistance based on flap position. Will have it back together tonight and drive it to work tomorrow, and take some logs...

 

Something is still effed up... super lean & missing.. will check it out more tomorrow.

 

So the old one is good. I was doing it wrong. The meter would read OL because the resistance was greater that 1K ohm when on the ohm setting and not the Kohm setting. (reads 2.173 Kohm) E2 to THA

I still needed the AFM because I was using the NA one, but now I gotta find the problem.

Symptoms: extreme lean 14-15 AFR's, missing at idle & revs (too scared to boost it now). Like not getting fuel, but fuel pressure is good. Going to pull the Fuel Filter and see if it's clogged. I am using S4 NA 680cc injectors, not sure how old they are. The last time I drove it, it Boosted fine, but lean when cruising and idle.

Yay, it's nice out and I get to troubleshoot! Bleh.

 

sure your grounds are good?

 

if your fuel pressure is solid I doubt the filter is restricting. all my issues were due to having left the ECU ground loose.

 

Any specific grounds I should check?

It just came on all of a sudden and had been running great prior. I did premix it a little rich once. Could it be the stock o2 sensor? I get no errors on the palm. I didnt see or hear any vacuum leaks. Grounds look fine from what I could see. Tweaking the fuel correction seems to have little to no effect. Any and all suggestions are appreciated.

 

is there full volts going towards the fuel pump?

 

^ I believe there is, when cranking it builds 40psi of pressure pretty quick and I've wired it from the stock main relay directly to the pump. (I don't have a fuel pump check plug, or I can't find it, LoL)

I just don't see/notice/smell/hear anything out of the ordinary besides the Lean AFR's and Miss fires. It's been running great before this. I'm left scratching my head... For this to happen out of the blue, and no changes or modifications, leaves me to believe a sensor or someshit went bad. It seems to get worse as it warms up.

I've been pretty busy lately and haven't been able to really dig into it, but not sure where to start.

I did put solid trans. mounts on, and it's kinda vibraty, maybe something came loose? I will pull the carpet and check the ECU grounds.

 

try recalibrating the wideband maybe

 

Check your coils, especially the leading. Mine did this after running perfect beginning of last winter. I took a drive and everything was fine. Next morning, the car wouldn't start. It kept after firing and kicking back. When it finally started, it was 17-18 AFR and I had to keep the throttle on just to stay running. Sounded and ran (obviously) terrible. It went from perfect to not running over night. My leading coil actually died. Very rare thing...

 

I still use the Stock O2 sensor for the ECU. The PLX wideband doesn't need to be calibrated from what I understand... when it reads ~12.5 AFR it idles pretty well for a few seconds but then goes to **** @ 14-15 AFRs and revs like ****... Maybe I'll make a little vid.

 

Does playing with the variable resistor setting help at all at idle? Does the AFR change correspond to the idle speed dropping below ~1000 RPM?

 

Yes, but it's at 0, and when I tried to turn it up, it got worse(leaner) and won't Idle...

 

That's weird. Higher voltage should be richer. I just retuned my car for 720/880cc injectors on the 720/720 setting, and I had to move the VR to about 4.0 volts to get it to idle at 12.5-13.0 AFR. With 550cc primaries I had it at about 2.2 volts, but that same voltage with 720s made it try to idle at 14-15AFR. To make matters worse, the VR setting stopped doing anything at all & I had to reinstall the pocketlogger software on my Palm. I think I had some file corruption from the Palm battery dying. Maybe try a reinstall to see if there's any effect?

www.digitaltuning.com/software/rtek.zip

 

Hrmmm. I might have to mess with that again. And I might reload my last saved map. Thanks

 

Ok, here is a video, it runs ok when I first fire it up for a little, then goes to crap after it warms up a little. It seems to have ok AFR's when I rev it sometimes, other times it's sluggish and lean.

The whole story. I was DD'ing it for a while, and I had noticed that it started having a little miss here and there at Idle. Then it started getting worse, I thought it could be the plugs, so I checked them out and they seemed to be fine. I cleaned them up with a wire brush and it didn't change anything.

Continued driving it and it just kept getting worse, lean AFR's at cruise and at Idle causing hesitation and miss fires.

The one thing I can think of that could have adverse effects was that I premixed it a little heavy once about 12 oz to about 9-10 gallons. But I did go back and put in a few gallons after I had drove it a little bit.

I took it out to a meet and I went out and tore up some backroads and it boosted great, but then it got real bad, serious lean/hesitation/missing and I was/am scared to boost it now.

Anywho, going to replace the plugs tomorrow.

 

Try changing the fuel filter at the same time as your spark plugs, mine was doing something similar and now runs brand new after a little tune up. I do believe premixing clogs up the fuel filters pretty quick.

 

The ground wire to rule out is the main ECU ground. They are two black wires bolted down together to the block located below the TB inlet area. They have to be clean and on tight.

PS - Nice vacuum @1100! Engine ported?