camry air flow meter?

[AJ'S 88NA]

Yep, the other part of the AFM (the part that measures air flow) is an entirely different story. If that's bad it'll cause lots of grief. Try another one. Be aware you may have to adjust the idle mixture screw if it's from another model car.

We have a idle mixture screw???

 

[jetjock]

You do. When closed the vane in your AFM presents a physical restriction to flow. This restriction forces air to pass through the unmetered chamber where the screw is. Because of this arrangement adjusting the screw will shift the vane's idle position, which means the screw can be used to indirectly adjust idle mixture and, in fact, that's what it's there for. As airflow increases and the vane opens there is less of a restriction and therefore the screw's position has much less effect on it.

It's why the screw's factory insertion depth for that particular engine is coded (stamped) right into the housing. Not that you should be playing with it

In the Karman used on turbo motors the screw has very little such impact for what should be obvious reasons and serves a different purpose, which is why you don't find the coding on that AFM.

 

[AJ'S 88NA]

You do. When closed the vane in your AFM presents a physical restriction to flow. This restriction forces air to pass through the unmetered chamber where the screw is. Because of this arrangement adjusting the screw will shift the vane's idle position, which means the screw can be used to indirectly adjust idle mixture and, in fact, that's what it's there for. As airflow increases and the vane opens there is less of a restriction and therefore the screw's position has much less effect on it.

It's why the screw's factory insertion depth for that particular engine is coded (stamped) right into the housing. Not that you should be playing with it

In the Karman used on turbo motors the screw has very little such impact for what should be obvious reasons and serves a different purpose, which is why you don't find the coding on that AFM.

Another tid-bit of info brought to you by non other than JJ. Always a pleasure reading your posts

I wish I would have known that when I had a AFM. CRE said to get rid of it I didn't need it anymore. You see what happens when I post something stupid I've done.....he's right there:biglaugh: He has to keep an eye on me.

 

[Nick M]

The two things to consider if the electronics are compatible but it's of a different size are: Erratic tip-in and choking at higher RPM.

The VAF can go out fairly easily, it's an entirely mechanical contraption. It's not built much different than a TPS which most acknowledge to be a wear component (which should be replaced periodically). I have had one fail on me, not from wear but a fracture in the circuit.

You're right. I need to consider the age, and I wasn't doing that. For example, back in 99, a 95 Camry still had that airflow meter. Most of the problems I saw were people that dropped them.

 

[CRE]

We have a idle mixture screw???

:3d_frown:

I wish I would have known that when I had a AFM. CRE said to get rid of it I didn't need it anymore. You see what happens when I post something stupid I've done.....he's right there:biglaugh: He has to keep an eye on me.

Hey, if you want to drop in a AFM on top of the MAFT Pro, by all means... You can actually use the MAFT Pro to just tune the AFM and keep the SD setup running to compare the airflow calculations and see how changing intake design with the AFM changes manifold pressure at different stages of engine operation.....

....Oh, I'm sorry, you were just joking. :icon_razz

You're right. I need to consider the age, and I wasn't doing that. For example, back in 99, a 95 Camry still had that airflow meter. Most of the problems I saw were people that dropped them.

Of course I'm right! I'm always right! (JJ, shhhh please, tryin' to look good for the guys! )

IIRC, the circuit in the AFM is on a ceramic board (same as the TPS). This is less susceptible to thermal expansion and deterioration but much more susceptible to damage from shock.



It was asked earlier if the thermistor could be replaced. Of course it can. You'd need to break the connection to the original one, figure out the type NTC or PTC) needed and then find one with the correct range of resistance. I think it was a 2.2KΩ (25ºC) NTC.

Look at the stats for P/N NCP[][]XW222 in this catalog: http://www.murata.com/catalog/r44e9.pdf :biglaugh:

 

[AJ'S 88NA]

:3d_frown:



Hey, if you want to drop in a AFM on top of the MAFT Pro, by all means... You can actually use the MAFT Pro to just tune the AFM and keep the SD setup running to compare the airflow calculations and see how changing intake design with the AFM changes manifold pressure at different stages of engine operation.....

....Oh, I'm sorry, you were just joking. :icon_razz

Like I need something else to try to tune, watch, and not understand???:nono:

But back on topic, I guess it's safe to assume that if your AFM takes a crap you should get another 7m one to replace it, alot less trouble, less problems with performance, and no messing around with the internals to maybe get it to work. Just my opinion, I like things simple though.

 

[CRE]

I guess it's safe to assume that if your AFM takes a crap you should get another 7m one to replace it, alot less trouble, less problems with performance, and no messing around with the internals to maybe get it to work.

\

It's not just a matter of hassle. If the internals are different enough you could damage the meter or worse your ECU. Just throwing a part on a car because it "looks like it'll fit" is downright foolish. This is more a matter of possible damage to the electronics than the ECU.

Whether the other VAF has a larger or smaller vane isn't going to destroy a stock N/A engine... they really don't have enough suction and the ECU's on top of the fuel mixture so frequently that unless you're going for a speed record it's unlikely you'd be able to run the car lean.

 

[kelner]

well good news is that the rx-7 meter does work. Comparing the numbers on the unit reveals they are not the exact same unit. I have pictures but did not get a chance to upload them yet, I will here shortly. The external dimensions appear to be the same and the opening measured the same on the inlet and outlet. I can't really say much for the "flapper" door and bypass path but they look very similar.

Either way, I put it on the car to test it out. Cranked right up which made me smile I drove it a bit and everything seems normal (even gassing it a bit produces smooth power output). I'll attempt to replace it with a 7m unit as soon as possible (since he needs it back anyways). Just need to wait for one to show up in the junkyard.

 

[jetjock]

You're lucky because many vane AFMs signal in reverse from the 7M. That said, simply because the engine seems to be running OK is no indication it is. It may not be in fuel control for example. After all you've messed with one of the two primary engine signals. As long as the AFM is the close to the same volume it should be OK but if it were me I'd be checking fueling. At least see if the engine is in closed loop because it can seem to run fine even when it's not.

 

[kelner]

You're lucky because many vane AFMs signal in reverse from the 7M. That said, simply because the engine seems to be running OK is no indication it is. It may not be in fuel control for example. After all you've messed with one of the two primary engine signals. As long as the AFM is the close to the same volume it should be OK but if it were me I'd be checking fueling. At least see if the engine is in closed loop because it can seem to run fine even when it's not.

Sorry to be ignorant, but how would I check to see if it is in closed loop? I understand that closed loop is when the engine is getting readings from the o2 under certain conditions (engine temperature, throttle input etc).

Thanks for being so helpful JJ!

 

[jetjock]

Do the O2 sensor test as outlined in the TSRM. Or you can use Vf.