170Hz.

Measured today on a friend's 97. Time to put the uncertainty aside.

Dimitris

 

Probably explains why my 1.6L valve is running so well with 195Hz on MS-III.


fwiw, the MSPNP 90-93 msq has always used 161Hz, the 94-97 msqs always used 384Hz.

 

I haven't played with my MS3 card yet, does it have hardware PWM for the idle valve?

 

yes PID closed loop with a/c idle up feature. and an Idle VE table to boot.

 

Q: did you notice that the idle up feature doesn't work well all the time? It may be fine when the car has just warmed up but not so well when the engine bay has heatsoaked (hint: I'm using an idle-up circuit on the MS2).

 

A: It works wonderful.

 

I'm not talking about 10 minutes after, more like 45 minutes or more.

 

never had an issue so far, dunno. drove it on the highway the other day a good hour-and-a-half round trip.

 

You don't happen to have a datalog of that trip?

 

nope. i can datalog saturday for a 25 mile drive. Once I finally got my idle control settings down, I haven't had to touch them. I just idle it a little high else it sometimes stalls on quick decelerations, i blame other settings like the lock-out numbers and the triggers. idle is always smooth at 1000rpm so i leave it there.

 

Please, don't feel obligated just because I asked.

 

weird I always thought the 1.8 Idle valve was around 400hz.

Al well I'll move it down and see if I gain some granularity

 

is the same valve on the 94 as on the 97?

I have the 9093pnp but a 1.8 swap (a 94). I only recently realized the idle valve is from the 1.8 so my settings need to be changed.
Probably explains my idle troubles. doh!

 

The 99+ 1.8 idle valve is 500Hz:




Dimitris

 

But I'm using a 96 idle valve

 

Ah, ok, I thought you were using the 2001 idle valve.

Dimitris

 

Was going to and I can understand you thinking I was, but it made the swop a tinsy bit simpler, (wiring/plugs for the ICV and TPS), to just bolt the NA TB on in place of the NB one.

 

Changed to a multiplier of 6 - from 13 - and when the engine wants to idle at a DC that was in-between it's two previous points it's now far happier.

I'm still not convinced 100% that 170Hz is the right frequency though, occasionally I hear a low drone from the valve, the sort of noise you get from valves when they're not at the correct frequency, except very quiet and subtle.

See how I get on over the next week or so.