A better Auxilary Air Regulator

[rcb280z]

And my Z has that "new routing". I believe it was changed in 4/77 and mine is a 5/77. I never have any "clogging" issues or anything interfering with operations.

Ah yes, I see Canada now, thanks.

Although when I owned a 76 about 18 years ago I had the problem with the throttle blade and AAR fouling, IIRC.

Edited October 27, 2014 by rcb280z

[Chickenman]

Yep... the original post was just an FYI for an alternate part to the original 280z and 280ZX AAR valve. The part about mixtures etc wasn't really a concern of mine. If it does affect my idle in a negative way then I can easily connect the AAR valve up the correct way in 5 minutes. I do appreciate the heads up though...

The later revision on the 280Z's AAR hose was in response to oil contamination as mentioned. I was working for Nissan at the Time and remember the TSB's from " Datsun " at that time to modify the 1975 and 1976 models. If I do have to revert to using the factory routing, I'll upgrade to the later style method or add a closed catch can.

As I mentioned, I suspect my particular ECU has a bit of " drift " at idle causing a mixture that is richer than it needs to be. Even with the stock camshaft I had to lean the AFM mixture screw ( not the TB idle screw ) much more than necessary when the TPS idle contacts were closed. And I know that's not correct.

I'm not 100% convinced that the AFM does compensate for increased idle air going though the AAR. After extensive reading on the EFI Bible and the FSM's, it looks like idle enrichment may be a purely calculated Mapping that only varies with engine RPM and TPS contact position. Based partly on the fact that ALL Nissan AFM's have a hidden idle mixture trim adjustment on the AFM and the TPS has to mechanically tell ECU that engine is at idle. I don't think the AFM has enough sensitivity at idle to self correct for small deviations in air flow, and that is why you have the " hidden " Idle mixture screw and TPS idle contact signal. I could be totally wrong though...

I could be totally wrong, and it won't be the first time... but it does bear further investigation. TPS idle contact affects idle enrichment ( adds fuel at idle ) and also allows fuel cut between, 3,200 rpm and 2,800 rpm on Decel. Other than that, the TPS idle contact, open or closed has no bearing on fuel curve.

Once I get the new AAR installed I'll do some simple comparison runs. and report back. Sorry...no 4 gas analyzer this time. Car's unlicensed for winter. Nose, tachometer and vacuum gauge is gonna have to suffice

PS: Car pulled 28.6 mpg on a recent long run ( with stock cam and 5 speed ) ..so fueling and tune are pretty danged good.

Edited October 27, 2014 by Chickenman

[FastWoman]

Hey, even though you really can't put an air filter on the thing...

REALLY NICE FIND! Thanks!

[rcb280z]

Post #6 you state the car has a "big" cam in it. And that it idles rich.

Post #14 says you are running stock cam.

What am I missing?

[Chickenman]

Post #6 you state the car has a "big" cam in it. And that it idles rich.

Post #14 says you are running stock cam.

What am I missing?

That the " Old " motor, with the stock cam, blew up just outside of Portland back in August, while on the way to the Monterrey Historic races at Laguna Seca. Ruined my whole freakin' vacation

Then I had a brand new motor built from the ground up at Bills Datsun Shoppe in Clackamas Oregon. That's when we put the " bigger " cam in. Intake system, and AFM settings were all the same. It was a very long Tow back to Vancouver, BC and it worked out cheaper having it done there than back home. Very pleased with new engine.

Actually, we adjusted the AFM a few " clicks " as it had a lean spot at around 3,000 to 3,500 RPM's when the new cam was installed.

Edited October 28, 2014 by Chickenman

[Captain Obvious]

There's good info on the AAR in this thread:

http://www.classiczcars.com/forums/fuel-injection-s30/47447-help-me-understand-aar-please.html

About a third of the way down, there is some discussion about the screw together AAR versions (Look for TomoHawks posts) . Some with two tubes like you posted above and some like one I nabbed off a Pathfinder that has one tube and a hole in the mounting face that ports air right into the intake manifold.

I assume you searched around for aar stuff and that thread didn't show up. I couldn't find it with the search function... I'm guessing that "AAR" is too short of a keyword and it doesn't work?

So about the mixture running lean if the AAR is ported to atmosphere... If you're running too rich for some reason, then having the AAR artificially lean the mixture will be a positive, right? At least until the AAR heats up and closes. And then you're back to your original rich running anyway.

So what was your original AAR doing (or not doing)?

[Chickenman]

^ ^Yep... have read all through that thread and researched several others. Pathfinder and Toyota Cressida AAR valves are close, but the have holes in bottom etc. 22660-45P00 is a direct bolt on for our cars. Bolt holes, hose sizes etc all match up. The only thing you have to do is file down that one locating tab on the electrical terminal. Easy Peasy.

My original AAR was just tired and gunked up. Thoroughly cleaned it with Brake cleaner, but heater element had came loose. Re-clocked it and epoxied in place, but sliding disc was still " sketchy " in operation. I wasn't getting repeatable results. Hell..it was simply old and tired. Did some more searching and found the Z32 AAR was an exact bolt on.

As mentioned it has the new style Composite ( Graphite? coated ) slider that works much better than the old Brass sliders. The Brass ones seem to gall with age. And the cover easily comes off with four Phillips screws if you ever need to fiddle with it.

Richness at idle can be eliminated just by adjusting the TPS so that the idle contacts are open at idle. I'm pretty sure that there's something fishy with my ECU ( probably ECU drift as FastWomen has experienced ) but at least I can work around it.

Other than that, the ECU works pretty damned good as car pulls super hard to 7,000 rpm with the bigger Cam. Haven't run fuel mileage tests on the new motor yet, but the old motor with same specs, but with a stock cam, was pulling excellent fuel mileage numbers ( 26 to 28 MPG Highway ) and ran really sweet. The old Analog dog can't be that bad... .

Edit: PS. I've been lurking for several months at this site and others..... gathering Intell... Been super busy on my Audi forums but will be posting more often here now that I have a bit more free time.

Edited October 28, 2014 by Chickenman

[Captain Obvious]

Gotcha. My original AAR didn't work right either. It was mechanically fine, but electrically intermittent.

Anyway, welcome aboard and glad you got your car running well. Here's hoping you get to the bottom of the rest of the running rich issues.

[rcb280z]

I may order one just to check it out....how it performs. Is it really better or not. Curious minds need to know.

[Chickenman]

I did some bench testing on this AAR valve, a new Toyota Cressida valve and my 38 year old valve. Use an ATX power supply and spare terminals. New valves opened and closed as smoooooth as a hot knife through butter. Old valve opened and closed in fits and starts. Even after a thorough cleaning and a light spray with WD-40.

I think that the fact that these AAR valves were brand spanking new had a lot to do with it.

PS: Don't bother with Toyota Cressida valves. The bolt spacing and hose size is off. The 22660-45P00 fits a 280Z/ZX perfect.

[rcb280z]

Yeah thats the one I ordered, 22660-45P00. Found it used on ebay for $28. Will open it up for a peek. Will clean it if necessary.

[rcb280z]

Okay got it in yesterday. First thing I did was open it up for a peek. Same principle as the stock one. Except for operation. When I had it open I saw a very clean AAR interior. So I put it back together and installed it on my car and started it up (cold engine). She idled about 900 rpms (400 less than stock one) and within 2 minutes I was shutting down the car. It was running very rich. The car was cold when I installed it. I re-installed my stock one and she ran the way she is supposed to (1200-1300 rpm's). So this requires a little more looking into. I did get it used off ebay. But from a reliable source. Just my 2 cents.