| Author |
Message |
Verell Boaen (Verell)
Junior Member
Username: Verell
Post Number: 192
Registered: 5-2001
| | Posted on Thursday, July 11, 2002 - 4:49 pm: | |
I'm aware of the single wire O2 sensor positioning sensitivity, & don't have any problem with mounting it in the collector. While a 3-wire sensor gives more flexability, it doesn't give more accuracy than a well positioned & warmed up single wire sensor.
(FLAME ON)
What Irks me is that all of the A/F meters under $200 or so use narrow range O2 sensors (3-wire or single wire) & the LM3914 or something similar to drive the display. That means you might as well go as cheap as possible because you won't get a better reading for $200 than you can for a $29.00 A/F meter from JC Whitney, or by just using a good voltmeter!
Last time I looked for a sensor bung in SummitRacing, all I could find was: One packaged with a plug for $30 or so, one packaged with a 3-wire O2 sensor for $50, or one with an A/F LED display for $150 or so. (That was a year ago.)
All I wanted was the darned threaded ring or an 18x1.5 nut.
I already had the A/F meter and a pair of universal O2 sensors I bought for about $20 each.(It helps to have a son that works for an auto parts store.)
(Flame off)
I just searched SummitRacing again & they now have bungs by themselves for $5.39. Still seems high for all they are, but that's in the spare change range so I guess I'll just order a couple.
(Ed G. Just saw your post & will call a couple of local exhaust system shops tomorrow AM.) |
Edward Gault (Irfgt)
Intermediate Member
Username: Irfgt
Post Number: 1563
Registered: 2-2001
| | Posted on Thursday, July 11, 2002 - 4:47 pm: | |
The 02 sensor bungs are available at most any independent exhaust system shop. There are several designs of these things and if you cannot find some let me know as I can get them. |
Steve Magnusson (91tr)
Member
Username: 91tr
Post Number: 835
Registered: 1-2001
| | Posted on Thursday, July 11, 2002 - 4:05 pm: | |
Verell -- Do an internet search on something like "K&N O2 sensor" and you should get plenty of hits to look at. Summit Racing I think is a source (bung, sensor, gage, plug for bung), and I noted someone mentioned: "spend the extra money and get a 3-wire (self-heated) O2 sensor" otherwise the low RPM readings may not be that valid. If you go with a 3-wire O2 sensor placement should be less critical and anywhere before the 1st muffler/cat element should be OK-ish -- with a 1-wire O2 sensor I think you're stuck with putting it in the header collector area itself to keep the temp up -- JMO.
|
Verell Boaen (Verell)
Junior Member
Username: Verell
Post Number: 189
Registered: 5-2001
| | Posted on Thursday, July 11, 2002 - 3:40 pm: | |
OK, sounds like the screws work just like the corresponding adjustments on my Rx7's Jetronic EGI system.
Only problem is, I could set my Rx7's mixture based on the O2 sensor signal, & my Euro QV doesn't have one.
Since I adjusted the speed by about +150 RPM using the throttle screw, & since I don't believe there was any way the bypass air screw could have been moved, I'm going to go with the current settings until I can install O2 sensor bungs in my collectors & hook up my A/F ratio meter.
BTW, ANYONE KNOW WHERE I CAN BUY 02 SENSOR BUNGS OR 18x1.5MM NUTS i can weld on to mount O2 sensors in my exhaust manifold collectors?
ANY RECOMMENDATIONS WHERE ON COLLECTOR TO MOUNT THE 02 SENSORS? I want to ensure I see the mix of all 4 cylinders.
|
Steve Magnusson (91tr)
Member
Username: 91tr
Post Number: 832
Registered: 1-2001
| | Posted on Thursday, July 11, 2002 - 3:09 pm: | |
Verell -- On the K, K-lambda, and KE systems, B and C work in parallel to control the idle speed. The usual F adjustment scheme is to fully close (seat) the air bypass screw and get a certain lower idle RPM (like 700 RPM on a TR) with the air only flowing thru the thottle plate opening -- then open the air bypass screw to increase the idle speed up to the desired value (like 1000 RPM on a TR). This ensures that the relative amounts of air flowing in each path are as intended (i.e., you could still probably get a 1000 RPM idle speed if the thottle plate was more closed and the bypass screw was more open to compensate, but I think the partial thottle performance would be compromised). When running at 1000 RPM then adjust the mixture -- if the RPM changes, go around the adjustment loop again until you get both (RPM and mixture) to be OK simultaneously. |
Verell Boaen (Verell)
Junior Member
Username: Verell
Post Number: 187
Registered: 5-2001
| | Posted on Thursday, July 11, 2002 - 2:57 pm: | |
I'm confused. I just adjusted my idle speed using screw B based on the 308 QV owner's manual. The previous post & the 328 owner's manual leave me uncertain if I've twisted the right screw.
The 308 QV ownere's manual Carburation heading and figure 52) Adjusting screws on Pg 67 identifies three adjustment screws. They are labled:
A - CO Adjusting Screw (On fuel regulator, down below the air box.)
B - Idle Adjusting Screw (Left side of throttle body, adjusts minimum closure of butterfly valve).
C - By-pass Screw (large allen head screw on the front of the intake manifold just under the air hose.)
My understanding has been that:
A controls the idle mixture
B controls the idle speed
C controls ???
However, I just looked at the 328 Owner's manual.
In Fig. 58) on pg 66: Screws A & B are in the same places & labled the same. What looks like C (ie: A quite large screw) is located down near where the air hose joins the fuel distributor. and the screws are labled:
A Air Mixture Adjustment Screw(Sealed)
B Throttle Position Adjustment Screw (Sealed at the factory)
C Idle Speed Adjustment Screw
On Page 65, the Idle Speed Setting heading reads:
"With engine warm check by a rev/counter, that engine RPM be as specified on the engine tuneup label.
If required, adjust by the idle speed by-pass screw(See Fig. 58)following the procedure described in the workshop manual."
I can't find any procedure in the 308 QV/328 Workshop manual. Possibly it's in the 308i manual that I don't have??
IF SOMEONE HAS THE PROCEDURE, COULD THEY POST IT, OR SEND ME A COPY by eMAIL or FAX?
|
Donny Bridges (Wildcatfans)
Junior Member
Username: Wildcatfans
Post Number: 62
Registered: 9-2001
| | Posted on Thursday, July 11, 2002 - 11:45 am: | |
That is your idle adjustment. It bypasses air around the butterfly valve in the intake causing a higher or lower idle. |
Anthony Tipton (Tonyt)
New member
Username: Tonyt
Post Number: 17
Registered: 5-2001
| | Posted on Thursday, July 11, 2002 - 7:30 am: | |
There is a rather large allen head screw on the front of the intake manifold just under the air hose. The owners manual identifies this as a "by-pass screw".
What is the purpose of this screw and what effect does turning it one way or the other have?
Thanks |