Within the last 1000 miles or so a set of NGK UR5 plugs were installed, and I pulled numbers 2, 4, and 6 to observe their color on Monday after a 25 mile run with mostly easy diving on two lane roads. All three plugs had bright white with no black spotting on center porcelain, and light tan deposit on grounding electrode. This made me think that it has been running lean, or the plug is too hot for my application.

Today the o2 sensor got installed that is read by a SunPro Gage that has three lights each for lean and rich, four lights for Ideal where progressing clockwise indicates a richer condition. After a short test drive several conditions became apparent.

While under light throttle middle rich light is lit.
WOT made middle and first rich lights cycle back & forth.
At 1000 rpm idle the thing goes from lean to rich, rich to lean off & on so signal from combustion, and o2 sensor heater aren’t keeping up for a good reading.

So which indicator do I use to determine how to proceed with jetting & power valve changes; techno gage, or eye balling plug color?

Bill

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

what's the cylinder compressions...valves adj?

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slant six's RULE!
http://www.usajon.com

wjajr, I will not say anything that may ruin your engine, so please only take this as my observations only.

I have used NGK in bikes and cars since the early seventies, and I feel that they often read different than many other makes. From what I have seen, they often tend to be on the light side in color when they are correct, and very quickly get dark, or even black, when running rich. It seem they either do not show as wide a specter of colors as many other brands, or they are far more sensitive to small changes when going rich, than they are when running correctly or a bit lean. That may also be intended, the japanese have always been sensitive to both consumption and pollution, and having a spark plug indicating richness better, will tell with a glance you're running a bit rich. I have also pulled NGK plugs that had a very nice, light tan color, and then turned almost white after riding very hard - without going lean, and later going back to the nice tan again, after a period of normal driving. It is almost like they were 'blasted' clean under hard driving.

It will be very interesting if this fits with other members' observations as well.

I have also often seen, that original japanese Denso plugs, often read 'better', with more variation in color than the NGK, when run normally in the same engine.

Olaf.

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Aspenized

I never look at plugs, only O2 sensors nowadays. I have run the same setup you have to great effect, although WB is better. Hard to tell "shades" of rich or lean on a NB-O2, but there is some relative info there.

Lou

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Home of Slant6-powered fun machines since 1988

[quote]I have used NGK in bikes and cars since the early seventies, and I feel that they often read different than many other makes. From what I have seen, they often tend to be on the light side in color when they are correct,[/quote]

Olaf, this is the first time I have used NGK plugs excepting the ones factory installed in wife’s Dodge Nitro that I discovered when performing 30,000 mile change. I don’t recall their color, but can say that they must have looked rather normal for that mileage or it would have caused me to ponder the situation. 10,000 mile Autolite plugs that were removed from Dart had a rich patina indicating correct air-fuel conditions, and I have not made any changes except to check valve lash, and tune idle circuit since going to NGK. Having such bright white plugs was rather surprising even with so few miles.

USAJon, Cylinder pressure’s run 150 to 160, lash is lose at 0.025â€￾ & 0.026â€￾ to get better idle quality due to a lumpy cam.


[quote]I never look at plugs, only O2 sensors nowadays. I have run the same setup you have to great effect, although WB is better. Hard to tell "shades" of rich or lean on a NB-O2, but there is some relative info there.[/quote]

Lou, I looked for information on o2 sensor I’m using, and can’t find it other than it is one that an early nineties V6 Chevy Astro used purchased fro Rock Auto on a close out. Wide Band or Narrow Band that is the question, can’t recall.

Also directions to gage have evaporated, and Sunpro dose not appear to have online Tec to double check.

I did take a few voltage reading as I am currently back to using a mechanical voltage regulator that cam with the car which I had replaced with a faulty electronic device this summer, and it’s giving 14.5 – 14.8 volts a bit on the high side. But come to think of it that voltage would only be applied to the o2 sensor heater, not the sensor as it produces’ a voltage based on what comes down the exhaust pipe.

Also the sensor is located just down stream a few inches from header’s collector, or about 28 inches from #1 exhaust port.

[img]http://i294.photobucket.com/albums/mm87/wjajr/Dart%20Engine/100_1540.jpg[/img]

Before I can start playing with jetting & power valves, I have to send for new bowl gaskets as the ones in place currently have been on & off one too many times, and won’t take another bowl removal with out self destructing. If I recall correctly, one should jump three jet sizes at a time to make enough of a difference to be noticeable with a 390, right?

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Definitely a NB sensor. That's where I have mine on my '64 Dart.

Lou

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Home of Slant6-powered fun machines since 1988

After a bit of self education on o2 sensors, I do have a narrow band unit as wide band devices were not put into use until late nineties and beyond.

Also I located Sunpro’s tec. page, and down loaded a copy of instructions.

Now to order new blue gaskets, a 54 jet, and one more PV yet to be determined to round out my selection.

I should have installed this thing in June when gage was installed and wired up. Procrastination is a wonderful thing. LOL.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Per Lou’s instruction I have driven the Dart around a bit more to get a feel for how the o2 meter reacts under different driving conditions. Tuesday the last of the Holley parts arrived via UPS, and I decided to rejet, replace the self destructing reusable blue gaskets with same.

Installed 5.5 PV knowing it is too high rating just to see how it would react with down jetting from 57 to 54. (If you remember under way second rich light is constantly lit, under acceleration it dips to lean indicating the 3.5 PV is not activating). During the install I didn’t notice power valve gasket was not centered, and once bowl was back on, engine flooded… I mean LOADED UP, and would woulden’t run, this happened twice before I found the PV gasket problem, than put it all back together.

Figuring my nice new clean plugs needed attention I pulled them finding they were fouled soot black & wet, spun over engine and puked out a big spray of raw gas. Cleaned plugs with carburetor cleaner, dried every thing out, reinstalled the plugs, and this time it started right up.

O2 gage read rich while choke was close during warm up, and once under way the first rich light was illuminated, one notch closer to ideal, that is; the first rich light. Progress!

As I drove, slowly the reading stepped back to the lean side one light at a time, and under hard acceleration it would dip to leanest point on gage. After about four miles the gage when dark as it ran out of lean lights to light. I suspected a blown fuse that powered the gage caused the darkness, but that was not the case.

Now I suspect that the o2 sensor did not react well to a moist soot bath. Have I killed that infernal device, or will a cleaning bring it back? Presently that part of the car is a bit hot to fiddle with, but in a short while I shall remove the sensor for a look-see.

Any advice?

------------------

Part 2:

Car has cooled down, o2 sensor removed, soot wiped from element with dry towel, and reinstalled. Drove a mile and a half starting with gage reading richest, and as choke pulled off gage steeped down to leanest reading, than to no reading.

Car runs fine, no flat spots, no bucking, no farting up through carburetor, no drivability indicating a super lean condition. So I don’t think is overly lean.

I can’t believe dropping from a 57 jet to a 54 would lean this carburetor out that much, where previous reading was a constant middle rich light.

Once back at the ranch, I shut the engine down, let is sit for about one minute, restarted it, and o2 gage once again illuminated leanest light.

Can I trust this o2 sensor?

Tomorrow I shall reinstall 57 jets & 3.5 PV going back to ground zero, and see what happens.

Bill


Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Bill, I did not see you write anything about calibration of the sensor, is that not required with your setup? My Innovate wide-band sensor is not in the car now, but it requires a calibration before use.

BTW, Innovate has begun using a 1 inch bung now, just letting the very tip of the sensor into the exhaust gas flow, and they say it does not mean anything for the resulting measurments. Keeps it cleaner.

Olaf.

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Aspenized

Olaf,

I’m using a narrow band three wire o2 sensor that would be used on an early 90’s Chevy Astro Van I got from Rock Auto. Here are the directions for installing the gage, and the sensor had no directions.

Up-date:

I reinstalled the 57 jets, and a 2.5 PV that were what I started with before changing gaskets, and flooding engine. I did not drive the car on the road, but let it idle in the garage out of the rain until it warmed up, and the gage fluttered between first rich, and second rich light after choke pull off.

I took temperature reading on header tubes, and exhaust pipes front three ran 320* F, back three 450* F, and collector area where sensor is located 260* F while idling. Fan cools surface of front three header pipes, once air flow is deflected temperature pops right up close to rear three.

Tomorrow is to be rain free, so I shall give it a run and see how the gage readings compare to pre flooding.

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

It is hard to soot up a NB O2, and there is no calibration possible or required. Maybe your flooding could have damaged/crudded it? I hate Holleys...

Lou

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Home of Slant6-powered fun machines since 1988

Lou,

I removed the sensor, dry wiped the soot from its outer shielding, and examined the inner bits. One side is white to light gray ash, the down wind side has a blacker carbon deposit neither look to be more than just a light coating.

This sensor grounds through its outer fitting to exhaust system where it is a three wire. When cold there is a good electrical connection to ground, I wonder if once hot that ground path becomes incompetent with enough resistance to alter the sensor’s voltage output?

I’m off to the scrap yard with another bucket of brass from the old lock shop. This will double as a 20 mile test drive, and a chance to test that hot grounding point.

Yesterday I left off 200 pounds of key blanks at the yard. Just love it when metal’s price is up!

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I just got back from the scrap yard. Trip into town gage gave second & first light on rich, with dipping into ideal zone under light acceleration, much the same as when first installed. Once in town, it flickered lean to ideal at low rpm 1000 to 2000 rpm, and back to constant 35 mph to 45 mph, gage settled into lean side of ideal zone. This is a first.

At 1100 rpm idle in garage leanest ideal light is lit, blip of throttle brings a dip into lean, and back to lean ideal.

I checked voltage difference between battery posts while car was idling & hot, and positive battery terminal and base of o2 sensor and got 1/100 volt difference. The ground path when exhaust is hot is acceptable.

Voltage reading at sensor output was .4 to .45 when at idle, which corresponded with gage reading of lean ideal and graph in gage directions. I now trust gage reading as correct representation of sensor’s voltage output.

When I removed the o2 sensor the other day after its baptism, there was a slight white residue of some type of thread never seize. I wonder if it was impairing the flow of electrons. Should I remove that residue, and in place of it apply a coat of copper based high temperature never-seize?

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

More farting around with carburetor jetting, and o2 sensor has been under way this week. After jetting down to 54 and changing to 5.5 power valve and finding that combo unacceptable I decided to step back to original 5.7 jet and 2.5 power valve.

The gage during one test drive began to swing in and out of rich side of ideal under light acceleration and mid rich at cruse. This lead me to believe that it was giving correct readings, and all was hunky-dorry.

Next drive a few days later, the gage sat on mid rich, and barely flickered to line side of rich… This lead me to wonder if carburetor is producing consistent mixtures, the o2 sensor not responding correctly for whatever reason, or grounding of sensor is seeing a bit of resistance skewing voltage out-put, and gage readings.

More head scratching, plan B implemented; make one change at a time, and make it big to better see any changes. So in went to a pair of 51 jets that were installed when I purchased the car, and had been used pre 10% ethanol. The engine developed a flat spot that was felt under any acceleration, and gage showed lean to lean ideal mixtures to no reading at all after dropping off the lean side of the gage with all lights off. WOT would bring back readings flickering back and forth between lean & rich presumably while power valve was open, and perhaps secondary’s cracking open. Can’t be sure exactly what is going on, except it ran like crap.

I than installed 54 jets, leaving 2.5 PV in place, This jetting gives mid rich to lean rich readings, dropping to rich side of lean under light acceleration with gage wagging back & forth between the to, and at WOT moves gage back to lean side of rich. Acceleration is flat spot free. There is not enough road with high enough speed limits near by to let this car run into high rpm with secondary’s & PV open for anything but a very short burst. 70+ mph in a 40 zone is unwelcomed by the local constabulary even in second gear if you get my drift.

I beginning to think this will be as close to an acceptable tune possible with a big cam.

Come this winter I hopefully can swap in a more tame cam that develops much more vacuum at idle, and a better vacuum signal that the carburetor can live with aiding in a proper tune were WOT goes a bit rich, cruse is in steady ideal, as well as idle, the opposite of what is going on now.

Incidentally, the plugs returned to their preteen white ceramic, and good deposit color on grounding electrode since the great flood at the beginning of this thread.

I’m open for ideas with this.

Bill

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Are you running a Y pipe? And shouldn't the sensor be down in the Y pipe? I seems to me that you are only measuring the front 3 cylinders.