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Well well..I knew it wasn't that lean!

General engine tech -- Drag Racing to Circle Track

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427dart
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Well well..I knew it wasn't that lean!

Post by 427dart »

Took my '85 LX out for another carb tuning session this time with the new AEM wideband A/F meter in place of my very old LM-1.
Good thing I didn't go larger than current .073 secondary plate holes as now I see steady 11.3 at WOT in 3rd gear up to 6000 RPM.
Before I was dealing with crazy scattered lean readings in the high teens...16-18.
My crusie and medium accel readings show about same as before in 13.7 thru 14.4 with a nice 13.7 idle.
Now I need to go back a few holes sizes towards the stock 1850's .067 secondary hole.
So now question is how small to go?
The new AEM is a sweet little gauge as it sits right next to dash mounted tach and very easy to see and read the larger digital numbers!
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BOOT
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Re: Well well..I knew it wasn't that lean!

Post by BOOT »

I'm no expert on the stuff but I have read that some sensors(o2) will degrade and maybe it just needed a new sensor? By some I mean other widebands can be recalibrated once in awhile. Like I said no expert so idk if when they degrade it goes richer or leaner?

Any changes or exhaust parts removed that may be sealed better now?

edit: I have no preference in either brand I am only curious of the factors
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427dart
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Re: Well well..I knew it wasn't that lean!

Post by 427dart »

There were no changes in exhaust system. I priced a new Bosch sensor and they have jumped up to $118 bucks via Advance Auto.
So for about 80 bucks more I got a new gauge which is a ton easier for my 62 yr. old eyes to see and it came with new sensor.
I did do a free air calibration test on the LM-1 with the old sensor and it would read the 20.9 A/F as noted plus with sensor out of exhaust it would read full rich when placed in a gas soaked rag and then go slowly to lean in free air. Could have been an issue inside the electronics.
But I know if it was running that lean at WOT I should have heard some breaking up going on.
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Re: Well well..I knew it wasn't that lean!

Post by 77cruiser »

The sensors read oxygen so any misfire will read a lean spike. I don't know how the gas soaked rag would make it show rich, unless it's displacing oxygen somehow.
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Re: Well well..I knew it wasn't that lean!

Post by Tuner »

Probably misfires or detonation. The Innovate digital system is fast enough to detect individual cylinders miss or knock, the analog systems are not.
427dart
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Re: Well well..I knew it wasn't that lean!

Post by 427dart »

Tuner wrote:Probably misfires or detonation. The Innovate digital system is fast enough to detect individual cylinders miss or knock, the analog systems are not.
Well all I can say is the new gauge gives me stable within couple tenths of variation a good 11.2 reading and everywhere else a similar reading that compares with the LM-1 during idle cruise and mid power. So should I count that as a true rich read.
If that thing was showing 17 's at WOT as with the LM-1, it would be surging popping and laying down which it wasn't.

The gas rag test works...try it one time.
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Re: Well well..I knew it wasn't that lean!

Post by Xnke »

So will blowing shielding gas from your welder over the sensor...doesn't mean it's the correct way to calibrate one.

Follow the instructions and calibrate it every 3 months, replacing the sensor every 2 years, or get a proper WBO2 controller that doesn't abuse the hell out of the sensor like the old LM/LC 1 units. I don't know how rough the LC2 is on sensors, but the LC1 control scheme was HARD on sensor elements.

Also if you ever get coolant vapor in the exhaust from a BHG or leaking intake manifold or use an acidic-curing silicone sealant it'll murder an O2 sensor fast.
427dart
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Re: Well well..I knew it wasn't that lean!

Post by 427dart »

No..I didn't calibrate any sensor with the gas rag test. You calibrate for free or clean air which according to Innovate should give a 20.9 reading.
The gas rag test was what A guy used to test his AEM gauge for a bad sensor. A faulty sensor would go down to full rich and then come back to full lean.
The good sensor would go to full rich and stay there until removed from the rag. Tried that test and my old LM-1 unit and the new AEM tested fine.
I don't know what's up with the LM-1 could be anything...but getting what I think is an accurate reading with the new AEM unit.
Now if a wideband sensor works everyday for many years in it's correct automotive use,why does it have to be replaced every 2 years after short term use?
These things are ex$pen$ive to replace at least for me at 118 bucks a pop.
Innovate also told me that when cold starting the engine to run the engine for 30 seconds then turn the unit on. This would prevent moisture/condensation from blowing on the element while it was heating up.
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Re: Well well..I knew it wasn't that lean!

Post by Tuner »

427dart wrote:
Tuner wrote:Probably misfires or detonation. The Innovate digital system is fast enough to detect individual cylinders miss or knock, the analog systems are not.
Well all I can say is the new gauge gives me stable within couple tenths of variation a good 11.2 reading and everywhere else a similar reading that compares with the LM-1 during idle cruise and mid power. So should I count that as a true rich read.
If that thing was showing 17 's at WOT as with the LM-1, it would be surging popping and laying down which it wasn't.

The gas rag test works...try it one time.
The carb cleaner soaked rag, the propane torch, both lit and unlit, most of us know of these things, and ..... the Innovate will measure the diminished O2 in your exhaled breath, try that sometime. A drunk reads richer than a sober person, imaging that.

What is the difference in the way the rigs were/are wired? Is the new gauge hard wired to the electrical system? Is the new gauge grounded in a different location in the car than the Innovate? Was the Innovate powered by a cigarette lighter socket, or was it wired direct to the battery? A steady power supply is important. A misfire doesn't need to be a hard miss to pass unburned O2 and detonation is another deal altogether, sometimes you can see it in the Logworks logs. It is too bad you weren't logging and downloading so you can look at it in Logworks, because how the trace looks in the graph screen can give clues you can't get just looking at the gauge.
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Re: Well well..I knew it wasn't that lean!

Post by CharlieB53 »

427dart wrote:...............
Innovate also told me that when cold starting the engine to run the engine for 30 seconds then turn the unit on. This would prevent moisture/condensation from blowing on the element while it was heating up.
This is good to know as the moisture very well could degrade materials and contribute to an early failure.

I don't doubt two years is simply a recommended change to keep the unit in maximum condition.

Religious late switching on should help keep the unit functioning for many more years.
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Re: Well well..I knew it wasn't that lean!

Post by 427dart »

I use my A/F monitor as a temporary tuning device when setting up and testing a new carb setup. When I and the engine are happy out it goes back on the shelf. From time to time I will hook it back up and do a check if I feel something is out of tune. Usually around here in Central Va. all I have to do is go up or down 3-5 thousandths on the Idle Air Bleeds from Spring,Summer or Fall cruising to stay in the happy zone.
So my LM-1 has always been powered thru the lighter socket for years and years of use.
The new AEM is powered the same way and I get good readings from both until this recent testing of my new carb setup when I saw LM-1 readings popping up leaner than what they should be only during the WOT test.
Now I'm getting a more steady rich reading at WOT with the AEM which I believe is the correct reading.
All I'm trying to do here is get this puppy in the 13.0 -12.5 range for overall street use when in WOT mode which would be of short duration...a blast thru the gears on a nice evening!
This is fun muscle car use not all out race.

So that being said..If I'm at .073 on the Secondary Metering plate main hole and showing a 11.3 reading going back to .070 might get me there?
My choices are drill size .070 or all the way back to stock 1850 which is .067 and of course smaller if needed but wouldn't think so.
I have drilled and tapped one metering plate for a brass 8-32 set screw which I could drill and use for a jet. If not buy two new 134-9 metering plates.
Not going to reuse the AED jet plate since I don't like the .030 space between the jet face and the notched area on the float...looks to tight for good fuel flow.
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Re: Well well..I knew it wasn't that lean!

Post by RevTheory »

I would say that if it's starting out at one place and going richer or leaner as you near the top of the rpm, then the air bleed would be the one to look at but if it's holding steady, I'd probably look at the fuel jet to change the a/f ratio.
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Re: Well well..I knew it wasn't that lean!

Post by dfarr67 »

Innovate is the only manufacturer that does free air that I know of. This cancels out the WB O2's factory calibration.
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Re: Well well..I knew it wasn't that lean!

Post by user-23911 »

77cruiser wrote:The sensors read oxygen so any misfire will read a lean spike. I don't know how the gas soaked rag would make it show rich, unless it's displacing oxygen somehow.
They don't actually "only" read oxygen....that's another myth.
It's a bit more complicated than that.
A WB is like 2 NBs in one, the WB was developed from the NB.
They only read the oxygen concentration when leaner than lambda 1. When richer than lambda 1 they read the concentration of combustibles in the exhaust.

All sensors degrade.

Calibration in free air is free air so it's only calibrated at 20 to 1.
They have a natural calibration at lambda 1 so that's fixed.
The rich end of the scale is always floating so it's pretty much guesswork.They're far less accurate than the sales and marketing gurus want you to think.

Yes the gas rag works well......bench test any NB sensor (WB as said works in a similar way).........any fuel source, acetylene, alcohol, brake clean, they read full rich..........try it with argon. It's not a fuel but it displaces oxygen.

The internet and car enthusiasts.........the biggest ever source of misinformation.
dfarr67 wrote:Innovate is the only manufacturer that does free air that I know of. This cancels out the WB O2's factory calibration.
That's the sensor calibration, it's got nothing to do with the calibration of the unit it's self.
The sensor is calibrated.......then the box has to be calibrated on top of that for it to work.
Last edited by user-23911 on Mon Mar 14, 2016 5:39 pm, edited 1 time in total.
fdicrasto
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Re: Well well..I knew it wasn't that lean!

Post by fdicrasto »

I will probably get in trouble for this, but how about a couple WOT blasts, clean cut and pull plugs and see what they show? I believe a spark plug can be more honest then any politician and even some electronics.
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