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View Full Version : An interesting point of view on O2 sensor manipulation



Painless
08-07-2008, 08:23 PM
I was back browsing through the files on the yahoo watercar group today and found another doc on working with the O2 sensor. It basically states that an EFIE is overkill and even some reasons as to why they sometimes cause hell with the check engine light.

Would definitely be interested in anyone's opinions on this and any ideas for how such a circuit could be built?

Apologies for the formatting, the original file is non-linkable and I had to convert it from doc to txt to fit the upload size limit.

Russ.

JimDShendo
08-15-2008, 02:13 AM
Thanks for that info. This subject is the most plaguing. :confused:

I'm going to hook up a 0-2 VDC voltmeter to my dash so I can read my O2's behavior while driving. I live in a mountainous area, so I don't want to screw up with choosing a bad 'standard' voltage.

I found a little meter in the Allied Electronics catalog. The model number is SP 400-blue. It's listed for $32.36. With a couple extra resistors, you can get it to accuratly read the 0-2 VDC range. I'll have a POT to adjust the O2 reading to what I want...while seeing it.:D

Good idea?

Keith's Garage
08-15-2008, 02:01 PM
Hooking up a voltmeter to watch the O2 might be a little confusing, considering how fast the switch rate is. The biggest thing people need to remember is that the O2 sensor is just a tattle tell sensor. It's not a bad idea to enhance the 02 signal, but you should also manipulate a demand sensor like the MAP/ MAF.

Another thing is that in order to tell the computer the motor is running rich (that way the computer leans the motor out) the 02 sensor voltage is high not low. So, just using a potentiometer will not work.

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08-15-2008, 07:38 PM
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Jaxom
08-21-2008, 05:57 PM
That paper has some good information in it, but some bad information as well. The explanation about why EFIE's sometimes set a check engine light makes perfect sense, but they're a little bit off on their ideas of how the PCM monitors the O2 sensors, and how the fuel trim feedback loop works.

" In looking for Horsepower, the O2 signal is fixed to whatever level the tuner needs,by using a fixed resistance in the early O2 models,or a fixed voltage signal in the later O2 models"

This is crap. Sending a fixed signal to the PCM in place of an O2 signal will do more harm than good. The PCM expects to see a signal switching back and forth from ~.2-.8v, and if it doesn't see that switching signal it will decide that the O2 is bad and set the appropriate trouble code. Without the O2 signal, the PCM will use a default fuel curve, which may be too rich or too lean for the current conoditions. If the fixed O2 signal is low, the PCM will increase the injector pulsewidth until it reaches the max. allowed in the programming. The converse is also true. Unless the O2 signal changes in response to the fueling changes, the system will either max out lean or max out rich. This is true for nearly all closed-loop fuel control systems.

Also, the PCM doesn't just add or subtract fuel based on the O2 voltage. There is a very complex set of algorythms that the PCM uses to calculate the injector pulse width based on a number of engine parameters. I could write chapters on the O2 feedback PID (proportional, integrative, and derivative) controls alone, without even brushing against the MAP, MAF, CTS, IAT, Barometric pressure, RPM, Accel. Enrichment, Decel. Enleanment, Highway mode spark and fuel control, Power Enrichment (a.k.a. wide open throttle,) Overheat mode, Startup Enrichment, and a number of other parameters.

I hate it when bad information like this gets circulated.

SamB52
08-23-2008, 01:34 AM
That paper has some good information in it, but some bad information as well. The explanation about why EFIE's sometimes set a check engine light makes perfect sense, but they're a little bit off on their ideas of how the PCM monitors the O2 sensors, and how the fuel trim feedback loop works.

" In looking for Horsepower, the O2 signal is fixed to whatever level the tuner needs,by using a fixed resistance in the early O2 models,or a fixed voltage signal in the later O2 models"

This is crap. Sending a fixed signal to the PCM in place of an O2 signal will do more harm than good. The PCM expects to see a signal switching back and forth from ~.2-.8v, and if it doesn't see that switching signal it will decide that the O2 is bad and set the appropriate trouble code. Without the O2 signal, the PCM will use a default fuel curve, which may be too rich or too lean for the current conoditions. If the fixed O2 signal is low, the PCM will increase the injector pulsewidth until it reaches the max. allowed in the programming. The converse is also true. Unless the O2 signal changes in response to the fueling changes, the system will either max out lean or max out rich. This is true for nearly all closed-loop fuel control systems.

Also, the PCM doesn't just add or subtract fuel based on the O2 voltage. There is a very complex set of algorythms that the PCM uses to calculate the injector pulse width based on a number of engine parameters. I could write chapters on the O2 feedback PID (proportional, integrative, and derivative) controls alone, without even brushing against the MAP, MAF, CTS, IAT, Barometric pressure, RPM, Accel. Enrichment, Decel. Enleanment, Highway mode spark and fuel control, Power Enrichment (a.k.a. wide open throttle,) Overheat mode, Startup Enrichment, and a number of other parameters.

I hate it when bad information like this gets circulated.

Man, I wish you'd write the chapters for us lay people. I have a Jeep Hemi that will not budge on its mileage while all these Dodge Hemis around me are going from 12 mpg to 25mpg...I have contacted KRC performance about hho fuel and ignition maps using the SCTFlash hardware. They have experience with all sorts of engine manipulations, including nitrous, which may have similar impact to hho in terms of more rapid and complete combustion. One of the owners of KRC put hho on his wife's 5.8 liter Caravan and she's getting 25 mpg, too.
Anyway, we're glad you're here, and welcome any clues you can give us.
BTW, are you using hho, and if so, on what vehicle?
Thanks

singnpreacher
08-28-2008, 10:20 AM
Hi, everyone! I have a 2006 Ford Econoline E350 van. I don't know if the three HHO generators I installed are giving me any change in mileage or not, but have a big trip this Saturday.

My worry is that my engine light is on, and I'm really hoping I didn't royally mess something up in my engine! I installed everything but the O2 sensor extenders on Saturday, and then installed two extenders on each of my two O2 sensors Tuesday afternoon. My wife says the light came on while she was driving yesterday. It hasn't gone off yet.

Should I try removing the extenders to see if the light goes off? I'm told that the HHO system won't work without the extenders.

What I'd really love is for someone to reassure me that my engine light isn't telling me that I've messed up my van!

Thanks!

Westcoastrocks
08-28-2008, 10:28 AM
Hi, everyone! I have a 2006 Ford Econoline E350 van. I don't know if the three HHO generators I installed are giving me any change in mileage or not, but have a big trip this Saturday.

My worry is that my engine light is on, and I'm really hoping I didn't royally mess something up in my engine! I installed everything but the O2 sensor extenders on Saturday, and then installed two extenders on each of my two O2 sensors Tuesday afternoon. My wife says the light came on while she was driving yesterday. It hasn't gone off yet.

Should I try removing the extenders to see if the light goes off? I'm told that the HHO system won't work without the extenders.

What I'd really love is for someone to reassure me that my engine light isn't telling me that I've messed up my van!

Thanks!
When i was installing my HHo gas output into my air intake, I had to remove the MAF sensor on the air intake cause it was in the way. I forgot to put it back on and the same thing happen to me. The first time i ever started my truck while running HHO gas and the engine light came on. Scared the crap out of me! So maybe beings your O2 sensors are farther away now your engine thinks that they are not there.

singnpreacher
08-28-2008, 12:36 PM
When i was installing my HHo gas output into my air intake, I had to remove the MAF sensor on the air intake cause it was in the way. I forgot to put it back on and the same thing happen to me. The first time i ever started my truck while running HHO gas and the engine light came on. Scared the crap out of me! So maybe beings your O2 sensors are farther away now your engine thinks that they are not there.

Thanks for the reply! I never had to remove my MAF sensor, BUT, I got a MAF sensor enhancer with the HHO kit I bought on eBay. I'm pretty sure I have that installed correctly, though.

So, do you think I ought to try just having one O2 sensor extender on each sensor?

Thanks!

Omega
08-28-2008, 01:28 PM
When I installed my O2 extender my check engine light came on... it wasn't because the sensor was effected, I had hurried too much and forgot to plug it back in :p

In my experience, a check engine light will not go out by itself. I reset mine with a code reader I've got. You can get the computer to reset by unhooking the battery hot lead for a few minutes and the computer will "forget" that a code was set.

singnpreacher
08-28-2008, 01:35 PM
OK. Thanks! But if I unhook the hot lead to my battery, and the code is reset, will the check engine light come on again?

singnpreacher
08-28-2008, 10:36 PM
Well, I managed to remove one O2 sensor extender from each sensor (keeping the power lead unhooked from the battery to reset the code).

When I got it all back together, no more engine light!

Driving to the gas station, I tried using the wipers, and they wouldn't work. I had hooked into the power for the wiper motor to power my HHO generators, and had blown the puny 5 amp fuse! The generators haven't even been running!

Now I've hooked into the 20 amp fuse for the fuel injector, and replaced the wiper motor fuse. All's running now. I'll post my gas mileage after my trip this weekend, but I'm afraid I don't know the pre-HHO mpg, as we've only had the van for a little while, and I haven't taken the time to check.

Jaxom
08-29-2008, 09:33 AM
You shouldn't use the fuel injector fuse to power your generator. In fact, I wouldn't recommend using ANY factory circuit as the power supply for an HHO system. The generator just pulls too much power and the factory circuits are specifically designed to handle the factory parts and no more. Get a seperate fuse holder and a relay from the parts store and use an independent circuit if you want safety and reliability.

singnpreacher
08-29-2008, 03:19 PM
Thanks for the advice! I decided to go ahead and run it straight from the battery to a toggle switch just under my dash. I've got 3 inline fuses at this point, but I'll likely rewire to where I just have one.

I can now choose whether or not I want the HHO generators to run. My wife and I just have to remember to flip the switch to off when we turn off the engine, or to turn the MAF enhancer all the way counterclockwise so the van will run on just gasoline if we're not going to run the generators.

scrode
08-29-2008, 03:52 PM
or to turn the MAF enhancer all the way counterclockwise so the van will run on just gasoline if we're not going to run the generators.


just curious, does turning the maf sensor enhancer all the way, turn it off, or take it to the super rich state? I just work with a map sensor enhancer which is, I know, different.

scrode
08-29-2008, 03:57 PM
You shouldn't use the fuel injector fuse to power your generator.

I did that and blew a fuse on freeway, DOH. to say the least, I had to walk a mile for a camel. hehe. put it on the unfused side and put a 25 amp fuse inline to generator. haven't a problem since.

singnpreacher
08-30-2008, 12:41 AM
just curious, does turning the maf sensor enhancer all the way, turn it off, or take it to the super rich state? I just work with a map sensor enhancer which is, I know, different.

It turns it to "rich mixture." That's what it says on the sticker on the far counterclockwise position. I don't think it's really turning it "off."

Westcoastrocks
08-30-2008, 02:36 AM
You shouldn't use the fuel injector fuse to power your generator. In fact, I wouldn't recommend using ANY factory circuit as the power supply for an HHO system. The generator just pulls too much power and the factory circuits are specifically designed to handle the factory parts and no more. Get a seperate fuse holder and a relay from the parts store and use an independent circuit if you want safety and reliability.

Yeah just get a 30 amp relay circuit.

Cadillac
08-30-2008, 02:39 AM
In fact, I wouldn't recommend using ANY factory circuit as the power supply for an HHO system. The generator just pulls too much power and the factory circuits are specifically designed to handle the factory parts and no more.

I would add that in car wiring at least, wires are designed to melt at certain temperatures. Using stock wiring to supply power to something that is more powerful will melt the wire used and a lot of times all the surrounding wiring. This happens to a lot of people who install powerful aftermarket stereos without knowing the consquences. Then they can't figure out why the stereo and tailights (or other) quite working at the same time. Then it just gets expensive.

boogeyman
09-02-2008, 11:15 AM
Thanks for the reply! I never had to remove my MAF sensor, BUT, I got a MAF sensor enhancer with the HHO kit I bought on eBay. I'm pretty sure I have that installed correctly, though.

So, do you think I ought to try just having one O2 sensor extender on each sensor?

Thanks!

Try disconnecting the battery for a few minutes. This should clear the CEL.

Drive the car for a while afterwards and see if the light comes back on.

If it does, remove the O2 extender and do it all again. If it doesn't come back on, your problem is with the Oxygen Sensor extender.

You may want to consider using an EFIE instead.

I hope this helps.

Please let me know how you make out.

DaneDHorstead
09-02-2008, 06:42 PM
Thanks for the advice! I decided to go ahead and run it straight from the battery to a toggle switch just under my dash. I've got 3 inline fuses at this point, but I'll likely rewire to where I just have one.

I can now choose whether or not I want the HHO generators to run. My wife and I just have to remember to flip the switch to off when we turn off the engine, or to turn the MAF enhancer all the way counterclockwise so the van will run on just gasoline if we're not going to run the generators.
Preach.........

If you can spare the bucks, use a marine type battery, as it has both top post, and side post. At your generator negative, you can ground to the car frame, and don't need to buy the negative cable.

Hook all the normal car stuff, to the top post, and run the HHO feed from the positive side post, and to a solenoid that is rated for constant run time.

You can either toggle the solenoid, from your ignition circuits, or steal powrt through the toggle, from virtually any circuit (I use the headlight power input wire).

Its also a good idea, if using just a toggle switch, to add a LED (light) to the circuit, as a reminder, to turn it off, when shutting the car down.

Matine battery usually runs $70 - $100, and "permanent rated" solenoid is about 35 bucks.

Carolinablue
09-06-2008, 10:32 AM
Just fyi, when you have an engine coming on, what I call throwing a code, you can take your car to any Advance Auto and they will give you a reading for free to tell you exactly what's causing the problem or throwing the code. For some reason though they don't won't to take the trouble to clear it. Guess it's asking too much to hit a few more buttons.

Jaxom
09-06-2008, 03:04 PM
I'll have to argue that one. Many parts stores will hook a code reader to the ODBII port and tell you what codes are stored in the PCM's memory, but that only tells you what part of the system is having a problem, not what the actual faulty component is. An O2 sensor code, for instance, can be caused by a bad sensor, bad PCM, weak fuel pump, clogged air or fuel filter, vacuum leak, wiring problem, worn rings, contaminated fuel.....need I go on? The trouble code is just a starting point for the diagnostic process.

Keep in mind, those guys are being paid to sell parts, not fix cars.

Keith's Garage
09-11-2008, 02:45 PM
Jaxom,
I am so glad that somebody actually knows something about vehicles on this forum. I keep seeing to many people that don't know what they are talking about. Keep educating people so they don't keep making the same mistakes.

Chris65
09-11-2008, 08:29 PM
When I installed my O2 extender my check engine light came on... it wasn't because the sensor was effected, I had hurried too much and forgot to plug it back in :p

In my experience, a check engine light will not go out by itself. I reset mine with a code reader I've got. You can get the computer to reset by unhooking the battery hot lead for a few minutes and the computer will "forget" that a code was set.

I know I am replying to an old post, but I want to add to this. Not all cars will reset the check engine light by disconnecting the battery. Some may also trigger the factory anti theft system or disable the radio, which will cause you to have to call a dealer for your make of vehicle and get the enable code.

Usually AutoZone and some of the other chain auto stores will check and clear your codes for free.