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Reading my multimeter AND unable to adjust EFIE? - Printable Version

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Reading my multimeter AND unable to adjust EFIE? - guitargerber - 01-06-2009 03:03 PM

Hello all,

Let me start by saying my knowledge of electrical things is extremely limited. I had my step-son, who graduated from UTI and knows his way around a car install my EFIE, as I was sick the only day we had to get it installed. He had to take apart the whole dash to get to the computer, as he wanted to be certain that the connections were right, and I trust he did a good job of it.

I just added my EFIE to my system, and I'm having two problems - first of all, when I turn the adjustment screw on my single EFIE, there is no change in my multimeter reading. I've even tried turing the screw clockwise 10 revolutions to get a big change, and still nothing. All I have to do is use a tiny screwdriver to turn the screw, right?

Secondly, when I have the leads hooked up with my multimeter set to read 2000mv, it shows "-180" at idle and goes up to "-212" while cruising. Should I be seeing negative values? I figured the EFIE would be showing a POSITIVE number as it is adding voltage to the O2 signal. The O2 reading is showing .16 instead of the .2 - .7 range I was expecting. Anyone have any ideas? Thanks so much!

Smiles,
Eric

2000 Toyota Corolla, Magdrive Dual Brick HHO system, single EFIE


RE: Reading my multimeter AND unable to adjust EFIE? - colchiro - 01-06-2009 03:18 PM

Hi Eric.

Did you confirm you have a narrow band o2 sensor before installing? Most Toyotas from 2000 up use a wide-band o2 sensor, incompatible with a narrow band efie. If you haven't checked, you can email Bruce and find out which efie model you need. He will need all the details about your car, year, model, engine size, etc.

OTOH, one thing you could check, if you insert your red probe in the black jack and your black lead to the car chassis (wherever you can find a ground screw nearby), you should see a voltage that varies a lot between 0 and 1 volt DC or a stable voltage around 3 volts. If it's the quickly changing 0-1 VDC, you're ok, otherwise you have the wrong efie model.

Once we know you have the correct efie, we can proceed.


RE: Reading my multimeter AND unable to adjust EFIE? - guitargerber - 01-06-2009 03:28 PM

I did email Bruce before buying, and he said it was the narrow band I needed. I am seeing 0.18 and 0.17, with my DCV set at 20 and my EFIE turned on. It doesn't seem to fluctuate much, stays pretty steady. At idle, I'm showing -202 to -203 on the EFIE offset - are these negative values right?

(01-06-2009 03:18 PM)colchiro Wrote:  Hi Eric.

Did you confirm you have a narrow band o2 sensor before installing? Most Toyotas from 2000 up use a wide-band o2 sensor, incompatible with a narrow band efie. If you haven't checked, you can email Bruce and find out which efie model you need. He will need all the details about your car, year, model, engine size, etc.

OTOH, one thing you could check, if you insert your red probe in the black jack and your black lead to the car chassis (wherever you can find a ground screw nearby), you should see a voltage that varies a lot between 0 and 1 volt DC or a stable voltage around 3 volts. If it's the quickly changing 0-1 VDC, you're ok, otherwise you have the wrong efie model.

Once we know you have the correct efie, we can proceed.



RE: Reading my multimeter AND unable to adjust EFIE? - colchiro - 01-06-2009 04:36 PM

I'm concerned your efie may be connected to the wrong wire. You should not be getting a negative reading on your meter, if you have the black wire connected to the black jack on both the meter and efie and the red to the red. Of course, the engine needs to be running and warmed up for at least 5 minutes.

[Image: wiring-diagram.jpg]

Your green wire should be connected to the o2 sensor, which is directly connected to the black jack on your efie.

[Image: SingleEfieDeluxeParts.jpg]

That's why I prefer to connect under the hood so you're 100% sure you have the correct wire. When connecting to the harness inside the vehicle, there's always a chance you have the wrong wire.

Assuming you have the right wire and a functioning o2 sensor, you should see a rapidly changing voltage between .2 and .8 volts, changing so fast it's hard to say what the reading is.


RE: Reading my multimeter AND unable to adjust EFIE? - guitargerber - 01-06-2009 05:13 PM

Could I just cut in to to the wire near the EFIE itself and switch around the green and white wires to see if it's connected wrong? Could that cause the negative readings on my multimeter? Or is that what it should show?

Also, what's up with the adjustment screw not making any changes? Would that be the result of a faulty wiring job?

Thanks so much for your help, btw!!


RE: Reading my multimeter AND unable to adjust EFIE? - colchiro - 01-06-2009 05:34 PM

I suspect if you disconnected the green wire, the efie will change the meter reading correctly.

Your efie is designed to add a voltage onto the signal connected to the black jack and send the results to the red jack. Swapping wires won't help since you'll should always see a higher reading on the right (if connected properly). You should be able to reverse the wires if you wanted to make a richer mixture.

I've seen a negative reading before when it was connected to a wide-band o2 sensor tho. If you have a current passing backwards thru the efie, it'll act like that. The efie creates a weak signal. It sounds like you have a stronger signal going backward thru it, giving you a negative reading.

The problem isn't the negative reading. I believe it's the fact your input signal doesn't act like the right wire.

Are you checking the voltage with the vehicle running and warmed up? Was it running ok before the install and getting normal mileage? Did you have a check engine light before or after the install?


RE: Reading my multimeter AND unable to adjust EFIE? - guitargerber - 01-06-2009 06:21 PM

Yes, the car is running and warmed up - I drive 46 miles one way to work, and checked it several times to and from work today. The vehicle was running just fine and getting an average 38 MPG before the EFIE - no check engine light has ever come on. My MPG went down to 35.5 with the EFIE hooked up and turned on, though it was quite cold and rainy today.

I'm not sure what you mean when you say I should always see a higher reading on the right.

So you're thinking I might need to go back in and re-do all the wiring, eh? I sure hope I won't have to!



(01-06-2009 05:34 PM)colchiro Wrote:  I suspect if you disconnected the green wire, the efie will change the meter reading correctly.

Your efie is designed to add a voltage onto the signal connected to the black jack and send the results to the red jack. Swapping wires won't help since you'll should always see a higher reading on the right (if connected properly). You should be able to reverse the wires if you wanted to make a richer mixture.

I've seen a negative reading before when it was connected to a wide-band o2 sensor tho. If you have a current passing backwards thru the efie, it'll act like that. The efie creates a weak signal. It sounds like you have a stronger signal going backward thru it, giving you a negative reading.

The problem isn't the negative reading. I believe it's the fact your input signal doesn't act like the right wire.

Are you checking the voltage with the vehicle running and warmed up? Was it running ok before the install and getting normal mileage? Did you have a check engine light before or after the install?



RE: Reading my multimeter AND unable to adjust EFIE? - colchiro - 01-06-2009 06:54 PM

(01-06-2009 06:21 PM)guitargerber Wrote:  I'm not sure what you mean when you say I should always see a higher reading on the right.

Like I said, "Your efie is designed to add a voltage onto the signal connected to the black jack and send the results to the red jack." Unless you have a strong signal going backwards thru your efie, you should see a positive reading with black probe in black jack and red in red. "on the right" meaning your red jack should have a higher voltage. I guess I shouldn't say on the right, b/c you could have the red jack on the left.Gasp


RE: Reading my multimeter AND unable to adjust EFIE? - guitargerber - 01-06-2009 07:08 PM

OK, I'm now looking at a Haynes manual that my step son picked up, and I'm really confused. It reads that the Oxygen sensor in 1996 and later models has two heated oxygen sensors. It says the main(pre-converter) o2 sensor is ahead of the catalytic converter and monitors the exhause exiting the engine. The post convertor sensor monitors the gasses after passing through the converter. It then goes on to say that the post-converter sensor has no effect on ECM control of the a/f ratio. So, if the post converter sensor has no effect, all I would need would be the single EFIE, right? Or do I need a Dual?

I'm guessing he wired in the post-converter sensor instead of the pre-converter. Could that cause my problems?

It doesn't say anything in the manual about whether it is a narrow band or wide band sensor, but Bruce did tell me it was a narrow band, so I trust that is correct.

(01-06-2009 06:21 PM)guitargerber Wrote:  Yes, the car is running and warmed up - I drive 46 miles one way to work, and checked it several times to and from work today. The vehicle was running just fine and getting an average 38 MPG before the EFIE - no check engine light has ever come on. My MPG went down to 35.5 with the EFIE hooked up and turned on, though it was quite cold and rainy today.

I'm not sure what you mean when you say I should always see a higher reading on the right.

So you're thinking I might need to go back in and re-do all the wiring, eh? I sure hope I won't have to!



(01-06-2009 05:34 PM)colchiro Wrote:  I suspect if you disconnected the green wire, the efie will change the meter reading correctly.

Your efie is designed to add a voltage onto the signal connected to the black jack and send the results to the red jack. Swapping wires won't help since you'll should always see a higher reading on the right (if connected properly). You should be able to reverse the wires if you wanted to make a richer mixture.

I've seen a negative reading before when it was connected to a wide-band o2 sensor tho. If you have a current passing backwards thru the efie, it'll act like that. The efie creates a weak signal. It sounds like you have a stronger signal going backward thru it, giving you a negative reading.

The problem isn't the negative reading. I believe it's the fact your input signal doesn't act like the right wire.

Are you checking the voltage with the vehicle running and warmed up? Was it running ok before the install and getting normal mileage? Did you have a check engine light before or after the install?



RE: Reading my multimeter AND unable to adjust EFIE? - colchiro - 01-06-2009 07:22 PM

We recently found out that certain Dodge and Jeep vehicles need an efie on the pre and post catalytic converter o2's. So far it appears that isn't necessary on the Toyota/Lexus/Hondas.

The rear o2 is almost always narrow band (old style), but the front one is usually wideband on most 2000+ Toyotas and narrow band before that. I'm thinking the manual is mistaken or the wrong wire harness was used and somehow you have another wire, probably not even related to the o2 sensor. It could be the seat belt retractor sensor for that matter.

If it was the rear, you'd have that quickly changing voltage between .2 and .8 vdc. Wink