I have map AND maf...now what?

[Dustin]

I own a 1997 Oldsmobile Bravada with a 4.3 liter V6. It has a
MAP sensor and what appears to be a MAF sensor too. The Haynes manual I have dosen't say anything about this engine having both but Auto Zone does have a parts listing for both MAP and MAF sensors. I just got my HHO cell up and going and I built a MAP enhansor using a schematic from this forum. I can manipulate the signal from the MAP sensor and get the engine to start "pinging" or "spark knocking" so I know it is working but wonder if I also need to be "chatting" with the signal from the MAF sensor before it gets back to the ECM. I read the MAF is a demand sensor so it gets what it wants. Is this true for the MAP sensor also?

Dustin

[hg2]

I own a 1997 Oldsmobile Bravada with a 4.3 liter V6. It has a
MAP sensor and what appears to be a MAF sensor too. The Haynes manual I have dosen't say anything about this engine having both but Auto Zone does have a parts listing for both MAP and MAF sensors. I just got my HHO cell up and going and I built a MAP enhansor using a schematic from this forum. I can manipulate the signal from the MAP sensor and get the engine to start "pinging" or "spark knocking" so I know it is working but wonder if I also need to be "chatting" with the signal from the MAF sensor before it gets back to the ECM. I read the MAF is a demand sensor so it gets what it wants. Is this true for the MAP sensor also?

Dustin

If you built a map en. I would intall it on the map sensor,If you in fact do have one.

[Dustin]

Oh, I'm 110% sure it has a MAP sensor and about 95% sure it has a MAF sensor.....I think! Would I just set the MAF down a little and adjust the MAP a little and see what happens or will the MAP adjustment be sufficient?

[hg2]

I own a 1997 Oldsmobile Bravada with a 4.3 liter V6. It has a
MAP sensor and what appears to be a MAF sensor too. The Haynes manual I have dosen't say anything about this engine having both but Auto Zone does have a parts listing for both MAP and MAF sensors. I just got my HHO cell up and going and I built a MAP enhansor using a schematic from this forum. I can manipulate the signal from the MAP sensor and get the engine to start "pinging" or "spark knocking" so I know it is working but wonder if I also need to be "chatting" with the signal from the MAF sensor before it gets back to the ECM. I read the MAF is a demand sensor so it gets what it wants. Is this true for the MAP sensor also?

Dustin


I would install an O2 efie before a map en.They work better.

[Dustin]

10-4.....thanks! Is there any certain EFIE that is available people seem to have more luck than others or are they pretty much the same?

[hg2]

10-4.....thanks! Is there any certain EFIE that is available people seem to have more luck than others or are they pretty much the same?

You can shop around on e bay and others ,but take a chance on the quality and any tech support you may need on installing and adjusting.
This guy has a great efie,stands behind what he sells and offers great tech support either by e mail or forum.Plus the deluxe model has handy ports for probes for installation and ajustment.

http://www.fuelsaver-mpg.com/store/

[Jaxom]

That truck does have both MAP and MAF sensors. The MAF is the primary sensor for fuel calculations under steady cruising, while the MAP is given a little more weight during transients (throttle changes, deceleration, etc.) and at low RPM.

I'm not going to comment on which would be better to modify, as I don't believe in fooling around with sensor readings and "tricking" the PCM. It can easily do far more harm than good.

[Keith's Garage]

That truck does have both MAP and MAF sensors. The MAF is the primary sensor for fuel calculations under steady cruising, while the MAP is given a little more weight during transients (throttle changes, deceleration, etc.) and at low RPM.

I'm not going to comment on which would be better to modify, as I don't believe in fooling around with sensor readings and "tricking" the PCM. It can easily do far more harm than good.

I am just curious as to what you believe is the best way to have the computer lean out the motor?

[hg2]

I am just curious as to what you believe is the best way to have the computer lean out the motor?

There is no real best way to mod sensors and Jaxom is right saying that more harm than good can result from it,there are though right and wrong ways to do it.
I can tell you this that I've had both O2 and map en. along with several other mods on my truck for over a year now and havn't had any problems to date.I did research all of them for months before attemping any of them.
I've been on more than a half dozen forums in the last year and a half and have seen only one mishap caused from overleaning,and the person posted he'd fried his plugs but didn't think he had any other damage.Personally I feel if there were a number of people that did significant damage to their motors using leaning devices we would see more posted somewhere.Think how many have been sold on just e bay alone.
I noticed your ASE certification and with that you should be able to detect any signs of over leaning such as chugging,pinging and knocking,and know when to back off.It's the guy that has little automotive training trying to see how many mpg records he can break the first day with his newly installed O2 or map en. leaning the motor to death is the one that's going to have problems.
It's my opinion that if you detect any distress from your motor or any changes at all except mpg gains I would back off and try again.
I'm in no way trying to encourage you to proceed with your modifications just giving you infoformation of my experiences with them.You'll have to make your own decision on which way to go with it.

[Dustin]

Man, you guys are awsome. The more I've read, I do believe I will concentrate on the O2 sensors. Seems like it may be slower but yield more solid returns on fuel economy.

I'm really into building my own stuff. I get frustrated buying things like O2 enhancers, taking them apart, and seeing I could have bought the stuff at Radio Shack for a few dollars and put out a little effort to build it myself. I went to Radio Shack today with an idea of how to introduce a few millivolts to the O2 signal to the ECM. After talking with the owner he determined that I needed a certain trim pot I think it was. I came back to the garage and wired it as the schematic described on the back of the package. I applied 12 volts to it and adjusted it down to .200 volts output. Now, can I introduce that .200 volts which is what I'm just guessing as a starting point, I can adjust it with very high accuracy anywhere from 0 volts to battery voltage to the signal wire from the O2 sensor to the ECM. I'm thinking (hoping!) I can simply build a box that has 12 volts to it running through the pot adjuster and send the adjusted .200 volts to the 3 pre-cat O2 sensors......1 from the left bank, 1 from the right bank, and 1 just before the catalitic converter. There is one after the converter but I've read that just checks its work. Since I will be running one adjuster, all the sensors will be receiving the same skewed signal hopefully convincing the ECM that things are "normal" and to look elsewhere for something to do.
I'm kinda concerned that the voltage I'm sending might backfeed into the O2 sensor but I don't think it will do anything but stop right there.

Am I on the right track or on the verge of costing myself alot of cussing and money?!

[hg2]

Dustin make sure to check your voltage of the 2 pre cats upstream from the one before the cat.I've not familar with that set up with 3 O2s.I'm unsure if you need to address those 2 or not they may just be egt sensors.I can ask over at another forum that deals with O2s quite a bit bit and get you an answer,might take a day or so.Or ask Jaxom if he knows,he's well versed on sensors and may be able to help you.

[Keith's Garage]

The maximum O2s you would have to mess with would be two. Each bank has only one pre cat oxygen sensor (upstream). every other sensor is like Hg2 said, an egt sensor or post cat.

[Jaxom]

I am just curious as to what you believe is the best way to have the computer lean out the motor?

Teach the computer to use the HHO instead of fighting it.

Unfortunately that's a lot easier said than done. Simply changing the fuel and spark curves programmed into the PCM will help, but won't fix the problem. In closed loop, the O2 will still fight any sensor/programming changes you make, because it will always strive for a 14.7:1 air/fuel ratio. If you can figure out how to force your PCM to stay in open loop, the O2 readings are disregarded and the PCM runs strictly off the programmed calibration. That's the short term fix. The long term fix is a fundamental reprogramming of the computer's fuel trim feedback calculations to accouont for HHO and it's effect on the O2 readings, which is way beyond what 98% of people can do. The manufacturers may eventually address this, but unless you're an automotive engineer who's good with computer programming and youo have access to the source code for your vehicle's PCM programming, you just can't do it yourself.

As it happens I do have a reverse-engineered copy of the code for my IROC-Z. You can find stuff on the 'net if you get pretty deep into the performance tuning community. The code for my 20-year-old car is over 300 pages in print form, and things have only gotten more complex since.

[Jaxom]

Also, I agree with Keith on the O2's. The ones nearest the engine on each side are the feedback sensors, the others are for emissions diagnostics.

[Keith's Garage]

Jaxom, I completely agree with you on teaching the ECU to use the HHO. I just dont see that happening unless the manufacturers do it. The complexity of the newer vehicles is way to much for most people. For right now, I feel we need to "trick" the computer, though try to still leave as much control as we can to the computer.

[H2OPWR]

Man, you guys are awsome. The more I've read, I do believe I will concentrate on the O2 sensors. Seems like it may be slower but yield more solid returns on fuel economy.

I'm really into building my own stuff. I get frustrated buying things like O2 enhancers, taking them apart, and seeing I could have bought the stuff at Radio Shack for a few dollars and put out a little effort to build it myself. I went to Radio Shack today with an idea of how to introduce a few millivolts to the O2 signal to the ECM. After talking with the owner he determined that I needed a certain trim pot I think it was. I came back to the garage and wired it as the schematic described on the back of the package. I applied 12 volts to it and adjusted it down to .200 volts output. Now, can I introduce that .200 volts which is what I'm just guessing as a starting point, I can adjust it with very high accuracy anywhere from 0 volts to battery voltage to the signal wire from the O2 sensor to the ECM. I'm thinking (hoping!) I can simply build a box that has 12 volts to it running through the pot adjuster and send the adjusted .200 volts to the 3 pre-cat O2 sensors......1 from the left bank, 1 from the right bank, and 1 just before the catalitic converter. There is one after the converter but I've read that just checks its work. Since I will be running one adjuster, all the sensors will be receiving the same skewed signal hopefully convincing the ECM that things are "normal" and to look elsewhere for something to do.
I'm kinda concerned that the voltage I'm sending might backfeed into the O2 sensor but I don't think it will do anything but stop right there.

Am I on the right track or on the verge of costing myself alot of cussing and money?!

Dustin, I thind the Idea you have described might just work but make sure that you put a diode (one way check valve for electricity) in the circut. If you put one in the added voltage can not feed back to the 02

[Boltazar]

I also agree that we should be able to reprogram our computers to use HHO ..........BUT..........what happens when the HHO generator fails, the engine stops. It would be nice to be able to switch back to stock programing on the fly

[Dustin]

I had given the diode idea a thought but wasn't sure if the voltage would just end at the sensor or meet the reference voltage and stop there. I guess the diode wouldn't hurt anything would it? They don't have a voltage drop of any kind do they? What about when the signal voltage from the O2 sensor goes above my .200 volts I'm feeding into the signal wire? Wouldn't it force it's way back to the pot adjuster totally erasing what I'm trying to accomplish? I think I'm only going to be raising the bottom side of the voltage "swing" with my .200 volts. Anything higher from the O2 sensor than MY voltage is going to be erased......I think. Voltage is pressure. Higher pressure wins everytime.

I think there needs to be a way to "amplify" a given voltage. I'm absoutely no electronics person by any means but I do somewhat understand how DC voltage flows and behaves. If a voltage signal was rerouted to something that could amplify voltage by a couple of millivolts, I think it would be more consistant and believable by the ECM.

Again, I'm just getting started in this stuff and maybe way off track. I will say that JAXOM is right with the idea that a whole new program needs to be written for hydrogen. I wonder if a company like Hypertech or Diablo knows of such a possible need?

[Dustin]

I thought of something today. Instead of modifying the signal back to the ECM from the O2 sensor, what would happen if you modified the reference voltage going to the O2 sensor. Isn't the O2 sensor just a variable resistor that reacts with oxygen to vary the signal voltage back to the ECM? If it is just a resistor, then any input change would surely effect the output.....wouldn't it?

[Jaxom]

It's not really a variable resistor, but an actual voltage generator. Nonetheless, raising the reference voltage (a.k.a. sensor ground) to the sensor should raise the output by the same amount. We recently figured out that Dodge does this from the factory (http://hhoforums.com/showthread.php?t=1429) with the Hemi trucks.

[Painless]

It's not really a variable resistor, but an actual voltage generator. Nonetheless, raising the reference voltage (a.k.a. sensor ground) to the sensor should raise the output by the same amount. We recently figured out that Dodge does this from the factory (http://hhoforums.com/showthread.php?t=1429) with the Hemi trucks.

Same thing happens with the 4.7L, mine supplies a 2.5v base bias.

I'm wondering if changing the bias would be a problem though, I noticed that upon engine start the voltage from the O2 sensor starts at 0v then slowly works it's way up over about 5-10 seconds to 2.5v, where it stays until the sensor is warmed up. Adding to this might upset the ECU? Guess it's a try it and see scenario as always.

[Jaxom]

Yeah, it'll be trial-and-error. I don't think it'll cause a problem since you're introducing such a small change, but you never know until you try.

[Roland Jacques]

That truck does have both MAP and MAF sensors. The MAF is the primary sensor for fuel calculations under steady cruising, while the MAP is given a little more weight during transients (throttle changes, deceleration, etc.) and at low RPM.

.

This is a great piece of information. thanks

[wide open 97]

Hi I am new to all this hho stuff and have questions.I recently purchased a hho kit with bubbler for my 01 malibu.So far i put the kit in plus a scanner 2 and now a map sensor efie.Can someone help me on how to make this efie work??I ahve heard alot about all different kinds of efie's but i have this one and need some info on how to make it work.Thanks for all help