map/maf or O2 sensor

[kiki]

hi there.

there are a lot of threads about map/maf sensor enhancers, and efie units for O2 sensors. i know whta the units do but still have 2 questions:

- which one should i use to start.
- what is the difference in use

i am driving a grand cherokee with a 5.9 v8 engine, which has up and downstream o2 sensors.

hope someone can help me with some advise on this, thanks
arjen

[Keith's Garage]

I would actually use a MAP enhancer and a 02 extender. I just got done installing a unit on that exact car. Install the extenders on the upstream 02 sensors. Doing it this way, you don't have to enhance the MAP signal as much. The motor will be able to run a lot better.

[bwhite757]

^^^^ What he said...

I'm using the O2 extenders plus MAP enhancer, works well on my 07 Dodge Ram 5.7 Hemi..

[Painless]

If I remember correctly, the MAP sensor is to do with manifold pressure? How exactly does this effect fuel mixture?

[BigTruck]

MAF stands for mass air flow. I guess MAP would be mass air pressure. At any rate, these sensors measure the amount of air flowing into the engine. More fuel requires more air.

I used to think the best HHO input was the intake under vacuum. The problem is that the vacuum is reduced when you accelerate, therefore you get less when you need most, and vice-versa.

Now I'm thinking the idea HHO input area is between the map and the butterfly. This way the HHO flow increases with the air flow when it is needed most.

Somebody please correct me if I'm missing something here.

[Cadillac]

The MAP (manifold absolute pressure) sensor is used to determine the amount of fuel need as it relates to the mass of the air entering the engine.

The mass of the air is proportional to the air density, which is prosprional to the abosolute pressure and inversly proportional to the absolute temperature (this is the Ideal Gas Law).

So basically if you know the pressure in the manifold you take the rpms and the air temperature to determine the speed density. The car shoots for a 14.7:1 AFR (air fuel ratio). 14.7 in-HG is around sea level and is where this ratio comes from. By fooling the computer in terms of pressure you are changing the equation the computer is doing and thus changing the ratio.

Most cars that use MAP sensors also use these as a mean to determine elevation (altitude). When the key first starts to turn it takes a reading. It can also do so at WOT as the engine nears outside atmospheric pressure.

On some GM cars that ran through the late 80s and into the 90s they have both a MAP and MAF sensors. The MAP sensor in this case is primarily used to check the function of the EGR (exhaust gas recirculator) system. I would imagine if you where directly injected the HHO into one of these manifolds that you would set the EGR trouble codes off. It would also see the variations from the MAF to the MAP setting one of these codes as well.

[BigTruck]

Good job Cadillac. So are you thinking airbox or intake? What's the best way to trick the computer? Map and/or O2 adjustments with an Effie?

[kiki]

ok, so in my opinion ( i am not a car mechanic but have a degree in electronics.
i you trick the map sensor to make a leaner fuel mix , because you are inputting hho, the o2 upstream sensor will make a correction and will input more fuel again because it sees to much o2. so what you try to do on the frontend will be evaluated by the o2 sensor that will make a correction again.
so a map sensor without doing something with the o2 sensors will not work. is this a logical way of thinking?

so best will be to buy a efie that will enhance map and upstream o2 sensor?

the downsream o2 sensors are not affacting the fuel mixture?

i so some really great obdII bluetooth devices on ebay!! really handy to measrure the o2 signals and the map readings! would be a nice tool! you can have software on your windows mobile device and have wireless connection with your car!

http://motors.shop.ebay.com/_Automotive-Tools__obd-bluetooth_W0QQ_nkwZobdQ20bluetoothQQ_fxdZ1QQ_ptasZ 1

[kiki]

keith,
since you did the install on he exact same car, can i bother you with a few questions?
what unit did you instal (how much hho/minute)
what was the mpg result
since there is not much space under the hood (to much xtra stuff on a gc 5.9) what was the spot you mounted the hho genny?
the best place for inputting the hho into the air inlet.

i know thats a few questions, but since you've done this on this jeep i hope you can help me.
thanks,arjen

[Cadillac]

I just opted for the MAF sensor enhancer. I did put spacers on my O2 sensors. My system is installed on a Cadillac, hence the name. Almost every Cadillac since 82' has the ability to access the computer reading from the dash. Not only can you see MPG, scan for codes but you can see what almost every sensor is sending to the computers. This allowed me to fine tune my MAF enhancer since the O2 sensors are not variable. No other cars have this and the even with a scan tool you can not normally access information this deep (depends on the car).

My main reasoning behind why I would not mess with the O2 sensors any more then I did is simple. O2 sensors read in millivolts. That makes the resitance in the wiring very sensetive. If you where to say ever want to return the car to stock condition you would have to replace any wiring that was cut or perhaps the sensor itself depending on where you cut. My front two sensors cost $500, the wiring I would assume is pretty high as well as being a complete pain in the butt. Seeing as how this was an experiment for me at least in the beginning I saw no reason to incure that cost should things not work out. Since I have it installed and am getting what I want I see no reason to change it out.

If I had to try and work this system on a car that was more blind with cheaper parts I would probably try out some of these O2 sensor products.

[boats.petty]

has anybody thought of changing the computer signal to the computer through the obd2 port for 59.00 you can do this and no tinkering or gussing these guy's have got it figgured out I found this on anouther web site but they have been getting the same results as the controlers with out all of the fuss and same results




http://yhst-19807630266082.stores.yahoo.net/

[boats.petty]

you want the fs1 designed to work with hho I am going to try this on my diesel only good on 96 and newer
http://yhst-19807630266082.stores.yahoo.net/fuel-saver--fs1.html