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Modifying MAF signal - How to set ?
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jbalat Offline
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Post: #1
Modifying MAF signal - How to set ?
Does anyone have any first hand experience modifying the MAF signal with the O2 unplugged ? I guess what I need to know is how much to lean the mixture and what am I supposed to observe when leaning ?

Background:
I adjusted the frequency modifier board to lean about 10% before the car started losing power then backed off a little bit. So for 10%... I mean that I lower the frequency of the pulse. eg. at 1000rpm @ 40Hz the frequency will lower to 36Hz therefore there will be less fuel added to the air. At higher rpm 300Hz will lower to 270Hz and so on. The response of the board is always 2 pulses behind the actual but this should not be a problem. ...Only 1 bank of my Fuel cell is working and I estimate under 900mL/min at around 24 Amps, not sure if this is enough for my 3.0L engine.


Bottom line is that I was not able to make a fuel savings with this setting ? Also, I was not able to get the EGT to go up at all, in fact it actually went down by approx 50 degC

More Unexplained events:
So I decided to set up my board to RICHen up the mixture by making the frequency higher. At no setting did the car gain any extra power, in fact it actually lost power ? I could not rev the engine as it would just surge. This makes me think that the board may not be working or the ECU is not using the modified MAF signal properly....I was expecting to get a turbo effect.

...While playing around a while ago I connected up the rpm signal to my ECU in place of the MAF sensor. At around 2500rpm the car would produce a huge amount of power and EGT would go up over 100degC. The car was flying. The ECU was registering a fault, but I assumed that because the RPM signal does not carry the load (as the MAF does) then the difference was causing a leaning effect and therefore extra power and EGT.. For some reason I am no longer able to reproduce this effect however I did expect to get this power increase with my Frequency modifyer board but sadly did not Sad
When I checked the rpm pulse going to the ecu it only measured around 1Vp-p so I knew than if fact the rpm signal was probably being ignored.. this lead me to believe that the car was actually running rich.. No O2 and no MAF...hence my test to try and richen up the mixture which failed.

Sorry for the long post. Lots of unexplained observations, no savings, where to go from here ?
01-03-2010 04:17 AM
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AlexR Offline
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Post: #2
RE: Modifying MAF signal - How to set ?
jbalat,

One thing I do when I play with modding sensors is that I drive around with the HHO generator turned off. I then adjust each mod to make sure that it has an effect on the engine as in more or less power. It's my way to be sure that what I did is working as it should.

Have you modified the IAT sensor at all? I'd try that also. Make the ECU read a temp warmer than actual, this will help retard your timing. In reference to my above statement, modding the IAT sensor will not make a significant change in performance in my observations.

.

Alex

Cool Flame, LLC
http://www.cool-flame.com
01-03-2010 09:23 AM
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thomasbala Offline
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Post: #3
RE: Modifying MAF signal - How to set ?
(01-03-2010 04:17 AM)jbalat Wrote:  Does anyone have any first hand experience modifying the MAF signal with the O2 unplugged ? I guess what I need to know is how much to lean the mixture and what am I supposed to observe when leaning ?

Background:
I adjusted the frequency modifier board to lean about 10% before the car started losing power then backed off a little bit. So for 10%... I mean that I lower the frequency of the pulse. eg. at 1000rpm @ 40Hz the frequency will lower to 36Hz therefore there will be less fuel added to the air. At higher rpm 300Hz will lower to 270Hz and so on. The response of the board is always 2 pulses behind the actual but this should not be a problem. ...Only 1 bank of my Fuel cell is working and I estimate under 900mL/min at around 24 Amps, not sure if this is enough for my 3.0L engine.


Bottom line is that I was not able to make a fuel savings with this setting ? Also, I was not able to get the EGT to go up at all, in fact it actually went down by approx 50 degC

More Unexplained events:
So I decided to set up my board to RICHen up the mixture by making the frequency higher. At no setting did the car gain any extra power, in fact it actually lost power ? I could not rev the engine as it would just surge. This makes me think that the board may not be working or the ECU is not using the modified MAF signal properly....I was expecting to get a turbo effect.

...While playing around a while ago I connected up the rpm signal to my ECU in place of the MAF sensor. At around 2500rpm the car would produce a huge amount of power and EGT would go up over 100degC. The car was flying. The ECU was registering a fault, but I assumed that because the RPM signal does not carry the load (as the MAF does) then the difference was causing a leaning effect and therefore extra power and EGT.. For some reason I am no longer able to reproduce this effect however I did expect to get this power increase with my Frequency modifyer board but sadly did not Sad
When I checked the rpm pulse going to the ecu it only measured around 1Vp-p so I knew than if fact the rpm signal was probably being ignored.. this lead me to believe that the car was actually running rich.. No O2 and no MAF...hence my test to try and richen up the mixture which failed.

Sorry for the long post. Lots of unexplained observations, no savings, where to go from here ?

In general, very few, if any, have obtained any gains from any kind of MAF/MAP modifications. The reason is because the O2 or A/F sensors have the last word and override any MAF/MAP modifications. If you want gains put everything back the way it was. Inject about 1 lpm HHO per liter of engine displacement. What are your results? If you have a gain, great, either increase or decresas HHO. If you have a loss you know that the HHO is causing a more complete burn of your fuel and the O2 or A/F sensors think that the air/fuel mixture is too lean; thus they send a signal to the ECU telling it to richen up the mixture; thus your loss of mpg. Now that you know HHO has an effect on your mpg by lowering it you need an EFIE to make the O2 or A/F sensors send a different signal to the ECU telling it the mix is too rich and to lean it out. I know logic tells you that the MAF just has to be the master, but it's not; it's the O2 sensor.
01-03-2010 01:16 PM
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jbalat Offline
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Post: #4
Sad RE: Modifying MAF signal - How to set ?
Alex, I have tried the IAT trick and I did use it for a while even to retard my timing but with unfortunately with no luck with increasing mileage.

Thomasbala, HHO on its own reduces my economy from 12.5L/100 to 13.5-14 L/100.. You can argue it is due to a better burn but you can equally argue it is because of the extra load on the alternator.

I tried 3 types of Efie's and the best I could do was bring the mileage back to nominal (12.5/100) and no better. I even monitored this in real time on an oscilliscope to ensure the ecu did not go into open loop. Perhaps this is the maximum amount of fuel trim that the O2 is programmed to vary.

I tried my servo butterfly leaning device ... 14L/100
Now I tried my MAF frequency modifier (no O2) and got 12.8 L/100.. Yes I unplugged the O2 sensor because I know it will always win against the MAF.

As for 3.0 L/min of HHO, well only Bobs Hex controller can help me there and you had to scare Bob away Sad

So three scenarios, the technology doesnt work on my car, either I am not generating anough HHO (which is possible) or my MAF frequency board is not leaning the engine as it should (even though I can adjust it so the engine loses power and even stall) ?
(This post was last modified: 01-05-2010 08:14 PM by jbalat.)
01-05-2010 08:10 PM
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