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95 Protege - MAF Mod or O2 Mod?
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sumbich Offline
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Post: #1
95 Protege - MAF Mod or O2 Mod?
Hi all. I have a question about modding either my two Narrow Band 02 sensors (2 wire) or modding my MAF sensor.

A while back I purchased a MAP/MAF Enhancer off ebay and hooked it up to the MAF. All was fine until I tried to turn the dial - it simply cut the engine completely off by 1/4 turn and also threw my CEL.

I let HHO go for a while but I decided to try again as I have now purchased an OBD2 scanner to clear the CEL and get my cell working well without modding the ECU. I have completed this task as I am now getting 46 MPG (up from 28) running at 9 amps. The only problem is, I must clear the CEL before the next ignition of the car to have the engine auto adjust for the mix, and it's quite annoying.

I am now ready to mod the ECU, and read a few several threads on the use of potentiometers (certain ones being better than the others, 10-20k ohms to be exact). I took another look at the MAP/MAF enhancer I purchased a while back, took it apart and saw that the pots used were 50k. I was thinking of simply going to radioshack tomorrow, purchasing 10k pots to replace the others, and hooking it back up to the MAF to see if a finer tuning will result. Would this be the way to go, or would something else work better for my setup?

Again, I believe I have 2 narrow band 02 sensors, one mounted on the front of the engine, and the other just after the engine.

Any help would be much appreciated. Thanks to all in advance.

1995 Mazda Protege 1.5L DOHC
02-28-2009 07:38 PM
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colchiro Offline
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Post: #2
RE: 95 Protege - MAF Mod or O2 Mod?
Congrats on the gain.

I had a Toyota with a wide band o2, (before Mike's wide band efie) and my experience with just a MAF wasn't good. It was too easy to throw codes when driving at low speed and I was constantly changing it. The efie has a better success record of the two and is easier to set and forget.

IMO, MAF/MAP are best set at a low setting like IAT, CTS and other sensors and leave the real work to an EFIE. You should only need to treat the pre-cat o2.

A resistor-type MAF should work better with 10-15k linear pots. Like you noticed, 50k is too touchy.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
(This post was last modified: 02-28-2009 08:06 PM by colchiro.)
02-28-2009 08:05 PM
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sumbich Offline
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RE: 95 Protege - MAF Mod or O2 Mod?
(02-28-2009 08:05 PM)colchiro Wrote:  Congrats on the gain.

I had a Toyota with a wide band o2, (before Mike's wide band efie) and my experience with just a MAF wasn't good. It was too easy to throw codes when driving at low speed and I was constantly changing it. The efie has a better success record of the two and is easier to set and forget.

IMO, MAF/MAP are best set at a low setting like IAT, CTS and other sensors and leave the real work to an EFIE. You should only need to treat the pre-cat o2.

A resistor-type MAF should work better with 10-15k linear pots. Like you noticed, 50k is too touchy.

Both of my 02 sensors are pre-cat. As for now, I have ordered the 10k pots, and plan to rebuild MAF enhancer for another go. Thanks for the info. Smile Will report back in a few days to a week, as I am waiting for pots through mail.
03-04-2009 08:15 PM
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colchiro Offline
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Post: #4
RE: 95 Protege - MAF Mod or O2 Mod?
Your local Radio Shack probably had them for about $5 each.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
03-04-2009 08:42 PM
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Zipstor Offline
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Post: #5
RE: 95 Protege - MAF Mod or O2 Mod?
(02-28-2009 07:38 PM)sumbich Wrote:  I let HHO go for a while but I decided to try again as I have now purchased an OBD2 scanner to clear the CEL and get my cell working well without modding the ECU. I have completed this task as I am now getting 46 MPG (up from 28) running at 9 amps.
Wait a minute.. are you saying that you are injecting the gas without leaning your mixture.. And you are not overfueling...? Or I just miss understood... Hmm

And I have a question.. how do you clear the CEL with a scan tool? Does it just tell the ECU to shut up or are you leaning the mix this way..

Cheers mate

>> http://brownsgas.com
03-06-2009 04:33 AM
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sumbich Offline
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RE: 95 Protege - MAF Mod or O2 Mod?
(03-06-2009 04:33 AM)Zipstor Wrote:  
(02-28-2009 07:38 PM)sumbich Wrote:  I let HHO go for a while but I decided to try again as I have now purchased an OBD2 scanner to clear the CEL and get my cell working well without modding the ECU. I have completed this task as I am now getting 46 MPG (up from 28) running at 9 amps.
Wait a minute.. are you saying that you are injecting the gas without leaning your mixture.. And you are not overfueling...? Or I just miss understood... Hmm

And I have a question.. how do you clear the CEL with a scan tool? Does it just tell the ECU to shut up or are you leaning the mix this way..

Cheers mate

I just received my 10k pots in the mail and have wired the enhancer once again, but the car turns on and shuts off. Colchiro, I have used a MAF Enhancer wiring diagram I dug up from an old post of yours to be sure I wired it correctly. I am assuming the pots are being viewed from the front, not back. The pots I received have a larger diameter than that of the 50k ones I had before. The watt rating of the one I received is 1/2 watt. I now understand from your description you say 1 watt. Is there a problem between the two?

[img][Image: mafenhancer.th.jpg][/img]

Zipstor, as for your question, yes I am injecting the gas without leaning of the engine. The engine simply adjusts to the combustion. The check engine light was cleared by using the scan tool but would only work temporarily as it would come on and cause the car to go into open loop the next time the car would be turned on after shut off. You can easily do this by removing ground from the battery terminal, pumping the brake about 5 times to get the remaining static electricity from the car, and resetting the terminal. This will give you a temporary clear of CEL. Hope that helps. Smile
03-08-2009 09:25 PM
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colchiro Offline
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Post: #7
RE: 95 Protege - MAF Mod or O2 Mod?
Try it without connecting the ground. Half watt should be good enough.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
03-09-2009 05:37 PM
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sumbich Offline
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Post: #8
RE: 95 Protege - MAF Mod or O2 Mod?
(03-09-2009 05:37 PM)colchiro Wrote:  Try it without connecting the ground. Half watt should be good enough.

Worked without ground connected. Smile Thanks. Only one more problem to solve: The rotation is a little better as I can rotate up to 1/3 and 1/2 and then the engine shuts off. I read in the diagram that the resistor is attached to ground to allow full rotation. Would I try a resistor then, and if that were true, where would I incorporate it as I now have no ground? Or should I opt for an even lower pot? Say 5k?
(This post was last modified: 03-10-2009 07:07 AM by sumbich.)
03-10-2009 06:41 AM
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colchiro Offline
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Post: #9
RE: 95 Protege - MAF Mod or O2 Mod?
What resistor value do you have on the grounds? The higher it is, the more you can turn your know.

BTW, you do have linear taper pots, right?

My original said 50k pots and 33k resistors. I bet you have 33 ohm or a low value on yours.

If you have 10k pots, the resistor going to ground should be about 5k or more.

Rick

Links: Documents / Tuning for Mileage | Toyota Sensors | Autoshop Sensor Tutorials
03-10-2009 02:51 PM
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sumbich Offline
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Post: #10
RE: 95 Protege - MAF Mod or O2 Mod?
I am using linear taper, with no resistor on the grounds. 10k 1/2 watt works pretty well, but I just picked up a 5k 1/2 watt at Radioshack. I shall be trying it out in a day or two. I believe this one will get me where I want to be.
03-10-2009 03:06 PM
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