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Reprogramming ECU?
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jasonporter181 Offline
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Post: #1
Reprogramming ECU?
I was just wondering anyone has tried re-programming their ECU's to set the AFR lean and what the results are? I am currently setting up a control board that includes an EFIE, MAP sensor adjustment board, 25Ohm pot for MAF, 5K pot for CTS which are all connected to test ports via 5 position switch. All this will be in conjunction with a scan gauge so I can monitor everything and also have all these sensors fully adjustable. However I have a feeling re-programming the ECU would be sooo much easier. Any thoughts?

By the way I am running an HHO gen w/ 16 2.5"x8" plates set up
-nnnnnn++nnnnnn- producing 1.5 liters/minute at 10 amps
05-02-2008 07:57 AM
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mike Offline
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RE: Reprogramming ECU?
I have no experience with this subject. I've looked around a bit on the internet, but didn't find anything that was practical for this purpose. But I didn't look very long, nor very hard.

If you find something workable and somewhat within reason price-wise, please post and let us know.

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05-02-2008 06:58 PM
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ptours99 Offline
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Post: #3
RE: Reprogramming ECU?
jasonporter181 Wrote:I was just wondering anyone has tried re-programming their ECU's to set the AFR lean and what the results are? I am currently setting up a control board that includes an EFIE, MAP sensor adjustment board, 25Ohm pot for MAF, 5K pot for CTS which are all connected to test ports via 5 position switch. All this will be in conjunction with a scan gauge so I can monitor everything and also have all these sensors fully adjustable. However I have a feeling re-programming the ECU would be sooo much easier. Any thoughts?

By the way I am running an HHO gen w/ 16 2.5"x8" plates set up
-nnnnnn++nnnnnn- producing 1.5 liters/minute at 10 amps
if you have a gm go to http://www.wait4meperformance.comthey will do any mod you want that can be done for under 150.00.

selling an enclosure for the rear of cab semi truck 28''X20''X6'' CUSTOM MADE ALUMINUM TO HOUSE HHO GENERATORS AND INCLUDING A RESERVOIR BUBBLER AND REGULAR BUBBLR ptoures@sbcglobal.net usa only
05-05-2008 04:23 PM
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jasonporter181 Offline
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Post: #4
RE: Reprogramming ECU?
I have a Nissan and have been doing exhastive research on the internet. So far I have found that my vehicle cannot be flashed. I have to re-program the chip itself. I am currently doing research to figure out how to reprogram my chip. Also before I do that I need to figure out my optimum lean AF ratio. To bad they can't make thus stuff easy!
05-07-2008 11:46 AM
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Jeephigh_11 Offline
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RE: Reprogramming ECU?
Tell me about it. I went as far as asking Siemens the computer manufacture for my Jeep how I would go about it, they didn't even give the time of day, I should have said I was from Jeep and would like to test out a possible programmer for the company to offer to the public. If we only had somebody that knew the proper parameters and coding then we'd be set. All we need then is a guy at the dealer to flash it into to the ECU.

Why can't we all just get along with the Car companies and get them to make high quality vehicles and programmable ECU's............. because we'd get 50+ MPG's and our cars would last twice as long and we wouldn't have to go to the delaer in five years to buy a new one.

Anyone know someone that works for an ECU manufacturer?
05-07-2008 12:45 PM
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rpatzer Offline
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RE: Reprogramming ECU?
I think what we need to realize here is the bottom line- pollution. They have determined that, short a lean-burn car, that the best/optimim ratio is 14.7:1 and that is best for the cat/pollution. Anything else they would have to redo the ECU, O2 sensor and the cat. The Honda Insight has done that, but it is a wholly re-done car. There is only so much that can be done with the narrow-band cars. The narrow band only reads from 14.5:1 to 15. Anything leaner and you mess with pollution, besides the stock ECU won't let you get leaner.

If you go to this site, they will explain what is involved in a lean-burn engine. Also go to their Direct Injection engines. You can see that everything has been retooled and computed. You can see what the lean burn cars are all about. What we can do with the conventional-burn cars is limited.
http://en.wikipedia.org/wiki/Lean_burn
(This post was last modified: 05-07-2008 02:08 PM by rpatzer.)
05-07-2008 01:44 PM
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mike Offline
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RE: Reprogramming ECU?
I have to controvert one thing you're saying rpatzer. With a combination of an EFIE, HHO, and tuning the sensors as per Tuning For Mileage, you can get the mix much leaner than 15:1. I'm not sure where you're getting your info that a narrow band sensor can only read 14.5 to 15. It actually can't read those values. It reads very high and very low and is constantly switching between the two, and the ECU times the injector pulses in such a way that the 2 are balanced. If the sensor gives .45 volts (which is theoretically 14.7:1 AFR), the ECU knows that the sensor is not operating, because that's actually an illegal value. Only values above .45 volts and below .45 volts (usually far above/below) are given.

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05-07-2008 08:23 PM
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snc22782 Offline
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Post: #8
RE: Reprogramming ECU?
I know that the aftermarket efi systems are very easy to reprogram. If I had the $ I'd buy an aftermarket efi system for my 67 Nova with a 350 V8. Then I could run all kinds of tests with an HHO device.
05-19-2008 10:20 PM
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Sartech Offline
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RE: Reprogramming ECU?
In general,

PCM programming is an expensive alternative to using addon mods to accomplish leaner afrs. I currently am achieving afr's in the 17/1 range on a 98 suburban with good results-running brown's gas also. I have achieved this using VCM tuning software. The fundamental tuning options are fairly straightforward but not for the novice.

Testing is not complete so results will not be posted at this time.

A note about afr calculation. The system running in closed loop will use a base afr of 14.7/1 on all gasoline engines mfr'd since at least the late 80's. The current version of software is called OBDII and uses the O2 sensor in closed loop for fuel control-almost exclusively. All other sensors function to allow the ECM to manage spark advance for torque control, among other things. If the ECM sees a problem in the O2 mode (insufficient cross counts, weak or low or high volts) it will revert to open loop and use MAF or MAP input for fuel calculations (Alpha N or speed density fuel management) Some performance guys will program for open loop operation and avoid the O2 closed loop mode altogether. Of course, we can't do that and avoid a run in with the EPA cops so we are stuck using the closed loop function. With that in mind, modifying the O2 signal becomes the most effective mod we can do to accomplish a leaner afr-hence the EFIE that Mike sells. By shifting the signal higher with the EFIE, the computer sees a rich condition in the exhaust and adjusts the injector pulsewidth accordingly resulting in a leaner run condition in closed loop. Should you force the signal too high, the vehicle will revert to open loop and ignore the O2 sensor signal altogether. It is important to know the difference when making modifications for lean run.
A note about stoichemetric ratios. The manufacturers use 14.7/1 as the baseline due to a calculation on fuel at standard atmospheric conditions in a liquid form. One of the reasons we know we can run leaner is due to fuel calculations done with fuel in a vapor state yield afr's in the 150-200/1 range. This is why vaporizers will work also as vaporizing the fuel results in better, cooler, faster combustion also. The mfrs ignore this and use the liquid fuel in copious amounts to cool the secondary flame front in the combustion process and let the emmissions components deal with the effect (ie. cat converters). Because of this we know the most efficient EFI IC engine is running at best 40% efficient. Carbureted engines struggle to be 30% efficient. The mfr's all know this information by the way, but they are committed publicly to 14.7/1 stoich because they know it works and they can meet EPA standards easily by using the extra fuel to quench. Everything else is secondary to their strategies, yes even fuel economy.
Mike is accurate in his descriptions of what is occurring and what is needed to get results. I might add that the timing becomes somewhat of an issue as well due to the increased flame speed that brown's gas precipitates in the combustion process, causing a need for timing retard to allow the burn to stay in the power stroke. This is why you see efforts to modify the MAP signal in an effort to shift the timing tables lower across the cruise range to accomodate this fact. The results will vary from car to car as the torque curves are drastically different for a 4cyl car versus an 8 cylinder car. By the way, the torque to weight ratios are significantly better the fewer cylinders there are, so you can expect greater % results in a 4cyl car versus an 8cyl car.

Until programmers get into this side of the game, don't expect to be able to send your PCM into someone and have it "tuned" for brown's gas. To my knowledge there are very few programmers even aware of this technology. They are geared for performance which is a whole different approach to air/fuel management tuning. I expect we can see more of this as the technology gets a foothold.........we can only hope.

sartech
05-21-2008 07:52 AM
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01olds Offline
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RE: Reprogramming ECU?
HI about doing mods to the c t s... so i hook the resistor in parelle? to which wire ground or signal....i see the water temp is near 193 degree driving...& 195 around town slower speeds....& which about what ohm resistor to use to increase fuel effiency......is it when the PCM sees a slight higher temp it leans out more? what you recommend... thanks don
05-24-2008 03:24 AM
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