ECU thread

[hg2]

yeah. which has a bigger influence, MAF vs IAT

Got this from a tuning doc I use


IAT
The IAT is less sensitive to cold start issues. You can add more temp to this signal than you can to the CTS. Just keep in mind that you are not only lowering your lean-out limits, you are also retarding your ignition timing. If you put a timing light on the engine as you adjust IAT values, you won’t see the timing change. The timing changes under load. Hotter air is more prone to detonation. This is why the ECU retards the timing.

If you are tuning on the hottest day of the year, you may find out just how high of a signal you can generate before setting codes. Typically it is in the 240° F range. If you are tuning in the middle of February, then you can offset the signal from your base cold reading and things will be fine for now. Come June or August, this setting may be high enough to trip codes. Allow for this when tuning.

the MAP sensor sees a given load, the TPS sees a corresponding throttle angle, the CTS sees a normal operating temperature, and the O2 sensor is saying the engine is too rich, the ECU will comply…to a point. When the ECU has leaned out the AFR (Air/Fuel Ratio) beyond what the programming claims is an acceptable range, the ECU will go into Open Loop and ignore the O2 sensor. It then reverts to Look-Up tables for its source of information. At this point, mileage will invariably go down, and often a trouble code is set.

Consider the conditions needed for the ECU to accept lean fuel commands. If the engine is warmer than it actually is, the ECU will accept leaner. If the engine is under less of a load, the ECU will want to deliver less fuel. If the incoming air is hotter, the ECU will accept lean commands more readily. If MAF (Mass Air Flow) sensor equipped, less air entering the engine will require less fuel.

[scirockett]

sweet. a good ECU thread!

I always thought the only sane mod (imo) is the o2 mod. This only effects fuel mixture in closed loop (when efficiency is important), and not in open loop (when HP is important).

Does anyone have any data on how HHO effects o2 readings, either narrow or wideband?

how about EGT's with HHO?

My experience with MAP based ecu's shows the fuel and timing maps are primarily based off a MAP vs. RPM table. Intake air temp and coolant temperature will modify timing depending on temps.. ie, high IATs = timing retart and low cts = timing advance (usually up until 30-40deg C for cts). when conditions are met for closed loop, the o2 plays a role in injector cycle time to get to your target afr. alsdjkfl bla, goota run,.

[jacobnbr1]

I ran one today with the intake air restricted.

As far as the data on the machine it did what i thought it would do.

As far as the driveability it sucked.
The car was very slugish and didn't want to respond to accel off idle.

Perhaps i taped off too much intake air but in values it didn't change all that much.

I need more time to think about this...

Here is a read about the MAF>

2002 chev astro 4.3 engine

Mass Air Flow (MAF) Sensor





The Mass Air Flow (MAF) sensor measures the amount of air entering the engine. The VCM uses this information to determine the operating condition of the engine in order to control the fuel delivery. A large quantity of air indicates an acceleration. A small quantity of air indicates a deceleration or an idle.

The scan tool reads the MAF value and displays the MAF value in grams per second (gm/Sec) . At idle, the MAF value should read between 5 gm/sec - 7 gm/sec on a fully warmed up engine. The values should change rather quickly on acceleration, but values should remain fairly stable at any given RPM. When the VCM detects a malfunction in the MAF sensor circuit, the following DTCs will set:


DTC P0101 System Performance
DTC P0102 Frequency low
DTC P0103 Frequency High





And LTFT=

RANGE (0-255 COUNTS): The Long Term Fuel Trim (FT) is derived from the Short Term FT value. The VCM uses the Long Term FT for the long term correction of the fuel delivery. A value of 128 counts indicates that the fuel delivery requires no compensation to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced, requiring decreased injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel, increasing the injectors pulse width.

RANGE (PERCENTAGE OF COMPENSATION REQUIRED): The Long Term FT is derived from the Short Term FT value. The VCM uses the Long Term FT for the long term correction of the fuel delivery. A value of 128 counts indicates that the fuel delivery requires no compensation to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced, requiring decreased injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel, requiring increased injector pulse width. As fuel compensation is required, the difference between commanded Long Term FT and 128 counts will be displayed as a percentage.






I hope i don't get in any trouble posting these...

[jacobnbr1]

yeah. which has a bigger influence, MAF vs IAT

Between those two options the IAT for sure...

If say you were in one of the southern states were the ambiant temp is always hot the ECM will keep the timming lean based on this data.

However; although it may retard the timing some the KS (knock sensor) will assist the ECM on where to place this advancement/retard setting...

Here is a read on the KS

2002 chev astro 4.3 engine.


RANGE (-90 TO 90 DEGREES): The knock sensor is a piezoelectric device which detects vibration due to spark knock. The VCM monitors the knock sensor signal while it performs spark advance calculations. This allows the engine to operate at maximum spark advance without spark knock to improve driveability and fuel economy. This parameter is the number of degrees.

[hg2]

Jacobnbr1
Does any of your training include stand alone systems? I can't find much info on these and have wondered if the application of this type system would allow me to eliminate map enhancer and o2 efie along with all other mods for mpg gains with hho.From what I know and have read these computers allow for total control over fuel and ignition systems.If you have any links or docs for these systems and how they work that would be helpful.

[jacobnbr1]

Jacobnbr1
Does any of your training include stand alone systems? I can't find much info on these and have wondered if the application of this type system would allow me to eliminate map enhancer and o2 efie along with all other mods for mpg gains with hho.From what I know and have read these computers allow for total control over fuel and ignition systems.If you have any links or docs for these systems and how they work that would be helpful.

Not sure i follow you on the "Stand Alone Systems" can you elaborate further...

[hg2]

Not sure i follow you on the "Stand Alone Systems" can you elaborate further...

I'll try but my knowledge is limited.Looking for different ways to control afr ratios I found on several sites selling stand alone computers used mainly in high performance applications.These units are used to bypass pcm control and give the user control over functions such as fuel air ratios and timing.Most of these units are high priced more so than say superchips tunners that only have about a 10% control ability,such as(and I think this is what they call it)their mileage miser unit.Sorry I'm not very well versed in this type technology and this is the best explanation I can offer.

[scirockett]

Originally Posted by resago
yeah. which has a bigger influence, MAF vs IAT

Between those two options the IAT for sure...

Not sure I'm onboard with that. Usually primary lookup tables are MAP vs. RPM or MAF vs. RPM and IAT is then factored in.

Stand alone replaces your factory ECU and gives you control of the timing and fuel maps, weight of other sensors like cts and iat, etc. etc. however; without understanding exactly what X amount of HHO does to say an o2 sensor reading, it would be impossible to tune.

here are my issues:

Do we understand what HHO does to the A/F mixure and/or EGT's? We need to understand this in order to tune to it.

Second, how do we expect any computer to compensate for varying amounts of HHO in the A/F mixture? Ie, there's X unmetered amount of HHO at 2000RPM and X unmetered amount of HHO at 5000 RPM. How can we program to that 1) not knowing the effects of HHO on the sensors, 2) not knowing the exact amount of HHO thats going in, and 3) knowing the percentage of HHO in the A/F mixtures will vary throughout the RPM band, which actually provides the least mixture of HHO when under load. Hope nobody thinks I'm obnoxious, because these are serious questions.. Isn't anyone concerned there is no metering of HHO? That's the name of the game in engine management - closely metering everything.. but unfortunately here, our X factor (HHO) is unmetered so everyone will get different results and our data will mean nothing. as negative as this may sound over the internet, I'm optimistic and just bringing up a point that any HHO critic would have a field day with...

[resago]

in a previous thread, I suggested the use on an RPM switch to activate efies. Also I agree we do need a way to measure the hho and have that be a factor used by efies.

If we are talking standalone ECUs, then we would have to come up with our own maps. we could use our observed LPM and factor that into the values.
we would need to know at what concentration that fuel and timing can be adjusted vs RPM.

[hg2]

Originally Posted by resago
yeah. which has a bigger influence, MAF vs IAT

Between those two options the IAT for sure...

Not sure I'm onboard with that. Usually primary lookup tables are MAP vs. RPM or MAF vs. RPM and IAT is then factored in.

Stand alone replaces your factory ECU and gives you control of the timing and fuel maps, weight of other sensors like cts and iat, etc. etc. however; without understanding exactly what X amount of HHO does to say an o2 sensor reading, it would be impossible to tune.

here are my issues:

Do we understand what HHO does to the A/F mixure and/or EGT's? We need to understand this in order to tune to it.

Second, how do we expect any computer to compensate for varying amounts of HHO in the A/F mixture? Ie, there's X unmetered amount of HHO at 2000RPM and X unmetered amount of HHO at 5000 RPM. How can we program to that 1) not knowing the effects of HHO on the sensors, 2) not knowing the exact amount of HHO thats going in, and 3) knowing the percentage of HHO in the A/F mixtures will vary throughout the RPM band, which actually provides the least mixture of HHO when under load. Hope nobody thinks I'm obnoxious, because these are serious questions.. Isn't anyone concerned there is no metering of HHO? That's the name of the game in engine management - closely metering everything.. but unfortunately here, our X factor (HHO) is unmetered so everyone will get different results and our data will mean nothing. as negative as this may sound over the internet, I'm optimistic and just bringing up a point that any HHO critic would have a field day with...

I think that monitoring the cylinder and exahaust gas temp. is more important than how much hho is being used.Extreme overleaning could result in catastrophic engine failure.It's said when using a stand alone,a monitoring meter such as the ones sold on sumit racing site,is a must when using one.They have bulit in alarms to alert you to problems that may occur before you do damage.This is just my humble opinion and what I've read and it's possible it could be incorrect.