MM-I and MM-II Secret Revealed!
08-07-2003, 01:30 PM
#1
Happy CL-S Pilot
Thread Starter
MM-I and MM-II Secret Revealed!
Yeah.. I am a reverse engineer so I was intrigued by the mystery of the Mystery Mod-I (RES) and the MM-II.
Interesting no...Here you go...
First MM-I, Scalbert did a MM-I clone with no success. Simply, the as stated by syncivic himself enlarging the volume of the center chamber is the not the secret, he added a special attention to the shape of the interior of RES was needed.... hmm, Juker008 mentioned that he learned that the EGR ports have something to do with the RES.
Since I have the Helms Service Manual and decided to do some Research and Reverse Engineering to reveal the secrets of the mystery mods, MM-I and MM-II.
And, I came to conclude the following.
The Concept of the Mystery Mod:
=======================
By blocking or reducing the EGR ports( Exhaust Gas Recirculation, to reduce Nox, nitrous oxide, emission) the engine will use more of fresh air i.e. more O2)
Applications: (MM-I and MM-II)
Application #1 (MM-I) Drawback: Totally blocking the EGR ports or even partially will result in PCM DTC code P0401: insufficient flow of EGR system.
So, how about reducing the port without tripping the EGR DTC code? if successful, you have your FREE HP, and MM-I works!
Now what is the MM-II? It is simply an electrical mod for EGR valve as shown on Page 11-24 in the helm manual. The idea is to close the EGR valve. It is in fact the same concept done electronically.
However,
Application #2 (MM-2) Drawback: Modding the EGR valve may result in PCM DTC code P1498: Bad EGR valve position sensor or even DTC P1491 Failure of EGR system (bad Valve).
So, the MM-2 is to be designed to close the EGR valve more than what the PCM is ordering without tripping DTC P1298.
What do yo think? anyone wants to verify my discoveries?
Interesting no...Here you go...
First MM-I, Scalbert did a MM-I clone with no success. Simply, the as stated by syncivic himself enlarging the volume of the center chamber is the not the secret, he added a special attention to the shape of the interior of RES was needed.... hmm, Juker008 mentioned that he learned that the EGR ports have something to do with the RES.
Since I have the Helms Service Manual and decided to do some Research and Reverse Engineering to reveal the secrets of the mystery mods, MM-I and MM-II.
And, I came to conclude the following.
The Concept of the Mystery Mod:
=======================
By blocking or reducing the EGR ports( Exhaust Gas Recirculation, to reduce Nox, nitrous oxide, emission) the engine will use more of fresh air i.e. more O2)
Applications: (MM-I and MM-II)
Application #1 (MM-I) Drawback: Totally blocking the EGR ports or even partially will result in PCM DTC code P0401: insufficient flow of EGR system.
So, how about reducing the port without tripping the EGR DTC code? if successful, you have your FREE HP, and MM-I works!
Now what is the MM-II? It is simply an electrical mod for EGR valve as shown on Page 11-24 in the helm manual. The idea is to close the EGR valve. It is in fact the same concept done electronically.
However,
Application #2 (MM-2) Drawback: Modding the EGR valve may result in PCM DTC code P1498: Bad EGR valve position sensor or even DTC P1491 Failure of EGR system (bad Valve).
So, the MM-2 is to be designed to close the EGR valve more than what the PCM is ordering without tripping DTC P1298.
What do yo think? anyone wants to verify my discoveries?
08-07-2003, 03:09 PM
#5
Happy CL-S Pilot
Thread Starter
Proof?
Understanding exhaust gas recirculation systems
By Henry Guzman
Exhaust gas recirculation (EGR) systems were introduced in the early '70s to reduce an exhaust emission that was not being cleaned by the other smog controls. Oxides of nitrogen (NOx) are formed when temperatures in the combustion chamber get too hot. At 2500 degrees Fahrenheit or hotter, the nitrogen and oxygen in the combustion chamber can chemically combine to form nitrous oxides, which, when combined with hydrocarbons (HCs) and the presence of sunlight, produces an ugly haze in our skies known commonly as smog.
How to reduce NOx NOx formation can be reduced by:
Enriching the air fuel (A/F) mixture to reduce combustion temperatures. However, this increases HC and carbon monoxide (CO) emissions.
Lowering the compression ratio and retarding ignition timing; but this leads to reduced performance and fuel economy.
Recirculating some exhaust gases.
How EGR systems work The EGR valve recirculates exhaust into the intake stream. Exhaust gases have already combusted, so they do not burn again when they are recirculated. These gases displace some of the normal intake charge. This chemically slows and cools the combustion process by several hundred degrees, thus reducing NOx formation.
The design challenge The EGR system of today must precisely control the flow of recirculated exhaust. Too much flow will retard engine performance and cause a hesitation on acceleration. Too little flow will increase NOx and cause engine ping. A well-designed system will actually increase engine performance and economy. Why? As the combustion chamber temperature is reduced, engine detonation potential is also reduced. This factor enabled the software engineers to write a more aggressive timing advance curve into the spark timing program. If the EGR valve is not flowing, onboard diagnostics (OBD) systems will set a code and the power control module (PCM) will use a backup timing curve that has less advance to prevent engine ping. Less timing advance means less performance and economy. Do your customer a favor and fix those EGR codes that you may have previously deemed as unimportant.
Evolution of the EGR systems The first EGR valves appeared in 1973 on GM cars. Bolted to the intake manifold next to the carburetor, it has ports to the intake and exhaust manifolds. It has a diaphragm that pulls open a valve stem, which allows exhaust to enter the intake manifold when ported vacuum is applied to it. Ported vacuum increases with throttle opening. A thermal vacuum switch prevents vacuum from reaching the EGR during cold engine starts. This system had many problems. It would often open too soon or too much, which caused a hesitation on acceleration as massive amounts of recirculated exhaust hit the combustion chamber. Many people simply disconnected it when it began to cause problems because they did not understand its importance or design. By 1975, if you unplugged an EGR valve, you'd have a driveability complaint of engine ping. Manufacturers and technicians of that era experimented with vacuum orifice restrictors and vacuum delay valves to try to find a happy medium between clean air and performance.
Closed loop systems By 1981, closed loop computer controls were in place. EGR flow was now more carefully controlled with dual diaphragm and back-pressure EGR valves. Modulating the vacuum to the EGR valve's pull, open diaphragm controlled the flow of recirculated ex- haust. Called by various names such as amplifiers, transducers and modulators, both remote and integral vacuum modulated devices were used. The flow of vacuum was further controlled by solenoids that blocked the vacuum ports until certain criteria were met such as engine temperature, rpm and manifold absolute pressure (MAP).
As the manufacturers began to use these complex schemes with vacuum amplifiers, delay valves and solenoids, they added a lot of "spaghetti" to the engine compartment. Plastic vacuum connections would break and rot with age and were not very reliable. Vacuum diagrams were invented and became essential to the smog driveability technicians of the day. As these systems evolved, they had fewer parts and less vacuum tubing. This was achieved by the use of pulse width modulated EGR solenoids. The PCM controlled EGR flow through the use of these solenoids to modulate vacuum to the EGR valve instead of just turning it on or off periodically.
What is pulse width modulation? Let's take a moment to discuss how computers think so we can better understand this common form of PCM control. Computers are binary. The machine language they operate in consists of only two variables: on or off, true or false, high or low. That's the only way a PCM can think. As a result, computer controlled outputs are always on or off, high (system voltage) or low (ground). Therefore, a computer output is always a square wave, or an on-off step when viewed on a lab scope. The high portion of the waveform will usually be battery voltage or PCM voltage of approximately 5 volts, with a few exceptions where the PCM operates at a different voltage.
Once the PCM receives its inputs, such as rpm, throttle angle, coolant temperature and MAP, it then calculates a response based on the software program that is embedded into it. Next, it makes its decision and sends a command in the form of a pulse width modulated signal to turn the EGR solenoid on and off rapidly. The EGR solenoid has two vacuum nipples. One side gets either manifold or ported engine vacuum. The other nipple goes to the EGR valve. Its default position is to block vacuum to the EGR valve. A vent is incorporated to bleed off vacuum when the solenoid is being pulsed. Vacuum flows to the EGR in rapid on-off pulses as the solenoid is commanded by the PCM.
OBD I systems With each succeeding year, the EGR designs became more refined. The California Air Resources Board (CARB) liked GM and Chrysler's onboard diagnostic systems. In 1988, CARB required that all cars sold in California be equipped with an onboard diagnostic system and a "check engine" light to notify the driver of emission system failure. By this time, all manufacturers had to have an EGR system that was capable of alerting the driver if it was not working. OBD I diagnostics and trouble codes were added in to flag opens, shorts and sticking solenoids.
OBD II EGR systems OBD II requires that the EGR system be monitored for abnormally low or high flow rate malfunctions. The EGR is considered malfunctioning when an EGR component fails or a fault in the flow rate results in the vehicle exceeding the Federal Test Procedure (FTP) by 1.5 times. FTP is the government-mandated drive cycle smog test that all new cars must pass and adhere to.
The diagnostic executive, also called the diagnostic task manager by Chrysler, controls the EGR monitor. The executive is an OBD II software agent given the task of managing all the onboard monitors and the scan tool interface. The executive coordinates the sequencing and actuation of all the monitor's test routines. There are eight main monitors whose sole function is to directly monitor and test the components assigned to them to ensure they meet FTP standards for life. These monitors are:
Catalyst monitor
EGR monitor
EVAP monitor
Fuel system monitor
Misfire monitor
Oxygen monitor
Oxygen heater monitor
Secondary air injection monitor
A closer look at the EGR monitor Monitor tests are both intrusive and non-intrusive. An example of an intrusive test is when the EGR monitor cycles the EGR valve during a condition when it normally would be closed. In some cases, the customer may feel an intrusive test as a slight miss.
The method of testing used by the EGR monitor varies according to the manufacturer, but there are three main types.
One method includes looking for a change in manifold pressure as the EGR valve is actuated on and off.
A second method involves cycling the EGR valve and looking for a change in short-term fuel trim. When the EGR valve is opened, it displaces some of the air fuel mixture. When the EGR valve is closed, more oxygen enters the combustion chamber, which then leans the mixture somewhat. The O2 sensor will respond with a lean signal to the PCM, which in turn increases pulse width. This is called short-term fuel trim compensation. The EGR monitor looks to see that all these things are occurring as they should. It repeats the tests and averages the results. Before the EGR monitor can begin its testing, it must first receive clearance from the diagnostic executive. The executive ensures that there are no conflicting conditions that would invalidate the EGR monitor's tests. For example, if the car had a lazy O2 sensor, fuel trim compensation to the EGR opening and closing would be inaccurate. Therefore, there are many safeguards built into OBD II to prevent this type of occurrence from happening. OBD II also has rationality checks. In other words, it uses deductive logic and constantly compares its inputs against each other to make sure all are in sync with one another. After the EGR monitor gets the OK to run its tests, it uses strict enabling criteria to ensure accurate testing such as:
Engine temperature more than 170 F.
Ambient air temperature more than 20 F.
Engine run time more than three minutes since 170 F.
Engine speed 2248-2688 (auto. trans.), 1952-2400 (manual trans.).
Manifold absolute pressure from 5-20 hg.
Short Term Adaptive Fuel Trim is adjusting pulse width by less than +7 percent and more than -8 percent.
TP sensor from 0.6 to 1.8 volts.
Vehicle speed sensor more than 40 mph.
The above is used for illustrative purposes only. Refer to your manual or CD-ROM information system for specifics to the car you are working on.
The third type of EGR monitoring design includes monitoring an EGR position sensor and a back-pressure sensor. Some Fords use a differential pressure feedback sensor that reads exhaust back-pressure upstream and downstream of the EGR valve to determine its flow rate and operation.
While OBD I systems would usually flag an inoperative EGR system, OBD II systems are given the task of determining the correct amount of EGR flow to keep the car running clean.
Next month, we will get into diagnosis, testing and repair techniques for all the different types of EGR systems. I will also cover pattern failures of all types, including mechanical problems such as plugged EGR passages that can cause rpm specific misfire concerns.
Henry Guzman is an ASE master tech with L1 certification. He has 20 years of experience working as a technician on foreign and domestic cars.
Source: http://www.asashop.org/autoinc/nov97/gas.htm
By Henry Guzman
Exhaust gas recirculation (EGR) systems were introduced in the early '70s to reduce an exhaust emission that was not being cleaned by the other smog controls. Oxides of nitrogen (NOx) are formed when temperatures in the combustion chamber get too hot. At 2500 degrees Fahrenheit or hotter, the nitrogen and oxygen in the combustion chamber can chemically combine to form nitrous oxides, which, when combined with hydrocarbons (HCs) and the presence of sunlight, produces an ugly haze in our skies known commonly as smog.
How to reduce NOx NOx formation can be reduced by:
Enriching the air fuel (A/F) mixture to reduce combustion temperatures. However, this increases HC and carbon monoxide (CO) emissions.
Lowering the compression ratio and retarding ignition timing; but this leads to reduced performance and fuel economy.
Recirculating some exhaust gases.
How EGR systems work The EGR valve recirculates exhaust into the intake stream. Exhaust gases have already combusted, so they do not burn again when they are recirculated. These gases displace some of the normal intake charge. This chemically slows and cools the combustion process by several hundred degrees, thus reducing NOx formation.
The design challenge The EGR system of today must precisely control the flow of recirculated exhaust. Too much flow will retard engine performance and cause a hesitation on acceleration. Too little flow will increase NOx and cause engine ping. A well-designed system will actually increase engine performance and economy. Why? As the combustion chamber temperature is reduced, engine detonation potential is also reduced. This factor enabled the software engineers to write a more aggressive timing advance curve into the spark timing program. If the EGR valve is not flowing, onboard diagnostics (OBD) systems will set a code and the power control module (PCM) will use a backup timing curve that has less advance to prevent engine ping. Less timing advance means less performance and economy. Do your customer a favor and fix those EGR codes that you may have previously deemed as unimportant.
Evolution of the EGR systems The first EGR valves appeared in 1973 on GM cars. Bolted to the intake manifold next to the carburetor, it has ports to the intake and exhaust manifolds. It has a diaphragm that pulls open a valve stem, which allows exhaust to enter the intake manifold when ported vacuum is applied to it. Ported vacuum increases with throttle opening. A thermal vacuum switch prevents vacuum from reaching the EGR during cold engine starts. This system had many problems. It would often open too soon or too much, which caused a hesitation on acceleration as massive amounts of recirculated exhaust hit the combustion chamber. Many people simply disconnected it when it began to cause problems because they did not understand its importance or design. By 1975, if you unplugged an EGR valve, you'd have a driveability complaint of engine ping. Manufacturers and technicians of that era experimented with vacuum orifice restrictors and vacuum delay valves to try to find a happy medium between clean air and performance.
Closed loop systems By 1981, closed loop computer controls were in place. EGR flow was now more carefully controlled with dual diaphragm and back-pressure EGR valves. Modulating the vacuum to the EGR valve's pull, open diaphragm controlled the flow of recirculated ex- haust. Called by various names such as amplifiers, transducers and modulators, both remote and integral vacuum modulated devices were used. The flow of vacuum was further controlled by solenoids that blocked the vacuum ports until certain criteria were met such as engine temperature, rpm and manifold absolute pressure (MAP).
As the manufacturers began to use these complex schemes with vacuum amplifiers, delay valves and solenoids, they added a lot of "spaghetti" to the engine compartment. Plastic vacuum connections would break and rot with age and were not very reliable. Vacuum diagrams were invented and became essential to the smog driveability technicians of the day. As these systems evolved, they had fewer parts and less vacuum tubing. This was achieved by the use of pulse width modulated EGR solenoids. The PCM controlled EGR flow through the use of these solenoids to modulate vacuum to the EGR valve instead of just turning it on or off periodically.
What is pulse width modulation? Let's take a moment to discuss how computers think so we can better understand this common form of PCM control. Computers are binary. The machine language they operate in consists of only two variables: on or off, true or false, high or low. That's the only way a PCM can think. As a result, computer controlled outputs are always on or off, high (system voltage) or low (ground). Therefore, a computer output is always a square wave, or an on-off step when viewed on a lab scope. The high portion of the waveform will usually be battery voltage or PCM voltage of approximately 5 volts, with a few exceptions where the PCM operates at a different voltage.
Once the PCM receives its inputs, such as rpm, throttle angle, coolant temperature and MAP, it then calculates a response based on the software program that is embedded into it. Next, it makes its decision and sends a command in the form of a pulse width modulated signal to turn the EGR solenoid on and off rapidly. The EGR solenoid has two vacuum nipples. One side gets either manifold or ported engine vacuum. The other nipple goes to the EGR valve. Its default position is to block vacuum to the EGR valve. A vent is incorporated to bleed off vacuum when the solenoid is being pulsed. Vacuum flows to the EGR in rapid on-off pulses as the solenoid is commanded by the PCM.
OBD I systems With each succeeding year, the EGR designs became more refined. The California Air Resources Board (CARB) liked GM and Chrysler's onboard diagnostic systems. In 1988, CARB required that all cars sold in California be equipped with an onboard diagnostic system and a "check engine" light to notify the driver of emission system failure. By this time, all manufacturers had to have an EGR system that was capable of alerting the driver if it was not working. OBD I diagnostics and trouble codes were added in to flag opens, shorts and sticking solenoids.
OBD II EGR systems OBD II requires that the EGR system be monitored for abnormally low or high flow rate malfunctions. The EGR is considered malfunctioning when an EGR component fails or a fault in the flow rate results in the vehicle exceeding the Federal Test Procedure (FTP) by 1.5 times. FTP is the government-mandated drive cycle smog test that all new cars must pass and adhere to.
The diagnostic executive, also called the diagnostic task manager by Chrysler, controls the EGR monitor. The executive is an OBD II software agent given the task of managing all the onboard monitors and the scan tool interface. The executive coordinates the sequencing and actuation of all the monitor's test routines. There are eight main monitors whose sole function is to directly monitor and test the components assigned to them to ensure they meet FTP standards for life. These monitors are:
Catalyst monitor
EGR monitor
EVAP monitor
Fuel system monitor
Misfire monitor
Oxygen monitor
Oxygen heater monitor
Secondary air injection monitor
A closer look at the EGR monitor Monitor tests are both intrusive and non-intrusive. An example of an intrusive test is when the EGR monitor cycles the EGR valve during a condition when it normally would be closed. In some cases, the customer may feel an intrusive test as a slight miss.
The method of testing used by the EGR monitor varies according to the manufacturer, but there are three main types.
One method includes looking for a change in manifold pressure as the EGR valve is actuated on and off.
A second method involves cycling the EGR valve and looking for a change in short-term fuel trim. When the EGR valve is opened, it displaces some of the air fuel mixture. When the EGR valve is closed, more oxygen enters the combustion chamber, which then leans the mixture somewhat. The O2 sensor will respond with a lean signal to the PCM, which in turn increases pulse width. This is called short-term fuel trim compensation. The EGR monitor looks to see that all these things are occurring as they should. It repeats the tests and averages the results. Before the EGR monitor can begin its testing, it must first receive clearance from the diagnostic executive. The executive ensures that there are no conflicting conditions that would invalidate the EGR monitor's tests. For example, if the car had a lazy O2 sensor, fuel trim compensation to the EGR opening and closing would be inaccurate. Therefore, there are many safeguards built into OBD II to prevent this type of occurrence from happening. OBD II also has rationality checks. In other words, it uses deductive logic and constantly compares its inputs against each other to make sure all are in sync with one another. After the EGR monitor gets the OK to run its tests, it uses strict enabling criteria to ensure accurate testing such as:
Engine temperature more than 170 F.
Ambient air temperature more than 20 F.
Engine run time more than three minutes since 170 F.
Engine speed 2248-2688 (auto. trans.), 1952-2400 (manual trans.).
Manifold absolute pressure from 5-20 hg.
Short Term Adaptive Fuel Trim is adjusting pulse width by less than +7 percent and more than -8 percent.
TP sensor from 0.6 to 1.8 volts.
Vehicle speed sensor more than 40 mph.
The above is used for illustrative purposes only. Refer to your manual or CD-ROM information system for specifics to the car you are working on.
The third type of EGR monitoring design includes monitoring an EGR position sensor and a back-pressure sensor. Some Fords use a differential pressure feedback sensor that reads exhaust back-pressure upstream and downstream of the EGR valve to determine its flow rate and operation.
While OBD I systems would usually flag an inoperative EGR system, OBD II systems are given the task of determining the correct amount of EGR flow to keep the car running clean.
Next month, we will get into diagnosis, testing and repair techniques for all the different types of EGR systems. I will also cover pattern failures of all types, including mechanical problems such as plugged EGR passages that can cause rpm specific misfire concerns.
Henry Guzman is an ASE master tech with L1 certification. He has 20 years of experience working as a technician on foreign and domestic cars.
Source: http://www.asashop.org/autoinc/nov97/gas.htm
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08-07-2003, 03:56 PM
#8
Happy CL-S Pilot
Thread Starter
now the question where in the world the EGR valve is located?
In Helm manual, it is not clear. Anyone has a photo?
how about doing a mod for this, dyno tyned too!?
Are you willing to help for the cost of 1hr dyno time?
In Helm manual, it is not clear. Anyone has a photo?
how about doing a mod for this, dyno tyned too!?
Are you willing to help for the cost of 1hr dyno time?
08-07-2003, 04:36 PM
#9
Three Wheelin'
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Page 8 of the SC install has a pretty good shot of it.
http://www.comptechusa.com/instructions/ins125.pdf
http://www.comptechusa.com/instructions/ins125.pdf
08-07-2003, 05:26 PM
#11
Senior Moderator
well nashau i think the EGR system has something to do with it...but i dont think it's all of it..or even most...why would the plenum cover have to be enlarged in order to lesson the egr flow?...doug did mention EGR to me ..when i mentioned i think that Steve was building his own he maid an off the wall comment like sure you could block the EGr flow...second not trying to rain on your parade but MMII the main thing i took away from that was dougs big conceren about cold weather testing and setting a code in the winter months up north...this leads me to beleive that he was messing with ECT/IAT sensors tricking them into thinking it was cold...so that if it acctually got real cold that maybe the car would think it was you know too cold 50+ below or something...obviously im no engineer ,and i like for anyone try...check into the ECT/IAT sesnsors and see what you think....
08-08-2003, 05:58 AM
#12
Happy CL-S Pilot
Thread Starter
TypeR,
MM has all to do with EGR. The increase volume of the center chamber showed no HP gain, and theoritcally, it will increase the resonance frequency beyond redline.
messing with the EGR Valve will trip at least 2 DTC code. the PCM has built-in self test for EGR valve. If the PCM decides that the EGR valve is out of command or not tracking the valve position that he expects , the PCM will flash a DTC code.
As you know, once the engine PCM sees a lean condition and by opening the EGR valve to compensate to reduce the lean condition, if the lean condition does is not corrected, another DTC code will be flashed (EGR system failure).
I am planning on designing a mod that will do what the RES was doing. I will test it on my CLS. If I can come up with the cost of dyno rent, I will dyno tested too.
Nahsua.
MM has all to do with EGR. The increase volume of the center chamber showed no HP gain, and theoritcally, it will increase the resonance frequency beyond redline.
messing with the EGR Valve will trip at least 2 DTC code. the PCM has built-in self test for EGR valve. If the PCM decides that the EGR valve is out of command or not tracking the valve position that he expects , the PCM will flash a DTC code.
As you know, once the engine PCM sees a lean condition and by opening the EGR valve to compensate to reduce the lean condition, if the lean condition does is not corrected, another DTC code will be flashed (EGR system failure).
I am planning on designing a mod that will do what the RES was doing. I will test it on my CLS. If I can come up with the cost of dyno rent, I will dyno tested too.
Nahsua.
08-08-2003, 06:36 AM
#13
TRELOS
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Scalbert and I are working on it. I am going the mechanical route. Scalbert may try to go the electronic route. I can easily reroute the recirculated gas from going back into the intake track, but i am wanting my cake to eat as well. Tring to figure out how I can recirculate the exhaust back into the intake when I am just crusing to save fuel economy.
Juker008
Juker008
08-08-2003, 06:45 AM
#14
Happy CL-S Pilot
Thread Starter
Juker, I am doing the same thing.
I have 2 options:
1) permanent mod
2) 2-way mod... On-Off... You can be back to stock as easily as flipping a switch.
I will design both. 2. Howver number 2) will cost a lot more.
Nashua.
I have 2 options:
1) permanent mod
2) 2-way mod... On-Off... You can be back to stock as easily as flipping a switch.
I will design both. 2. Howver number 2) will cost a lot more.
Nashua.
08-08-2003, 07:48 AM
#17
TRELOS
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Originally posted by Nashua_Night_Hawk
Juker, I am doing the same thing.
I have 2 options:
1) permanent mod
2) 2-way mod... On-Off... You can be back to stock as easily as flipping a switch.
I will design both. 2. Howver number 2) will cost a lot more.
Nashua.
Juker, I am doing the same thing.
I have 2 options:
1) permanent mod
2) 2-way mod... On-Off... You can be back to stock as easily as flipping a switch.
I will design both. 2. Howver number 2) will cost a lot more.
Nashua.
Haa yea that is exactly where I am at right now. We seem to think alike. All three of us should discuss this further. PM me ur EM address, I just checked and I can't seem to find it.
Juker008
08-08-2003, 07:50 AM
#18
TRELOS
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Originally posted by Nashua_Night_Hawk
TypeR, my guess, doug was trying to make the RGR channels longer which slow the EGR flow.
Nashua.
TypeR, my guess, doug was trying to make the RGR channels longer which slow the EGR flow.
Nashua.
Personally I think the EGR was removed from the intake all together by rerouting the exhaust gasses.
Juker008
08-08-2003, 12:31 PM
#19
Lead Footed
Originally posted by Nashua_Night_Hawk
TypeR, my guess, doug was trying to make the RGR channels longer which slow the EGR flow.
Nashua.
TypeR, my guess, doug was trying to make the RGR channels longer which slow the EGR flow.
Nashua.
Do you think in addition, if one increased the capacity of the air chamber allowing more cooler air in, it would accomodate more EGR flow and thereby not tripping the codes?
So more air, cooler air, still allowing full EGR benefits, and MMII allows for more advanced timing.
If I'm not to out of it, that would mean MMI (RES) gains and also explain the incremental MMII gains.
Ruf
08-08-2003, 01:09 PM
#20
Happy CL-S Pilot
Thread Starter
Ruf, I think if both MM mod are messing with the EGR, you can do either, it is another way to exploit the gains hindered by OBD-II emissons controls.
08-08-2003, 03:10 PM
#21
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Nashua - good detective work
the EGR valve is operational during normal driving speeds to help with the emissions of the car. its just running hot air back into the intake manifold. it is only open during some WOT runs.
IMO the benefits you would see from this on a stock car are minimal. it also seems like they have reinvented the wheel when it comes to the number of CEL codes one crappy ERG can display. if you did decide that removing it/blocking it was something you wanted to do, i would look at using a relay to make the computer think its still there.
the EGR valve is operational during normal driving speeds to help with the emissions of the car. its just running hot air back into the intake manifold. it is only open during some WOT runs.
IMO the benefits you would see from this on a stock car are minimal. it also seems like they have reinvented the wheel when it comes to the number of CEL codes one crappy ERG can display. if you did decide that removing it/blocking it was something you wanted to do, i would look at using a relay to make the computer think its still there.
08-08-2003, 07:03 PM
#27
Senior Moderator
Originally posted by Nashua_Night_Hawk
DTC check engine
DTC check engine
08-08-2003, 07:34 PM
#28
Community Architect
robb m.
robb m.
ok...guys, this is great stuff...BUT....
I can only assume Steve's absence means that Jennifer has given birth!
so, I'd like to say CONGRATS STEVE I know it's been an awfully long process, but it's finally come full circle, congrats on the success
I can only assume Steve's absence means that Jennifer has given birth!
so, I'd like to say CONGRATS STEVE I know it's been an awfully long process, but it's finally come full circle, congrats on the success
08-08-2003, 07:35 PM
#29
Senior Moderator
i bet you're right. 
08-09-2003, 05:58 AM
#30
Happy CL-S Pilot
Thread Starter
Originally posted by typeR
instantly? and would it stop egr flow and would the code go away after several hot/cold starts
instantly? and would it stop egr flow and would the code go away after several hot/cold starts
Also, I am not sure if you disconnect the EGR Valve, it would stay closed... maybe...one can try.
For anyone who is going to the dyno soon. Please disconnect the EGR valve and have some more runs and let us know.
Nashua.
08-09-2003, 06:19 AM
#31
ex 6 Speed owner :(
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I have messed around with EGR on my Accord recently by simply unplugging the vacuum like going to it. It will throw a CEL after a few minutes of driving. I noticed no better performance or gas mileage so I plugged it back in (also had a SMOG check 
). Anyway just today I realized on this car I could probably block the valve with a plate so it will still operate but not flow. This should not give me a CEL although reading through this thread:
I don't think my Accord is smart enough for that second one but we will see. Has anyone confirmed that second DTC code?
p.s. In the pic the square port is EGR IN, the round port is the OUT.
p.p.s. Will EGR work on a FI engine with positive manifold pressure
). Anyway just today I realized on this car I could probably block the valve with a plate so it will still operate but not flow. This should not give me a CEL although reading through this thread:
messing with the EGR Valve will trip at least 2 DTC code. the PCM has built-in self test for EGR valve. If the PCM decides that the EGR valve is out of command or not tracking the valve position that he expects , the PCM will flash a DTC code.
As you know, once the engine PCM sees a lean condition and by opening the EGR valve to compensate to reduce the lean condition, if the lean condition does is not corrected, another DTC code will be flashed (EGR system failure).
As you know, once the engine PCM sees a lean condition and by opening the EGR valve to compensate to reduce the lean condition, if the lean condition does is not corrected, another DTC code will be flashed (EGR system failure).
p.s. In the pic the square port is EGR IN, the round port is the OUT.
p.p.s. Will EGR work on a FI engine with positive manifold pressure
08-09-2003, 06:35 AM
#32
Happy CL-S Pilot
Thread Starter
Originally posted by BlueCLS6
..Anyway just today I realized on this car I could probably block the valve with a plate so it will still operate but not flow.
..Anyway just today I realized on this car I could probably block the valve with a plate so it will still operate but not flow.
08-09-2003, 08:45 AM
#33
ex 6 Speed owner :(
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Oh :o. I suppose that's why clogged EGR ports lead to CEL's... didn't think of that. But how does it know what the flow through the valve is... all I see is a vacuum actuated needle valve . Please excuse my ignorance
Correction... I just looked at my old Accord intake manifold and the round port comes from the exhaust side, the square port leads into the intake manifold... sorry for the error.
. Please excuse my ignorance Correction... I just looked at my old Accord intake manifold and the round port comes from the exhaust side, the square port leads into the intake manifold... sorry for the error.
08-09-2003, 03:49 PM
#34
Happy CL-S Pilot
Thread Starter
Next week, I will do the first prototype of the mod. If there is no CEL, I will try make a custom fab mod. It is time to look for a good shop.
08-13-2003, 06:43 PM
#39
Happy CL-S Pilot
Thread Starter
Originally posted by Nashua_Night_Hawk
Next week, I will do the first prototype of the mod. If there is no CEL, I will try make a custom fab mod. It is time to look for a good shop.
Next week, I will do the first prototype of the mod. If there is no CEL, I will try make a custom fab mod. It is time to look for a good shop.
After a quick test fit, NO Check Engine light. It is working as designed.
However, Theere is a weird sound coming from the EGR valve. I guess, the mod is interfereing with the EGR ports. I need to modify the EGR mod as not to interfere with EGR valve.
I removed the mod and the Engine sounds normal.
Nashua.
