You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
ECU flow chart ??
- Thread starter pcb
- Start date
- :
- Banned For Being A Troll
Do you mean a list of fault codes?
Do you mean a list of fault codes?
Sort of,... I'm trying to figure out what parameters are being monitored to get our P5's to go closed loop. The scan gauge and even the Blue-tooth Android app combination show Closed Loop. My Ultra-Gauge won't show Closed-Loop.
I have some factory published stuff. not sure if its what you're looking for. Can you be a little more specific?
That might help,... I've got some factory stuff too (they won't show us everything though cause we could steal cars easily with too much information out there) I've got most of the P5 wiring info but I'd like to see what the ECU is doing in terms of soft ware (things that need to be met to throw our cars into closed-loop)
Everything I can find indicates the only thing the PCM is looking for to determine loop status is temp input, it must be more than 167 degress F to be considered in "closed loop". That is the one requiste I am seeing to allow continous monitors to run to completion.
Installshield 2
Gothenburg Superiority
Do you have any info on what takes it back out of closed loop then? So we know the engine start parameter is an open loop-like protocol...then water hits 167*F, closed loop is 'allowed'...but what exactly pulls it back out to open loop?...Is is just rpm, just load, just TPS, etc...or a combination of all of them? switching from closed to open loop is one area that the stock computer versus msp computer are pretty different...the msp unit seems to hold closed loop longer (to nearly 3800 rpm i thought i read), even to a dangerously lean mixture...where the stock computer seems pretty consistent with switching to open around 3300 rpm iirc...
On my MSP I see openloop at about 4000rpm. I think I read somewhere that after 1.5-2sec of WOT it will switch. Also if you pull up the voltage on the primary 02 sensor you can force open loop. Flying Miata has a voltage clamp that works well for forcing open loop. The MSP is supposed to allow a lot more OL events without acting up but I don't know exactly how picky the NA ECUs are.
Justin2129
Member
- :
- 2002 Mazda Protege 5
my scangauge goes to closed loop within 30-60 seconds of startup, but it takes a few minutes of driving for it to get to 167*F...could the scangauge just be behind on the temps?
- :
- Banned For Being A Troll
When I had an OEM ECU it would go OL as soon as I hit 70 mph no matter what until I came back to legal speeds
- :
- Banned For Being A Troll
Wait, what?
there is no confusion, many cars have two.
Can you explain the logic in that statement.
there is no confusion, many cars have two.
Can you explain the logic in that statement.
In the instructions (for the UG) they said that normally if there is more than one O2 sensor, they are on separate banks, as in a "V" style engine (front and back). That way they are working in tandem, but our cars have one O2 sensor followed by another in the same exhaust stream. (I don't know that much about other cars).
From UG:
Raw output from the O2 sensor. 0 volts is equivalent of 100% lean fuel air mixture and 1.275
volts is 99.2% rich fuel air mixture. Bank1 is the cylinder bank with spark plug #1.
Typically only two O2 sensors are present, one on each bank.
Am I correct in assuming that when the car goes OL that the data from the O2 sensors is ignored and the ECU follows a MAP?
From UG:
Raw output from the O2 sensor. 0 volts is equivalent of 100% lean fuel air mixture and 1.275
volts is 99.2% rich fuel air mixture. Bank1 is the cylinder bank with spark plug #1.
Typically only two O2 sensors are present, one on each bank.
Am I correct in assuming that when the car goes OL that the data from the O2 sensors is ignored and the ECU follows a MAP?
Last edited:
- :
- Banned For Being A Troll
The two sensors are used to evaluate the condition of the Cat Converter.
Before and after the converter.
It will trigger a CEL if there is a fault with the function.
Before and after the converter.
It will trigger a CEL if there is a fault with the function.
In the instructions (for the UG) they said that normally if there is more than one O2 sensor, they are on separate banks, as in a "V" style engine (front and back). That way they are working in tandem, but our cars have one O2 sensor followed by another in the same exhaust stream. (I don't know that much about other cars).
Am I correct in assuming that when the car goes OL that the data from the O2 sensors is ignored and the ECU follows a MAP?
An inline 4 cylinder( most are, can't say I've seen a V4 in any vehicle I have seen through the shop in 20 years) has an upstream(pre-cat) o2 sensor used for fuel control and a downstream o2 (post-cat) used for catalyst monitoring. The downstream o2 (unless its a chrylser minivan) has no impact whatsoever on fuel control, all it does is judge how well the converter is working based on mathimatical formulas comparing the waveform and switch rate of the upstream sensor to the downstream sensor. Most late model "V" engines (be it 6 or 8 or in Bentley's case 12 cylinder) normally have one upstream sensor on each bank and one downstream sensor on each bank, depending on the way the exhaust is routed and the presence or lack of "pre-catalysts" (like the P5). The above Bentley I mention had 4 upstream (2 on each bank) and 2 downstream. Nothing that fancy on the Proteges....
Yes, when the car is in "open loop", its considered to be in enrichment mode, meaning its not relying on the o2 sensor to make fuel corrections, normally becuase the car is too cold (not up to temp) or you are at Wide open throttle....
Installshield 2
Gothenburg Superiority
^exactly...
pcb...when the UG people are talking about multiple O2 sensors...they're not referring to a set up like ours...There are some OBD-II equipped cars that actually have 2 engine computers entirely (the E39 BMW 5 series V8's to name one; it had a computer controlling each bank and set of throttle bodies)...and therefor multiple 'primary' o2 sensors...Our cars only have 1 o2 sensor that the UG should be worried about, the other one is just to moniter catalyst performance...as mentioned...
As far as the government...ideally a car should be in closed loop all the time...but processor resolution and sensor expense hinders that...open loop is needed because as load and rpm rise, there is less actual time to make the adjustments need to richen the mixture...which is why a system that uses data from a sensor AFTER the ignition event...becomes problematic...newer cars, and some full blown aftermarket stand alones...can do a high load closed loop protocol with a wide band o2 sensor and an extremely powerful central processing unit...a far cry from the calculator we have in our cars as standard...
I don't specifically know enough about these ecu's to know what exact sensor are used between the 2 loop modes...PCB, in theory, yeah...when the pcm goes to open loop, the data from the primary o2 sensor is arbitrary for fuel requirements...the ecu will still correlate data between BOTH o2 sensors, but ONLY for monitoring catalyst performance...when open loop is in place, the oxygen ppm of the exhaust gas will be outside of the primary sensors range for adjusting requirements, because everything is happening too quickly...but the computer can still compare what the first sensor sees with what the 2nd one does, if that makes sense...
and that is news to me about closed loop coming in just a minute or so after start up...I had read some Mazda tech documents a few years ago that explained how the VTCS functioned...and that it was part of an integral 'cold start' protocol the ecu would go through...which remained until the engine was warmed up past 149*F iirc...at that point the ecu triggers the opening of VTCS through vacuum assist...and normal operation is underway...it didn't specifically say if it was an open or closed status (when VTCS was activated i mean)...but implied the engine wouldn't be in 'normal' closed loop until almost fully warmed up...
what we can definitely say:
the ecu HAS to have some sort of cranking map for cold starts...When temps are extremely cold, many members with a VTCS delete have reported problematic starting and idle...that doesn't go away until the engine begins to warm up (several minutes at least when in below freezing ambient temps)...
however...those running an MP3 ecu (or just the car for that matter), which doesn't have VTCS to begin with...there is NO trouble starting in very cold situations...i can attest to that, 2 weeks ago my car fired right up in temps around 0*F with no trouble at all...and idled just as it always did...While i do currently have the VTCS system in tact, the MP3 ecu isn't using it..the solenoid never moves the arm connecting to it under any situations...so that proves that the 2 NA ecu's definitely do have different methods for cold starts, at least...
pcb...when the UG people are talking about multiple O2 sensors...they're not referring to a set up like ours...There are some OBD-II equipped cars that actually have 2 engine computers entirely (the E39 BMW 5 series V8's to name one; it had a computer controlling each bank and set of throttle bodies)...and therefor multiple 'primary' o2 sensors...Our cars only have 1 o2 sensor that the UG should be worried about, the other one is just to moniter catalyst performance...as mentioned...
As far as the government...ideally a car should be in closed loop all the time...but processor resolution and sensor expense hinders that...open loop is needed because as load and rpm rise, there is less actual time to make the adjustments need to richen the mixture...which is why a system that uses data from a sensor AFTER the ignition event...becomes problematic...newer cars, and some full blown aftermarket stand alones...can do a high load closed loop protocol with a wide band o2 sensor and an extremely powerful central processing unit...a far cry from the calculator we have in our cars as standard...
I don't specifically know enough about these ecu's to know what exact sensor are used between the 2 loop modes...PCB, in theory, yeah...when the pcm goes to open loop, the data from the primary o2 sensor is arbitrary for fuel requirements...the ecu will still correlate data between BOTH o2 sensors, but ONLY for monitoring catalyst performance...when open loop is in place, the oxygen ppm of the exhaust gas will be outside of the primary sensors range for adjusting requirements, because everything is happening too quickly...but the computer can still compare what the first sensor sees with what the 2nd one does, if that makes sense...
and that is news to me about closed loop coming in just a minute or so after start up...I had read some Mazda tech documents a few years ago that explained how the VTCS functioned...and that it was part of an integral 'cold start' protocol the ecu would go through...which remained until the engine was warmed up past 149*F iirc...at that point the ecu triggers the opening of VTCS through vacuum assist...and normal operation is underway...it didn't specifically say if it was an open or closed status (when VTCS was activated i mean)...but implied the engine wouldn't be in 'normal' closed loop until almost fully warmed up...
what we can definitely say:
the ecu HAS to have some sort of cranking map for cold starts...When temps are extremely cold, many members with a VTCS delete have reported problematic starting and idle...that doesn't go away until the engine begins to warm up (several minutes at least when in below freezing ambient temps)...
however...those running an MP3 ecu (or just the car for that matter), which doesn't have VTCS to begin with...there is NO trouble starting in very cold situations...i can attest to that, 2 weeks ago my car fired right up in temps around 0*F with no trouble at all...and idled just as it always did...While i do currently have the VTCS system in tact, the MP3 ecu isn't using it..the solenoid never moves the arm connecting to it under any situations...so that proves that the 2 NA ecu's definitely do have different methods for cold starts, at least...
Last edited:
I think what you may need is the parameters of a "Drive Cycle." It may be a good place to start anyways. The PCM needs to see a specific set PID's to complete a "Drive Cycle" which should send the PCM into "Closed Loop."
I will thumb through my stuff and see if I can come up with the "Drive cycle" & "Open/Closed Loop" Parameters.
You might try searching the Factory Service Manual or even Google for the spec's on your vehicle's "Drive Cycle"
I will thumb through my stuff and see if I can come up with the "Drive cycle" & "Open/Closed Loop" Parameters.
You might try searching the Factory Service Manual or even Google for the spec's on your vehicle's "Drive Cycle"
- :
- Banned For Being A Troll
What you are asking will not be in a book, the "Program" of the ECU or how it specifically works is not something that can be changed by a technician. If the ECU is not working, they change it.
I do not think that Mazda would have documents or technical papers published on the specific Cause and Effect of various conditions.
I do not think that Mazda would have documents or technical papers published on the specific Cause and Effect of various conditions.
