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D40 with DPF and CAT Exhaust Issues
- Thread starter auggie
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mgermasi
Member
Auggie, congratulation on the good job!
Based on what you found on the temp sensors do you reckon it could be applied to the DPF as well?
I mean by working out what value the ECU wants see from the 2 sensor we could simulate the same value by installing a resistor on either of the sensors feedback so that it will never regenerate.
The maintenance CD that I have does not show the DPF electrical information.
Good job
Thanks
Max
Based on what you found on the temp sensors do you reckon it could be applied to the DPF as well?
I mean by working out what value the ECU wants see from the 2 sensor we could simulate the same value by installing a resistor on either of the sensors feedback so that it will never regenerate.
The maintenance CD that I have does not show the DPF electrical information.
Good job
Thanks
Max
auggie
Member
Hi Max
The system i currently have install already covers Cat and DPF. The test car has neither functioning. I haven't had enough time to do much long term testing as yet but i nearly 3000km's the driver of the car hasn't seen any smoke what so ever. This to me means the car hasnt run a regen. Only thing that gives you any indication its running to CAT or DPF is it now smells like a diesel at idle.
I want to run it longer. It may turn out that if it car goes so far with no regen, even when the sensors say it dosent require one the ECU does one anyway after a certain time or distance has elapsed after pervious regen cycle. I'm still not 100% sure to how much of an impact on the regen system the O2 sensor has either. For example if it can trigger one of it just watches as it's happening.
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Auggie, the HO2S does two distinct functions that I know of.
1) Determines available oxygen in the exhaust stream in order to help decide if a regen will succeed (oxygen needed to burn fuel, of course).
2) Monitors oxygen levels as they fluctuate based on the slight (deliberately input) variances in the fuel rail pressure. A corresponding fluctuation in oxygen levels is expected and if it's not found, the sensor is considered faulty (ergo it can't decide to do a regen ergo it needs limp mode).
I doubt the O2 sensor will be the cause of a regen being triggered, but I do think that IF the output from the O2 sensor is within the appropriate range, then IF the regen is triggered it won't be prevented.
1) Determines available oxygen in the exhaust stream in order to help decide if a regen will succeed (oxygen needed to burn fuel, of course).
2) Monitors oxygen levels as they fluctuate based on the slight (deliberately input) variances in the fuel rail pressure. A corresponding fluctuation in oxygen levels is expected and if it's not found, the sensor is considered faulty (ergo it can't decide to do a regen ergo it needs limp mode).
I doubt the O2 sensor will be the cause of a regen being triggered, but I do think that IF the output from the O2 sensor is within the appropriate range, then IF the regen is triggered it won't be prevented.
mgermasi
Member
I thought the HO2S sensor was used as feedback of CAT working correctly.
auggie
Member
Another thing that happens in the regen cycle is the Ecu will close the throttle body slightly. This makes the engine run richer aka hotter.
The O2 sensor is most likely giving feedback as to how rich the exahaust gas is so the computer can use this information inconjunction from what it knows from the exhaust temp sensors to alter it's post injection parameters. Is what im thinking
The O2 sensor is most likely giving feedback as to how rich the exahaust gas is so the computer can use this information inconjunction from what it knows from the exhaust temp sensors to alter it's post injection parameters. Is what im thinking
Well, there is a third function of the HO2S - ensuring that the fuel/air mix is within programmed parameters - too little oxygen in the exhaust (when more is expected) means the fuel is too rich and vice versa.
The sensor is definitely providing information for post-injection calculations, it was the first function I listed above.
Post-injection occurs on both vehicles with a DPF and those without. For those without a DPF, the catalytic converter uses hydrocarbons (diesel) as a reductant. It gets these from the exhaust stroke injection (the injectors open just before the exhaust valve starts to close).
The sensor is definitely providing information for post-injection calculations, it was the first function I listed above.
Post-injection occurs on both vehicles with a DPF and those without. For those without a DPF, the catalytic converter uses hydrocarbons (diesel) as a reductant. It gets these from the exhaust stroke injection (the injectors open just before the exhaust valve starts to close).
jms86
Member
with all these issues is it worth battling thru?
Sure, why not ... if you want a combustion engine, emission controls are going to play a an increasingly major role in its operation. The DPF, CAT, post injection, EGR are ALL specifically designed around emission control. It isn't something the manufacturer WANTS on the car, but NEEDS to have it to comply with ever-tightening laws around the world.
To meet the legal requirements, every manufacturer is going to have these (or more) devices in their cars. If you want a modern internal combustion engine-powered vehicle, you won't find a vehicle that doesn't have them.
Mazda have a CAT that employs an AdBlue reductant and if you service the vehicle yourself, you need to remember to fill that tank too (our Navaras use diesel - it needs to be a hydrocarbon). Quite a few small passenger-car diesels have DPFs to remove the soot. EVERY passenger car for the last 20-plus years has had a CAT - catalytic converter - to reduce NOx emissions.
If you don't want any of it, you need to go electric or pedal-power. Neither can tow well, and while pedal-power is more effective in some off-road applications, you'd struggle in river crossings and on soft surfaces (sand, mud).
So is the battle worth it? It's a trade-off, like many things. And if we get enjoyment out of the end result - and sometimes even on the journey there - then my vote is YES.
To meet the legal requirements, every manufacturer is going to have these (or more) devices in their cars. If you want a modern internal combustion engine-powered vehicle, you won't find a vehicle that doesn't have them.
Mazda have a CAT that employs an AdBlue reductant and if you service the vehicle yourself, you need to remember to fill that tank too (our Navaras use diesel - it needs to be a hydrocarbon). Quite a few small passenger-car diesels have DPFs to remove the soot. EVERY passenger car for the last 20-plus years has had a CAT - catalytic converter - to reduce NOx emissions.
If you don't want any of it, you need to go electric or pedal-power. Neither can tow well, and while pedal-power is more effective in some off-road applications, you'd struggle in river crossings and on soft surfaces (sand, mud).
So is the battle worth it? It's a trade-off, like many things. And if we get enjoyment out of the end result - and sometimes even on the journey there - then my vote is YES.
