TOPIC: 2006 Frontier 4.0 4x4 has been grooved!

2006 Frontier 4.0 4x4 has been grooved! 04 Apr 2020 10:47 #49

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neil wrote: my replies are in this colour –Greg
my replies in this bold- Neil
I like Purple - Greg

neil wrote: Thought I may make some comments here, being referred by Greg.
My comments are not following much knowledge about having success with the groove but I have done lots of similar stuff.
Here goes, please question anything I say that you disagree with or makes no sense.
Firstly any ECU can run a motor with probably only 2 inputs (sensors). These are crank angle and load. These are the "essential" inputs, we can easily verify "essential sensors" by unplugging them with the engine running and the motor will immediately stop. Non essential sensors will not stop the motor when unplugged (but will cause open loop operation and perhaps a code) that's exactly what happens - a code triggers open loop Hmm! A code won’t always cause open loop, I think Vernon is experiencing a code ATM in closed loop because he still has fuel trims active. In open loop there would be no fuel trimming and no crazy stuff for Vernon to deal with. Being in open loop is a very common and normal thing and doesn’t always mean there is anything wrong….just that there is at least 1 sensor not yet in its normal range. I have no fault codes with the o2 sensor being disconnected, if a did get a code I can easily find another way to have the computer stay in open loop, I could get a spare temperature gauge and connect it to the vehicles harness so the computer doesn’t think the engine has warmed up yet, or a spare o2 sensor not installed in the exhaust…and so on. Open loop doesn’t mean there is a code or problem present.OK, good point; maybe it isn't indicative of an actual problem
Imagine an ECU operating a motor through its outputs, with "programs" when only connected to two inputs (also check 12 volt power supply and good earthing wires, This is called OPEN LOOP and ignores all the other (non-essential) sensors it might be connected to. This is a normal scenario every time we first start a motor because it is impossible for a ECU to immediately be optimizing operations. A lot of people worry about an ECU running permanently in open loop but I have found negligible difference in fuel economy or performance. Unplugging a correctly functioning MAF sensor might shut down fuel injectors - the computer has no reference as to the MASS of air getting sucked into the engine, so it can't do the math to reckon fuel injector pulse durations for 14.7:1 - zero air means zero fuel required, right? Yes agreed. One exception is that some engines have two sensors to give engine load, one can be manifold pressure (MAP) and the other can be air flow measuring (MAF).like mine
Now an ECU operating like this is operating well below its capability; so the ECU monitors all of the non essential sensors and switches to CLOSED LOOP after they have come into a desired RANGE. This is where a faulty sensor can trick the ECU and cause all sorts of problems, any diagnostic procedure should include forcing an ECU back to OPEN LOOP to help isolate the problem. This is as easy as cutting a wire to any non ESSENTIAL sensor. or disconnecting it from the wiring harness Yes, but as stated best if it is done in a way that does not result in a code.
I explain all this before saying what I have done.
I did fuel economy checks for OPEN and CLOSED loops, in my case there was no difference in fuel consumption, so I have forced OPEN LOOP operation for ease of "adjustments".
After grooving I think there would be 2 things that primarily need to be changed - fuel and timing, comments are below.
ADJUSTING FUEL RATIO- The only simple ways I can do this is to go into OPEN LOOP and adjust the Air flow meter signal to ECU or change the fuel rail pressure. Option 1: the preset program opens the injector for a set time if I reduce the pressure less fuel will go through in that time. Actually, I would increase the pressure: if More fuel is sprayed by the injector under higher pressure when it's open, the more likely it is that the o2 sensor feedback will shorten the time that they're open Yes I like the idea of higher fuel pressure but in open loop it will over-fuel and in closed loop the oxygen sensor will still cause the same amount of fuel to be delivered, so apart from slightly better atomisation I don’t see any benefit of higher fuel pressure being likely in seeking economy. That's why you need to be in closed loop - for the control mechanisms to actually do the jobs they were designed to. We've both used modifiers on the sensors to try to take further control of things, and from a mileage/fuel consumption perspective, if you've disabled the mechanism that's meant to optimise that, you'll get the base mileage/fuel consumption This can only work in OPEN LOOP because in CLOSED LOOP the o2 sensor would simply cause the ECU to compensate by opening the injectors longer. right, that's why you want to boost pressure I still think this will only lead to more fuel being used correct, in open loop. by turning the pressure down at the injectors, you're giving them the basic equivalent of prostate problemsOption 2: (I did this one) use a 50,000 ohm variable resistor to reduce the voltage from the air flow meter to the ECU, the ECU then delivers the correct amount of fuel for a lesser perceived amount of air making for a higher actual ratio of AIR to fuel...more air for the same amount of fuel Yes, so it is leaning out the motor.yup, I get that. My variable resistor is mounted on my dash and I can change it whilst driving.
ADJUSTING TIMING- When in OPEN LOOP timing curves are always very safe, many older people have always advanced timing (petrol and diesel) and seen benefits by advancing more than the manufacturers have dared to. The better "PREPARED" an air charge is prior to ignition then the less advance is required. I can best explain this in a story of my following a very clever mans advice to optimise motors running on Propane. I built a hot air box for the intake air and was aiming to having the intake air at hotter than 100 degrees Celsius (212 Fahrenheit), he advised me to dismantle my distributor and remove all advance capabilities, I did this and ran fixed advance of about 5 degrees before TDC (including highway cruising at 3000rpm). This is radically different to standard advance curves that see spark ignition occurring more than 40 degrees before top dead centre. Crazy to think about fuel starting to burn 40 degrees before tdc. actually, contrary to popular knowledge/belief, it's not explosions happening in the cylinders, but fairly controlled burns that take time for the combustion event to reach peak pressure and expansion for power/force to move the piston.
You have to light the charge off earlier at higher rotational speeds because that expansion time (flame front speed) is fairly fixed
Yes, agreed, but really any explosion is a controlled burn, even gun powder comes with specific burn speeds for different applications. I think that flame front speed is actually very variable and I suspect that the groove causes a much faster flame front speed/explosion which is why a lot less ignition advance would be my guessI wish we had the ability to test that. My belief is that the Groove's waveform makes for a more evenly mixed air-fuel charge in the cylinder, which makes for a very predictable and even burn that allows for the monitoring and managment mechanisms to tighten tolerances to the maximum. I'd also like to test that
It is my opinion that standard advance curves are way to advanced for successfully Grooved motors. someone makes the decision about power vs efficiency for the average user. people who choose to modify their car do so to impart their own decisions in the place of that decree from "on high" I am not sure if power needs to vs efficiency, i like to think the best power comes at the same time as best efficiency, in any case I am only trying to go the next step to see the groove do something amazing on my vehicleOK, I meant power vs mileage. Ron has said from the beginning that with great power comes great responsibility, so if you're not getting gains in mileage or reducing your consumption, there probably are things you can do to change that
I have not investigated how to change the input to the ECU to reduce degrees of advance, I am hoping that the ECU will "hear" any detonation and retard timing until it stops detonating. I am confident reducing fuel ratio is the first and most important thing to do. that's why we're here Well I am happy to cut the fuel but I had hoped that the groove would have done this for me, I hoped that a better burn would have caused me to lift the accelerator pedal and fuel would have been saved automatically, I still wonder if I have something else that prevents my groove from doing what I hoped forI don't doubt there is, but until it's found and rectified, we're simply whistling in the dark. (they're called DIAGNOSTIC Trouble Codes for a reason, hint hint ;) My scan tool shows me the amount of advance, I am now curious and wish I had tried to record degrees of advance in all different circumstances. When I was playing with propane engine ignition advance, it seemed hard to optimise and the benefits were quite small.
Regarding advance- cold motors need more advance and vice-versa. slow RPM requires less advance and Vice-versa. Slow burning fuels need more advance and Vice-versa. Petrol vapor burns much faster than liquid petrol. liquid gasoline/petrol doesn't burn - the fuel injectors atomize it, making it easier for engine vacuum to vaporize more of the smaller droplets. That's why Direct Injection engines have such high fuel pressures. Yes I agree but liquid fuel is still what goes in! The vaporising process you describe just becomes part of the process, takes time and why earlier ignition is required with liquid fuel having more stuff to do before it can burn.to allow the fuel time to vapourize and mix with the air charge on the intake stroke, before compression and the ignition event? Timing the ignition event to allow for all of the factors to be correct if not perfect is a fine art bordering on black magic
Vernon, I would be interested if you have any luck with the o2 sensor extenders, in my last post I explained what I did and saw no change in the o2 sensors output with extender fitted. I guess from my comments above it is obvious I think it is a very complicated way to change the computers fuel delivery and only works after the ECU switches into closed loop. correct - the engine only listens to the o2 sensors when the coolant temperature sensor determines the engine to be at correct operating temperature Yes, but to be more clear the engine must be at the right temperature AND in closed loop, there are other reasons why it must not be in closed loop even with correct engine tempPlease share what those are
Being able to see fuel trims is evidence of being in closed loop, Im pretty sure the two trims are showing the short term and long term changes it is making to the ECU's self learning, not left and right banks of the motor. it depends on a lot of things - I have a V motor but only one upstream o2 sensor - convention is one on each exhaust manifold IF the computer can control individual injectors well enoughIf there is two sets of trims these are what change the self learning and there are short term and long term self learnt adjustments, Right, Short term trim is fine tuning the long term trim, which indicates deviation from programmed fuel map. when it's all tuned and correct, long and short will show zeros (naughts). the whole trick to is to find the right balance of performance and fuel consumption, and that varies car to car and driver to driver I did not know any scan tool could reduce timing advance, perhaps it is only the closed loop adjustments that you can adjust? I would be even more surprised if it the OPEN LOOP presets that can be changed by a scan tool. there is a difference between a scan tool and a programmer tool. certain tuners go so far as to build their own computer and customize the fuel map for that car/driver. base fuel map numbers - for open loop it's the coolant temp; for closed loop - is what the o2 sensors "Trim" in either direction based on air/coolant temp/pressure, knock...Hmm! Open loop needs no inputs apart from crank position and engine load MAF or MAP. Closed loop uses all the sensors, more specifically it does not use any sensor/s until all are in a desired range, I just want to be clear that in open loop there is no adjusting or input from coolant sensors and in closed loop the computer uses all inputs and if it can't then it reverts back to open loop.
My ECU stays in open loop because I cut one wire on the o2 sensor.
I think this is the easiest way to seek the grooves potential and experiment, I hope to later get it back into closed loop operation.please keep us posted on your findings and progress! I will do but with this corona virus we are in lockdown so longer trips are gonna be a while

Neil - I suspect in your case on your truck, you may want to look into replacing the fuel filter (if it has one - it could be gummed up, reducing pressure at the injectors) or the pump itself if the pressure spec is outside of factory norms at the rail(s). (One easy way to boost pump pressure is to boost the voltage the pump runs on by a volt or two - there are electronic hacks for that, and I know of one video I could point you to for reference if you want to test that) Yes could you please point me to that video? I tested my fuel economy in both closed and open loop and everything behaved perfectly (apart from economy) so I am not sure of how the fuel filter could be causing any problem, even if it does have some restriction a restriction in the filter would reduce system pressure AFTER the filter, possibly causing your injectors to stay open longer than required to deliver the fuel the computer calculates is required based on MAF/MAP sensor data. without lambda feedback, which happens when conditions are set for closed loop, it adjusts based on what it can be certain is happening...and rewrites the stored fuel map continuously
Video
You should also see his video on Hysterisis...something that the computer uses to determine if a DTC is warranted or if most things are close enough to not throw one


Another thing that comes to mind - voltage - what is the alternator putting off vs what it should be? might you need a rebuild to replace a bad rectifier or regulator? or is there a grounding issue? I'd start here before the fuel system stuff I mentioned above. it could be that your alternator operates at 13.5v and the computer needs 14.4 (or the opposite!)...that will travel downstream to computer AND sensors and fuel pump and injectors and and and... Remember: battery voltage is not the same as alternator supply voltage - batteries build up resistance over time - measure from the alternator output red positive and a chassis ground you know/trust. if it's below a voltage that will top the battery off and keep it charged (over 13v in either case), there is your first problem Again I am curious about how changes to fuel pump voltage can affect anything. Fuel pressure is controlled by the fuel pressure regulator, it is not like a power steering system where relief pressure is rarely seen. Having constant fuel pressure is critical for maunfacturers because it is factored into the ECU programming, changes in fuel pressure would mess up open loop operation hugely when there is no computer feedback. My car uses the same amount of fuel in open loop as it was designed to. I think rather than worrying about fuel pressure accidentally being wrong I would say that causing fuel pressure to be incorrect would take major modification of fuel pump output. boosting supply voltage to the pump will make it work harder. (you'd have to make sure you keep the tank full so it's constantly cooled by the fuel) is your pressure regulator prior to whatever filter? is it working correctly?

Summary; The reason for this discussion is because some engines are not responding to the groove. not really - we're discussing modifications ancillary to the groove to further fine tune how the computer sees what is happeningPerhaps this is because the computer doesn’t see the benefit of the groove. In open loop the computer just injects a preset/same amount of fuel so that there is no saving. Worse than that the o2 sensor also does not see any benefit either(I thought it should btw) actually, the o2 doesn't see that anything is out of the ordinary, meaning it has no reason to signal the computer to do anything differently and in closed loop we are still not seeing a benefit to the fuel economy. To run further with this theory requires “lying” to the computer, so we just need to know how to do it easily, safely and reliably. I think doing it through the o2 sensor is difficult, hard to adjust and maybe doesn’t allow an adequate range of adjustment either which is precisely why i recommend a holistic, 40000' view of things rather than hyperfocus...paying attention to tweaking the little things gently to not overwhelm, and to find the right balance. The groove changes things in the manifold, which can have effects on several other systems, and until the computer sees that those systems are once again harmonized, it won't make any changes. If the groove makes a change in manifold presssure and the sensor there doesnt respond, we have to modify it as well, just like the o2 sensors.. and often those adjustments are more related to each other than we may care to admit, so changing one might mean that we have to address the others as welland can only be done as the computer works to its best capacity in closed loop. I like what I have done forcing mine into open loop and make the fuel adjustable from the dashboard. This discussion is getting quite involved but it is good to be clear and hopefully everybody gains.

AGREED!!!
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2006 Frontier 4.0 4x4 has been grooved! 04 Apr 2020 20:43 #50

  • neil
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Thanks heaps Greg!
Well we covered so much info that I think I will deal with this bit at a time to simplify posts, please raise anything again left unaddressed for too long.
We are both doing the same thing (modifying signals to the computer to get it to put in less fuel), I am forcing permanent open loop and changing airflow signal; you are doing it in closed loop with modifications to o2 sensor, and happy to address the additional ECU problems/ codes/etc because of the benefits you see from having the computer do its thing.
I guess it comes back to my disrespect for computers, I simply check that its economy is the same in open loop and if it is then I dont accept any significant benefit in closed loop computer functions. Not to say that modern engines cannot do some things that old engines couldn't I basically maintain that power at a given RPM relates direct to engine size; and computers have been no real advantage. In fact carburetors have one benefit EFI cannot copy - carbies mix air with petrol (air bleeds) prior to the petrol hitting the air stream. Simply put carbs atomize petrol but EFI only sprays petrol (try as they might by increasing pressures).
Anyway to keep this point simple I attached some data I collected in 2013. It is the only motor I know of that has been used for 43 years and had all manner of technology evolved/added where we can see the (lack of) KW benefit; regretfully an Australian motor that I presume many of you won't be familiar with. This motor started basic! with pre-crossflow cylinder head and points ignition; and progressed up to state of the art DOHC, canbus, etc. Take notice of the column "KW @ 4250rpm" and you will see basically no change (3KW) in engine output over 43 years of development. In the mid 90's the cylinder bore was reduced changing displacement from 4.1l to 4.0 l displacement but still the same motor. Several points of interest 1. In the late 70's there was no sports model and emissions killed the output significantly. 2. The only noticeable KW changes (10KW's!) were in the late 80's on XF and EA models where both models were made with a standard short runner intake manifold, as well as a "modern" long runner intake manifold. Basically, long runner manifolds offer more power than any other motor evolution/ computer function etc - BY HEAPS! (the XF was carby vs long runners EFI -13kw difference) (the EA was a centre-point vs multi-point EFI 19kw difference). The carby performed better against long runners with multi-point, than the centre-point system!!!
Just to stir the pot further I think that the 1970 motor being 3 KW lower in output than the modern motor is at a disadvantage because I would love to run it again with the same modern oils, coolants, precision Machining etc. Also mechanical fan and fuel pump removed....it might even beat the new motor?!
This information would be obvious if manufacturers would have simply stopped increasing RPM for KW output measurements every new motor, they needed to show increased output and the only was to do it is rev the motor harder. As a result we now have race-tuned motors with peak torques often over 4000 rpm. this is useless when towing or driving at low RPM and wondering why nothing seems to sync in the motor. and fuel economy is bad.
I would love to see the same data taken from another motor but I am not familiar with any other motor than has evolved like this one. Perhaps a 350 chev has seen all these evolutions and is a contender but I am not sure...
I guess I am only showing this information to defend my decision to ignore/ not utilize the full capabilities of an ECU, which I would also suggest is deeply flawed if we are going to corrupt one of it primary inputs(o2 sensor) anyway.
Please comment with any thoughts etc
I hope you like the attachment.
PS there is some interesting points about high compression use in modern motors when we have switched to unleaded fuel which really requires lower compression ratios - but that is for another thread... i suspect it is done for emissions only....but might help the groove....i presume others motors have done it to.
PPS The column with KWs @ 4,250rpm is mathematically recalculated by me from manufacturers specs, I treated the torque curve as if it was linear (straight line) and I know this is not the case. I feel it is still roughly correct and if anyone knows a better way I am keen to hear it.
PPPS If anyone starts a new thread from anything in this thread can you say so because my internet is bad and I may not follow to the new thread.

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2006 Frontier 4.0 4x4 has been grooved! 05 Apr 2020 12:28 #51

  • GregK
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Thank you, Neil, for debating with me. (+1 karma)
It's a discussion that newcomers to the forum like Vernon need to see so they can make up their own minds on the best way to approach grooving their vehicle. In fact, I may edit our "replying on replies to replies" posts above into a more post-to-post thread and sticky it somewhere on the forum, because while there are still plenty of carbed vehicles out there still, there are many more with computers and sensors and electronic ignition and drive-by-wire throttle bodies, and will continue to be until battery power densities are increased to give EVs comparable range to gasoline&diesel powered vehicles (...and then there is charging time, but we'll not go there...).

So, Vernon - sorry for hijacking your thread, but I hope you were reading along and thinking about what Neil and I were going on about in relation to your Frontier (and your Mini). Hopefully we cleared up the picture for you, and you were able to take some steps over the weekend that have gotten you closer to the results you had hoped for before you grooved it.

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2006 Frontier 4.0 4x4 has been grooved! 06 Apr 2020 00:55 #52

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What causes open loop operation.
Vernon- I re-read my post and where I said the fuel trims being visible on your car are evidence of your computer being in closed loop...and attempting to fix stuff....I retract that and say using the scan tool is always the primary way to identify if you are in closed or open loop operation. Fuel trims may still be visible during some circumstances of engine operating in open loop. I think tho if you are concerned about the computer doing crazy stuff then I suspect that the computer is in closed loop, using all the inputs (some modified by you) and getting muddled up. I think the chances of a computer getting muddled up is much less whilst operating in open loop.
Greg- I referred to other sensors that can cause ECU to be/ go into open loop, beside coolant temp. As I review this there are not many other actual sensors that can cause open loop. I should have just said all the "events" that can cause open loop. Manufacturers howevercan add whatever sensors they want for ECU closed loop operation, these non-essential sensors could include ambient air temp and a MAP or MAF can be a non-essential sensor, and hence would need to be in a range before closed loop is possible (without any code).There are large wiring harnesses and any broken wire or bad connection in any of them can cause open loop operation (and probably a fault code). Any malfunction in the o2 sensor, coolant temp, plus any other senor that a manufacturer might include in the ECU fuel mapping will cause open loop. I beleive an ECU will not enter closed loop until ALL sensors and connections are happy (the ECU won't attempt to partially control anything). In addition to this an ECU switches to open loop for high load , the throttle position switch (Tps) will cause open loop for load demand, usually above 60% will do it, Also the ECU doesn't map for high rpm, usually 3,500rpm will see the ECU back into Open loop.
And obviously initial startups, it is only with heated (3 and 4 wire) o2 sensors that cars doing short runs ever get to see any closed loop operation at all.
Hope this helps. just tidying up...B)

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2006 Frontier 4.0 4x4 has been grooved! 06 Apr 2020 09:09 #53

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I might have to get a tuner. The best one in the frontier community is Uprev. It allows for fuel adjustments

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2006 Frontier 4.0 4x4 has been grooved! 06 Apr 2020 11:00 #54

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neil wrote: Greg- I referred to other sensors that can cause ECU to be/ go into open loop, beside coolant temp. As I review this there are not many other actual sensors that can cause open loop. I should have just said all the "events" that can cause open loop. Manufacturers howevercan add whatever sensors they want for ECU closed loop operation, these non-essential sensors could include ambient air temp and a MAP or MAF can be a non-essential sensor, and hence would need to be in a range before closed loop is possible (without any code).There are large wiring harnesses and any broken wire or bad connection in any of them can cause open loop operation (and probably a fault code). Any malfunction in the o2 sensor, coolant temp, plus any other senor that a manufacturer might include in the ECU fuel mapping will cause open loop. I beleive an ECU will not enter closed loop until ALL sensors and connections are happy (the ECU won't attempt to partially control anything). In addition to this an ECU switches to open loop for high load , the throttle position switch (Tps) will cause open loop for load demand, usually above 60% will do it, Also the ECU doesn't map for high rpm, usually 3,500rpm will see the ECU back into Open loop.
And obviously initial startups, it is only with heated (3 and 4 wire) o2 sensors that cars doing short runs ever get to see any closed loop operation at all.
Hope this helps. just tidying up...B)




Neil - Here's a page from a document I found online pertaining to my computer's logic tree for some common DTC's pertaining to the MAF in my car. It's a 60 page document for the engine, with another one for the transmission. This is why I was pointing you in the direction of the Hysterisis video: all these conditions have to be checked/met to trigger the money light on your dash...it's like a checklist that pilots follow.
Look at the 2nd last column on the right - the conditions to the left of it have to be met for 320 samplings out of 400 in a 100ms timeframe for a P0101...that's fairly specific. (I would love to see if there's a document like this for your Isuzu - I got this from GM's website, and Isuzu was once a GM company as I recall...)
You're absolutely correct - it's way more complex than it should be.

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2006 Frontier 4.0 4x4 has been grooved! 07 Apr 2020 06:08 #55

  • Vernon
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The first 11 mile trip with the spacers on the front sensors tripped codes for the front sensors “slow response” the last 2 11 mile trips it was just for catalyst efficiency. And it does smell richer so I’ll take them back out

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2006 Frontier 4.0 4x4 has been grooved! 07 Apr 2020 09:59 #56

  • Ron Hatton
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The "Catalytic Converter Efficiency" code is caused by the sensor cooling off. The whole system is designed to keep the cat consuming fuel.

Knowing this, you can make other adjustments to retain the heat in the exhaust. Insulate it. There is a thread on this somewhere here.
Ron Hatton
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2006 Frontier 4.0 4x4 has been grooved! 07 Apr 2020 11:07 #57

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Vernon wrote: The first 11 mile trip with the spacers on the front sensors tripped codes for the front sensors “slow response” the last 2 11 mile trips it was just for catalyst efficiency. And it does smell richer so I’ll take them back out


This is exactly the situation where EFIE can help - the computer isn’t seeing the signal from the sensor crossing back&forth between rich and lean often enough, like the diagrams in the article I linked in a previous post on this thread. By applying an offset voltage to the signal now, you’ll get rid of this code.

This is not to discount Ron’s insulation: I’d put that at the downstream o2 sensors in this case to further reinforce to the computer that it is, indeed, burning enough fuel to stay at the temperatures it expects.

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2006 Frontier 4.0 4x4 has been grooved! 07 Apr 2020 11:35 #58

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Ron Hatton wrote: The "Catalytic Converter Efficiency" code is caused by the sensor cooling off. The whole system is designed to keep the cat consuming fuel.

Knowing this, you can make other adjustments to retain the heat in the exhaust. Insulate it. There is a thread on this somewhere here.


To reinforce Ron's Insulation mod a bit further, I've found a series of youtube videos by an experimenter here in my own backyard that shows that a catalytic converter converts the hydrogen and oxygen in exhaust to heat. without enough of those two things, the heat output drops, and even with a heated rear o2 sensor, a computer will throw a code.



It's not the heat of combustion - it's the heat of the reaction between the combustion byproducts being and the catalysts in the converter; after all, less fuel means less heat, so if you keep the heat in the system leading up to the rear o2, you'll be code free and keep your computer in line.

Vernon - get your EFIE to make the computer think everything is ok upstream, and insulate downstream and I'll wager you'll see your mileage gains start to stack up.
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2006 Frontier 4.0 4x4 has been grooved! 07 Apr 2020 11:59 #59

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The EFIE was on the front sensors. Not the rear. The reason the cat efficiency codes weren’t there I suspect is because it wasn’t running as rich with the EFIE connected. The EFIE affecting the front sensors isn’t making the computer think the cats are working/not working. These are cheaper aftermarket cats so they aren’t as powerful as the factory ones so higher temperature isn’t going to make them burn everything

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2006 Frontier 4.0 4x4 has been grooved! 07 Apr 2020 12:27 #60

  • Tracy Gallaway
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The thread re: exhaust insulation is in the Service Bulletins category, 13 topics down from the top. I tried to cut/paste it here, but no dice!
Exhaust mod thread <- CLICK HERE
Tracy G

(There ya go Tracy - greg)
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