PLX Gauge And Hptuners Doesn't matched ? wtf?

[Texas_WS6]

I tried some tuning with the NGK today. So far I have no reason to dought its accuracy. That said there is two minor details I do not like about it. The range is much narrower then the PLX was. It is 9:1 to 16:1, which does not matter once you finaly get the tune inside of that range. I think the PLX was suposed to have a range of 10:1 to 18:1.

I would also like to say the NGK kit comes with more parts, i.e. a bung and plug to mount the sensor in the exhaust and to cap the bung when the sensor is not in use. The wiring harness in the NGK kit is a much nicer set up. You do not have to put pins on the wire conectors, just plug it into the sensor, then the little box, then land your + and - wires, then land your data wires to the HP Tuners device. The hardest part of the hole swap was routing the larger conector into the car were I wanted it. It also has a very good manual with it that will explain alot more info then the PLX had. So far I like it. But I have only been able to play with it for one day, so I will see how it goes.

[Texas_WS6]

Also you can calibrate the NGK.

[jackedupcanyon]

Based on what you are saying, if this one dies soon after the warranty is up I won't likely buy another PLX.

I've had the NGK for a few months and sort of forgot about it sitting on the shelf.

If your PLX is accurate and it lasts a while, I might be tempted to stick with PLX and buy another one. Sounds like you are getting good customer service. PLX may also be making better product and working on a better reputation. From the research I have done, DynoJet and NGK widebands are good products. Many people are satisfied with them. Innovate seems to be up there also but it also seems to be the luck of the draw with them. Around half seem have luck with Innovate while others want to throw theirs out the window.

Always good to have a backup but I am sure you could get rid of the NGK system if you wanted (might take a loss). With the luck you are having with PLX, you may just need to replace a sensor????

[IndeedSS]

My PLX has a range of 10.0:1 - 20.0:1 AFR. It doesn't require manual calibration, but like most people feel while extremely convenient, wonder how accurate this method is long term. It is nice that they use their AFR box as a voltage regulator for the sensor, allowing more flexible source voltage options. The downside to the voltage regulation is, the "box" gets quite hot.

I agree the NGK packaging, construction, manual, additional supplied hardware etc, is impressive, especially for the price. The couple of things that I didn't care for, was no a-pillar gauge, the specific power wire requirements and the need for a relay in permanant installations. If I ever wind up using the NGK it will likely only be ued in temporary installations just for tuning and then removed.

[Texas_WS6]

My PLX has a range of 10.0:1 - 20.0:1 AFR. It doesn't require manual calibration, but like most people feel while extremely convenient, wonder how accurate this method is long term. It is nice that they use their AFR box as a voltage regulator for the sensor, allowing more flexible source voltage options. The downside to the voltage regulation is, the "box" gets quite hot.

I agree the NGK packaging, construction, manual, additional supplied hardware etc, is impressive, especially for the price. The couple of things that I didn't care for, was no a-pillar gauge, the specific power wire requirements and the need for a relay in permanant installations. If I ever wind up using the NGK it will likely only be ued in temporary installations just for tuning and then removed.

I did read it sugest to run the power wires back to the batter. I did not do this. I found an unused power slot in my fuzz box that I could tap into and installed a fuzz. It is also controled with the vehicals ignition key. I used the same spot for the PLX. I might be doing something wrong in using this power point.

I have done enough tunning with the new NGK yesterday to now be a little baffled. It seams to be doing very close to the same thing the PLX was, except at WOT. So maybe I should retract my previous flaming of the PLX. At this time I will retract my negative words about the PLX. Here are the problems I am having with both of them and maybe someone can chime in and let me know what the heck I am doing wrong.

I followed the same procedure for both the PLX and the NGK. Here it is.

First I set the tune up for tuning with WB only, SD mode. Turned off the MAF and made it fail. I also shut down the Deceleration fuel by setting the DFCO to 284 degrees. I then set my Power Enrichment set the EQ ratio vs. RPM to 1.13 (13.0:1) from 0 to 3600 rpm (I have a 4000 stall), then from 4000 to 6400 I set it to 1.167 (12.6:1), then 6800 and up to 1.145 (12.8:1). I set my open loop EQ ratio to 1.00 in all cells. Turned LTFT to disabled. Then I set all closed loop enable temps to 284 so the STFT will not come into play. I then went out and corrected all my VE cells under 4000 rpm as compared against the WB (both with the PLX and then with the NGK). I then tryed tuning my WOT. After wich I reset my Closed Loop Enable temps to stock. After that I placed the MAF back into service and attemted to tune it.

Here are the results.
After reseting the Closed Loop temps to stock, and my STFT was back into service, under normal driving, in both cases with the PLX and the NGK, the STFT leaned the car out. With the PLX it read 17:1 up to 18:1 afr. With the NGK it simply maxed out at 16:1 and flatlined. The fact that two completly different WB do not match the commanded AFR of 14.6 once the STFT come back into play, leads me to think there must be an issue with my NB's. Calibration/Settings of the NB O2's. I have no idea how to correct for this.

The WOT tuning results were different between the two. The PLX always just recorded rich. It always went to 10:1. I kept correcting for it and the VE cells in that zone went as low as 35. All the way to the point the engine would lean missfire. The NGK on the other hand, it lowered the VE a little. Now I did not get it dialed in with the NGK. I kept over correcting one way or the other. I never did get it to fall in the NGK's narrow window. I am going to work on it more today.

As for the MAF tuning. I turned everything back on. I did not even try to tune the MAF with the PLX. I did try with the NGK. Every correction I would make would bring the WB reading down to the Commanded AFR, then the STFT would lean it back out again.

Anyone have any sugestions? I am thinking the NB sensors are not calibrated or something. I am not using the factory F-body sensors. I have Hooker Long tube headers, and they would not work with them. So I went with the Corvette rear O2 sensors as sugested at LS1Tech.com . I am not sure if that has anything to do with it. I also have nothing conected to my rear sensor wires. Not sure if that comes into play either.

[Texas_WS6]

I have been thinking about it and looking for air leaks. I do not see any leaks before the WB. But I did notice, I still have my EGR or AIR piping (what ever it is) still installed on my headers. I am starting to wonder if I am getting O2 coming into my headers from this point, throwing my AFR off on my WB and NB. I am not sure what this piping does or were it goes to. I can tell you there is a hard pipe line that goes in to the top of my header on both the right and left bank.

Does anyone know what this is for? Can it draw in fresh air and scew my readings? I am thinking of disconecting them and pluging them to see what will happen.

Car is a 02 WS6 F-body.

[jackedupcanyon]

My PLX has a range of 10.0:1 - 20.0:1 AFR. It doesn't require manual calibration, but like most people feel while extremely convenient, wonder how accurate this method is long term. It is nice that they use their AFR box as a voltage regulator for the sensor, allowing more flexible source voltage options. The downside to the voltage regulation is, the "box" gets quite hot.

I agree the NGK packaging, construction, manual, additional supplied hardware etc, is impressive, especially for the price. The couple of things that I didn't care for, was no a-pillar gauge, the specific power wire requirements and the need for a relay in permanant installations. If I ever wind up using the NGK it will likely only be ued in temporary installations just for tuning and then removed.

Whatever WB you use, it needs to be powered on with the vehicle either thru a relay or a specific fuse or ignition key source (especially if permanent installation). If not, you sensor is going to fail rapidly.

[jackedupcanyon]

I have been thinking about it and looking for air leaks. I do not see any leaks before the WB. But I did notice, I still have my EGR or AIR piping (what ever it is) still installed on my headers. I am starting to wonder if I am getting O2 coming into my headers from this point, throwing my AFR off on my WB and NB. I am not sure what this piping does or were it goes to. I can tell you there is a hard pipe line that goes in to the top of my header on both the right and left bank.

Does anyone know what this is for? Can it draw in fresh air and scew my readings? I am thinking of disconecting them and pluging them to see what will happen.

Car is a 02 WS6 F-body.

Sounds like an air pump. This is used for emissions to dilute the exhaust. Yes, this should be disconnected or powered off for the tune and reconnected or powered back on when finished but your tunes indicate this is already disabled. May want to try zeroing out the ADD vs ECT and ADD vs IAT just for the WOT tune also. These may be adding adding fuel which will effect your VE. Also thought it could be COT protection but you already have this disabled also.

[Texas_WS6]

I do have it disabled in the tune, but I rremoved the lines from the headers and welded up the ports to make sure no air was being back flowed/sucked into the exhaust. I was pretty sure this was the case. But I have been out checking the WB AFR against my NB's and when the closed loop is turned back on, the STFT drives the WB AFR readings back up by 1.0:1 (15.6). This is at idle. The last thing I can think of to cause my WB to report different then comanded with closed loop enabled is maybe my cam. I have a MS3 in my 346. It is 237/244 with I think 114 center. It realy lopes hard. Maybe it is the cause.

I will do as you have sugested on zeroing the other charts out. I should have some info back in the next couple of days.

I should have completed the tuning of this thing by now. How hard is it to install a distributor drive? I might just go old school with this thing if I can not get the dang WOT set up right. Just kidding!!

[IndeedSS]

Whatever WB you use, it needs to be powered on with the vehicle either thru a relay or a specific fuse or ignition key source (especially if permanent installation). If not, you sensor is going to fail rapidly.

I do have the PLX on an ignition source, via an add-a-circuit in the dash fuse panel. Because the PLX has it's own voltage regulator, a relay to switch a higher current carrying capable power source isn't needed. Although the PLX comes with 22g power and ground wires, I replaced them 16g.

[IndeedSS]

The WOT tuning results were different between the two. The PLX always just recorded rich. It always went to 10:1. I kept correcting for it and the VE cells in that zone went as low as 35. All the way to the point the engine would lean missfire. The NGK on the other hand, it lowered the VE a little. Now I did not get it dialed in with the NGK. I kept over correcting one way or the other. I never did get it to fall in the NGK's narrow window. I am going to work on it more today.

This worries me. What AFR was the NGK showing when the PLX was showing 10:1? Were you ever able to get the PLX not to read "rch" at WOT? I adjusted my base PE a little and the PLX WOT AFR readings followed. However, now I'm concerned that perhaps the AFR readings are not accurate.

[Texas_WS6]

I never could get the PLX to read anything but 10:1 at WOT. When I went to the NGK AFX I re-installed the VE tables I had before I tuned with the PLX, that is 4000rpm and up. I did like the previous tune in the lower rpm for daily driving. So I can not equate the PLX and NGK at WOT, but I can say at Stoich (or normal driving/14.6 AFR Commanded) there was no differance worth stateing. With both systems, when I turn closed loop back on, the STFT leans the engine up and drives both the PLX and the NGK WB readings up to 15.6:1 with the NGK(flatlined/max range) and 16.6 with the PLX(still in its range of reading). I can not figure out why the NB/STFT and both the PLX/NGK are 1-2 AFR different. I would think that they would be much closer then they are. Anyone have any ideas?

[Texas_WS6]

This worries me. What AFR was the NGK showing when the PLX was showing 10:1? Were you ever able to get the PLX not to read "rch" at WOT? I adjusted my base PE a little and the PLX WOT AFR readings followed. However, now I'm concerned that perhaps the AFR readings are not accurate.

The PLX always read rich at WOT. Thats why I replaced it with the NGK.

[jegten]

As far as I can tell you can't edit the pre installed ones. I had to create that one myself. Their formula should be .5 and 10, where I had to go with .5 and 10.2 for a match.

At the top of this forum there is a sticky that explains how the formulas work.

Also at www.hptuners.com/help , there are some nice demos that show you how to do this.

btw also in the help section there is a list of the offsets programmed in the pre installed AFR PIDs.

bringing this back from the dead.

what if the gauge is off by ~.4, but only at idle? when stepping on pedal, it matches what the wb connected to HPTuner scanner is reading.

thanks!

[jackedupcanyon]

How odd. Personally I would leave it if it is only off at idle.

[jegten]

How odd. Personally I would leave it if it is only off at idle.

thanks for the response.

i know. i noticed this within the last month and a half.
threw me off, and made think my tune was off when looking at the gauge. lol
but, when i looked at my logs, all was fine.

[jackedupcanyon]

When and if you idle tuning, you will know how much it is off. You can also copy and adjust the formula specific to correct the WB for your idle tune.

[jegten]

i did a base running airflow, but have not really done idle tuning.

[jegten]

When and if you idle tuning, you will know how much it is off. You can also copy and adjust the formula specific to correct the WB for your idle tune.

are you talking about the linear equation for the WB?
i can do that, but that means i am adjusting the formula to match the gauge, right?
that's where my confusion comes in.

[jackedupcanyon]

Yes (or copy and create another) but only for idle tuning since you know it is accurate when moving and not accurate at idle.......Are you sure it is off at idle?