Who here is using a PLX M-300?

[Vtec Killer]

for a diect replacement for the stock narrow band O2? I just picked one up and the installation instructions advise not to expose the wide band O2 to exaust temps over 850 degree's. Is this a fact my ETG's read about 950 am i gonna mess up this sensor or what? If anyone is running this wide band let me know what you did. This is going in a 1g using the heavily ported 1g O2 housing. thx.........

 

[90AWDTalon]

for a diect replacement for the stock narrow band O2? I just picked one up and the installation instructions advise not to expose the wide band O2 to exaust temps over 850 degree's. Is this a fact my ETG's read about 950 am i gonna mess up this sensor or what? If anyone is running this wide band let me know what you did. This is going in a 1g using the heavily ported 1g O2 housing. thx.........

I went to an exhaust shop and had an o2 sensor bung welded lower down the down pipe where exhaust temps are lower and installed the wideband there. I blocked off the stock location with a plug.

 

[T9S1i]

read the directions with the m-300 if you have already purchased it. It should say somthing like 24" from the turbo... im not exactly sure. If been looking into buying the m-300 and probably will in the next week or so and have been doing a lot of searching on this very topic and the best answers that i have found are:
"look in the manual"
and
"anywhere between the flexpipe and cat"
are the typical mounting points. I really wouldnt put it in the stock location as EGT there are way above 850.

Hope this helps

happy boostin

 

[Vtec Killer]

ok first i got this set up used hell of a deal tho and i just downloaded the instructions according to PLX's web site they say mount 24" from the block. And i asked on several local DSM boards everyone is claiming that the O2 housing is much cooler than the exaust manny. I'm guessing mainly because of the turbo as a drop in temp. so im still undecided on where im going to mount it. I was mainly just wondering what other people on this board were doing. This is going on a fresh engine (only has 80 miles on it so far) that i wont start tuning on for prob another month or so since it still cold out here in the midwest. Alot of guys here locally all seem to run the LM-1 and run it in the stock location without an issue so who knows.

 

[BREW]

Well I have done plenty of research and I own the m-250. The m-250 is essentially the same unit as the m-300, less the display.

The conclusion that I came to as far as location goes is as follows, and you can decide which way you want to do it:

Stock location will work, for how long, well thats up to the sensor. Putting a sensor in a location that it's not meant to be in, is lazy in my opinion. The reason you purchased a wideband oxygen sensor is to tune your car with an accurate benchmark, by installing the sensor out of the manufacturers specifications, you compromise the accuracy of unit, which in turn will compromise your tune. It becomes a domino effect, for the worse.

Stock rear o2 location will work as well. Heat will not be as extreme as the front location, so sensor life should last far longer. Once again putting the wideband oxygen sensor in the rear location is after the catalytic converter, which if you read the users guide, is ill-advised by the manufacturer, for the same reason, inaccuracy of the unit. And again compromised readings, and tune.

Welded bung 18-24 inches after the turbo is where I decided to install mine. The manufacturer agrees. The exhaust gas is not as extreme as the front o2, which translates to long sensor life, and is before the cat, which means accurate readings. In short, the best of both worlds. The only setback is that you will need to remove your downpipe and have the bung welded in, either by yourself or a welder. This is a very small drawback for the peace of mind that the accuracy of a properly functioning unit can provide. Accurate readings provide an accurate tune, and thats the whole reason you buy the unit in the first place. Isn't it?

edit: I also run the unit to simulate the narrowband signal for the front o2 sensor and couldn't be happier with its performance.

 

[Vtec Killer]

Well I have done plenty of research and I own the m-250. The m-250 is essentially the same unit as the m-300, less the display.

The conclusion that I came to as far as location goes is as follows, and you can decide which way you want to do it:

Stock location will work, for how long, well thats up to the sensor. Putting a sensor in a location that it's not meant to be in, is lazy in my opinion. The reason you purchased a wideband oxygen sensor is to tune your car with an accurate benchmark, by installing the sensor out of the manufacturers specifications, you compromise the accuracy of unit, which in turn will compromise your tune. It becomes a domino effect, for the worse.

Stock rear o2 location will work as well. Heat will not be as extreme as the front location, so sensor life should last far longer. Once again putting the wideband oxygen sensor in the rear location is after the catalytic converter, which if you read the users guide, is ill-advised by the manufacturer, for the same reason, inaccuracy of the unit. And again compromised readings, and tune.

Welded bung 18-24 inches after the turbo is where I decided to install mine. The manufacturer agrees. The exhaust gas is not as extreme as the front o2, which translates to long sensor life, and is before the cat, which means accurate readings. In short, the best of both worlds. The only setback is that you will need to remove your downpipe and have the bung welded in, either by yourself or a welder. This is a very small drawback for the peace of mind that the accuracy of a properly functioning unit can provide. Accurate readings provide an accurate tune, and thats the whole reason you buy the unit in the first place. Isn't it?

edit: I also run the unit to simulate the narrowband signal for the front o2 sensor and couldn't be happier with its performance.

Thanks for the advise Brew thats what i was looking for. I have a few questions for you First i got this set up barely used but i was reading through the instructions and they said you need to install a set of noise capactitors? According to plx these are for engine noise filtration correct. Second was that if you want to simulate the narrow band/ wide band signal you have to install the 20 ohm resistor for heating up the O2 element on the wideband O2 but then they warn these will become extremely hot so keep then away from plastic/ other wires if at all possiable. Basically im looking for some install advise before i dive in and screw something up. Thanks for your time.

 

[BREW]

If you followed my advice for installing it 18-24 inches from the turbo, then take it one step further and follow what to do next:

As far as the capacitors go, it follows on the same thought of proper installation of the sensor. Some people feel they aren't neccessary, but the manufacturer is clearly adament about their installation for the most accurate logging, and accurate logging is what I want. Which brings me to my next point.

I don't know if, or what, you are logging with. The best advice I can give you is to keep the stock front o2 sensor in place regardless of if you are using it's signal or not. With it installed you won't have to worry about wiring in resistors because the sensor heater wire from ECU, IS still connected to the sensor. Which means it still heats the sensor, which keeps the ECU happy, but its the signal wire that gets manipulated.

**On a side note: Until you have the logging capabilities(dsmlink for example) to read the signal that the ecu is seeing from the stock front o2 sensor, I would be hesitant to use the simulated narrowband. I must admit that I set my sensor up initially to transmit wideband and the simulated narrow band. I don't recommend this only because the front o2 signal plays a big part in the way the car runs at idle. I also have the ability to make sure the narrowband signal is doing what it is supposed to with DSMlink, so it was a calculated risk, easily erraticated if it wasn't performing the way I wanted it to. In short if it's not broke, why fix it. Once again this is up to you.

edit: When grounding the unit, I initially used pin 26 on the 2G ECU (ECU sensors ground), I'm not sure which pin that is on a 1G. I was having problems with the unit when it was grounded like this, so I opted to ground it to the chasis through a bolt on the big metal bracket that contains the radio and HVAC controls.

 

[Vtec Killer]

thanks again for the info I am using a Pocket logger ver. 2.03 which will log wideband O2's and i found out today from digital tuning ( the company that makes the software for pocket logger) that i need to hook it up to pin 15. My set up has been driving me crazy getting a tume on it on which part to tune the SAFC vs MAFT i figured this will be the last peice of the puzzle hopefully. I'm still in the process of breaking the engine in so it changes alot everytime I drive it.


A little cliff notes on my set up are as follows:ross pistons 8.5:1, eagle rods, PTE 50 trim, heavily ported head, large FMIC, 650cc injectors, 3" GM Maf, walbro 255, areomotive afpr, and all other supporting mods.........

 

[GVR4592]

You can't accurately log the PLX using the egr temp circuit without some modifications. The PLX widebands use a high impedance output that the egr temp circuit doesn't like. The stock ecu has a reisistor for the egr temp circuit that throws off the scaling of the PLX widebands. It won't be accurate. I know this because I dealt with this problem with my PLX M300. I had somebody build me a buffer circuit to wire inline with the PLX to change the output to something that the egr temp circuit can accurately read.

 

[Vtec Killer]

You can't accurately log the PLX using the egr temp circuit without some modifications. The PLX widebands use a high impedance output that the egr temp circuit doesn't like. The stock ecu has a reisistor for the egr temp circuit that throws off the scaling of the PLX widebands. It won't be accurate. I know this because I dealt with this problem with my PLX M300. I had somebody build me a buffer circuit to wire inline with the PLX to change the output to something that the egr temp circuit can accurately read.

Do you remember the material/components used to build this buffer?

 

[93jdmlaser]

Im logging with mmcd 1.8 with the egrt so are my readings not accurate and what do I need to make them read right?

 

[Mr96GSX408]

I am using my M-300 with my DSMLink, thanks to the guys there, the unit logs flawlessly. They have written a method in Java to read in the 0-5v output from the M-300 and convert it to 10:1 to 20:1. According to PLX, the wideband is linear, so a trivial mathematical function should do the trick.

 

[GVR4592]

With a 2g you log it with the rear o2, on a 1g you are limited to the egr temp. Unless you have maft, then you can use intake temp or barometer. The 1g egr temp circuit will not work properly for the PLX widebands without modifications.

 

[scottsee]

With a 2g you log it with the rear o2, on a 1g you are limited to the egr temp. Unless you have maft, then you can use intake temp or barometer. The 1g egr temp circuit will not work properly for the PLX widebands without modifications.

Exactly. The PlX widebands use a high-impedance outputs. the reasion the 2g MDP ECU input works so well is becasue if its high 100K ohms to ground.. The 1g EGR has only 6k ohms to ground. Dave Mertz mentions the need for a "low-impedance buffer circuit" to use the EGR input on the 1g ECU. Thats why the MAFT is being used on 1g's becasue it also has a 100K ohms to ground!

This is only a problem when loging into DSMlink. Your M-300 gauge will read accuratly becasue it dosn't require ecu fedback.

 

[93jdmlaser]

When I installed mine I wired in the narrowband output to replace cause my stock one crapped out so it took care of that but seems like the car driving normally now just runs like always going rich or lean during normal driving just jumping around. I been knocking like hell just on normal driving. Has anyone else had any problem with running the m300s narrow output as the stock o2?