C5Swede

Ok, great.
Thanks//C5Swede

racetchr

Excellent post and information!

Quicksilver Vert 01

The new style sensor appears to have less mass to heat up, as compared to the old style.

This might be the reason that it gets hotter with less heater current draw.

RonSSNova

First, Print makes an interesting point. He tried the NTK? parts and they were different enough they didn't work. I assume you have headers? Would make sense if for whatever reason they don't get hot enough. Especially when idling and the exh temp would be cooler.

That said, the next step would be to cut the sheilds off the end and use an infra red gun, or thermocouple to see how hot they really get. I was just gauging by feel with my fingers.

However, I don't wish to spend the $$$ doing this. I'm cheap!
Needless to say, I won't be throwing away my stockers.

BTW, I bought mine through RichieRichZ06 here on the forum. He works for a GM dealer.

Ron

printmanjackson

I have been messing with my tune for months now trying to fine tune it in CL (closed loop) using the O2's. One thing I kept noticing was when I first starting driving down the road from a cold start, I would feel a slight surging. This was consistant every time from a cold start and I could even feel it slightly from a warm start. It would go away after driving some so I have come to the conclusion there was something going on with the o2's till they got hot. Today I did nothing to the tune but kept it in OL (open loop). I noticed the slight surging was gone completely and I was having some "coming to idle issues" when I came to a stop somtimes where the idle would drop a little then catch. This was also gone. This points directly to the o2's and I had the same problem with the new NGK's but they were worst. I think what is happening is they are not getting hot enought because of the headers. I'm thinking now using the rear o2's up front might rid this problem because they are suppose to have better heaters.

Ron, if I were you I would consider using the rear sensors instead.

printmanjackson

I have come to the conclusion that any modded car puts out a different heat range...which throws the o2 sensors off as they are designed to be within a very small heat range to be accurate...

If you have a medium to large size cam you are better off with a speed density tune and forget the O2's.

RonSSNova

I'm thinking the headers are the issue. They give up heat, and locate the O2 sensors a lot further away from the exh ports.

Stock manifolds put them approx 12" away, and don't give up the heat.
Medium length long tubes move them 30" away, and give up the heat.
Full length long tubes move them 38" away and give up even more heat.

I'm also thinking coated headers would work better. Yours coated?

My test didn't show much if any real difference in the heaters between the fronts and rears.

The new and improved part however is a bit disturbing. But I bet works perfect on a stock car. If it didn't, then it's not a replacement is it?

What tells the car to go to closed loop? More than one thing right? Can you adjust it to take longer?

Ron

Quicksilver Vert 01

Engine coolant temperature is the biggest determining factor.

printmanjackson

No, my headers are not coated. I'm not sure it it would help.

It's simple to keep the tune in OL, just max out the "Closed Loop Enable Coolant Temp vs IAT" table. Most people report that they have better throttle response and I'm seeing the samething.

Ron, do you have tuning software?

RonSSNova

Yes, I have HPT. Took my car apart though shortly after buying it (the car), so have done nothing more than download the tune that was in it.

Well, I did alter the fan run temps that previous owner had screwed up.

I see mine is set to 93 degrees F. Which is stock.

tblu92

My opinion---UNLESS you have tuning software and know how to use it--I wouldn't use a SD tune of a daily driver--several reasons--
1st the PT AFR does not self adjust via the fuel trims for any reason--And with today's crappy gas even just a bad tank of fuel will throw the tune off--as will Altitude--density of outside air--moisture in air (fog)
outside temperature-ANY new mod--If you were hardcore--you would have to re-tune it at any of these changes to have it 100% accurate
I often use a OLSD tune--(open loop)--or sometimes called semi-open loop----With this tune it still uses the MAF as a reference--but NOT the 02's - So the PT fueling is a lot more accurate--commanded vs. actual--A SD tune does NOT use the MAF as a reference at all--
Of course on any of these options it is a MUST to use a wideband to try and get accurate AFR readings for both PT and WOT fuel--

printmanjackson

I'm working now on fine tuning mine using just as you describe, the MAF along with the VE table and not the O2's. Sofar it's looking better and better, I just need to fine tune the VE table some more. It seems to come to idle much smoother when coming to a stop.

BTW, I do have tuning software along with a WB and I do know how to use it

printmanjackson

update: I have to say this is by far the best tune I have run on my car since my last mod. Ditching the O2's has solved allot of weird things that were happening and I was chasing my tail trying to find the problem. I truely believe now that headers and O2's are not the best combination.

Quicksilver Vert 01

I would be afraid of the long term effects on engine longevity, if you are forcing the engine to run at 100% OL operation. It's much like going back to the days when carburetors and distributors controlled everything.

Trios

Yeah, and we all know that engines only lasted 10k miles during those days.

Wait, what?

Quicksilver Vert 01

So what's your point? Are you saying that always running in open loop will not harm a modern LSx engine?

Trios

I'm sure that entirely depends on how it's been tuned. If you have a wideband and are consistently monitoring and adjusting your tune as things change, no, I don't think it'll harm the motor.

My point was that you stated that "it's going back to the days of carbs" as if somehow, during those days, engines didn't last very long.

I actually think it's quite possible you can get a better tune and a smoother engine without the O2s, as the PCM is programmed to run rich/lean cycles to properly burn off hydrocarbons and CO, each of which requires different oxygen content. An excellent tuner with good data can smooth this out so the engine runs stoichiometric all the time.

printmanjackson

it's a FACT that you can tune and run an LS engine in SD mode only without and AFR swings that will harm the engine. Tuned correctly you don't have to "re-tune" the engine all the time. There are lots of people on the HPTuners forum running like this

Bill Curlee

How do you compenstae for drastic changes in Barometric pressure, Temp, and Humidity??

BC

printmanjackson

Bill, I'm still learning about SD tunes but what they are doing is using the Bias Table and dialing it in to the IAT. You still use the MAF along with the VE table.