Speed Density tune......should I do it....?
 

Yes I read the sticky and searched....

My issue is my car keeps frying 02 sensors after my new 390ci engine went in. For some reason they last only a couple months and then I start running so rich I only get 100 miles to a tank of gas during regular street driving.

Should I just go get it SD tuned and toss the 02 sensors.....?

Other option is pretty expensive (about $1,800 total parts and labor) which will mean a new complete wiring harness install and a new 0411 PCM at the same time.....and a quick dyno tune anyway to make sure its right.

SD tune is probably $300-$400.....

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Try it. If you don't like it you can go back or change it. Software can be overwritten.

Note, if the car is driven on the street, I would VE tune it and then see what happens first.

I run a MAF less, no 02 setup and it runs great. I do have my own software though and can touch it up as needed, which is required time to time.

I say give it a try. Its fun to experiment with these toys we own.

Is it basically the same length dyno tune session as a normal MAF/02 sensor tune...?

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A competent tuner can write a speed density file in the same time it would take for a MAF file.

https://sites.google.com/site/sloppywiki/ this may help!

Are you going to install a Wideband? I love SD and I run a mafless no 02 setup as well going straight SD. But I still have a wideband in the car (I actually have two widebands since I run TD's) to keep an eye. How else will you know if something goes wrong? You pcm won't it gets no feedback after the combustion cycle if you eliminate o2's.

A stupid ?? Why not fix the problem w/ the sensors??

Any DTC's? As it is very common to get slow response and insufficient switching codes with LT headers, and will put the car into open loop when the codes are current. The fix is to set these codes to no error reported & uncheck the SES box in the tune.

Russ Kemp

This^^^^^^ It would drive me crazy not knowing what caused the problem in the first place.

A good tuner should be able to whip this out pretty fast. If you haven't had a tune for your setup, could be a simple tune will help your situation also.

easy old guy. he is just asking a question. lmao.

Seems like the beef is with closed vs open loop, not MAF+SD
vs SD-only. But the sensor problem doesn't have any popular
solutions (mine was to go back to shorties; I'm happy, people
sneer, I don't care).

Anyhow, going to SD-only would not address your trim-drift
problem. Going to full time open loop, perhaps with OL STFT
enabled (you might elect to set all of the idle-range EQ values
to something a bit off from stoich, to inhibit idle trimming which
will remain bent) may be more what you're looking for. If the
MAF is not causing you problems (you have raised none MAF-
related) then it's really not a bad instrument, much more
forgiving of environment, minor mods and state-of-things than
speed density alone can be. As long as you keep it clean.

MAF tuning is WAY quicker than a good speed density tune. Tuning the entire VE table, plus temp compensation curves is no way near as quick as tuning a MAF frequency curve. And JimmyBlue hit it, why throw away the maf when the problem isnt related to the MAF. You can run OL MAF all the time too if you wanted.

My 02 sensors never had a problem in 10+ years with these same LTs and my 427ci. I'm suspecting that when my new 390ci was installed last year the wires have been pinched somewhere and they are either melted or getting very hot and causing a problem with the signal in the wires.

We are going to trace everything and see if we can find an issue. I might also just buy a brand new wiring harness re-pinned for an updated 0411 PCM and just install that....get a new tune....then it will be fine.

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Hey dickhead.......I was asking a question. You can't deal with people asking questions around here...stay the fuck out.......prick.....

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Thanks.....yea, Im just gonna stay norm al tune and probably just upgrade my wiring harness and PCM. My original one is old anyway.

I was just thinking it might be easy just to get a SD tune......but I need the front 02's anyway for that, so I need to find the problem no matter what.

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Not a good way to continue to get help. It was a very valid question. If there is now a problem with the o2 sensors, there is a good chance the problem could present itself elsewhere too. It's much better to fix the problem than bandaid it.

I run SD CL in my ls1, i drive the car every day and it got good drivability, good fuel milage and makes good power for the mild mods it has, ive tuned a number of cars in SD, the throttle responce is much better than a MAFF tune, iam not a fan of MAFF, but i guess it has its benefits at times, SD all the way for me

IMHO; I think what Old Geezer was saying IS :
(I have) "a stupid ??? (???=question)
Don't think he was calling anyone stupid...FWIW

If the throttle response if better, then the maf tune was off, I have done both and cannot say one to the other, A member way back stated the same thing that he got better throttle response with a SD tune, When I asked how could he tell, he had some comparisons of something on MAF vs SD and quoted that the SD tune was x milliseconds faster. MILLISECONDS? and he could feel that, wow.