Tuning update and more questions.

[Linxs]

Well he's my update, I adjusted my VE table from 4K rpms and up, to 150 and up. No change. Once i maxed the MAF the injectors drop to 7.1 again and I found the stumble. So i also disabled the MAF max error code and tried again. No dice. I'm open to ideas The v8's do this all the time why is this so difficult (multiple people have looked at my tune and offered suggestions, all ending in the same problem)......

[T-Punk]

Gotcha, i'll talk to you or tofu when i get to the point that i need to get a hold of him then.

[HAZ-Matt]

Originally posted by Linxs:
Well he's my update, I adjusted my VE table from 4K rpms and up, to 150 and up. No change. Once i maxed the MAF the injectors drop to 7.1 again and I found the stumble. So i also disabled the MAF max error code and tried again. No dice. I'm open to ideas.

When does the MAF max out, 4000RPM? The injectors drop to 7.1... so what is the A/F? Is there KR? I read that in SD the computer uses the low octane spark tables and does not adjust them, I don't know if that is true.

I found a thread on clubgp about a guy that made a WOT switch that would turn off his MAF so that the car would switch to SD. Apparently it would stutter for a second and then go back to normal.

It seems to me like it would be less of a headache to go with an LSX MAF, change the MAF table to correlate, and use PE mode like phoenix was doing to dial in the tune.

EDIT: One more suggestion. Register at clubgp and see if they have any ideas.

[Linxs]

Originally posted by HAZ-Matt:
</font><blockquote>quote:</font><hr />Originally posted by Linxs:
Well he's my update, I adjusted my VE table from 4K rpms and up, to 150 and up. No change. Once i maxed the MAF the injectors drop to 7.1 again and I found the stumble. So i also disabled the MAF max error code and tried again. No dice. I'm open to ideas.

When does the MAF max out, 4000RPM? The injectors drop to 7.1... so what is the A/F? Is there KR? I read that in SD the computer uses the low octane spark tables and does not adjust them, I don't know if that is true.

I found a thread on clubgp about a guy that made a WOT switch that would turn off his MAF so that the car would switch to SD. Apparently it would stutter for a second and then go back to normal.

It seems to me like it would be less of a headache to go with an LSX MAF, change the MAF table to correlate, and use PE mode like phoenix was doing to dial in the tune.

EDIT: One more suggestion. Register at clubgp and see if they have any ideas. </font>[/QUOTE]Thanks for the suggestions, I did order a new MAF. I'll get it tomorrow and install it this weekend. Everything points to the MAF as the problem. I'm hoping this resolves it, and if so 10 PSI here i come [img]smile.gif[/img]

[phoenix64]

Originally posted by GN-T66:
</font><blockquote>quote:</font><hr />Originally posted by phoenix64:
Thanks for proving me right.

I really don't have time for this **** anymore. [img]graemlins/wavey.gif[/img]

lol.... Proving you right? seriously, you're a moron that doesnt know the first thing about tuning. Keep up the good work with your car though! [img]graemlins/rofl.gif[/img]

Edit: I understand how you are trying to use your wideband. You're trying to use it as the sole signal to the PCM for air/fuel control. Now, I'm not even sure of the compatability of the wideband signal to the PCM, and how it interprets it. That being said, even if the wideband signal is accurately interpreted by the PCM, it still isnt the right way to do it for a couple reasons. One, you need the signal that goes to the PCM to be closer to the engine, not after the entire up-pipe and behind the turbo, which in theory could dilute or change the readings going into the wideband . Second, you need to have two O2 inputs for the engine, one per cylinder bank. You're counting on both banks being equal. If you have one bank that is running lean, you might never know it if the other bank is running equally too rich. It might average out to an acceptable number, but you might be ready to fry one entire side of the motor. The PCM typically interprets two O2 signals, and it needs to stay that way. IF you look at any scan tool, you will have long term fuel trims for bank one and bank two. I dont know if and how your PCM might be displaying these numbers. If the numbers are showing up identical, then it is simply interpreting the same signal for both banks. I am all for the use of a wideband, but it should be used as a final judgement in addition to factory O2s. It's signal should not be the sole factor used to control air/fuel. Again, it should be used in conjunction with factory O2s. </font>[/QUOTE]You don't have the slightest clue how I'm tuning my car. The widband is not hooked to ANYTHING but a 12v source. The computer makes fuel calculations using the VE table, the injector flowrates and the MAF. I change the A/F ratio by changing the VE tables, the injector flowrates, and the maf table.

Oh and how many cars did GM build that used one o2 for 8 cylinders? Only a couple million, so I'm not particularly worried.

[ February 21, 2005, 02:20 AM: Message edited by: phoenix64 ]

[Teufel Hunden]

Originally posted by phoenix64:

Oh and how many cars did GM build that used one o2 for 8 cylinders? Only a couple million, so I'm not particularly worried.

How many vehicles does GM make now that have 2 or more O2 sensors? During the time GM made vehicles with only one O2, the school of thought was that only one was needed. Compare the automotive technology from the mid 80s to the mid 90s. Now compare that technology to the current vehicles being produced. Things change for a reason... adding more O2 sensors into the overall system wasn't done for the novelty of having more than one.. they were added for greater safe control of the different variables that make up gas mileage, AFR, etc..... You saying something to the effect of "Oh, well, back in the day, the now out of date vehicles with inferior technology compared to the car i have now used XXXXX method, so it must be GREAT" is just a show of flawed reasoning.

[phoenix64]

Originally posted by Teufel Hunden:
</font><blockquote>quote:</font><hr />Originally posted by phoenix64:

Oh and how many cars did GM build that used one o2 for 8 cylinders? Only a couple million, so I'm not particularly worried.

How many vehicles does GM make now that have 2 or more O2 sensors? During the time GM made vehicles with only one O2, the school of thought was that only one was needed. Compare the automotive technology from the mid 80s to the mid 90s. Now compare that technology to the current vehicles being produced. Things change for a reason... adding more O2 sensors into the overall system wasn't done for the novelty of having more than one.. they were added for greater safe control of the different variables that make up gas mileage, AFR, etc..... You saying something to the effect of "Oh, well, back in the day, the now out of date vehicles with inferior technology compared to the car i have now used XXXXX method, so it must be GREAT" is just a show of flawed reasoning. </font>[/QUOTE]Never said it was "great", I said it worked on millions of cars. What wrong with that reasoning?

[Teufel Hunden]

Originally posted by phoenix64:
Never said it was "great", I said it worked on millions of cars. What wrong with that reasoning?

Using out dated methods on new technology is how i'd look at it. Running open loop all the time on a racecar is fine... Like you said in another post, you know of someone who did it on a different car, but it was by no means a street car. Closed loop is needed for street cars. The computer has different checks and balances, so to speak, that it does through during closed loop operation, and eliminating that aspect prevents it from doing so. Sure you might be getting decent mileage out of it, but is it the best way of going about it? No way. You could go to any tuning shop in the country, even the very bad ones, and they'd all tune your car using all the O2s, and they'd use closed loop for part throttle driving.

[phoenix64]

Oh well it works. a few hp or mpg at part throttle doesn't worry me enough to mess with it.

My jeep got 5 new o2's in its first 30,000 miles. The techs at the dealership finaly unplugged the check engine light. That was 200,000 miles ago. Still runs like a champ, and thats speed density. Gets 19mpg, but who cares it works.

I'm on an extreemly limited budget, so if I works I'm inclined to stick with it. But you are absolutly right 2 o2's is better than 1, but idealy you would have 6 so you could argue that too.