DIY PROMDo It Yourself PROM chip burning help. No PROM begging. No PROMs for sale. No commercial exchange. Not a referral service.
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I also believe I'm walking a very fine line by tuning according to the ZT-2's curve. That little b**tard curve is VERY steep around 14.7 and the mv equivalents of 14.5 (what I'm kind of shooting for) will be hard to nail down. I think I got it though. I'm gonna keep messing around with the voltages and stuff and see what I can come up with
wish I had the function they made that curve with or something. hell, I could just plug numbers in -I'm in college for crying out loud LOL
I've underestimated how susceptible the voltage is to the rest of the electrical system. serious. that little NB doesn't live by the voltages in the table like I think it does
. . . Here's the kicker- had no issues with the stock one-wire O2 immediately after I installed the engine a year ago. BLM was 127/8 at idle in closed loop. Something about needing to change settings when you stray from stock that I sometimes overlook
A silicone poisoned O2 sensor reports rich. Drives the INT/BLM down until the engine cuts out. Silicone can be from RTV (sealants), caulk, sprays, spark plug wires, fuel, etc.
To me the simulated NB output from the Zeitronix is not correct. It does switch at 14.7:1, but the curve isn't right.
I think you are fighting a separate issue with each (zeit & NB) as an input to the ECM.
The NB issue could also be grounding between the exhaust system and the engine block. The return for the NB O2 is through the sensor shell to the exhaust pipe to the header to the engine block. All ECM grounds should be to the engine block.
I hear ya, junk. there is more going on here, though. your tables make sense for your app. I see you like to run lean under low load areas and more rich under the high MAP areas. makes sense-after all, your F-body weighs what...3600 pounds with you in it?
The tables I posted are for a vehicle weighing 5,000 lb with a driver. It is a stock 305ci TPI engine with a power adder. It is very close to the weight of your vehicle.
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Originally Posted by 91chevz71
wish I had the function they made that curve with or something. hell, I could just plug numbers in -I'm in college for crying out loud LOL
Try emailing them and asking if there is a way to reprogram the NBO2 output. Enjoy your break from school.
To me the simulated NB output from the Zeitronix is not correct. It does switch at 14.7:1, but the curve isn't right.
RBob.
I agree that that simulated NBO2 curve is not correct. I don't think any of the aftermarket simulated curves are any good. 91chevz71 is having a problem I spoke about earlier. That is, the simulated NBO2 curve needs to more linear for 0-1 volts. Some of the steep "S" to it needs to be removed. Once it is more linear, one can tune the O2 tables very reliably. With the stock simulated O2 curve it is too sensitive around stoich to tune the O2 tables.
The only real cure is to get a WBO2 controller with a programmable NBO2 output or a code mod. that creates the simulated NBO2 from the WBO2 value. A simple WBO2_volts/8 would be a start, but a [(1/WBO2_volts) * K] - C would be better and allow more room for tuning so that the O2 tables look "normal".
Key ON engine OFF. Give the sensor time to heat up then check the reading & see if it's close to 450mv or higher towards your 800mv.
Scratch that, don't know what I was thinking. Was trying too see if maybe you have ground bias issue but that isn't a good test.That only test pcm internal logic.Try doing voltage drop on sensor ground to battery negative and see if that might be a factor.
looking at my logs, I have multiple NB mv values for 14.4, which makes sense. range is about 25 mv for 14.4 according to wideband. I set the min value to change INT to 21 and the window to 91 mv. works pretty good. some of the very light throttle issue is from the 50mm TBI I think. Barely cracking the blades lets more air in than it really needs, which confuses the BLM/INT momentarily. but above say 1000 rpm things are normal, closed loop running 14.3-14.7.
THe wiring is straight from what I can tell for the NB. I've replaced all my grounds
you guys think my 3 wire NB O2 might be getting TOO hot?
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Barely cracking the blades lets more air in than it really needs, which confuses the BLM/INT momentarily. but above say 1000 rpm things are normal, closed loop running 14.3-14.7.
I thought there was a constant to allow open loop under a certain TPS %? Or maybe same for RMP threshold?
Might that not help to stay OL at smaller TPS % or under 1200 RPMs ??
