I hooked up the serial cable to the wideband this morning and at cooler ambient temps it's giving an error 8 during warm-up. So it seems the sensor is boned. It's a 4.9. The troubleshooting guide says it could be getting too hot during PE events or the sensor is damaged. I think the heating element is burning out due to cold ambients.
Car runs a bit different with the 82c thermostat. I'm seeing a bit more knock above 2400rpm but that doesn't worry me a lot right now. I'm just concerned with what it will do during the summer months. The high today here was 16c and the fans basically ran on high all the time to keep coolant temp under 100c. Unfortunately no-one seems to make a 77c or 79c thermostat in this size so I don't think there will be a happy medium.
After some testing yesterday, I reverted to essentially stock individual trims. I added a couple points to #1 at closed TPS since I enlarged that feed hole, and added a bit to #6 which is quite a bit rich in the stock tune and I noticed my balance tests showed it seemed to be pumping the strongest at closed TPS. I don't know if anyone's noticed, but at part-throttle the base Y-body tune takes a lot of fuel out of #6 so it goes from way lean at closed throttle to way rich at part. Go figure. Low-speed cruising is good here, so I'm not going to make many changes. However, I'm somewhat baffled as to why if I have a 3 count split at idle, and add 1 to the lean side and remove 2 from the rich side, why that doesn't "cure" the split. But it doesn't. I suspect its just the nature of the cam.
I did another EOIT sweep from 523 to 624. I noticed another variable that probably explains why I'm noticing splits increase with idle time - IAT. After a short drive to warm it up for the test, when I pulled in the driveway with EOIT in the tune at 579 BTDC it idled for 2-3 minutes at 128/130 (timestamp 1500).
My process was to change EOIT then reset BLMs, then log for 100 seconds. I noted the timestamp at each change, and recorded BLMS and other relevant data after 99 seconds. During the log my IAT climbed from 32c to 44c. I suspect this is relevant so I'm hoping to reproduce today's test with a fan or something blowing cool air near the air box.
Code:
ts eoit lbl rbl iac ect afgs split
1500 579 128 130 27 91.3 8.11 2
1600 523 118 141 28 90.5 8.17 23 < iat @ 32c
1700 528 120 139 29 90.5 8.27 19
1800 534 126 134 29 90.5 8.19 8
1900 540 126 133 30 90.5 8.28 7
2000 545 127 133 31 90.5 8.37 6
2100 551 127 132 29 90.5 8.04 5
2200 556 128 133 30 90.5 8.20 5
2300 562 128 133 30 90.5 8.16 5
2400 568 128 134 31 90.5 8.20 6
2500 573 129 134 29 90.5 8.16 5
2600 579 129 135 29 91.3 8.09 6
2700 585 129 134 29 91.3 7.98 5
2800 590 128 134 29 91.3 8.13 6
2900 596 131 135 28 90.5 8.02 4
3000 601 131 135 28 91.3 7.93 4
3100 607 132 136 26 90.5 7.75 4
3200 613 131 135 27 90.5 7.86 4 < iat @ 44c
3300 618 129 136 26 90.5 7.78 5
3400 624 129 136 25 90.5 7.75 5
As you can see there's no magic value here - the only thing that seems relevant is that after 590BTDC the left side goes lean. Otherwise it seems like I want to be between 613 and 596. So bearing in mind that lower coolant temps need more time for evaporation, I did this with my EOIT table.
Code:
-40 180
-28 180
-16 180
-4 180
8 360
20 360
32 360
44 618
56 613
68 607
80 601
92 596
104 596
116 596
128 596
140 596
152 596
A short drive with these settings showed about a 5 point split in BLM cell 2, and less everywhere else. I think I'm going to drive this tomorrow or the next day weather permitting and see what happens. If this is as good as it gets I'm happy with it - it runs very well. My clutch isn't quite able to handle 2nd and 3rd gear under full throttle.
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