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post #16 of 31 (permalink) Old 11-06-2012, 02:24 PM
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Starting with your idle.. You look pretty good except for the bad left O2.. It's holding BLM ready off and your staying in open loop. Your desired RPM is 800 and you are idling fine at 800-825, MAP (vacuum) is good at 32-33 KPA. IAC is running near 45 so that's good, TPS voltage is .69 a tad high but within specs no need to mess with it. Close TPS timing is OK at 20*. AFGS at idle is 8.29 both injectors at 2.3 Ms looks good also.

Now the bad part for some reason your PCM is locked into using BLM cells 16,17 & 18. You never use 0-15. I have seen this caused by bad tunes messing with EGR or EVAP settings, and I believe I saw it once caused by altering BLM boundaries (Mysterybird are you out there ??) You are getting knock retard whenever you hit the throttle. The knock may be a lean condition caused by the combination of open loop and using incorrect BLM cells. Can't see BLM's in open loop both LT & ST read 128.. Your right O2 voltage seems to go full rich 900 Mv when you hit the throttle left stays stuck at 450 Mv . Not sure how the PCM software calculates fueling when using the VE tabels in open loop and when it's stuck in BLM cells 16-18. Sort of a double failure, that's not worth chasing, let's fix open loop first.

Work on that left O2 . And let's get this thing into closed loop before moving on. I'd like to see a posted copy of your tune if it's not a purchased one. If purchased then it's proprietary property of the tuner, don't post it. Trying to see why PCM is stuck in cells 16-18.

I'm Bob.. 1994 Z28, A4, Stall, CAI, Cam, RR's, 342 rear, LT's , CatBack, Tuned

Last edited by bobdec; 11-06-2012 at 02:29 PM.
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post #17 of 31 (permalink) Old 11-06-2012, 03:32 PM Thread Starter
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Okay so the left 02 that's constantly stuck at 450mv is the one that's bad. I'll pick a new one up when my paycheck comes in Friday. Now onto the Blm cells, I'm new to tuning and only have a simple understanding of what Blm cells are but I can see that its very odd the pcm never uses 0-15. I'll shoot you a pm about the tune.

Edit: Went and did some reading on why the pcm would stay in cells 16-18 and never any others. According to post #3 here: http://www.camaroz28.com/forums/lt1-...n-isnt-737956/ the pcm will stay in cells 16-18 until the car enters closed loop. Which mine will not do, because of the o2 sensor. If this is true then the blm cell problem would also be caused by my fault o2 sensor. The Op of that thread seems to have a *similar* problem.

Last edited by aappss01; 11-06-2012 at 03:41 PM.
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post #18 of 31 (permalink) Old 11-07-2012, 11:01 AM
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Lots of modded setups only run in open loop, have not heard they only use cells 16-18, bit I'm always open to learn.. if you read that thread down to post #15 you will see he fixed the open loop problem, went into closed loop, PCM was updating ST and LT BLM's. But still only using cells 16-18, the thread ended there. Seen a few threads indicating stuck in 16-18, all seemed to be related to bad software or non stock tune input. Usually on the forums once things get fixed the poster dissapears. So it's hard to put a thumb on exactly what fixed the problem. Let's fix the left O2 and then see what happens to the BLM cell selection..then we will know for sure if it's that bad O2 reading causing it.

I'm Bob.. 1994 Z28, A4, Stall, CAI, Cam, RR's, 342 rear, LT's , CatBack, Tuned
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post #19 of 31 (permalink) Old 11-07-2012, 12:55 PM Thread Starter
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Alright, ill be ordering the o2 friday and switching it out saturday. The left o2 is the one on the drivers side correct?
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post #20 of 31 (permalink) Old 11-07-2012, 04:16 PM
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Correct, drivers side.. Stay away from Bosh O2's our LT1's sometimes get testy when using them. Delco or Denso are good choices. Any time to swap left to right and verify it's the O2 not wiring ?? It's a PITA, but could save $30.00 if it's wiring, not the O2.

I'm Bob.. 1994 Z28, A4, Stall, CAI, Cam, RR's, 342 rear, LT's , CatBack, Tuned
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post #21 of 31 (permalink) Old 11-07-2012, 04:18 PM Thread Starter
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Quote:
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Correct, drivers side.. Stay away from Bosh O2's our LT1's sometimes get testy when using them. Delco or Denso are good choices. Any time to swap left to right and verify it's the O2 not wiring ?? It's a PITA, but could save $30.00 if it's wiring, not the O2.
Yep ill switch them from side to side tomorrow. And run the car. We'll see what happens.
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post #22 of 31 (permalink) Old 11-08-2012, 05:52 PM Thread Starter
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Well I switched them today. Knowing that the right 02 sensor and wiring worked perfectly fine I switched them. After switching the left o2 sensor did not work. (Which means the wiring is bad) and the right 02 sensor didnt fluctuate at all. (Which means that the 02 sensor itself is also bad. So to sum things up, the right side (passenger) is completely perfect. The left hand side, the o2 sensor AND the wiring are bad. I know where to get the 02 sensor, I do not know where to get the wiring. Any help on tracking that down and what all it entails would be great.

Edit: After swapping the O2's around and calling it a night I noticed my fans weren't engaging. I checked the fuse box and my #6 fuse was blown. So is it possible that the 02 sensor's are on the same fuse as the fans?

Last edited by aappss01; 11-08-2012 at 06:24 PM.
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post #23 of 31 (permalink) Old 11-08-2012, 06:52 PM
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The #6 fuse in the under hood fuse block is for both O2s in a '95, as well as fan relays, among other things. Not sure why your right one continued to work.

1995 Firehawk #528 resto-mod underway

Planned 383 rebuild: 195cc competition LT4 AFR heads, custom cam grind (still debating specs), 6" or 5.85" rods, forged internals

Upgraded T56: Viper mainshaft and 2nd gear, steel 3/4 shift fork, Billet keys 1-4, bronze shifter cup, internals Cryo'd and REM'd
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post #24 of 31 (permalink) Old 11-08-2012, 07:45 PM Thread Starter
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Exactly as I thought. The right one didn't continue to work. This is a little confusing but Ill try to explain. The first time I swapped the o2's the right worked and the left didn't. Well when I went to swap them back I wasn't sure if I completely clipped them both in. So I decided to run them to way they were originally and afterwards swap them again. I didn't blow the fuse until the last time I swapped. (The right, working, 02 is currently in the left side and vice versa.) I replaced the fuse after I was done working. So the right didn't work at all when the fuse was blown.

Anyways, the readings for each o2 in the opposite position are 457-457 for the left (formerly right) and 448.44 for the right (formerly left). So I know that the sensor and the wiring is bad. Any pointers on where to begin looking at the wiring? Is there a way to remove the 02 harness or am I just going to have to chase it through the engine bay?
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post #25 of 31 (permalink) Old 11-09-2012, 12:02 AM
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Quote:
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Anyways, the readings for each o2 in the opposite position are 457-457 for the left (formerly right) and 448.44 for the right (formerly left). So I know that the sensor and the wiring is bad.
So they're both not switching now? Just to clarify, with the O2's swapped, they both stay near 450mV all the time, with no fluctuations with the engine running and warmed up?

If this is still happening with the O2s fully warmed, you should check the wires for continuity and correct voltage before going through the trouble of changing them out. If you jumper the tan/white and purple/white wires to ground your scanner should show that o2 at <200mV. With a voltmeter and ignition on, engine off, check voltage on the purple/white wire, it should read >300mV. Finally, check the brown and black wires for continuity with a test light.


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1995 Firehawk #528 resto-mod underway

Planned 383 rebuild: 195cc competition LT4 AFR heads, custom cam grind (still debating specs), 6" or 5.85" rods, forged internals

Upgraded T56: Viper mainshaft and 2nd gear, steel 3/4 shift fork, Billet keys 1-4, bronze shifter cup, internals Cryo'd and REM'd
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post #26 of 31 (permalink) Old 11-09-2012, 10:13 AM Thread Starter
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Quote:
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So they're both not switching now? Just to clarify, with the O2's swapped, they both stay near 450mV all the time, with no fluctuations with the engine running and warmed up?

If this is still happening with the O2s fully warmed, you should check the wires for continuity and correct voltage before going through the trouble of changing them out. If you jumper the tan/white and purple/white wires to ground your scanner should show that o2 at <200mV. With a voltmeter and ignition on, engine off, check voltage on the purple/white wire, it should read >300mV. Finally, check the brown and black wires for continuity with a test light.


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Correct, when switched neither one of them function. And after about ten minutes of the car running the #6 fuse blows. But with them in their original position the right functions completely fine and the left doesn't function. So the left side has a bad sensor and something wrong with the wiring. I'll check the wiring. I'm wondering why the fuse would blow only when I swapped them from side to side. It's odd.
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post #27 of 31 (permalink) Old 11-09-2012, 01:31 PM Thread Starter
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Well I poked around under there today quickly before work and I think I may have found the problem. Here's a picture I took:

That is the left side 02 plug. As you can see one of the pins/plug is completely burnt and melted. Im not even sure if the pin is still in there. Would this be causing my problem then? And where would I go about getting a new connector?
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post #28 of 31 (permalink) Old 11-09-2012, 07:02 PM
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That would do it. I believe if that circuit (should be tan wire) is open, the O2 reading would stay constant at ~450mV. Hopefully replacing the O2 that was installed there will keep it from happening again.

I found that connector on eBay:

LS1 LT1 O2 Oxygen Sensor Wiring Connector Pigtail GM Camaro Firebird Corvette

http://bit.ly/TxHkk5



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1995 Firehawk #528 resto-mod underway

Planned 383 rebuild: 195cc competition LT4 AFR heads, custom cam grind (still debating specs), 6" or 5.85" rods, forged internals

Upgraded T56: Viper mainshaft and 2nd gear, steel 3/4 shift fork, Billet keys 1-4, bronze shifter cup, internals Cryo'd and REM'd
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post #29 of 31 (permalink) Old 11-10-2012, 08:12 PM Thread Starter
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Thank you sir I really appreciate it. So can I just splice the wires together with butt connectors?
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post #30 of 31 (permalink) Old 11-13-2012, 07:32 AM
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Quote:
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Thank you sir I really appreciate it. So can I just splice the wires together with butt connectors?
You can, but a metal crimp, then soldered, then shrink tubing would be best. Or better yet, you can search for just the connector, and save from having to splice anything. The connector will come with new terminals which are crimped to the wires, then they will snap into the connector. The included weather seals will keep out moisture and finish it off with a nice professional look, with no cutting of the original wires.


Sent from my iPhone using Autoguide.com App

1995 Firehawk #528 resto-mod underway

Planned 383 rebuild: 195cc competition LT4 AFR heads, custom cam grind (still debating specs), 6" or 5.85" rods, forged internals

Upgraded T56: Viper mainshaft and 2nd gear, steel 3/4 shift fork, Billet keys 1-4, bronze shifter cup, internals Cryo'd and REM'd
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