Weird O2 sensor behavior (and they're new!)
Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
Weird O2 sensor behavior (and they're new!) UPDATE! She's running on all 8 now (Freakin finally). My next problem, keeping it straight on the road. Every time it gets into boost, it starts spinning and the rear end tries to come around. 
I got my Turbo installation all finished, then started the car. My scanner immediately noted way lean on the Left O2 Sensor. I thought my O2 sensor might be bad. I bought two new ones. Hooked up scanner and started the engine. Doh! Same as before! Block learn pegged at 160. I converted the Bryan Herter Flash file (Via LT1 Edit) to Speed Density. This was 'better' but it still bucks and back fires. Sometimes it seems like a motor running on 7 cylinders with the 8th periodically firing. Weird!! So, then I decided to log the events while I drove it up and down the block. But, As I sat there with the key on (motor off though) and got the scan/log session going, I noticed something odd. You know that when you first turn the key on, the O2 heaters come on and start warming the O2. Well, both O2 readings (remember, the motor is still off at this point, just the key is in the 'Run' position) are showing 458 mv at first, then the right side (that's been normal from day one) starts slowly moving up to 7xx, 8xx millivolts. But the left side that's been giving me grief, goes down to low single digit millivolts and stays there. Wow... what the hell? Wiring issue? Must be! I went ahead and drove the car down the block and back with the scanner on. It's bucking, sneezing, backfiring... ugh... This is the same thing it did when the Turbo is not hooked up. I'm going to pull the wiring harness off that side, up into the engine bay and start looking for shorted wiring.
I got my Turbo installation all finished, then started the car. My scanner immediately noted way lean on the Left O2 Sensor. I thought my O2 sensor might be bad. I bought two new ones. Hooked up scanner and started the engine. Doh! Same as before! Block learn pegged at 160. I converted the Bryan Herter Flash file (Via LT1 Edit) to Speed Density. This was 'better' but it still bucks and back fires. Sometimes it seems like a motor running on 7 cylinders with the 8th periodically firing. Weird!! So, then I decided to log the events while I drove it up and down the block. But, As I sat there with the key on (motor off though) and got the scan/log session going, I noticed something odd. You know that when you first turn the key on, the O2 heaters come on and start warming the O2. Well, both O2 readings (remember, the motor is still off at this point, just the key is in the 'Run' position) are showing 458 mv at first, then the right side (that's been normal from day one) starts slowly moving up to 7xx, 8xx millivolts. But the left side that's been giving me grief, goes down to low single digit millivolts and stays there. Wow... what the hell? Wiring issue? Must be! I went ahead and drove the car down the block and back with the scanner on. It's bucking, sneezing, backfiring... ugh... This is the same thing it did when the Turbo is not hooked up. I'm going to pull the wiring harness off that side, up into the engine bay and start looking for shorted wiring.
Last edited by mightyquickz28; Jul 8, 2008 at 06:17 PM.
Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
I would think that would be loud, but it's quiet. I have the complete exhaust hooked up right now and I don't hear the noise that would I would expect with an air leak. Thanks though. I'm going to hook the wires from the right side to the left's O2 sensor, then scan it with the key on to see if it does the same thing. If it repeats that same drop in mv but now on the right side, I'll know it's something peculiar to the left hotside. If the mv are normal, I'll know it's the wiring harness on the left side.
Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
(UPDATE: This must have been imagined. As soon as I tried to drive it, it ran crappy again)
The left side always shows up as Lean. Which is so odd since the plugs looked like it's running damned rich. To update you all, I apparently have a compound problem. For one thing, I tried another set of LS1 Coils and found that it improved immensely! It now runs on 7 cylinders, which in and of itself is a HUGE improvement. Now I'm letting it cool down to see if one of the plugs is just fouled.
The left side always shows up as Lean. Which is so odd since the plugs looked like it's running damned rich. To update you all, I apparently have a compound problem. For one thing, I tried another set of LS1 Coils and found that it improved immensely! It now runs on 7 cylinders, which in and of itself is a HUGE improvement. Now I'm letting it cool down to see if one of the plugs is just fouled.
Last edited by mightyquickz28; Jun 17, 2008 at 06:38 PM.
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Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
Looks like I may have isolated it. TurboBobs LTCC has a couple of LED's inside the housing for the processor. I'd PM'd Bob last night asking if he had any idea if the LTCC could play a role in this. He asked me to pull off the cover of the box and look at the LED's.
Upon "KEY ON", they go thru a bulb test and flash once. Then, when you crank, the green LEN *should* illuminate and stay on. Mine does. The red LED is for diagnostics. Here's what the .pdf file just told me....
Red LED flashes once = Cylinder Decode sequence error.
Red LED flashes twice = Wrong number of Hi Res Pulses counted between Lo-Res Rising edges.
Red LED flashes Three times = Wrong number of Hi Res Pulses counted during a High Lo-Res pulse or a Low Lo-Res Pulse.
Red LED flashes four times = EST (Electronic Spark Control) signal from PCM = missed pulse. Check connection to white wire.
Mine is flashing 3 times.
I've sent a PM to TurboBob to see if this means its wiring or time for a new OPTI.
Upon "KEY ON", they go thru a bulb test and flash once. Then, when you crank, the green LEN *should* illuminate and stay on. Mine does. The red LED is for diagnostics. Here's what the .pdf file just told me....
Red LED flashes once = Cylinder Decode sequence error.
Red LED flashes twice = Wrong number of Hi Res Pulses counted between Lo-Res Rising edges.
Red LED flashes Three times = Wrong number of Hi Res Pulses counted during a High Lo-Res pulse or a Low Lo-Res Pulse.
Red LED flashes four times = EST (Electronic Spark Control) signal from PCM = missed pulse. Check connection to white wire.
Mine is flashing 3 times.
I've sent a PM to TurboBob to see if this means its wiring or time for a new OPTI.
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Verdad Gallardo Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
Well.... over nighted the Opti and a new Opti Pigtail and it was here to greet me when I came home from work. Tested them before installing it by just hooking up the harness to the new one, turned on the key, spun the opti. The red blinking light on the LTCC was gone and I could hear the spark plugs sparking. Cool ... So I installed it. Then swapped the injectors back to the mototrons. Reflashed the PCM with Bryans tune and fired it up.
IT RUNS THE SAME G*D DAMNED WAY AS IT HAD!!!! Running on 6 cylinders at the most.
UNbelievable! This is so sad it's funny.
I tried relashing it with the timing advanced 2 degrees across the board since it starts so weakly. Doesn't matter.
Ill get a timing light tomorrow and see it that reveals anything.
The scanner says it's got 32 degrees at 850 rpm now. It did say 30 before I added the extra timing.
I've gone on to Google looking for symptoms of cams degreed incorrectly (retarded too many degrees) The symptoms I'm seeing sure look familiar
I'm probably going to just pull the timing cover off and install it straight up. I sent an email to my engine builder and he said it used the '2 degree' slot on the crank sprocket but he can't recall now if it was 2 degrees advanced or 2 degrees retarded.
IT RUNS THE SAME G*D DAMNED WAY AS IT HAD!!!! Running on 6 cylinders at the most.
UNbelievable! This is so sad it's funny.
I tried relashing it with the timing advanced 2 degrees across the board since it starts so weakly. Doesn't matter.
Ill get a timing light tomorrow and see it that reveals anything.
The scanner says it's got 32 degrees at 850 rpm now. It did say 30 before I added the extra timing.
I've gone on to Google looking for symptoms of cams degreed incorrectly (retarded too many degrees) The symptoms I'm seeing sure look familiar
I'm probably going to just pull the timing cover off and install it straight up. I sent an email to my engine builder and he said it used the '2 degree' slot on the crank sprocket but he can't recall now if it was 2 degrees advanced or 2 degrees retarded. Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
Found my cam specs. Going to pick up the cam degree kit plus the nut you put on the crank to turn it over. I have to wait till about noon today to meet the guy (Fbody Buddy of course! The best guys/girls on the planet!) to pick up his kit, accessories. I did a little more research (prompted by fellow LS1Tech'r Chuck Norton. Thanks Chuck!) and found that not only did my engine builder not adv/retard the cam 2 degrees as he'd stated, the timing set (CLO-9-3145) doesn't even have a provision for just 2 degrees. It has 3 keyways. 4 degrees Advanced, "Standard/Dot-to-Dot" and 4 degrees Retarded. (For those in Rio Linda, that means you can't *just* add/subtract 2 degrees with this timing set). Something stinks here (and it's not just that shirt I've been wearing while under the car) Using the ICL (Intake CenterLine method) the cam should show a 112 ICL if it's degreed properly.
Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
Well... Just put a new stock coil ($37) and Ignition Control Module ($71) and a set of stock Duralast/Autozone Plug wires ($35) on the car and just the 'old' opti to spin/generate the spark signal. What? No spark? Wait, what's that noise? The old opti is making a bunch of Chattering noises inside. Then I remember, "Oh, that's right. This is that piece of crap non-functioning(the high voltage part) Opti of someone elses that HPE gave me when they screwed me over on that roller cam motor". So, I just put 3 plug wires with plugs on them onto the New Summit Opti bolted to the engine. I spun it over. What? No spark?.. Oh wait (sheepish grin) I forgot to hook up the harness to the engines opti. Hooked it up, said a prayer, spun the engine. Hot damn! Sparks! And evenly timed too (at least it seems so at this point). I'm going to put the sparkplugs in the heads, route the plug wires as best I can around the Hotsides Log manifolds and once everything is connected to the point I can start it (no waterpump, etc is hooked while I'm in diagnostic mode here) I'll fire her up. I sure hope I'm greeted by a V8 running on all 8 for a change. It appears now it's been the LTCC box the whole time
Thread Starter
Joined: Feb 2003
Posts: 2,145
Likes: 133
From: East Chatham, New York
UPDATE! She's running on all 8 now (Freakin finally). My next problem, keeping it straight on the road. Every time it gets into boost, it starts spinning and the rear end tries to come around.
