Excellent, will scan well tomorrow!

 

Ok I'm back after a little hiatus, but I'm dedicated to this thing. I got the car scanned with a tech2 and the CKP: Lo Res reading fluctuates a few degrees around 25 degrees.

A quick reminder of what that means from the repair manual, courtesy of GaryDoug: "The value displayed is the number of degrees that the camshaft deviates [either advanced (+) or retarded (-)] from its normal alignment with the crankshaft. During normal operation, on a vehicle with little or no timing chain wear, the value displayed would be near 0 • Dev." I revved it a few times, didn't really make it advance or retard, so looks like the timing chain is nice and tight.

So 25 degrees is pretty far off. I peeped in the CKP hole and turned the engine a few times and I don't see the reluctor wheel wobbling at an angle or anything, but I can't see much through that little hole anyway. I've checked everything else, signals from the crank sensor and opti are all good to the pcm, grounds are good, power is good. The opti has been replaced and reinstalled many times and I've checked to make sure it's fully engaged in the right hole on the opti, and the pin on the crank is long enough and I can see the engagement marks in the correct spot, so it doesn't seem to be coming out of place at all. So the opti seems fine by all accounts. That leaves me with the reluctor wheel, but 25 degrees seems like a lot to be off by. How could you install it so far off? My only guess is they have no keyway in it, and just put in on without it and called it good, at that point you can install it at any angle I think. Any thoughts on that? I'm ready to pull this thing apart to get to that reluctor wheel and fix it all, but I want to get some second opinions before I jump in. Car doesn't seem like cam timing is off cause it runs fine for a minute or so from a cold start, and if the timing was off I'd be able to tell as I've seen it before.

This thing has taken me for a ride, but not the kind I want yet

 

Reluctor ring requires a key, keyway provided in crank. Are you suggesting someone left the key out?

Are you getting a code for the CKP? They set when the CKP:Lo Res Angle gets outside an acceptable range.

If the CKP reluctor is off, it will set the codes, but should not affect the way the engine runs. If the deviation is caused by the Opti being off, it will affect the way the engine runs.

Have you resolved the running rich problem, and sorted out the actual injector flow rating?

"....CKP: Lo Res reading fluctuates a few degrees around 25 degrees". Is this indicating the CKP:Low Res Angle is always at -25-deg +/- a few degrees?

 

Yeah, I think for it to be 25 degrees off someone could have left the key out entirely.

I'm getting the P0336 code, never gotten the P0335, only P0336. It sets almost immediately after it's cleared.

I bought the proper injectors new so presumably they're correct now, but I never solved the running rich or misfire issue. No mechanic who's looked at it has gotten anywhere (and there's been quiet a few now). So I'm just trying to solve the issues I can. I'm hoping once I fix this I can get some misfire codes that will help point me in the right direction.

Yes that's exactly what I mean regarding the reading, here's a shaky video showing it https://photos.app.goo.gl/jmrGLmaTgMvEim6r7

 

Did you ever get to the bottom of it? This is and has been a problem in the industry for a while that’s only getting worse with the advancement of technology. You need to find a good technician that’s well equipped rather than a parts changer. It’ll serve you well not only for this issue but with any vehicle you have a problem with in the future. A good tech should be able to find that issue on a four channel scope fairly easily. Recording those signals and using rulers to compare them to a known good capture can tell whether or not the signal really is 25 degrees out. If it is then the problem has to lie somewhere with the reluctor, the optispark, or the PCM itself. A known good waveform can be very handy as you can see which part of the signal is out of place. Can you even see the reluctor through the CKP sensor hole?

 

May be a dead post but I'm just seeing it.

Have you observed under the hood at night e.g. in the dark. Sometimes that will help you see spark plug wire leakage. Should also do it in moist weather.

Also I don't remember which one exactly but I've seen some monitoring program for the LT1s that would let you disable each cylinder one at a time. That way when you have a misfire you might could tell which cylinder by not detecting a change in how the engine runs when the bad cylinder is disabled.

Hope you'll follow up as what you find could be a big help to a lot of others.

 

Sorry for the late reply. It's definitely 25 degrees out of place because the tech2 tool is reading that, and that's what the computer is calculating is how far the angle has deviated from where it should be. I'm about to take the engine out to fix that and then put it back in to read what codes come next, but I'm also debating just selling it because I've had this car for years and nobody has been able to make any progress with it. It's insane to me this issue is that hard to find. What's most important I think, is that the car does NOT misfire if I unplug the battery for a while and then start it, for like 15-45 seconds it's good, and then it starts missing super bad like normal. I'm not sure if it's running rich and that's causing it to miss, or it missing so bad is causing it to run rich. And get this, if I start the car again it will misfire right away, it will only not misfire if I leaving the battery unplugged for a while, then I get a little bit of time running good.
Any idea what the heck could cause it to not miss for about 30 seconds only after the computer is unplugged for a while? I want to drive this thing so bad

 

I have a 4 channel scope, but I'm not really concerned with the CKP sensor now that I have scanned it with the tech2, because it doesn't affect how the car runs. I can fix that later, of just ignore it for that matter, I need to figure out why this thing misfires like crazy. See my other latest reply if you haven't yet about how it doesn't misfire if I "reset" the computer by leaving the battery disconnected for a long time. Also yeah I can see the reluctor wheel, it's in there.

 

I'll never leave this post until I get to the bottom of this AND post the solution, or sell the car lol. Yeah I've check lots of times at night and with water and stuff for arcing, haven't seen anything. I'll look into the software to disable each cylinder but I doubt I'll be able to find someone who has it nearby. I'm in the middle of nowhere now lol.

 

I wonder if it's possible for the Opti shutter wheel mounting surface to be indexed incorrectly to the dowel pin hole on the back of the Opti? The shutter wheel clearly only connects to the mounting surface one way, so the only possible place for angular dislocation is somewhere between the back of the Opti where the dowel pin inserts, and the mounting flange for the shutter wheel. Is that piece made out of a single casting/machined construction, or is there a coupling between the two parts that could allow an assembly error? Would be interesting to find out.

 

Interesting you mention that because I was just talking with a shop manager reading their mechanic only forums, and one guy tore down the engine and checked the reluctor wheel because his LoResAngle was stuck at -20°, just to find it was the opti that caused the offset! I'm thinking that's the issue since everything else on the car seems fine. Mines stuck at about 25° if I recall, and symptoms do seem like an opti issue. Now I'm just wondering if it's the shutter wheel or casing / dowel mount that is off on this cheap opti, or the sensor itself can be off somehow. I have 2 OEM optis in pieces with oem sensors under my bed (safe place for such rare treasure &#128521 so I might try to find out how to put those sensors in this other opti casing. But if it's not the sensor that would be a waste and there's no way for me to tell. I'd rather just buy the $430 petris one at this point to avoid the headache, but I'm strapped for cash.

 

Ok recent thinking has led me to bite the bullet on a petris opti because if that doesn't solve the issue I can use it anyway since I had an ebay one on and it's bound to break, or another LT project that needs an opti. We'll see how that goes .

 

Ok well after all this time, installing the petris opti and going through all diagnostics again and again, it still misfires really bad so I've decided to sell it. I might just sell it as parts and scrap it because it has $750 of registration fees. Thanks for all the help anyway guys but unfortunately it feels like all the mechanics in the world couldn't fix this one lol.

 

i bet it's the Refurbished computer you have, you said its okay after power reset. and it's repeatable, power reset fixes it every time.