DNSTA

Some background on the car. LSX454, twin turbo and M6. ECM from a 2010 Camaro SS (E38 I believe)

I took the car out for some spirited driving last weekend and experienced a major misfire in the upper RPM range, around 5,000RPM+. This was the first time that has ever happened so I went a few more rounds and it continued to do it. I quickly though about anything I had done since it last ran well and the only item I even touched was the intake pipe which I powder coated. I’m going to go out on a limb and say that wasn’t the culprit. 😊

I scanned and got a P0016 and a P0507. I have to assume they’re related but if that doesn’t makes sense let me know. Anyway, my research indicated the P0016 is related the crankshaft and camshaft not seeing the same thing in relation to position or timing. This would explain the high rpm breakup but I’m trying to determine what my next steps should be. Other than the high rpm breakup the drive-ability isn't all that bad. Seems a little down on power but starts perfectly and can be driven around town. Here’s what I’ve done so far:

1.Replaced both the Crankshaft Position Sensor and the Camshaft position Sensor
2.Check all wiring: No breaks and I have continuity between the sensor and the ECM
3.Reflashed the ECU with the last known good tune.


Questions about diagnosis/fix:

How do I determine if I actually have a physical problem like a rotated reluctor wheel or perhaps the timing chain jumped a tooth. If so, how do I figure out which one it is? What else could throw this code?

Questions about theory:

If the sensors are looking to see the same thing, or some sort of signal that correlates between the two can I just trick the ECM into thinking it’s getting a good signal? In other words, is the comparison between the two signals actually necessary/useful? I’m aware it’s used to determine misfires but outside that would not having a real signal cause damage to the engine if it were running well otherwise? I’m not even sure that’s possible but I just wanted more information on the use of the correlation between the two sensors.

DNSTA

help......

ShiftyCapone

iTrader: (7)

After you cleared the codes did they come back?

DNSTA

Yes, multiple times.

GTA matt

iTrader: (1)

You're going to have to take it apart and visually inspect things. Even scoping the cam and crank signals wouldn't tell you much, other then that they are not in sync, which we already know because there is a code. Perhaps it could tell you if there is a bent or damaged tooth on the crank reluctor, but some time spent looking through the ckp hole while slowly turning the engine might be quicker then pulling the oil pan to fully inspect. Pulling the timing cover shouldn't be a big deal either, and will for sure tell you if something is going on at that end. I wouldn't attribute the breaking up at 5k to it being physically out of time just yet, although it may be slightly off. That is probably part of the programming when that code is set, I've been down that road before. The two codes are most likely unrelated. Possible vacuum leak or something of that nature causing the 507 code.

DNSTA

Good points GTA matt.

Would I be able to see if the reluctor wheel had rotated with only the pan off or does the trans need to come down or crank need to come out?

I should be able to determine a timing issue without disassembly though, correct? I've never check it on an LS-based motor but I do have HP Tuners so I assume I can do it via that tool. Would I be looking at something like commanded vs. actual or do I need to know what it should be and then compare it to what it actually is? I'm trying to do as much investigation as possible prior to opening it up. I just bolted it back together and there are absolutely NO leaks so I'm pissed at even the idea of taking it apart again.

I just have such a hard time believing the code! The engine has less than 5K on it and it's only been to the track one last year. Double roller, Callies dragon slayer crank, I have to assume the reluctor wheel was tacked on

GTA matt

iTrader: (1)

If hp tuners works for seeing data like a regular scan tool, you should have a pid that reads cam/crank offset or something like that. The code sets when they are more then 11 degrees off. If your balancer is marked, you could remove the cam sensor, roll the engine around by hand, you should see the leading edge of a raised tooth on the cam sprocket through the hole at 36 degrees before tdc on cylinder 1. If that is the case, you may have a crank reluctor problem. If it is off, pull the timing cover.

DNSTA

I'm looking into HP Tuner's ability to read offset but nothing yet. In regards to the timing I'm under the impression LS balancers don't have timing marks because they aren't keyed to the crank. I've got a PowerBond (Dayco) balance that does have marks and a Callies Dragonslayer crank that is keyed buy what would I reference on the block for timing if a stock unit doesn't have marks.

DNSTA

If it sets when they're 11+ degrees off wouldn't that cause some pretty serious driveability issues? I feel I'd know if it was that far out wouldn't I?

DNSTA

Still struggling here. I did crank relearn last night and I'll take it for a drive today. I had to clean DTCs to get the relearn to work and when I pulled them I saw that I now have Throttle Position Sensor voltage high and low code. I'm beginning to think something else is going on. There's no way I have all of these issue that just now happen to break. What's going on???

ShiftyCapone

iTrader: (7)

Can you get a file to your tuner so they can look through it?

dixiebandit69

Okay, when I have a car that starts trowing up random codes for seemingly no reason, MAKE SURE THAT YOUR CHARGING SYSTEM IS WORKING PROPERLY, AND YOUR BATTERY CABLES/ TERMINALS ARE CLEAN.

You wouldn't believe the number of times I've had some car come in the shop with weird problems, and it was something as simple as that.

If everything checks out, let us know, and we can give you more advice.

DNSTA

ShiftyCapone - I don't have a tuner that's worked on the car. The ECM was set up when I got it and I've made all of the finite adjustment so far. I'm hesitant to take it to a shop because what I really need is someone to scope it who understands the wave forms and can determine if the correlation is really an issue. Is it a timing chain, reluctor wheel or wiring issue??? And how does the P0507 come into play? I highly doubt my reluctor wheel moved AND I sprung a vacuum leak at the same time...

dixiebandit69 - All cables are good, system is completely charged and alternator output is good. The TPS codes have not returned but the P0016 and P0507 come back every time I clear them so there's definitely something happening there.

GTA matt

iTrader: (1)

Do a thorough check on all your grounds and check ac ripple at the alternator stud. Set your meter on ac voltage, under .2 volts is ideal, under .5 volts is fine, you start getting over a volt and it starts messing with things. As for the timing markers, you would have to make your own on the timing cover. Best way is with a piston stop, but i understand its not that easy with everything already together.

Another thing worth a quick check, all the wire terminals at the ecm for ckp, cmp and tps signal are all side by side, terminals 63-69 on the x2 connector. Make sure there's no water or corrosion inside the connector. And you are correct about finding someone trusted and knowledgeable to work on it. Most guys with the equipment and knowledge will probably run since it's modified.

DNSTA

Given the turbo piping taking the timing cover off is actually easier than putting in a piston stop and fabbing up a timing marker. If I had voltage issues I would expect other codes and not the same ones to continually return but I'm going to check it tonight to be absolutely sure. The ECM, like everything under the hood, has less than 5k miles on it and it is brand new condition. Interesting point regarding the position of the terminals. Probably a coincidence but interesting none the less.

DNSTA

Just finished a few test runs. I flashed the ECM back to the tune it ran all last year without a problem and it had no effect. I then unplugged my 2-step in case that was causing issue and no change. It's leaning more and more towards something mechanical I think...

LsxMatt

iTrader: (4)

I would just pull the starter and crank sensor to look at the reluctor wheel. Easiest thing before pulling the timing cover..

DNSTA

LsxMatt - Doing that won't tell you if the wheel has spun on the crank. But... I did it anyway and it looks fine. All teeth are intact, straight and show no signs of touching anything. The wheel doesn't seem to wobble and maintains it's distance from the back of the block during the entire rotation. I tried to move it around with a screwdriver but access was too limited. So I know it's not damaged but that still proves nothing and I'll need to remove the timing cover anyway. I'm going to try and find someone with a scope and see if I can get the cam/crank offset. This is the only real way to figure out if I have a physical issue without pulling the engine. At least that's what I think.... Could it be a bad ECM??? I know, I'm just grasping at straws now.

I did some logging as well. I'm not familiar with HP Tuners so I really don't know how to properly set the scanner to capture useful stuff but I did get a graph of spark advance in my effort to look at timing. It showed a maximum of 51 degrees of advance. Does that seem plausible? I can post the file/screenshots if it helps.

DNSTA

bump

cam-

You can set up the scan tool to verify every single data feed going to the PCM. You need to start with this and seek someone who knows what they are doing or get on the hp boards and start with a simple explanation of your troubles and post your tune and hope someone there will walk you through it. You could contact tuned by frost dot com who is a master of these systems. Good luck