symptoms of camshaft incorrectly installed
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From: Utah
symptoms of camshaft incorrectly installed Completing a v8 swap with the LY6 engine receiving a VVT1 camshaft.
I'm currently battling a mystery where the engine idles like crap when the crankshaft position sensor is plugged in. O2 sensors indicate lean exhaust and fuel trim is compensating causing a really rich A/F ratio, bad idle with lumpy stalling conditions. Oddly enough, when the CKP sensor is unplugged the car runs pretty solid.
Scanning shows no codes and and RPM signal coming from both. I'm curious, if this could be a symptom of the cam being installed upside down? Whereas the CMP is telling the PCM which stroke the cam is on, when the CKP sensor is communicating at the same time, they are both running opposite, so the CMP sensor is saying intake stroke, but the CKP sensor is actually on an exhaust stroke?
Could this be possible? We've run through everything mechanical the scanner watches and everything looks within spec once the CKP sensor is unplugged.
I'm currently battling a mystery where the engine idles like crap when the crankshaft position sensor is plugged in. O2 sensors indicate lean exhaust and fuel trim is compensating causing a really rich A/F ratio, bad idle with lumpy stalling conditions. Oddly enough, when the CKP sensor is unplugged the car runs pretty solid.
Scanning shows no codes and and RPM signal coming from both. I'm curious, if this could be a symptom of the cam being installed upside down? Whereas the CMP is telling the PCM which stroke the cam is on, when the CKP sensor is communicating at the same time, they are both running opposite, so the CMP sensor is saying intake stroke, but the CKP sensor is actually on an exhaust stroke?
Could this be possible? We've run through everything mechanical the scanner watches and everything looks within spec once the CKP sensor is unplugged.
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Completing a v8 swap with the LY6 engine receiving a VVT1 camshaft.
I'm currently battling a mystery where the engine idles like crap when the crankshaft position sensor is plugged in. O2 sensors indicate lean exhaust and fuel trim is compensating causing a really rich A/F ratio, bad idle with lumpy stalling conditions. Oddly enough, when the CKP sensor is unplugged the car runs pretty solid.
Scanning shows no codes and and RPM signal coming from both. I'm curious, if this could be a symptom of the cam being installed upside down? Whereas the CMP is telling the PCM which stroke the cam is on, when the CKP sensor is communicating at the same time, they are both running opposite, so the CMP sensor is saying intake stroke, but the CKP sensor is actually on an exhaust stroke?
Could this be possible? We've run through everything mechanical the scanner watches and everything looks within spec once the CKP sensor is unplugged.
I'm currently battling a mystery where the engine idles like crap when the crankshaft position sensor is plugged in. O2 sensors indicate lean exhaust and fuel trim is compensating causing a really rich A/F ratio, bad idle with lumpy stalling conditions. Oddly enough, when the CKP sensor is unplugged the car runs pretty solid.
Scanning shows no codes and and RPM signal coming from both. I'm curious, if this could be a symptom of the cam being installed upside down? Whereas the CMP is telling the PCM which stroke the cam is on, when the CKP sensor is communicating at the same time, they are both running opposite, so the CMP sensor is saying intake stroke, but the CKP sensor is actually on an exhaust stroke?
Could this be possible? We've run through everything mechanical the scanner watches and everything looks within spec once the CKP sensor is unplugged.
did you tune the car?
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From: Utah
Yes, car is tuned by TSP since I used their VVT-1 cam.
Car runs well enough besides some hard shifting when the CKP sensor is unplugged.
When you install the cam, don't you have to maintain the orientation of the dots used to keep everything lined up? Depending on the cam direction and the crank, you can either be at 1 TDC or 6 TCD from what I've found on other threads. I'm wondering if this might be the cause of the miscommunication that seems to be happening when both CMP and CKP sensors are feeding info to the PCM.
I wasn't there for the cam install, so can't speak to how everything was put together.
Car runs well enough besides some hard shifting when the CKP sensor is unplugged.
When you install the cam, don't you have to maintain the orientation of the dots used to keep everything lined up? Depending on the cam direction and the crank, you can either be at 1 TDC or 6 TCD from what I've found on other threads. I'm wondering if this might be the cause of the miscommunication that seems to be happening when both CMP and CKP sensors are feeding info to the PCM.
I wasn't there for the cam install, so can't speak to how everything was put together.
Last edited by DrWagon; May 22, 2016 at 04:18 PM.
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From: Utah
If someone can confirm that there is no way the camshaft and crankshaft position sensors could be out of sync because the CKP is reading cylinder 1 is TDC but the CMP is telling the PCM cylinder 6 should be fired that would greatly help me narrow down my issue to electrical vs mechanical.
Once again, when only the CMP is telling the PCM where the cycle is at, the engine runs well, but when both sensors are communicating with the PCM, that is most certainly not the case.
Once again, when only the CMP is telling the PCM where the cycle is at, the engine runs well, but when both sensors are communicating with the PCM, that is most certainly not the case.
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Yes, car runs without CKP plugged in. This confused my mechanic, and the PSIconversion rep who built the harness...both said car shouldn't even start with that sensor unplugged. A few threads here suggest otherwise, but nothing more than anecdotal.
We have tried a CASE relearn but after initial conditions are met and the engine is revved, it fails due to a few A/C codes thrown (only during the CASE relearn; they don't show up any other time and do not show up as stored or temporary in the scanner). I don't have A/C hooked up at all. Someday down the road...
The e38 is from the same engine, but TCU is from a different vehicle (PSI), as is the 60e transmission (Performabuilt).
Furthermore, when CKP is plugged in, but CMP is unplugged, car will not start, which is counter to everything I've read on here. When unplugging CMP when running and CKP sensor plugged in, car dies immediately. rpm signal is present for both sensors in the scanner. Everything I've read says the CMP sensor unplugged should just cause a hard start but no run issues.
We have tried a CASE relearn but after initial conditions are met and the engine is revved, it fails due to a few A/C codes thrown (only during the CASE relearn; they don't show up any other time and do not show up as stored or temporary in the scanner). I don't have A/C hooked up at all. Someday down the road...
The e38 is from the same engine, but TCU is from a different vehicle (PSI), as is the 60e transmission (Performabuilt).
Furthermore, when CKP is plugged in, but CMP is unplugged, car will not start, which is counter to everything I've read on here. When unplugging CMP when running and CKP sensor plugged in, car dies immediately. rpm signal is present for both sensors in the scanner. Everything I've read says the CMP sensor unplugged should just cause a hard start but no run issues.
Yeah, that's news to me too. I wish I had something else to offer. On the cars with a 1x CMP when it's faulted, it will guess based on crank angle. If car doesn't start it guesses out of phase (360 degrees) and try's again. I haven't really messed with the 4x stuff, maybe it is smart enough to figure out where it is based on the 4x low res CMP signal and take a guess based on that.
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Thread Starter
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From: Utah
Thanks. That's what I've been reading that if the CKP is working and the CMP is not, the only symptom is a hard start as the PCM has to use trial-and-error to determine which stroke to fire on. I have a hard start when CKP is unplugged, and no start when CKP is plugged in with no CMP...seems backwards based on everything I've come across.
To me, this indicates the PCM is not able to use trial and error with only the CKP sensor, possibly because the CKP is not sending the correct signal, or any signal at all. Confusing since the scanner shows an RPM signal from both sensors when plugged in???
I might check the PCM pins for the two sensors and see if they were accidentally crossed? Doubtful, but I'm grasping at straws here.
To me, this indicates the PCM is not able to use trial and error with only the CKP sensor, possibly because the CKP is not sending the correct signal, or any signal at all. Confusing since the scanner shows an RPM signal from both sensors when plugged in???
I might check the PCM pins for the two sensors and see if they were accidentally crossed? Doubtful, but I'm grasping at straws here.
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From: Utah
It is grey. Matched the original one we pulled out of the engine. Had two types sent from the parts store just to compare. I really wish we could get the CASE relearn to go through. Part of me things that's the issue, but no way to confirm without getting rid of the A/C codes.
The sensor tip had a coat of oil on it. Is this normal?
The sensor tip had a coat of oil on it. Is this normal?
Last edited by DrWagon; May 26, 2016 at 09:16 PM.
Yes it's open to the inside of the crankcase so I would expect oil on it. FWIW you can disable or force the computer to ignore and not error on most if not all of the diagnostic tests for things like A/C in tuner suites like HP Tuners.
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Thanks, that's what I suspected, but grasping at straws here.
I don't have access to HP Tuners, but if the computer goes back to TSP for tuning, I'll see if they can turn some things on and off.
Thanks for the help here.
I don't have access to HP Tuners, but if the computer goes back to TSP for tuning, I'll see if they can turn some things on and off.
Thanks for the help here.