Scott R Posted September 29, 2020 Share Posted September 29, 2020 Alright, I've got an 07 LGT Spec.b that I just did a full reseal on. After getting the motor back in I started it up and ran it to burp the cooling system. While it was running it threw a CEL for a cam position sensor circuit. Double checked the sensor and the plug just wasn't all the way on so I made sure it was fully plugged in and erased the code. Went to start it and it's going full crank no start. Not even trying to lug just starter motor turning the motor over. I have fuel at the rails and power to the plugs. Anyone have any ideas before I light this thing on fire? Haha I should also note that I have already tried a capacitive discharge and the battery has plenty of juice to crank the motor. Link to comment Share on other sites More sharing options...
darthqwo Posted September 29, 2020 Share Posted September 29, 2020 just a quick check, as sometimes it is an issue; are your ground straps connected on the bottom? Link to comment Share on other sites More sharing options...
seanyb505 Posted September 29, 2020 Share Posted September 29, 2020 How did you erase the code? ECU reset? You may need to turn the key to the on position for 30 seconds, remove key and then try to start. You've probably already tried this by now, just throwing it out there. Link to comment Share on other sites More sharing options...
Scott R Posted September 29, 2020 Author Share Posted September 29, 2020 just a quick check, as sometimes it is an issue; are your ground straps connected on the bottom?Yup, made sure those were good. Sent from my SM-N986U using Tapatalk Link to comment Share on other sites More sharing options...
Scott R Posted September 29, 2020 Author Share Posted September 29, 2020 (edited) How did you erase the code? ECU reset? You may need to turn the key to the on position for 30 seconds, remove key and then try to start. You've probably already tried this by now, just throwing it out there.I used an MD85 scan tool. Which works well for live data but unfortunately not well enough to show me cam and crank readings... Also, no dice on trying to reset the immobilizer. Sent from my SM-N986U using Tapatalk Edited September 29, 2020 by Scott R Link to comment Share on other sites More sharing options...
darthqwo Posted September 29, 2020 Share Posted September 29, 2020 i recently had a starting issue with mention of cam sensors; not sure if it will fix your issue, but mine is worth a read Link to comment Share on other sites More sharing options...
blackobxt Posted September 29, 2020 Share Posted September 29, 2020 This could be a fun one! So when it threw the cel did it stop running? On your scan tool are you getting an rpm reading during crank? Link to comment Share on other sites More sharing options...
Fabsx Posted September 29, 2020 Share Posted September 29, 2020 Crank position sensor connected all the way in? Under alternator .. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Scott R Posted September 29, 2020 Author Share Posted September 29, 2020 This could be a fun one! So when it threw the cel did it stop running? On your scan tool are you getting an rpm reading during crank?Nope, it stayed running while the CEL was on. I was able to check the code and even pull back into the garage. Just triple checked the crank sensor and unplugged and reconnected it just to be sure. I'm not getting an RPM reading on the scan tool when I'm cranking. Sent from my SM-N986U using Tapatalk Link to comment Share on other sites More sharing options...
Scott R Posted September 29, 2020 Author Share Posted September 29, 2020 (edited) Just pulled and checked the crank sensor and I'm getting the prescribed 2 k ohms so its not the sensor itself. Does anyone know what i should be getting from the circuit side? Is it just a 5v reference to the crank sensor? *edit* I'm getting ~1.35 volts at the connector to the crank sensor. Sent from my SM-N986U using Tapatalk Edited September 29, 2020 by Scott R Link to comment Share on other sites More sharing options...
Scott R Posted September 30, 2020 Author Share Posted September 30, 2020 Ok so strange turn of events. I unplugged the cam position sensor and it started right back up... Sent from my SM-N986U using Tapatalk Link to comment Share on other sites More sharing options...
blackobxt Posted September 30, 2020 Share Posted September 30, 2020 Double check the connector for corrosion. Link to comment Share on other sites More sharing options...
Scott R Posted September 30, 2020 Author Share Posted September 30, 2020 Double check the connector for corrosion.Connector is good. I just pulled it and checked resistance from reference to power and ended up with 25 M ohms. So I'm thinking the CMP might be my problem. Sent from my SM-N986U using Tapatalk Link to comment Share on other sites More sharing options...
Scott R Posted October 1, 2020 Author Share Posted October 1, 2020 Ok, so update: I have replaced the cam position sensor to no avail. As of right now I can get the motor to fire up and run smoothly with the cam position sensor unplugged but if I have the sensor plugged in the motor will crank but won't even attempt to start. Crank sensor tested appropriately and all of my ground straps are attached. I'm officially at a loss and I'm hoping that my timing isn't off. I did, however,, double checked that the timing marks would line back up after rotating the crank when I installed it so I really hope I haven't jumped a tooth... Sent from my SM-N986U using Tapatalk Link to comment Share on other sites More sharing options...
Fabsx Posted October 2, 2020 Share Posted October 2, 2020 Ok, so update: I have replaced the cam position sensor to no avail. As of right now I can get the motor to fire up and run smoothly with the cam position sensor unplugged but if I have the sensor plugged in the motor will crank but won't even attempt to start. Crank sensor tested appropriately and all of my ground straps are attached. I'm officially at a loss and I'm hoping that my timing isn't off. I did, however,, double checked that the timing marks would line back up after rotating the crank when I installed it so I really hope I haven't jumped a tooth... Sent from my SM-N986U using Tapatalk I had a similar issue last year for a my cousin’s legacy. I was surprisingly off 180 degrees on the crank timing. Double check everything, run a set of jumper cables from battery negative to engine and positive to top of alternator to see if it’s a voltage issue. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Scott R Posted October 2, 2020 Author Share Posted October 2, 2020 I had a similar issue last year for a my cousin’s legacy. I was surprisingly off 180 degrees on the crank timing. Double check everything, run a set of jumper cables from battery negative to engine and positive to top of alternator to see if it’s a voltage issue. Sent from my iPhone using TapatalkI just pulled everything apart and redid the timing just to verify that timing was good. So I know its not a timing issue. I know that the voltage is good because it will start just fine with the cam sensor unplugged. I'm at a total loss at this point... Sent from my SM-N986U using Tapatalk Link to comment Share on other sites More sharing options...
DaveWaters Posted October 2, 2020 Share Posted October 2, 2020 When I installed my top-feed ID injectors I discovered that it’s possible to plug the leftover tgv plug into an ID pigtail. Are you positive that the plug you’re using is the right one for the cam sensor? Looks like both the cam sensor and tgv are both 3 pin. Link to comment Share on other sites More sharing options...
Scott R Posted October 3, 2020 Author Share Posted October 3, 2020 When I installed my top-feed ID injectors I discovered that it’s possible to plug the leftover tgv plug into an ID pigtail. Are you positive that the plug you’re using is the right one for the cam sensor? Looks like both the cam sensor and tgv are both 3 pin.Yeah, for the spec b the TGV plug is a 5 pin. Sent from my SM-N986U using Tapatalk Link to comment Share on other sites More sharing options...
DaveWaters Posted October 3, 2020 Share Posted October 3, 2020 Ah yeah 07+ has tgv motor and sensor in one. Not sure if 07+ is the same but 06 most sensors share a common - shield back to the ecu and my tuner once explained that if a wire gets pinched and that shield is shorted to it can cause gremlins that are hard to find. I’d trace that cam sensor wire as far back as you can to make sure theres no pinch or short etc. When plugged in the short could pass through the sensor shorting the 3rd wire causing your issue. Also check fsm for any other wires that the sensor shares with other circuits in the car for short. Guessing something may have occurred during removal or reinstall of motor. How about the ground block on the back of drivers side tgv? 07 have those? Easy to miss those on reinstall. Link to comment Share on other sites More sharing options...
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