crankshaft reluctor wheel question
04-04-2013, 12:49 PM
#1
crankshaft reluctor wheel question I have a newly built motor that wont start, It crank and cranks and then randomly backfires through the intake after maybe 10 seconds. There is air, fuel and spark. It wont start it just cranks and cranks.
During the build I sent the crankshaft off to the machine shop to get polished (like i always do). My question is: is it possible that the machine shop accidentally moved the crankshaft reluctor wheel when they went to polish it?
The no start issue feels like a timing thing so im trying to narrow it down. I have sent many stock LS1 crankshafts off to get polished and have never run into any issues. Motor ran fine before the rebuild and its a stock LS1 crank from a 00' Camaro
During the build I sent the crankshaft off to the machine shop to get polished (like i always do). My question is: is it possible that the machine shop accidentally moved the crankshaft reluctor wheel when they went to polish it?
The no start issue feels like a timing thing so im trying to narrow it down. I have sent many stock LS1 crankshafts off to get polished and have never run into any issues. Motor ran fine before the rebuild and its a stock LS1 crank from a 00' Camaro
04-04-2013, 02:45 PM
#2
TECH Fanatic
iTrader: (5)
I have a newly built motor that wont start, It crank and cranks and then randomly backfires through the intake after maybe 10 seconds. There is air, fuel and spark. It wont start it just cranks and cranks.
During the build I sent the crankshaft off to the machine shop to get polished (like i always do). My question is: is it possible that the machine shop accidentally moved the crankshaft reluctor wheel when they went to polish it?
The no start issue feels like a timing thing so im trying to narrow it down. I have sent many stock LS1 crankshafts off to get polished and have never run into any issues. Motor ran fine before the rebuild and its a stock LS1 crank from a 00' Camaro
During the build I sent the crankshaft off to the machine shop to get polished (like i always do). My question is: is it possible that the machine shop accidentally moved the crankshaft reluctor wheel when they went to polish it?
The no start issue feels like a timing thing so im trying to narrow it down. I have sent many stock LS1 crankshafts off to get polished and have never run into any issues. Motor ran fine before the rebuild and its a stock LS1 crank from a 00' Camaro
04-04-2013, 03:17 PM
#3
ya that, and you can pull the sensor and check if the wheel in on the crank.
Seen that.. mystery how it removed itself?
also seen cam and crank.... the block painted, or RTV sealant ("extra" sealed with the Oring still) and not getting signal form that (grounding?).
Seen that.. mystery how it removed itself?
also seen cam and crank.... the block painted, or RTV sealant ("extra" sealed with the Oring still) and not getting signal form that (grounding?).
04-04-2013, 05:56 PM
#4
Hook up a scan tool (not a code reader) go into engine data or streaming data and look for a crank angle sensor reading when cranking, check for faults present. It may be the sensor itself or connection. A scan tool with lab scope or osciliscope capabilities would be ideal to see wave form of reluctor wheel. It's always best to see what the ecm sees (or doesn't).
04-04-2013, 07:53 PM
#5
TECH Fanatic
iTrader: (5)
Know anybody that does auto repair? A lot cheaper than buying one. Maybe drop a few bucks on someone that has one or access to one. I get hit up for this kind of thing all of the time from people I would otherwise never hear from.
04-06-2013, 08:58 PM
#6
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04-09-2013, 03:28 PM
#8
TECH Senior Member
Does a scantool show RPM and does it look correct...?
When you look thru the CKP sensor bore, does the reluctor wheel look aligned (does not wobble) as the crank is rotated...?
When you look thru the CKP sensor bore, does the reluctor wheel look aligned (does not wobble) as the crank is rotated...?
04-10-2013, 05:49 PM
#10
Well, installed a new crank sensor today and still have the same issue. Had a local mobile auto repair guy stop by today with a scan tool. Im getting a cam sensor signal but no crank. The PCM sees no RPM and has no crank fault codes. I probed the harness from the female plug to the corresponding pins on the PCM harness and have continuity. Ideas?
Troy
Troy
04-11-2013, 10:06 AM
#11
TECH Senior Member
Are the connector terminal pins making contact with the sensor pins (open up the connectors and re-form the terminal pins)...?
Is the reluctor straight, tight, and undamaged...?
Is the reluctor straight, tight, and undamaged...?
04-11-2013, 04:48 PM
#12
Troy
04-11-2013, 11:50 PM
#14
Pulled the sensor out again and used my cell phone to record the reluctor ring as we spun the engine. Everything looks as it should be. Im starting to run out of ideas. Don't understand why I can have spark but no RPM signal to my PCM. Here is something odd....As I crank the car my tach jumps RPM's ~2-500 for a couple secs then spins backwards and does a 360.
Troy
Troy
04-12-2013, 07:15 AM
#15
Check your cam sensor in the back of the block, I've seen when bolting the engine back together the cam sensor harness get pinched between the block and tranny and shorts out the signal ,Also check to make shore you have all the ground straps connected to the block. Check the drivers side head. there are three grounds that need to be bolted to the rear of the head, and also there's a ground strap on the radiator support on the drivers side straight in front of the fuse blocks. Theses ground straps hast to be connected to give the sensors a ground circuit . The engine block is insolated by the motor mounts and tranny mounts and so on. And also check the ground strap from the passenger side finder well to the block.
04-12-2013, 10:53 AM
#16
Check your cam sensor in the back of the block, I've seen when bolting the engine back together the cam sensor harness get pinched between the block and tranny and shorts out the signal ,Also check to make shore you have all the ground straps connected to the block. Check the drivers side head. there are three grounds that need to be bolted to the rear of the head, and also there's a ground strap on the radiator support on the drivers side straight in front of the fuse blocks. Theses ground straps hast to be connected to give the sensors a ground circuit . The engine block is insolated by the motor mounts and tranny mounts and so on. And also check the ground strap from the passenger side finder well to the block.
Thanks
Troy
04-12-2013, 11:12 AM
#19
Found something odd to me today. I was probing the cam sensor wire harness and from what I understand is the RED is 12v supply, PIK/BLK is ground, and BRN/WHT is sig. Here is what happens....
Power on to the PCM
Test light grounded and stick RED, 12v and it triggers the fuel pump relay...?
Test light on power(hot) and stick PNK/BLK and get ground...good
Test light on power(hot) and stick BRN/WHT and get nothing.....?
Why does the PCM get signal from the red 12v supply and nothing from the BRN/WHT??
Troy
Power on to the PCM
Test light grounded and stick RED, 12v and it triggers the fuel pump relay...?
Test light on power(hot) and stick PNK/BLK and get ground...good
Test light on power(hot) and stick BRN/WHT and get nothing.....?
Why does the PCM get signal from the red 12v supply and nothing from the BRN/WHT??
Troy
04-12-2013, 11:59 AM
#20
Is the PCM aftermarket or from a factory car ? If its from a factory car you might be having a security issue like a Passive key-II, Also have you tried to start it with starting fluid to see if it will run at all ? Have some one crank the engine and you spray starting fluid threw the TB.