Cam sensor and no start
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From: Sedro Woolley, WA
Cam sensor and no start A few quick details
I picked up a 98 firebird ls1/m6 roller. I purchased a 98 harness for the M6 and performed a 99+ ecu pin swap.
I started the car for the 1st time the other day. It started up and would idle erratically and die. After a few starts I got a P0343 code. I was able to pull it out of the garage and before I could drive it back in it stalled. After repeated attempts to start it, the motor would turn over and after letting off the key would make a thud sound, kind of like it was trying to fire out of sequence. It did eventually start up and I pulled it up my drive way. For fear of loosing a rod through the block, I have not attempted to start it again.
In the mean time I replaced the cam sensor and tested those wires to the ecu for continuity. All wires tested good and showed a value of .003. I double checked all wires at the ecu to ensure the pins were swapped correctly and double checked my grounds.
I did order a fuel rail mounted pressure gauge before I go any further.
The motor is an lq9 with l92 heads and ls3 intake and injectors. The motor was running great when pulled from my other vehicle back in December. I also pulled the valley cover. The cam is centered and the cam gear is not loose.
I wanted to see if anyone else experienced the same issues or had advice. I did read a lot of threads related to cam issues but it seems everyone asks but will not post if they successfully fixed the issue.
I picked up a 98 firebird ls1/m6 roller. I purchased a 98 harness for the M6 and performed a 99+ ecu pin swap.
I started the car for the 1st time the other day. It started up and would idle erratically and die. After a few starts I got a P0343 code. I was able to pull it out of the garage and before I could drive it back in it stalled. After repeated attempts to start it, the motor would turn over and after letting off the key would make a thud sound, kind of like it was trying to fire out of sequence. It did eventually start up and I pulled it up my drive way. For fear of loosing a rod through the block, I have not attempted to start it again.
In the mean time I replaced the cam sensor and tested those wires to the ecu for continuity. All wires tested good and showed a value of .003. I double checked all wires at the ecu to ensure the pins were swapped correctly and double checked my grounds.
I did order a fuel rail mounted pressure gauge before I go any further.
The motor is an lq9 with l92 heads and ls3 intake and injectors. The motor was running great when pulled from my other vehicle back in December. I also pulled the valley cover. The cam is centered and the cam gear is not loose.
I wanted to see if anyone else experienced the same issues or had advice. I did read a lot of threads related to cam issues but it seems everyone asks but will not post if they successfully fixed the issue.
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From: Sedro Woolley, WA
I got a hold of a fuel rail pressure tester. I have 55psi strong. I cranked it up and she started strong. After going in to open loop the fuel trims all shot to 20%+ but my o2's are sitting near open air at the end of the collectors currently. The P0343 was gone but now I have P0342. I am going to get the exhaust ran before I keep trouble shooting.
I wonder of the codes could be software related? I did a fuel segment swap from a van but also did the engine and trans segment swap from another 02 fbody that showed ls1/ m6. Maybe I need to swap the engine OS back to the original. Any ideas?
It may be a week or two but I will update this thread until it is fixed.
I wonder of the codes could be software related? I did a fuel segment swap from a van but also did the engine and trans segment swap from another 02 fbody that showed ls1/ m6. Maybe I need to swap the engine OS back to the original. Any ideas?
It may be a week or two but I will update this thread until it is fixed.
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From: Sedro Woolley, WA
I found this thread below so I may swap the wires and see if that fixes my issue. I have a 98 harness and got rid of the test port connectors.
We did a swap from a 99 WS6 T/A and 6spd into a 66 GTO Convertable. Had this exact same problem like cdk4219 had stated. Sometimes starts right up... other times would pop out exhaust with extended crank time. Could not figure it out... Did a pinout at ecm.. all good... 2 different sensors.. Nothing seemed to change it... stayed that way for the last 4yrs.
Just finished a 98 LS1 down into a 69 Camaro... Same issue!!!! GRRRRRRR...
Had the same guys weed the harness.
CDK4219's post here key'd me into that plug... It was nowhere to be found on the weeded harness. So I called the guy who did the harness and inside that blank plug it FLIPS the Cam signal. IF that plug is gone or the wires are weeded out you have to swap the A and C Pins.
With out doing that A-C pin swap it will not start correctly.
So We had the guy with the 66 GTO come over and swapped the pins while he waited and it fired up 10x's in a row.... So THANK YOU For this thread!
~Scott
Just finished a 98 LS1 down into a 69 Camaro... Same issue!!!! GRRRRRRR...
Had the same guys weed the harness.
CDK4219's post here key'd me into that plug... It was nowhere to be found on the weeded harness. So I called the guy who did the harness and inside that blank plug it FLIPS the Cam signal. IF that plug is gone or the wires are weeded out you have to swap the A and C Pins.
With out doing that A-C pin swap it will not start correctly.
So We had the guy with the 66 GTO come over and swapped the pins while he waited and it fired up 10x's in a row.... So THANK YOU For this thread!
~Scott
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From: Sedro Woolley, WA
The quoted article about was right. I swapped cam connectors to the newer style. The letting on mine was hard to read so I assumed it was the same as the 98. Wrong, A and C were switched. As far as I can tell, it only relates to a 98 fbody engine harness.
Problem solved.
Problem solved.
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From: Sedro Woolley, WA
Thanks for the reply. My wires needed to be switched because of the 98 jumper I deleted. The 98 cam sensor actually had the two wires switched, so when I swapped connectors I assumed it would remain the same. All is good now.
