New L92 runs but backfires?!! why?
05-25-2010, 06:10 AM
#24
Staging Lane
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Do you useally need to "calibrate" a new engine when you plug in a new wiring harness with a new ECM? I thought i did that by it self. The Cadillac workshop had time to look at my AC Cobra next wednesday.
05-25-2010, 11:14 PM
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I wonder if a crank case re-learn has been preformed or would help. It mates the reluctor and crank sensor to the PCM. I have tried a few times unsuccessfully with HP Tuners, it's suppose to work but had to borrow a Tech2.
My LS2 block with 24x crank ran like crap, backfires all the time, until we got that sorted out and the cam sensor wiring but the cam sensor did throw a code.
My LS2 block with 24x crank ran like crap, backfires all the time, until we got that sorted out and the cam sensor wiring but the cam sensor did throw a code.
05-26-2010, 02:25 AM
#26
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("I wonder if a crank case re-learn has been preformed or would help. It mates the reluctor and crank sensor to the PCM")
Could you explain that a little more in detail? What's a "crank case re-learn"?
Could you explain that a little more in detail? What's a "crank case re-learn"?
05-26-2010, 01:10 PM
#27
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"CASE" pertains to crank angle sensor error relative to crankshaft position. The ECM has to "know" what correct readings are so that it can determine when readings are incorrect. As the name implies, the crankshaft position sensor monitors crankshaft position so the ECM can determine when it's appropriate to command specific functions-- like firing the spark plugs. Input from the crank sensor is also used to determine if a misfire condition exists. A number of thing can affect the accuracy of crank sensor output, so it may be necessary for the ECM to relearn. A relearn is necessary if the physical relationship between the crank and the crank position sensor is altered, or if the ECM is replaced. If you have an ECM that has never operated with the specific engine you're using, or if you have significantly changed the mass attached to the crankshaft (clutch/flywheel or torque converter change) you'll most likely need to do a CASE relearn.
05-26-2010, 01:57 PM
#28
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Ok, now i understand better
thanks dfe1! I hope the workshop has the right tech ecuipment. I found a EFIlife seller and diagnostic in the south of sweden if the workshop fails.
The L92 came with a flex flywheel so I have changed for a 30lbs flywheel and a new clutch for my T5 transmission. The ECM is new and have never "worked" with the engine.
thanks dfe1! I hope the workshop has the right tech ecuipment. I found a EFIlife seller and diagnostic in the south of sweden if the workshop fails. The L92 came with a flex flywheel so I have changed for a 30lbs flywheel and a new clutch for my T5 transmission. The ECM is new and have never "worked" with the engine.
Last edited by ACCOBRA; 05-26-2010 at 11:40 PM.
06-02-2010, 12:48 PM
#29
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The Cadillac workshop found following error codes;
PCT
P0171 Lean bank 1
P0174 Lean bank 2
P0131 Low voltage bank 1 sensor 1
P0137 Low voltage bank 2 sensor 1
When we had the Tech 2 unit connected and ran the live plot on the O2 sensors it looked fine and suddenly they went flat. After some time it corrected itself again.
What could this be?
PCT
P0171 Lean bank 1
P0174 Lean bank 2
P0131 Low voltage bank 1 sensor 1
P0137 Low voltage bank 2 sensor 1
When we had the Tech 2 unit connected and ran the live plot on the O2 sensors it looked fine and suddenly they went flat. After some time it corrected itself again.
What could this be?
