P0342 DTC - Random and Intermittent - L31, cammed, 0411, 24x ignition, BB tune

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homeslice

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This is on '98 K2500, which now has a cam, 0411pcm, and 24x ignition, as well as 24x tune. Since making these mods, I keep getting 2 codes intermittently - P0706 and P0342. During the 0411 swap, I did install the 4 wires that tie into the transmission range switch (I spliced behind the gauge cluster and ran the wires to pcm). To address the P0342, I've replaced the camshaft position sensor on distributor, replaced the pigtail connector for the sensor, and ran a new low reference and signal wire to the pcm. The P0706 DTC does not trigger the CEL, but the P0342 does make CEL come on. I will be driving along and CEL will go out, and the P0342 DTC will not show up. Then, it randomly comes on again, and registers P0342 DTC.

The engine seems to run great, and starts just fine. When the P0342 triggers the CEL, there is no change (that I can detect) in engine performance. I don't like CEL's, and don't wont to get left stranded somewhere someday because of the P0342. I've tried everything I know to do to address and fix it.

Anyone have any ideas ?
 

homeslice

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Kind of surprised there haven't been any responses on this. Let me ask this question - since I'm still working with BB to dial in the 24x tune, could there be something in the tune causing the P0342 and P0706 DTC's ?
 

SAATR

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This is on '98 K2500, which now has a cam, 0411pcm, and 24x ignition, as well as 24x tune. Since making these mods, I keep getting 2 codes intermittently - P0706 and P0342. During the 0411 swap, I did install the 4 wires that tie into the transmission range switch (I spliced behind the gauge cluster and ran the wires to pcm). To address the P0342, I've replaced the camshaft position sensor on distributor, replaced the pigtail connector for the sensor, and ran a new low reference and signal wire to the pcm. The P0706 DTC does not trigger the CEL, but the P0342 does make CEL come on. I will be driving along and CEL will go out, and the P0342 DTC will not show up. Then, it randomly comes on again, and registers P0342 DTC.

The engine seems to run great, and starts just fine. When the P0342 triggers the CEL, there is no change (that I can detect) in engine performance. I don't like CEL's, and don't wont to get left stranded somewhere someday because of the P0342. I've tried everything I know to do to address and fix it.

Anyone have any ideas ?

Datalog the CMP signal and see what the ECM is seeing when the code is set. If it's a loss of signal, then see if it will display output voltage. Compare that to actual voltage measured with a meter. It's possible that it could be an ECM fault. Monitoring the voltage supply to the sensor would be another good idea. Seems that the sensor power supply wire is the only one you haven't replaced, and it could easily have an intermittent low voltage issue. Monitoring realtime voltage while driving is difficult, and there are tools to help, but they cost. Something like a Fluke 3000 FC series that can output data via Bluetooth are great. You can log voltages on your cellphone, and then compare it to the ECM datalog.

I don't have a list of the conditions needed to set p0342, but if erratic signal is all that is necessary, them a worn distributor gear could also be a possibility. I think you would have noticed a worn gear during your cam swap, but I'm covering the bases.
 
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homeslice

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Datalog the CMP signal and see what the ECM is seeing when the code is set. If it's a loss of signal, then see if it will display output voltage. Compare that to actual voltage measured with a meter. It's possible that it could be an ECM fault. Monitoring the voltage supply to the sensor would be another good idea. Seems that the sensor power supply wire is the only one you haven't replaced, and it could easily have an intermittent low voltage issue. Monitoring realtime voltage while driving is difficult, and there are tools to help, but they cost. Something like a Fluke 3000 FC series that can output data via Bluetooth are great. You can log voltages on your cellphone, and then compare it to the ECM datalog.

I don't have a list of the conditions needed to set p0342, but if erratic signal is all that is necessary, them a worn distributor gear could also be a possibility. I think you would have noticed a worn gear during your cam swap, but I'm covering the bases.
you are correct, the sensor power wire (pink) is the only one I didn't replace. I did check voltage at the sensor with ignition on and I'm showing 12v. I also replaced the distributor gear during the cam change, and there is no measurable play in the distributor rotor when I wiggle it back and forth. I have an autocal so I should be able to log the cmp signal while driving as you suggest. I may just replace the power wire and see what happens. Thanks for the suggestions.
 

homeslice

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just a follow up post to say I figured it out. I replaced the camshaft position sensor with the distributor installed under the hood, so I really could not see the fit between the sensor and the distributor rotor. Decided to remove the dizzy and check it out. Turned out the new sensor was slightly making contact with the OD of the rotor. There are 2 little pin bosses located on the dizzy itself, which locate the sensor. I had to drill out the holes on the sensor slightly to give more clearance to those pins, re install the sensor with an air gap on ID and OD of rotor - and viola ! No more P0342 code. Always learning something new with the ol L31 !
 
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