[Frostybravo]

04 3.5l still trying to figure out this p0300 p0171 misfire/lean. Don't have a scope but does this crank sensor active counter look like a problem? I'm starting to think there is something wrong with this sensor. Thanks!

 

[cart7881]

Welcome to the Nation.

I have no idea what an "active counter" measurement is. What device do you use to take the measurement and how is it connected? Do those two charts indicate readings with the engine running? Depending on the quality of the test equipment and the connections, the signals look 'wonky'. If the CKP signal in the second chart was on a straight line, like the CMP signal, it would be in a more normal mode. Looks like something is causing it to spike.

The CKP sensor produces AC voltage at different amplitudes and frequency, depending on the speed of the engine.
At whatever rpm the engine is operating at the voltage and frequency should be steady. There will be a frequency 'blip' whenever the missing tooth on the reluctor wheel passes the sensor.

 

[Frostybravo]

This is on a GM Tech 2 scan tool over obd2. It is GM dealer made software they have been using forever. This was at idle so I'm thinking judging based off the cam signal that the crank signal looks messed up. I don't know what active counter is, I tried Googling but couldn't figure it out. I know when the engine misfires there is a lack of accelerating of the crankshaft which could be why it looks like that but that makes me think the cam signal would match. So it seems like the sensor may be dirty or gone bad. It said online a p0300 could be a crank sensor. Just wanted to ask to see if anyone else is familiar with active counter readings. Just got done doing intake, throttle body and valve cover gasket which didn't fix it. New purge valve, evap system holds vacuum. Did a shitty smoke test of the intake with a cigar/hand pump and didn't find anything but will be redoing this test with a better diy smoke tester soon. Pressure tested both pcv hoses and they are good. Clamped off brake booster hose and nothing changed. Upstream O2 sensor data looks good, goes from .9 to .1 responds quickly. Couldn't see or hear any exhaust leaks, although I'll be rechecking this with the new smoke tester. Spark plugs looked good (they were white/lean) but forgot to check the gap, gonna recheck those. Coil packs were all Delphi looked like originals but were in good condition visually. Cleaned throttle body. Fuel pump pressure with key on goes to 57 psi but bleeds down 2 psi a minute, when the truck is running it holds 57 even when held at high rpm. Mind you, the misfire happens at idle aswell as higher rpms. Fuel trims usually go to about 14% after a while of driving to reset the computer but sometimes are at 18%. Also cleaned the Maf nothing changed.

 

[cart7881]

Fuel trims. Are those readings Short Term or Long Term fuel trims. Are they positive or negative readings?

 

[fdavidl0738s5bg]

grt


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[Frostybravo]

well looks like I found a leak in the intake resonator!

 

[cart7881]

What did you find? I'm not getting any reaction from what you posted. Is it a video or a set of photos? All I see is rhe first pic that looks like the throttle body with the hose connection for the purge valve.