Hoping to share my first valuable bit of lesson-learned here. I got a code for the cam position sensor, p0345 along with simultaneous p0420 and p0430 codes for the catalytic converters. Knowing that it’s rare for both cats to die at the same time (no codes previously) I head for the cam position sensors.

I dig out the first one from the driver’s side, have a closer look- and it’s definitely not oem. Looks like it has a UI logo and some numbers. I google the numbers and it matches up to an identical part for sale on eBay for $16. So it’s a cheap replacement that couldn’t have lasted long as the car has only 136k (I bought it last week). Looking closer, it appears there is wear and possible damage to the sensor- like it was rubbing or was scored by something.

Definitely makes you think twice before sticking a $16 piece of plastic in your engine. While it’s torn down, I ordered plugs, coils, new hood hinges, new cam sensors and intend to clean the throttle body and MAF sensor. Hoping all of this unlocks more power and impresses this new G35 owner more than he already is!

Thanks for having me.

ruzzell


The culprit

Wounded I see

Found ‘ya!

 

I bought new ones for peace of mind seeing all the threads about failures. Got "oem" hitachi ones off rockauto. 1 yr and no complaints at all.

 

I installed aftermarket cam sensors thinking I could get away with it, but nope. After a few drives the occasional engine stuttering was back. I swapped em out with the updated OEM sensors with the metal tips. Its been about 20K miles now and still running fine.

 

So I pulled the spark plugs, all OEM NGKs but all were heavily worn and had gaps of .060 to .070 - glad I checked.

cam sensors solved the cam position sensor circuit DTC.

Cat codes p0420 and p0430 still remain. Got my hands on good cats just in case, but ran an O2 sensor log to see what they’re up to first. Does the attached graph scream bad O2 sensors to you guys? Worth a shot to replace before I swap out these cats?


Too much gap

Boingy boingy boingy

 

Was that O2 sensor graph before or after the new spark plugs?

 

After new coils plugs and all 4 cam sensors.

EDIT: And after hand cleaning the throttle body and throttle body reset procedure.

 

Ok back on my pc, earlier I was on my phone and didn't realize the graph has your sensor 1 and sensor 2 data all on the same graph. Really the sensor 2 data doesn't matter, it doesn't affect your air/fuel it's mostly just a reference for the ECM to know that the cats are actually functioning.

Make a new graph with just the sensor 1 data so the data isn't so squished. It looks like it's cycling well but what you should look for in the live data stream is any long delay where it sort of flatlines. Unfortunately it's REALLY hard to verify if it's working 100% correctly without tossing a wideband in the exhaust to compare actual AF to your O2 data.

 

Will do. In the meantime I did capture some live sensor data while taking a drive the other day. I thought o2 sensors should always operate between .2 and .8, but when I am on a decel at 65-75mph, one of them pegs at 1.3v until I get back on the accelerator.


Coasting

On the gas

 

I run a $16 cam sensor, I had one die after 11 months and they sent me TWO replacements under warranty (by accident). The replacement has been running great and I have a third sensor in the glovebox just in case.


The OEM sensor costs 10x more and fails the same way.

 

You do you man, but the OEM sensors are pretty bulletproof for 100k and then it's time to replace them. Seen way too many aftermarket sensors with 5-10k on them fail miles from home in the middle of a cruise, completely ruining somebody's day.
Hitachis are $45 per side.