03 3.5 woes. Need help

[Thiscariskillingme]

Literally joined to ask around about this! Bought the car about a year ago, drove it cross country and back. Added the spring lift recommended on this forum and 31” tires, replaced a ton of worn suspension parts, new radiator and fan/clutch. All seemed to be going well. Left for another cross country trip recently and blew a head gasket, leaking exhaust into the coolant. Took it to a trusted mechanic for repairs, took off with it and made it 30 miles before I lost power and got a cel. Bank 2 (driver side) camshaft position sensor code. Have since replaced both sensors and the bank 2 VVT solenoid. Still having the problem once it’s warm and under load (towing a smaller trailer, maybe 7-800lbs). Never had this problem before the head job. Anybody have any advice???? I need to have this car in Washington state to put it on a ferry to Alaska may 1st. I’m getting a bit desperate. Oh, 191K miles on it. Super clean, one owner, dealer maintained before I bought it with 160K on it.

Many thanks for reading and the knowledge I’ve gained from this forum! Lemme see if I can take a low resolution photo I can post, the ones I have ate too big…

[adamzan]

I know this isn't what you want to hear but it sounds like something was missed/not done correctly during the head job and you should take it back. It is an awful coincidence that all those sensors would just fail all at once. You don't have any codes now? Does it use any oil?

 

If you want to post photos is easiest to use something like imgur and just post the link and it should embed just fine.

[Thiscariskillingme]

Yeah that’s where I’m at now, I mean I can see a couple overheats causing those 23 year old sensors to start kicking out, add to that being removed and handled during the rebuild. And old vvt tested at 9ohms, way out of the 7-7.5ohm spec. But now it’s all been eliminated. Gotta be something in that head. I just don’t understand why it can be driven hard for an hour or so with no issues, running great no less, then suddenly the issue pops up as a cam sensor. Damn I miss simple cars. 

[adamzan]

There is a reason I prefer the VG powered pathfinders lol. Way simpler, less power, but reliable like an old tractor.

[Slartibartfast]

The '03 service manual says the cam sensor code (P0340, P0345) is set if the computer doesn't see a cylinder number signal in the first few seconds of cranking (could be due to a low battery or weak starter not turning it over fast enough), or during engine running, or if the pattern of that signal is "not in the normal pattern." It suggests checking the sensors, connectors, battery, starter, and the intake camshaft. The manual has some troubleshooting instructions that might be worth going through to rule out the wiring. (The manual is a free download from Nicoclub, and you want the EC section, page 357.) Could be a harness got pinched or a connector broke during the head gasket job.

 

Outside of the manual--assuming all that stuff tests normal--I suspect your timing chain is off by one tooth on the bank that's coding. I suspect this because my dad's Tundra threw a cam sensor code when its timing belt slipped. The sensor was fine, but I guess the timing being a tooth off put the sensor's signal outside of what the computer considered normal, and it wasn't programmed to check for cam/crank correlation, so it blamed the sensor. I don't see a correlation code in the '03 R50 manual, either. And we know someone's been into your timing recently, because a head was off, which was when the issue began. (That's a long way of saying +1 to Adam's thought that the mechanic put it back together wrong.)

 

It's weird that it's taking an hour for the code to appear. I've heard of codes only tripping after a fault is detected however many times. Maybe it just takes an hour for the computer to admit that it has a problem? I would check for pending codes (assuming your scanner can do that--my cheap one can) and see if the code pops as pending soon after startup. 

 

And yeah, the VG is a gutless wonder, but I do not envy the complexity of more modern engines.