Thedriftbadger
05-28-2018, 12:34 PM
Car is an 05 g35, rev up, manual, completely stock.
First some backstory on the car: I bought it not running, the previous owner had tried to replace the head gaskets and couldn't get it running again. I didn't trust his work so i redid the entire job to make sure everything is right. Upon reassembly i found that he had disassembled one of the exhaust vtc sprockets. The fsm clearly states not to do this and it was put back together wrong. I took it back apart a reassembled it the correct way, lining up all the bolt and oil marks as perfectly as i could get it, making it identical to the other one (same part # for both sides). Timing chain is set exactly as the fsm states. It started up and idled perfectly, nothing weird at all.
Now the problem: When the engine is cold it runs absolutely flawlessly, plenty of power. The second it starts to warm up it feels choked under 3000rpm. Over 3k it just gets up and pulls strong until about 5500-6000rpm when it starts to feel choked again. It's not undrivable, it's plenty strong to move the car, i drive it every day, it's just annoyingly sluggish if i let the rpm drop under 3k.
The ecu has no codes, so that's no help. However, if i unplug the two vtc connectors for the exhaust cams on the front cover it makes absolutely no difference at all. Drives exactly the same. So obviously I'm leaning toward that being the problem.
At this point i don't know where to go. Is it possible that if the vtc gear is off by the smallest fraction of a degree that it could cause this? Visibly it looks like it's right on. And it doesn't throw a code for timing advanced/retarded, which i would think it would.
The other thing I'm thinking is that it's an oil pressure problem since it runs better cold when the oil is thicker.
Has anyone else had a similar problem?
First some backstory on the car: I bought it not running, the previous owner had tried to replace the head gaskets and couldn't get it running again. I didn't trust his work so i redid the entire job to make sure everything is right. Upon reassembly i found that he had disassembled one of the exhaust vtc sprockets. The fsm clearly states not to do this and it was put back together wrong. I took it back apart a reassembled it the correct way, lining up all the bolt and oil marks as perfectly as i could get it, making it identical to the other one (same part # for both sides). Timing chain is set exactly as the fsm states. It started up and idled perfectly, nothing weird at all.
Now the problem: When the engine is cold it runs absolutely flawlessly, plenty of power. The second it starts to warm up it feels choked under 3000rpm. Over 3k it just gets up and pulls strong until about 5500-6000rpm when it starts to feel choked again. It's not undrivable, it's plenty strong to move the car, i drive it every day, it's just annoyingly sluggish if i let the rpm drop under 3k.
The ecu has no codes, so that's no help. However, if i unplug the two vtc connectors for the exhaust cams on the front cover it makes absolutely no difference at all. Drives exactly the same. So obviously I'm leaning toward that being the problem.
At this point i don't know where to go. Is it possible that if the vtc gear is off by the smallest fraction of a degree that it could cause this? Visibly it looks like it's right on. And it doesn't throw a code for timing advanced/retarded, which i would think it would.
The other thing I'm thinking is that it's an oil pressure problem since it runs better cold when the oil is thicker.
Has anyone else had a similar problem?