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I could really use some help with this one its driving me crazy . ill try to explain the in and outs to see if any of this helps.
05 350z 151k miles Stock as far as i know until i added some small things. Car sat for about 3 years was used as parts for another 350 until this year we decided to pull it out of the back yard and get it running.
First problem dogs ate wire harness , removed replaced with one from same year .
Next was Nats - car had a key but no chip , had a Uprev tune done to the ecm and deleted nats.
Got Ecm back and car starts and runs.
Gas smelled real bad so i removed all gas , put in new gas and some octane booster
First thing i noticed was a miss fire , you can watch the tach it runs great for like 3 4 mins then drops on the tach bumps back up then drops again then goes back to running great.
Code checked had DS VVT P1136 - And a code for the Knock Sensor , Changed VVT and it would run fine with no codes then next time code was back with knock sensor
Replaced knock sensor and harness , all new ngk plugs gapped at 40 , ohmed all coil packs and injectors all checked fine ,installed new cam sensors while i was there also a new pvc valve , new valve cover gaskets , engine is very clean inside , installed all new gaskets put it back together and same thing.
Tried to reset throttle thru Autel Maxis will not complete , tried to reset service engine light cant get it to complete.
So today , im running it in the garage and reving it to see if maybe it would clear up , i get a backfire , my wife tells me i shot someones living room rug out the exhaust ......
so it seems while it sat for so long a mouse rodent rat something built a nest in the exhaust , >< i figure its got to be the exhaust clogged up , remove exhaust from the cats back , noticed the drivers side cat is DONE like maybe a fist size melted piece of stuff left inside , started the car just for the hell of it , still the exact same miss.
someone told me in a group that it was cats they need to be replaced , but i just do not see it , people are running no cats just fine , i have a 04 with no cats and it runs great.
Would love any help , sorry for the long read , im a diesel mechanic not a gas mechanic and for sure not a nissan tech , just trying to get this thing built for my wife.
Last edited by cajuncustom; 04-23-2022 at 07:18 PM.
Sounds like you are on the right track, looks like someone was working on the vehicle and left debris in the exhaust. Once cleared you can decide on cats. You don't need them for the car to run well, you need them to to keep the CEL off and that's all.
A word of caution on this engine, use only OEM sensors for replacement. I've heard dozens of stories about people not getting Hitachi and regretting it.
As far as the throttle body relearn some folks call it the "pedal dance." Find it on YT. Gl!
Thanks for the replay seems its hard to get any help on these matters .
Well today i went to get a engine hoist cause at this point the only clue i have is timing , got back to the car started it up to turn it around no cats oxy sensors just hanging , ran perfect , no check engine light , no codes , ran perfect , turned it around put it in the garage , shut it off , started it again , back to the same thing codes again.
Im clueless as to whats going on , bank 2 vvt that has been replaced still throwing a code along with multiple missfire code , so i figured maybe the new plugs were fouled because of the bad gas , started pulling plugs on the drivers side , all plugs black went and i assume fouled , changed them , went to passengers side , plug were dry and had normal looks to them no fouling , i flashed a light down in all cylinders the pistons look jet black and wet. changed the rest of the plugs installed another nissan pvc while i was at it , still no change.
other then timing or a jdm engine im not sure what to do at this point and could really use any kinda insite as i dont want to go to far into it if it isnt needed, pop checked the old vvt along with the current vvt both are popping.
have a video of it running but cant upload it here
small update nothing new as far as the codes , i decided to do a compression check on the engine as it has 151k on the speedo , all cylinders had 200 psi except 4 and 6 they were both at 240 psi , unsure as to the why or if it has anything to do with these codes.
I know nothing about the engine , i was surprised to see the values with a 151k motor , the car was bought from a wreck auction for parts then i decided to build it , it wasnt wrecked it was considered flood it got water to under the doors , but none in any of the important parts , engine / tranny
the car sat for 2 years and had a half a tank of bad gas in it , i removed all the gas put in 5 gallons of gas with lucas octane booster and a bottle of seafoam
all fluids have been change along with filters trans and oil
since the start i have got the vvt codes , first thing i tried was new cam sensors " cheep ones not Hitachi " nothing changed , have also replaced the vvt on the drivers side and pop checked it and the old one that i replaced because i assumed it was bad both popped fine.
i havent messed with the maf sensor at all other then installing it into a cold air intake from Z1 because the breather box was taken for another build.
as for computer i have a Autel Maxisys
Thanks so much for replying its hard to find any help
here is a link dont know if it will allow me to post , it running
Put OEM or hitachi sensors in there … one less thing to worry about
You might want to do two or three oil changes over the next 1000/1500 miles. I would suggest using a lighter (5w-20 or 5w-30) engine oil that will flow easy and get as much gunk out of the engine as you can. Seafoam might also be a good thing to do multiple times over. Just dont put much load on the engine.
Can you data log and compare your drivers side to passenger side VVT values? whether with uprev or with Autel? You’ll want to compare the duty cycle of the solenoid, the target/command value the ecu is requesting, and the actual position (which is based off the cam sensor).
if you have discrepancies than you either have a sensor issue, an oil flow issue, or a mechanical issue. If it’s mechanical that I suggest you open up the intake VTC cover (on the front timing chain case) and verify the spliced oring is present and in good shape - might as well replace both of them. Scale of 1-10 this is a 4.5. If it is and you are still seeing discrepancies between banks you may have ruptured another oring along the oil passages.
How are your injectors? Have you cleaned and flow tested them? I have a injector cleaning machine and if you want to send me your injectors I will clean them for free.
Video will only do so much but how does the engine sound? Does it sound balanced? Does it sound like it has a hiccup? Does it vibrate weird?
While you’re in/around your timing chain case you could open your timing chain tensioner window and verify you have good tension on the timing chain … but you’d probably be throwing all kinds of mis-fire codes if your timing chain was compromised.
how is oil pressure? Even off the OEM gauge - is oil pressure good?
i took this today , as for the Uprev i dont even know what it does , i sent it into Z1 because the car came with a key with no chip just the metal , and no one could get it to program a key because of the NATS , so i sent it in for a Uprev and Nat delete , they didnt tell me anything that was done to it so i have no clue lol im so green on this thing.
This car has never been ran since its been put together other then in the garage and out to the drive way , i have to get it state police inspected before i can tag it , im waiting on a air bag for it and now i have to buy a exhaust for it before even taking it on the road.
It was a whim we had it in the back yard we bought for parts never thought about building it then just started on it , i have about 5k into this right now total , 99% was parts replacements that we took off for the other 350z
The engine is wierd , like when the VVT issue happens it sits around 1k on the rpm then dips to about 7 then back to 1 about 3 times then levels out , and then like i said today i get in start it and its perfect no check engine lights sounds real strong , no misfire on revs , its like the VVT pops up and it hicups
as i said i only put about 5 gal of gas in it and it hasnt moved just starts and stops , im sure it still has bag gas somewhere in the system i can spell it when i did the compression check.
id really like to do everything i can before attempting to tear into the timing cover as ive read you need to pull the engine , ive timed cummins and cat engines but car engines is something ive never messed with and hope i dont need to with this one , im kinda thinking its not that bad as it like i said it ran fine no codes at all drove it around the driveway 0 issues but then turned it off and back on then check engine light , misfire code and vvt code.
Oil pressure is sitting over 60 on stock gauge
Id love to send you the injectors seeing as the only thing i can do right now is order new sensors and find a set of cheap test pipes / cats and exhaust before i can get it inspected and take it on the road.
Ok just ordered Hitachi cam sensors and crank sensor and just in case cause they wernt replaced when i put the new harness in new coil harness and new injector harness
04-23-2022, 07:14 PM
2005 350z VVT And a Miss
