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help! swapped my motor and now i can't get it to fire up

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Old 01-23-2013, 04:52 PM
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ursin
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Default help! swapped my motor and now i can't get it to fire up

Little background. So i bought a 2003 350z with a bad motor, it had severe rod knock. i Picked up a spare vq and did a full gasket refresh. Put everything together using pretty much all the parts that can with the came (manifolds, harness etc) and i cannot get the car to fire up. it had some old gas so i put new stuff in. i checked spark on the front two cylinders and they are firing, and the plugs are wet. The one other thing i did check also was scanned the codes and i was getting a few codes for the TPS signal. I don't know the code off the top of my head but it was a voltage malfunction. I have looked into the re-learn process for the TB but wasn;t able to get it to work for me. I have noticed that with the KEY on the throttle body will not move at all. i figured it should when the key is on the normal position. also won;t move at all while cranking so im figuring since i have fuel and spark this is probably a big issue. If anyone has any ideas please help! i want to get this car running asap! Im a 240sx guy so these cars have quite a bit of added technology and features that i am not used to so i need some guidance! thanks everyone.
Old 01-24-2013, 05:15 AM
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jasonG35
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flywheel?
Old 01-24-2013, 05:22 AM
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JGYMotorsports
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got interested with the "240sx dude" comment


One of the techs here bought a similar project..........actually he traded a 290HP turbo'd KA 240sx for a 350z that smoked.

We have extra VQ's here. He bought one and installed it after hours...............long long long long story short, from changing TB, to sensors, to you name it...............we urged him to take the tranny off...........low and behold the flywheel was exactly 45degrees off. He fixed that and drove home.

His would do the same thing.......it would not control the TB at all. We were monitoring stuff via Uprev as well.

Coming from the 240sx world, that can't happen. So, in the 350z world, why Nissan puts slots in the flywheel to allow a user to put in in the wrong position excapes us.

good luck
Old 01-24-2013, 01:26 PM
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G.Mello
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Go thru ALL your grounds! Double triple check the wire harness to make sure all grounds are bolted down. also check your fuses on the driverside kick panel underneath the dash. do that before you pull the tranny for no reason. I had the exact same issue last month with my build and all it was was one ground wire hidden underneath the wire harness near the front of the timing case. So all togther there should be 4 grounds total I believe; (1) on the waterpipe to the right of the engine near cylinder #1, (1) on the top front of the timing chain case, (1) on the alternator, (1) and one on the left side of the firewall to the block. Without everything grounded the engine will not fire. But just keep checking for hidden or loose wires. I missed that one ground and wasted a whole week and a half trying trouble shoot, even wasted my time pulling the tranny just to find out the flywheel was installed right the first time. if it was the flywheel the car would start but it will run like **** and throw CEL's. But if all else fails then it maybe the flywheel in your case

Last edited by G.Mello; 01-24-2013 at 01:31 PM.
Old 01-24-2013, 01:59 PM
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zakmartin
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A Power Probe III, an automotive scope and a (good) scan tool will be your friend. There's way too little info in your description to give you an informed assessment of what potentially went wrong with your engine swap. At the very least, do you have a scan tool that can give live readings of your throttle/pedal position sensor?
Old 01-24-2013, 06:18 PM
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ursin
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i don't like i said. im used to the older nissan motors. RB and SRs. this is pretty new to me. might i ask what relevance does the flywheel have? im 90% sure it went back on the same way it came off. is this used for ignition timing? and even if so... why would that have a effect on my TPS sensor code and why my throttle body isn't responding at all to the foot pedal?
Old 01-25-2013, 05:23 AM
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JGYMotorsports
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the crank angle sensor reads off the fly wheel, there is a dowell pin that is there to line up with but there is also several other holes in which it could line up with, but for example flywheel 45 degrees out, your car will take it as 45 degrees out of time, and it will throw every throttle related code,such as throttle control relay, throttle pedal position sensor, throttle position sensor,etc... about 4 or 5 codes throttle related to be exact. (maybe as a self defense so you dont blow it up?if actually out of time) but it will shut down the throttle body and the car will basically run off fuel and what air is already in the plenum, so basically start , run like hell and shut off. so basically yes for some odd reason, if this is the case the pedal will not communicate with the throttle body...
Old 01-25-2013, 05:46 AM
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TAHorizon
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Originally Posted by JGYMotorsports
the crank angle sensor reads off the fly wheel, there is a dowell pin that is there to line up with but there is also several other holes in which it could line up with, but for example flywheel 45 degrees out, your car will take it as 45 degrees out of time, and it will throw every throttle related code,such as throttle control relay, throttle pedal position sensor, throttle position sensor,etc... about 4 or 5 codes throttle related to be exact. (maybe as a self defense so you dont blow it up?if actually out of time) but it will shut down the throttle body and the car will basically run off fuel and what air is already in the plenum, so basically start , run like hell and shut off. so basically yes for some odd reason, if this is the case the pedal will not communicate with the throttle body...
You guys are the first vendor/tuning shop that has joined here that actually sounds like you know what you are talking about. I'm so glad you joined.
Old 01-25-2013, 05:54 AM
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JGYMotorsports
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Thanks! we take a lot of pride in that!
Old 01-25-2013, 06:26 AM
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HeatherG35x
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Originally Posted by JGYMotorsports
Thanks! we take a lot of pride in that!
It was weird, Jason showed me on the laptop. Andrew's car showed like 5 codes, Throttle Control Module Off and I think the pedal voltage wasn't working. Modern Infiniti suggested a pedal change.....

it was the flywheel
good luck
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