First let me start with a back story on the car.

I purchased a 2004 350z 6 spd base model roughly two weeks ago. The previous owner purchased it in a not running condition. He took the car to the local Nissan dealer for them to "fix". Long story short they replaced the heads, maf sensor, and computer. When trying to program the computer they said it was not getting enough air and they literally took a torch and cut two holes in the catalytic converter so the computer would program. They finally got the car to where it would run and start but it still had issues. Their next advice was a $800 throttle body. $4800 later he couldn't keep dumping money in the car.

I then purchased the car from him. Here are the issues the car is having:
When it is cold it will not start off the key. It will crank and crank but it will not start. When it is cold you have to roll it off and pop the clutch. When it is cold and warming up it idles perfectly fine. Once the car warms up it will not idle. When warm it will start off the key (it has to crank 4 or 5 times but it eventually starts). Also, the car will not pull past 4500rpm it is like it is hitting the rev limiter.

Hooked a obd2 reader and the car is showing no codes. I replaced the crank sensor and both cam sensors but that did not fix the issue.
I did the ecu, idle air, and tps reset and that did not fix the issue. I know the dealer said it is the throttle body but I do not trust that dealer. Any dealer that cuts holes in the catalytic converters to fix a issue I do not trust. Anybody have any ideas?

 

sounds like you bought someone else's headache

 

Lol, I agree. For the price I gave I can't lose money though.

 

I'm not sure how (illegally) modifying the exhaust provides the engine with more air?? this is a red flag...but the bigger red flag is that they charged that guy $5k and didnt fix the problem...

I've got an extra throttle body you can borrow/buy if you want to swap yours out to test it - PM me.

If youre gonna keep this car for a while and to eliminate the possibility and for good measure I would get a new starter, alternator, new battery and spark plugs (if you havent already). You may want to replace your o2 sensors...Anything that provides feedback to the ECU could be the culprit.

I dont know exactly 'exactly' how the OEM ECU functions but seeing that the car idles fine at warm-up but then struggles after warm up you it may be worth your time in checking the coolant temp sensor - I may have an extra one in my parts box.

If you do all this and you still have issues you may want to trouble shoot your intake cam variable timing solenoids/setup - your sensors may be providing accurate readings but if the solenoids arent functioning it could be a conflicting causing the idle/start/running issues...

If you are ankle deep in the engine you should also check your coil packs - doesnt sound like an issue but it'll be good measure...you gotta take them off in order to swap plugs so two birds one stone - there's instructions in the factory service manual.

post some pictures of your car. What did you end up paying for the car??

 

Thank you for the in depth reply. I actually have a throttle body on the way. I was also reading multiple threads to use oem sensors. I will try to troubleshoot all your ideas after I get in the oem crank and cam sensors and throttle body. I purchased the car for 1800.

 

wow, now I feel bad for the seller...keep the thread updated with your progress

 

was thinking...if you can take your head covers off and do a quick inspection on the cam shafts metal induction slots...head covers are pretty easy to take off (refer to the FSM) and inspect the back end of the camshaft. Even if your sensors are good but the mechanism providing the signal is bad the sensor won't send a legit signal...not likely your problem but a box to check.

 

If I were you I'd go with a standalone ecu haltech, that way you have access to all parameters. If your not getting codes I would not continue throwing parts at it. There should be resistance tests you could perform to verify a part is the problem. First try getting some test pipes if that helps then your cats may be an issue thus why these idiots at the dealer did what they did. Any smell of fuel while cranking? Have your vent on and open to fresh air when starting to check for a fuel smell, you may have fuel filling a cylinder or 2 giving you a hard start issue. Check plugs, take em out 1 by 1 and look at the the condition. Likebealljk said if they have been done that would be a good time to do them, get oem iridium ngk and gap them appropriately. Get back to us. Thanks

 

I got two thoughts on qew's post -

1. I think picking up a haltech platinum pro for $1000 might be a good third or forth step but I think the OEM ecu isnt the problem...Nothing against the OP, but I doubt he is the north american tuner of the year, so the haltech will have it's own learning curve and inherent problems. I would think spending the 200 or 300 on replacement sensors/plugs/coils/etc would be a step in the right direction for the longevity of the car...but

2. Having a system that you can install and near-instantly know which sensor is providing which data (or lack there of) would circumvent your trouble shooting process...seeing that the platinum pro is now near/under $1000 used this might be a upgrade worth doing.

I would PM 'silence eyes' he has a platinum his is selling (as he has to upgrade)...he's a great guy I know him locally - honest, reputable and a might be a good person to buy it from as he'd probably make sure you hit the ground running.

 

the OP paid 1800$ for a car and your advice is buy a 1000$ ECU?

LOL!

Start with the absolute basics. Get a compression and leak down test. Do not waste your time doing anything else.

If you think its a bad TB, take off your intake, turn the car to ON, put in gear and press the gas. The TB should open. YOu can hear it.

You are wasting tons of money. Step back and use some common sense.

 

The parts did not come in this weekend but I did manage to do a compression test.

165 160
170 160
170 160
Pass Driver
Front

Also a couple of the plugs looked black all the way up the threads. I have included a couple pictures below. The TB is opening when I press the gas and the car is in gear.

 

Not saying he should first get a standalone from the get go, but if he doesn't have the nissan software to access parameters,which I'm sure he doesn't, he has no way to look a various sensors.

Compression looks ok,if there were one cylinder,that had a difference of about 15% then I would say you have a problem.

Like I asked before any raw fuel smell when cranking?

If your not getting codes then really doubt the throttle body is gonna fix your problem,I would really be surprised if it did fix it.

Look online on how to read spark plugs,burn pattern color etc. its all on the internet.


start with basics. Air/fuel/ spark. Any way u can check fuel pressure? If not spray some carb spray, ether into ur throttle body, about a 2 second spray, it will probably set off a code because the maf isn't reading the air going into the engine. Spray then crank, if it turns on then, u may have a fuel issue.

 

Well I fixed the issue. It was the cam sensor. I put in a set of the redesigned metal Hitachi cam sensors and it fired up and ran great.

I then took it on a very spirited drive and when I pulled into the driveway it started knocking very bad. This is a bad knock from the bottom end. Probably buy a used engine and throw it in there.

 

Out with the old and in with the new. Just waiting to borrow my friends cherry picker. The engine was ready to pull out after 3 hours.