BlueThreefiddyz

I just bought a 2003 350z track and on the way home from the seller it's starts misfiring. I left it at a mechanic near where It started happening and had them replace all the plugs and 6&4 coils(the wires were swapped for the coils when I bought the car and #4 coil was no good so I just had them replace both). That didn't fix the issue so they did a compression test which was good so they tried cleaning out the injectors. They got back to me saying they were too clogged and it would be 1200 for new ones. I decided against having them do it because I work at a shop and can get it done for much less. They said there are 2 types of injectors 350zs have and mine has the more expensive ones. Would anyone know which injectors I need to get? Any information would be awesome as I'm still learning and don't really know what I'm talking about

BlueThreefiddyz

Forgot to add this in original post. The codes I got were cylinder 4 misfire and random misfire. They got the cylinder 4 misfire cleared and now I am just dealing with random misfire

icer5160

iTrader: (4)

Random misfire could be caused by clogged injectors, but more often than not, random misfires are caused by cam and crank sensors on higher mileage Z33s. If yours have never been replaced, I would do this 1st, just for peace of mind.

Make sure to use OEM sensors, these cars are picky about their ignition system. Here's a LINK to the early VQ35DE injectors. I would double check your injectors and make sure they match. But based on the product description, these are the ones you need.
"NOTE: This fuel injector is for the models that came with the UNISIA JECS injectors. This will not work with the models that came equipped with the BOSCH injectors."

At $140 a pop, they aren't terribly expensive, I'm guessing the shop is including the labor to get the job done which does take a few hours since you need to remove the entire upper intake manifold (pretty easy). Again, if you're going in that deep, just do the cam sensors and crank sensor for peace of mind. Use OEM.
Cheers!
-Icer

BlueThreefiddyz

so the car actually only has 53k miles and was kept in a garage the last 4 years and driven an average of 700 miles for those years. Should I replace them anyway?

icer5160

iTrader: (4)

Wow, congrats on finding a garage queen! I hope the paint/body/interior match up with the mileage!

With those miles, I think you can leave them be. The good news is that replacing the cam/crank sensors doesn't require the intake manifold to be removed. If the new injectors do not resolve the issue, then this is where I would look next. I would also run a can of "BG 44K" through your Z;s fuel system since it sat for long periods with little use (might even be worth a try before replacing the injectors). I use this stuff once every year or two in my vehicles and I've never had an issue with injectors, but I also use high quality petrol. Could be a placebo, but I've had great results with BG products over the years (BG EPR, 44K, MOA, and ATC Plus). Any "used" car I purchase, I always run some 44K through it.

With those miles, I would imagine that items such as brake fluid, coolant, power steering fluid, etc. are still original. I highly recommend doing a full fluid service on the car. Rubber hoses and bushings can be replaced as needed. If you do a coolant flush, I would recommend replacing the thermostat and inspecting some of the hard coolant pipes for corrosion. Replace the plastic coolant bleeder valve with an aftermarket aluminum unit.
Cheers!
-Icer

BlueThreefiddyz

Will definitely keep that in mind thank you. The link you sent me for the injectors are the ones for the track model? The mechanic that was looking at the car said there are 2 different types and I have the more expensive ones, I just want to make sure I'm getting the right ones

eZg

iTrader: (5)

I'd call Z1 and ask. gl

Aeneas137

I have a 2003 track edition. there's no difference in the engine. it uses the exact same injectors as all of the other DE engines. (03-04).

second / triple the suggestion on sensors first. The two cam sensors are really easy to replace. I did it myself this summer. The crank sensor is probably not a problem but if you're still having issues, even with low mileage it's a age related problem, not mileage. rubber parts and plastic parts get brittle with age.

do not get bigger injectors! And do not get the rev up injectors. these will not work with the 2003 tune. you'll have to get the car retuned if you screw with the injectors.

Aeneas137

by the way, welcome to the forum! And congrats on your first 350Z. you'll have a blast with it.

icer5160

iTrader: (4)

As Aeneas already stated, the early 350Zs, regardless of trim package and AT or MT, all have the same revision of the VQ35DE. I think your mechanic was referring to the later model years (2005-2006) that switched to the Bosch injectors and then it gets more fun when the Revup VQ35DE was introduced (which I have). The AT equipped 350Zs from 2005-2006 were non-revup VQ35DEs, but I think utilize Bosch injectors, while the MT 2005.5-2006 have the revup which uses a different P/N Bosch injector. The good news is that with some light reading, the online retailers such as Z1 have done a good job of differentiating which model years need which injectors.

Of course many people switch to the R35 GTR injectors on their VQs (NA or FI), but a tune is mandatory for this modification.

+1 on the Crank Sensor usually being "OK". I've got an 06 with 56k mi and I slapped a used Crank Sensor in it with 100k+ mi on it, no issues! (I replaced the original because it had a superficial crack in the plastic mating surface that I didn't like).
Good Luck!
-Icer

P.S. Post some pics of this preserved Z33!

BlueThreefiddyz

Thank you! I actually already had one but I didn't do much with it lol just had some fun. I got rid of it to get a cleaner one to build

BlueThreefiddyz

BlueThreefiddyz

Probably gonna do the sensors and run some of the fuel injector cleaner stuff through to see if that changes anything and then go from there

BlueThreefiddyz

Are these sensors OEM?
https://ebayvehicle.com/app/BL16

iideadeyeii

iTrader: (6)

Rockauto will tell you what brand sensors are OEM and then you can reference the brand in the listing

BlueThreefiddyz

I used a scanner and turned off each injector and it was #4&6 that are giving me problems. Can I just replace those 2? Would it give me issues because I didn't replace all of them?

bealljk

iTrader: (13)

Are you just using OEM 350z injectors?

Can I give you replacement injectrors

BlueThreefiddyz

That was the plan. What do you mean by replacement injectors. Aftermarket?

Aeneas137

in terms of reliability, I don't buy any engine parts from unknowns. denso is the usual supplier for Japanese oem parts. If you're replacing OEMs, then there's nothing wrong with replacing just one or two of them at a time. they are just replacement parts. you definitely do not have to do all of them at once.

bealljk

iTrader: (13)

I have a bunch of OEM 350z and 370z injectors hanging around my garage … if you want a set or two individual ones just PM me and I’ll send them to you … you can just have them, cover shipping and they’re yours.