the wiring harness isn't that fragile.

I remember that on the front passenger side coil, I had to pull the coil pack up about an inch or two and rotate it before I could unplug the harness from the coil. other than that, you should be able to put a plug socket and extension down each hole.

also, regarding cross threading, it is always a good idea to start each plug by hand before pull out the torque wrench.

 

Don't we need to change them about 100k or so?
Why are you guys looking in changing it so early?

 

ya i read on many forums and threads that our cars dont need plug changing until around 100k unless of course your going 1 step colder. Overkill IMHO

 

Probably more along the lines of 60-80K miles depending on the way you drive. The OEM NGKs used in the VQ35 are quite good though and replacing them before 60K is a waste unless you've added forced induction, nitrous, or changed compression ratio. It's always good practice to check the plugs every 20K miles or so to inspect for wear, gap, and any potential ignition or combustion chamber problems. The VQ motors, like most any other OHC motor, are also prone to leaky spark plug cylinder seals which allow oil from the upper portion of the head to leak into the spark plug cylinder.

 

these are easy to change......I like to change my plugs all the time...I am on my 4th set of plugs in 20K miles.

OEMs got pulled in the first few thousand miles when I switched to NGK Iridiums........those syated foranother 10-12K miles, when I swapped out to another set of the same, but this time I gapped them to .035 on my single turbo setup. Now, I just changed those for NGK-R Coppers (stock Gap)for my new Greddy TT. I think they are only about $6 per plug (Iridium or copper)

 

QuadCam,

A great job on the write up.

I followed the DaveO's old DIY write up. It took me about 50 minutes and a six pack of adult beverages to do wifey's 03 sedan. It took me about the same amount of time to do my 04 coupe since I wasn't in a hurry.

 

Very Cool... Nice write up.. I will get on this sometime this month. Thanks Andrew.

 

it takes about 30-45 minutes on a car with strut bar, engine cover and stock wiring harness.


its all just about knowing what 10mm bolts to get the wiring harness out of the way of it. then they come right out.

 

it takes about 30-45 minutes on a car with strut bar, engine cover and stock wiring harness.


its all just about knowing what 10mm bolts to get the wiring harness out of the way of it. then they come right out.

its a 5/8ths spark plug socket if you have one....

 

What about fuel injectors?

 

changing injectors is easy too!!!!

actually, it be easier than changing plugs, but then again, I removed those stupid heater lines that run in/out of the throttle area of the manifold.....without those, the manifold is so much easier to remove and reinastall.

 

Here's a writeup I performed several months back over on my350z.com:

DeatschWerks Injector Install w/ PICS!!!

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I decided to document the install of my DeatschWerks Injectors. If you are familiar with these injectors, they are modified factory-style injectors. They are flowed and matched. They come packaged as a set with flow sheets. I think mine varied from 549 cc/min -552 cc/min. that very tight!!!

I am starting the install process assuming that you have already removed the intake manifold......

1) plug the lower manifold holes with shop rags or use masking tape. Remember to remove the manifold gasket. I forgot to,a nd I had to take it off prior to step 3.



2) unplug the injector harness from the 6 injectors. They unplug very easily. no tools are necessary, just your fingers.



3) Unbolt the 4 bolts that hold down the rails to the manifold. IIRC, you need a 12mm socket. There are 2 bolts toward teh front of the rails and 2 bolts toward the back.. They are easily identifiable.



4) Once the rails are unbolted from the manifold, you can lift up on the front of the rails to pull the injectors out of the manifold. pull up on both rails at the same time with even but moderate pressure. They should pop out fairly easily.



5) Now comes the injector removal. This is also easy, but you will spill some gas! The injectors are held onto the rail with a clip. the clip comes off easily with your fingers. Just wiggle them off. You can the clips where the injector connects to the rail. I choose to unclip each injector one at a time, but you can take them all off if you want to. Save the clips. you'll need them to reinstall the new injectors. Once you have the clips off, pull straight down on the injector. There is an O-ring that is holding and sealing the injector into the rail. again, light force will get the injector out. no tools needed.



Here's a pic of the stock injectors.



Here's how the DeatschWerks injectors come packaged



A shot of the new injector side-by-side with the stock injectors. The new one are slightly shorted on the nozzle end. all else is the same! That's what makes these injectors so nice!



here's the nozzle openings...sorry the pic didn't come out too clearly.



6) Back to the installation. Prior to installing the new injectors, DeatchWerks recommends lubing the o-rings with a little motoroil. I used some Mobil 1 5W30 I had on the shelf. I just dipped my finger into the oil and then massaged a little oil into the O-rings. very simple. You don't need much!

7) Now that the injector O-ring are lubed, it is time to seat the injectors into the rail. The injectors fir perfectly up into the rail, but you can push them in too far. If you do, the injector reatining clip won't have it's little slot to clip into. Again, I installed each inject on-at-a-time and then installed the reataining clip. The clips are easy to put on, but it takes a little wiggling to make sure they are seated correctly. At first, I thought I had it clicked in right, but then I wiggle the injector and realized that I could moved it around and pull it out. When clipped properly, the injector is well locked into place.



8) Once all the injector are seated and clipped, you can push the injectors/rails back into the manifold. the, finger tighten the 4 bolts to hold the rails onto the manifold. Then toque the bolts sequentially....1st torque then to 8ft-lbs. Then go back and retorque then to 19 ft-lbs. (this is from the service manual.)

9) almost done. clip the wiring harness connectors back onto each injector. It should look like this.



10) at this point I doubled checked my installation and wiped up any excess fuel that spilled from the rails during removal. Then, I turned the key to the "ON" position. I did this about 5 times (wait about 5 seconds between each time). This is doen to pressurize the fuel rail so that you can check for leaks. Hopefully, NO LEAKS!!!!

go ahead, and put your upper manifold back on and all other piping , TB, hardware, etc. I am using a UTEC, and I had to make an educate guess on how much to scale back these larger injectors. For those familiar with UTEC, I used a "-15%" value on the "0" column to scale the injectors. The car started right up and idled perfectly. the idle A:F ratio was rith between 14.7:1 and 15:1,....just like stock.

I haven't had a chance to do much testing yet, but I am really happy with these injectors. I don't know if there are any downsides to them.
The upsides are these:

Less expensive....about $400 for 6) 550cc/min injectors
wiring harness is plug-n-play! NO SOLDERING!!!! and no harness adapters to buy!!
Reuses Factory rataining clips!!! some other injectors don't use any at all.

Have Fun!!!

Andrew

 

Great injector DIY!

If I would have known about these I would have done them instead of my RC's with the Greddy kit.

 

My vote for a sticky in the DIY forum!

 

Thats no fun if you have the lower intake manifold off! I want to see one with it left on!

Great write up though!

My installer removed the coolant lines from my TB also, which I wasn't too crazy about, but it kind of worked out since I no longer drive the car in the winter.