How to replace injectors.

[dade280]

Hi i was just wondering if anyone knew the steps i need to go through to take out my injectors. I will be sending them to get cleaned to these people http://www.witchhunter.com/ .

Just wanted to know if anyone could tell me the procedure so nothing explodes (metaphorically speaking) when i try to take my fuel rail off. Any help would be greatly appreciated.

[zbane]

First of all, this photo of the FSM is for a 79 280zx, but the system and manner of relieving fuel pressure is the same (so far as I know, anyway).

The photo may be a little to fuzzy, so here is the jist of it.

And yes, I know I should just get a scanner :stupid:

1. disconnect ground cable from battery.

2. disconnect cold start valve harness.

3. using 2 jumper cables, attach each terminal to cold start valve connector

4. attach other end of cables to positive and negative battery terminals for a few seconds

5. disconnect jumper cables from cold start valve and begin disassembly

Just a heads up-there will still be fuel in the system when you disassemble. Have some rags around and set them down on the intake manifold. This will soak up the spilled fuel and will also catch any connectors that you may inadvertently drop.

Before you start disassembly, hit all the bolts that hold on the rail with PB Blaster (or other penetrating lubricant) to help ease the process.

Take your time-the job is not too hard, but care should be taken so that you don't break anything or bend the rail.

[sblake01]

I have my own little invention for that as well as testing injectors. It's a 9 volt battery connected to an injector connector with a momentary switch. I posted a picture of it on this site a while back and can't find it now but it's a pretty simple concept. (I came up with it, didn't I?)

[dade280]

Hey man thanks alot, it almost sounds too easy. Hopefully everything goes as smooth as butter and my 280 will run again. Once again thanks i appreciate the help.

[zbane]

One more thing (for now, anyway)- There are little rubber O-rings on the ends of the injectors. Make sure they all come out to prevent future frustration!

Also, while you have the fuel pressure released, you might as well go ahead and change your fuel filter (two birds, one stone)

[dade280]

Thanks i will probably do that when i re-install them tho.One more question, should i plug or cover the area with anything to prevent any debris or moisture from getting in while the injectors are getting cleaned? Thanks.

[zbane]

It would be a good idea to cover the openings. You don't want any bugs or anything getting in there. I would probably use some electrical tape or gaffer tape.

Since the car will be without injectors, and therefore not drivable, you should probably do ALL of your fuel line stuff at one time. Replace all of your rubber fuel lines with tubing rated for FI engines. Double check what the parts store tries to sell you-sometimes they get it wrong and will cut the other stuff.

Drop and clean the gas tank-they get nasty over time.

Pull off the fuel pump and clean the filter on the pump inlet side (if you have the original pump).

Be sure to use NEW FUEL LINE CLAMPS! Don't be cheap and use normal old clamps-when you tighten the cheapos they cut into the line.

[dade280]

Yea the gas tank has been dropped and cleaned by my mechanic. This was done about 5 months ago so it should be good. And yea i was going to change all the tubing and clamps while i was in there. Might as well spend the extra 5 minutes now than spending hours or days later.

[sblake01]

These are my homemade test tools. The one on the left is for testing injectors or releasing the pressure from the cold start valve and the one on the right is used inline to check injector signals while the car is running or cranking.

[WingZr0]

Come on Bro, you couldn't upgrade to an Energizer ?

[sblake01]

Hey, it's rechargable!

[dade280]

Took em out today. The screws were so ****ed up. Stripped to hell, broke a injector holding plastic piece in the process but better than a screw or something breaking.