# Replace fuel injector



## bandon (Dec 12, 2005)

Hello, I new here. I have a 90 Axxess and the injector to the driver side is leaking. I would like to replace it. How do I determine which color I need? How do I release the pressure? Where is the best place to purchase? Lastly, what all do I need? I looked at some places an O ring, crush ring, what all is involved? Thank-you, Bandon


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## alexnds (Oct 1, 2005)

*injector questions*



bandon said:


> Hello, I new here. I have a 90 Axxess and the injector to the driver side is leaking. I would like to replace it. How do I determine which color I need? How do I release the pressure? Where is the best place to purchase? Lastly, what all do I need? I looked at some places an O ring, crush ring, what all is involved? Thank-you, Bandon


Here's the deal with injectors. First of all, how do you know you have a leaky or bad injector? Which cylider is it? A good test is along these two different lines:

If you have a long enough connector/adapter, disconnect your electrical connector to each fuel injector, one at a time, and use an ohm-meter to measure impedance of each injector. All the good ones will be about 12 ohms and any clogged ones will be about 17 ohms, or higher. On other hand, a leaky injector will be zero ohms, since it's open all the time. (The engine is completely off for this test).

A second kind of test you can do is called the "which cylinder is it?" test. Basically, every engine needs two things to run: fuel and spark. So here's how the test goes. Open up your distributor cap cover and you'll see your spark plug wires labeled w.r.t to the distributor cap. Pull out the wire, one cylinder at a time, and see if the engine starts to misfire, because it should now, and it's running on 5 out of 6 cylinders. If it bogs down and dies, re-attach that wire, restart the car, and try the next one, and the next one and so forth, until you've done all 6 cylinders. If the car RUNS THE SAME, even though you've pulled out a particular wire, then THAT cylinder is not getting spark, since the condition of the car didn't change as you pulled out that particular ignition wire. THe injector test is similar to the spark plug test I've just described, except, rather than pulling wires one-at-time from the distributor cap, you're leaving the spark plug wires completely alone this time around. Instead, you'll out the wire feeding the connector to the fuel injector. Do the same thing, one cylinder at a time. When pulling out the wire supplying current to the fuel injector, one-at-time, it's like you're pulling fuel away from a particular cylinder (instead of spark, like in the earlier test). The car will start to misfire since again, just like pulling spark, you're pulling fuel from a 6 cylinder motor, making it limp on 5 out 6 cylinders. The cylinder that DOES NOT CHANGE when you pull fuel (i.e: connector to the injector) is the cylinder that has the bad injector.

In terms of how to change them, you're ideal situation is to change all of them, not just one. The labor to remove one is the same as to remove all, so since it takes you time to get to the fuel rail to pull them, might as well change all of them, since you'd hate to redo this procedure if another one goes bad. 

Here's a quick summary of the procedure, but if you're not a mechanic, take it to a shop.

If you have the VG30E engine, you pull out the fuse supplying current to the fuel pump, relieving the system of fuel pressure. You then disconnect your negative battery cable, so no spark, or no electrical nothing is present. (spark and gas don't mix well). 

You then take off the intake manifold. This is the most labor intensive part. You then put some clean rags into the engine, so nothing falls in, because once you take off the intake manifold and something falls in, you'll have to take your entire engine apart.Be sure to have gaskets with which to re-attach it, the manifold, later. You need upper and lower gaskets. (about $22 bucks) You now have exposed the fuel rail and are able to get to the injectors. Just take out one at time from the fuel rail. Have fire extinguisher nearby, since you're working with live gasoline. You then install the "fresh injectors" in place of your existing injectors into the the two rails (each rail has 3 injectors). You can see the color "dot" on your injector. If you have a 1990 motor, you have the "blue-dot" injector, but 1993 and up, have the "yellow dot". PM me, since I have injectors for sale of the earlier kind. 

You then follow the installation procedure in reverse. You reattach your electrical connector per injector. You install your fresh gaskets. You re-installl upper intake manifold and you must use VERY LITTLE torque. You basically reconnect everything you've disconnected. Be sure you have no vaccuum leaks. Voila, reattach your battery and you should be good.

I've basically desribed the procedure in a very general way, but this is not a light procedure for a first-time home repair, so take it a shop.


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## bandon (Dec 12, 2005)

Thank-you for the reply. I ended up replacing the O rings. The injectors were fine. I didn't know how to relieve the fuel pressure so I removed the gas cap, loosened the fuel line. I removed the injector and what was once O rings, was now a black goop.


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