euphoria

Hi, I am a newbie here. Hope that I can find a solution here.

Car: 93 maxima GXE

symptom:

2 months ago, the check engine was on when I started the car in a late afternoon. The
car shaked a lot with that light on. I left the car alone for a couple of days and later on when I got back to it, the problem was gone! From then on, the check-engine light was on and off from time to time: sometimes at the beginning the light was on and after I drove a while it went off; and sometimes it's okay all the time when I was driving.

I checked the ECO myself on the passenger side and found out that the error was: fuel injector circuit fault. Can you tell me what kind of problem this could be, and can I fix it myself? I checked the manual and found out that to reach the injectors, I have to open the engine.

Also checked with some dealers in the bay area, they charge $100 for diagnosis only, which is basically read the error code from ECU, right?

tmnismo91

Save yourself the $100 for the diagnosis... If it isn't too late.

I just had the same problem and here is the easiest way to determine which injector is faulty. Mind you this only works when the CEL is on and the engine is acting up.

1. Start the engine
2. Pull each spark plug wire from the distributor ONE at a time. DO NOT PULL THE COIL WIRE.

As you pull each wire, if the injector is working properly, the engine will sputter and miss even more. When you pull the cylinder that IS acting up, you won't notice any change in the idle. That my friend is your faulty injector. You may even have more than one. Lets hope not, that is if you don't have the funds to replace all 6 like me.

The job is faily simple. Just follow the instructions in your manual. Be sure to take notes of hoses, wires, bolts, etc, there are a lot to remember. You will need both upper and lower intake manifold gaskets, and new injector o-rings, throw in a new plenum-to-egr valve gasket too. You need to order the o-rings seperately when you order your injector(s) since they don't include them. Try Courtesy Nissan for your injector. Tell them you are a Maxima.org member and they give you a discount. Good luck.

-Sean

tmnismo91

After proof-reading my post, and then proceeding to read the thread title I realized that you don't have a VG. So the information that I gave to you won't apply. But I will leave it here for anyone experiencing the same problem with their VG. Sorry.

-Sean

euphoria

Thank you for your reply. But could it be any electrical circuit problem, like wires not well connected. I am just confused why the car works normally sometimes (most of the time when it's cool outside, e.g., at night), and
sometimes it just screwed me up.

broncoguy

Sean's response is still pretty much right on for the VG, if the code is for the injectors. I checked mine using the exact process he mentioned- pull each wire one at a time, until you find the one that does not change the idle at all. One thing to note here- using this method only tells you that the cylinder is not firing correctly. It doesn't mean 100% that the injector is the cause.( probably is, though). I would go one step further and ohm out the injector on the non-firing cylinder to see if it is within spec (10-14 ohms). If it is out of spec, then I would go down the replacement road. Replacing them is not hard, although you do have to remove a lot to get to them. Took me half a day to do it, but I had never done it before on the Max, and I wanted to make sure I did it right. The injector I bought on-line came with the o-rings, so check that out before you go buy new ones.
Your point about the circuit or connection is valid, and I would check that out before assuming the injectors themselves are bad. (see ohm test)
Also, your comment about the car not working when it's hot has me puzzled. Don't know what effect the heat has on injectors or the circuit.. Maybe someone with a FSM will reply with the exact course of action for that error code..

euphoria

Broncoguy, I was going to check out the resistance on my injectors, but it looks not easy to me. Different from SE engines, to reach injectors, I have to take off a lot of things such as manifoid, etc, etc, etc. To me, it's like opening up the engine. Is it that hard, though?

broncoguy

No, not hard at all. All you need to do is get to the connectors, and they can be removed without taking any major components off. You may have to pull the plug wire on the cylinder you are working on to get clearance, but other than that, you should be fine. The only exception could be the one on the front left as you face the car. I can't remember if you can get to that one or not...
At any rate, the connectors are held on with a small wire clip that has to be pulled out before the connector will come off. Use a small pair of needle nose pliers and slide it out of the slot. It looks like a big staple. Once you slide it out, the connector should pull straight up. To replace it, put the ends of the clip just barely on either side of the connector, push the connector down on to the injector, and slide the clip into place. You'll see once you get to looking at it. This all pertains to the VG30 engine, so if you don't have that, none of this may work.

euphoria

I just got another point for this "injector circuit fault" problem. Is it possible that the problem is caused by insufficient supply voltage? Because I noticed that the problem only persists for a few moments when the car is just started. After I drive it for a while, the problem is gone and everything becomes normal again. Usually when I drive the car, I keep A/C and music on
and the problem comes and goes frequently. But since the last week, I turned off the A/C and audio, and apparently the problem happened less frequently.

I replaced my alternator a year ago at Pepboys, it's a refurbished one.
Anyway, I will check out the alternator output this weekend.