Nissan Maxima 93 runs on five occasionally

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I'd appreciate some help on this one. I've been investigating a 1993 Nissan Maxima (3.0, 6-cyl, less than 100 000 miles on it) which occasionally runs only with five cylinders. Here are the facts:

When the car runs normally with six, it's not jerky, it accelerates normally, just like it should. When it runs with five, the five cyls seem to work ok but the failing one doesn't work at all, it misses on every round.

Based on exhaust diagnostics, the carbon hydride level is ok but oxygen is bit high so obviously the problem is that the one cylinder does not get gas. The plug gives spark ok.

I'm pretty baffled with this one. Electrical problem? Faulty fuel injector? Or what? I've asked a couple of shops whether they could do something to it but none of them seem to have a clue about the problem. They said that they could start by replacing the fuel injector but with bad luck that would just be an expensive job with no help. Thus I'd appreciate on your help if you have encountered such a problem or could give me any diagnostic hints. Below are some of my observations about the problem. However, as the problem is occasional, it's pretty difficult to say whether these observations are worth anything...

After cold start, the car sometimes runs with six, sometimes with five. There might be some connection with stopping to traffic lights and accelerating and losing the one cylinder as quite often during the acceleration the problematic cylinder starts missing. On the other hand, after losing the cylinder it might suddenly come back a couple of seconds later. But it can miss for dozens of miles in a row. If the engine is stopped when it runs on five and immediately started again the problem seens to persist. But if the engine is on stop for a couple of minutes and it's then started again, it might very well run with six.

Gas additives which should clean the fuel injectors have not helped.

What I'm wondering:

If the fuel injector is faulty, why the car sometimes works ok for dozens of miles? Can it just lock closed somehow and then, suddenly, after some shock (a bump on the road for example) open up and start working ok? How does the fuel injector work after all? What causes the fuel injector to inject fuel, some signal from "the box" or is it purely mechanical? If the injector uses electricity to open, could "the box" be broken this way?

Please, any help is appreciated. The car is in great shape except for this and has probably a hundred thousand more miles on road left :)

Br,

Mika

Reply to
Mika
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GXE or SE? They had different engines in '92-'94.

which

Probably a bad injector. Place an ohm meter across the leads on each injector. If one of the readings is wildly off the other 5, it's almost certain that it's a bad injector. Did you get a Check Engine light? A failed injector usually triggers the light.

The injector problem can definitely come and go, but will eventually fail for good. It will probably cost about $600 in parts (if you use Nissan injectors, and replace all 6, which I recommend), and another $600 in labor.

This car will run on 5 cylinders without damaging the engine. It's very well balanced. So if you need some time to get the money together, you can still drive it. If you've got some mechanical aptitude, this is not a difficult repair, just time consuming. You'll need a manual and a torque wrench (don't even try it without both).

How does the fuel injector work after all? What causes the

Whatever the cause, this car is worth fixing. I had a bad injector at about

125K miles, and replaced all 6 (figured I'd be in there anyway). I'm at 168K miles and the car runs fantastic. I expect to get to at least 250K, maybe 300K. I hate the idea of a car payment.

Bill G '91 SE Auto

167,939 miles
Reply to
Bill G

I would suspect a faulty fuel injector, which apparently is a common problem with Nissan (A co-worker had injector problems with older Z cars). I forget if I have had to replace 2 or 3 on my 95 SE (one under warranty). Sometimes it may be intermittant and may not show up as a check engine light for a month, but other times it may be steady and kick out a code the same day it happens.

But I do not think injector cleaner would help because Nissan blames fuel additives (or alcohol), which hopefully they have figured out how to stand up to in current models.

Reply to
David Efflandt

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Hi Bill! Thanks for you reply. Below is some more information.

The model is neither GXE or SE. Those are probably US versions of Maxima. My manual says "Maxima series J30" and the engine model is VG30E.

I took a look at the injector wires but I didn't have a suitable tool to get them loose, they are locked with a metallic "U-ring" or whatever the correct term is. To get my hands better on the wires I'd need to get rid of some stuff attached on top of the engine. And I don't have a garage.. :(

I didn't get a check engine light, not a single time. That's one thing I'm curious about. It's like the "box" thinks that everything is all right.

There are two wires going to the injector(there is a small crack in the protective cap but the wires itself are intact - that's what I can see through the crack). So I could place an ohm meter there when the wires are attached but is there a risk that might break something as the ohm meter causes a small current and voltage to be in place? And on the other hand, which way the current would go, through the injector or the other end of those wires (the "box", I assume)? Or is the resistance of the "box" so high that doing the measurement this way would result in correct readings?

On the other hand, if I'd measure the voltage over the injector wires when the cylinder is working and when it is not (=when the engine is running), I could probably rule out the possibility of faulty "box"? Although a basic voltage meter probably can't handle the situation as the voltage rises and drops during each round... But might be worth a try, at least if I can get a more sophisticated meter somewhere.

I'm hoping that time would give some solution if nothing else will. Although I don't like driving around with a "broken" car. Changing all injectors will cost way more than you said, at least here in Finland. I got one price for a Nissan fuel injector and that's about 200 euros (around $250). Labor is some cheaper though. If it is the injector, I'm probably going to replace all of them as you suggested but hopefully there are also some non-Nissan injectors available. The best (and luckily, the only) offer I've so far would be about $2000 for replacing all the injectors. *sigh*

Br,

Mika

Reply to
Mika

Sorry about the delay replying. I was out of town.

It's a GXE. Same engine as my

Reply to
Bill G

Sorry about the delay replying. I was out of town.

You have a GXE. Same engine as my '91 SE.

First, you can get to them without removing anything off the top of the engine. It's a pain in the buttocks to get to the front ones, but they are reachable.

Second, you can use a small piece of tubing to listen to the injectors. Buy a 2 foot piece of tubing from an auto parts store (or a short piece of garden hose) and put one end in your ear, and the other down near the injectors while the engine is running. You should hear a soft pfft-pfft-pfft sound if the injector is working correctly. You won't hear anything from the bad one.

Third, you can use a small flat bladed screwdriver to gently ease back the C-clip. Be careful, or the clip will fly off. It's not the end of the world if it does, the connector will stay on without the clip. Put the ohm meter across the 2 leads (it doesn't matter which way, the reading is the same). Test the bad one, and a known good one. The bad one's reading will be wildly different. Don't worry, you won't damage anything using the meter.

Oops, didn't look at the header.

Damn, you should have someone here in the US send you 6 of them. I'm sure shipping would be less than $800 (US).

For the prices you've quoted, I'd look at an aftermarket injector as well. My only suggestion is do NOT get rebuilt ones. This component is too important to go cheap on. I bought a rebuilt water pump once, and had to replace it 30,000km later.

What's "Br" mean? It's not a phrase we Americans are familiar with (not enough exposure to other cultures in our crappy school systems).

Good luck,

Bill G '91 SE Auto

167,979 miles
Reply to
Bill G

Try replacing the pressurized gas cap. Get the correct one - mine said "pre-vented." Made my 92 SE stop all that rough running immediately. See my post from today 9/6/2004 at 12:03 AM. called "Mystery Solved."

The cap cost me $5.99 or so. Easy to try this - it made my Max purr again.

Reply to
NetComputerGuy

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