Murano fuel injector Repair- opinions please!

nissan
murano

#1

i have an 09 nissan murano. a few days ago was driving and the car lost power and started sputtering almost as if it felt like it was going to run out of gas. the CEL came on. I took it to Oreillys and it put out P0300 multiple misfire code. On the way back from the shop it got worse and CEL started to blink.
I had the car towed to ind mechanic. He has had it for two days and did compression test, leak down test, checking fuel lines, pumps, injectors, spark plugs, coils, intake manifold gasket, and nothing was showing it was bad.

He cleaned the fuel injectors which didn’t make a bit of difference. There are two cylinders adjacent to each other that are not firing. He took the fuel injector from those cylinders and moved it to another and the misfire is following the injector.

Thats a pretty solid sign that the problem is those two injectors in my opinion. What makes me nervous is the while the owner of the shop is confident they have found the problem the mechanic working on my car says he is concerned because the car is experiencing a loss of power while idling and in his experience a fuel injector does not generally cause that to happen during idle.

Thoughts? opinions?


#2

What does the mechanic mean when they say that the engine loses power while idling?

The engine is idling. So it isn’t producing any power.

Have the bad injectors replaced, and get the hell outta there.

Tester


#3

The more common cause of misfires is the ignition system. Coils overheating, going bad, spark plug fouled or gap incorrect, sensors not sensing, igniters not igniting, etc. Has your shop definitely ruled all that out? hmm … so he moved an injector from a cylinder that was misfiring to one that wasn’t, and the problem moved to that other cylinder? That’s a pretty good indication that injector is at least part of the problem. Presuming the test was interpreted correctly. For example if there were misfires on all of the cylinders, how could he move the injector to a cylinder that wasn’t misfiring?

Fuel system problems would normally start with a fuel pressure test. If the symptom only occurred at speed, they’d hook up a fuel pressure meter so they could look at it while driving. Has that been done? That would rule out the fuel pressure regulator, fuel pump, fuel filter, stuff like that. The injectors won’t work correctly if all that’s not working perfectly.

And it is entirely possible the shop has indeed found the problem, those two injectors are clogged. Until they are replaced with good ones, how it idles isn’t relevant. It’s not expected to idle correctly with two bad injectors. If I had two bad injectors myself, I’d replace all of them, and the fuel filter. I might also be tempted to have the fuel tank inspected for debris floating around.


#4

Assuming pressure test was done and it is indeed injector issue…

WHY injectors would be clogged on 2009, not that much old vehicle?

Would not replacement injectors clog too?

When playing “chicken run” game with my 2006 Pathfinder / 150K miles, I had a shot in the dark and removed injectors to check if any would be clogged. Two were slightly restricted and I was able to clean them instead of replacing them, saved a lot of $$.

Still, if we assume some of them are clogged, that dirt had to come from the fuel tank, so even if new ones would be installed, it is a good chance they will receive their shot of dirt from the same source, is it not?


#5

I don’t understand the mechanic’s assertion that a fuel injector won’t cause a loss of power at idle; which I take to mean rough running. Of course it will. My vote is with Tester.


#6

Very possible, if there’s debris still in the gas line. An injector could clog on a brand new car of course, if there was any debris in the fuel line past the fuel filter, or the fuel filter was defective. New isn’t a cure for dirt in the gas.

Fuel injectors aren’t magic. They are very similar to the spray nozzle on one of those spray bottles you use to wash your bathtub. And everybody knows what happens when those nozzles clog. Very sensitive to any debris at all.

I had a VW Rabbit that somehow dirt got past the fuel filter during a fuel filter replacement, and it caused a clog, not in the injector itself, but in the injection metering system. Mechanic fuel injection on that car. I cleaned the metering gadget, started the engine, ran fine for 5 minutes, clogged again … lol … So if OP has had any work done on the fuel injection system before all this happened, that’s a possible cause. Likewise, a defective fuel filter.


#7

Maybe clogging the internal fuel injector screen is not the problem. Maybe it’s electrically dead. Or the pintle is stuck closed.


#8

That would be my assumption :thumbsup:


#9

re-reading original post & considering OP’ mechanic tried cleaning injectors, likely it is either stuck or burnt…

what would be a root cause and is it a chance for reoccurrence?