Ok my first maxima had its injectors replaced a few years before we got it. Didn't get many miles put on it. I then put them in my current max and they now have 50-70K (probably more around 50K) on them.

I get a constant miss at idle. Like an injector isn't firing or something. 8.5MM plug wires helped, but its still there. I don't think John or Todd's maxima's sounded the same. And Todd injectors are about as old as mine are and his car runs nice and strong.

I drive pretty aggressive and use techron cleaner about every 4K so I know they are clean. I haven't ohm'd them though, even tho its the first thing I should have done.

Im about to get a bunch of 240sx top feed injectors and make my own fuel rails

~Alex

 

Did this start recently ?? I have the same problem and it started when they switched to the ethanol mix here in texas. The miss is like a lean condition - phut , phut type. Gets worse if I use cheaper fuel and get a lot better if I use Chevron or Shell.

 

Have you tried the power balance tests? Pull the connectors to each injector and/or the wire to each plug and see if you pull one and the miss doesn't change?

As for the ethanol mix, the ethanol tends to loosen things that are not soluble in normal gas and send them downstream to the filter. Have you tried changing the filter?

 

I ran a Fuel pressure test and the pressures were fine. My mechanic says the injectors need to spray a little more fuel when its an ethanol mix and since they are not programmed to do it, it runs lean at idle. The problem was helped a lot by turning in the idle adjustment screw which lowered the air intake at idle.

 

make sure the wire connectors on the injector are clean ive had it happen on my 89 and it turns out it was just a little corosion on the terminals on an injector

 

Shotty spark plugs will make a miss that can be mistaken for an injector.

Just go ohm them.....

 

Its been a constant problem for at least 5K miles. Not sure on the ethanol content around here but I know we have it at some stations and I hate it.

All the tune up stuff has 9K miles on them, plugs look perfect tho I haven't pulled them all.

The connectors clean, and the o-rings are all new and not leaking. I'll just ohm them tomorrow when I do my brakes.

~Alex

 

I'd suggest 2 things. first check the ohms of each of the injectors. a good injector is 10-14 ohms. then pull off each cylinder's spark plug wire from the distributor cap while the car is idling. if you pull of a wire and the idle does not get worse, then you have found the problem cylinder. now, is the ohm reading for that cylinder's injector greater than 14 ohms? if ohms are ok, try another spark plug and spark plug wire.

 

I know this just too lazy/working on the 240 too much. I hope to get to it tomorrow. I also hope I have a bad injector, I want some top feeds any way.

~Alex