1993 Maxima Rough Idle
1993 Maxima Rough Idle
I recently purchased a 1993 maxima. Looks like car has sat for a while (year). Car runs great at highway speeds but has a bit of a rough idle and some power loss on accelleration. I replaced the cap, rotor, wires, plugs, air filter, and fuel filter with no luck. does anyone have any ideas what else I could look into as a possible culprit of my issues.
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MinisterofDOOM
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Re: 1993 Maxima Rough Idle (satdog75)
Might be a bad MAF. It's possible to clean it if you're careful (use non-harsh alcohol based cleaners...they'll evaporate quickly and won't damage the element--I use electrical contact cleaner).
Also, what plugs did you use?
And welcome to NICO!
Also, what plugs did you use?
And welcome to NICO!
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mtcookson
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Hey, you're only 1.5 hours away from me. I visit Wichita every now and then.
Another thing to check is the idle air control valve. They have a bad habit of getting dirty and can definitely cause the idling issues. Carb cleaner will clean that up pretty well. Another thing to check would be the EGR valve, it can cause problems as well.
You also definitely need to check for vacuum leaks. Those can cause the exact problem you're having and are very common on older cars with rubber lines, especially if they've been sitting.
Since you had to do ignition stuff that means you have the VG30E (Maxima GXE) with an auto, be sure to check the hoses under the throttle body (where that big aluminum elbow meets the intake manifold). There are some hoses under there that get easily missed when inspecting. Those particular hoses shouldn't cause the problems you're having but are good to check regardless.
Another thing to check is the idle air control valve. They have a bad habit of getting dirty and can definitely cause the idling issues. Carb cleaner will clean that up pretty well. Another thing to check would be the EGR valve, it can cause problems as well.
You also definitely need to check for vacuum leaks. Those can cause the exact problem you're having and are very common on older cars with rubber lines, especially if they've been sitting.
Since you had to do ignition stuff that means you have the VG30E (Maxima GXE) with an auto, be sure to check the hoses under the throttle body (where that big aluminum elbow meets the intake manifold). There are some hoses under there that get easily missed when inspecting. Those particular hoses shouldn't cause the problems you're having but are good to check regardless.
Re: (mtcookson)
could someone please explain a bit more. i am aware of the maf seneson (next to the air filter) but is there anywhere to get a vac diagram or a way to test vac without pulling and checking every line. also, where is the EGR valve on this vehicle and how do I check. One final note, isnt it possible to start the car and ohm out the fuel injectors without removing them? i would like to check them as well since the car has sat for quite some time.
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mtcookson
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EGR will be on the left (driver's) side on the lower part of the intake manifold. You'll see a line running from it to the front exhaust manifold. Just make sure the diaphragm isn't stuck and moves freely. Its possible for the diaphragm to have a leak as well so one way to test it would be to run down to AutoZone or your favorite auto parts store and grab a vacuum pump (AZ has one with a gauge on it that is white) and you can make sure it holds vacuum. The pump can also be used as a vacuum gauge to check what kind of vacuum the engine is pulling.
As for a vacuum diagram, I can't remember if the FSM has one but you can find the FSM here, its for a 94 but will still apply. You can also pick up a manual from an auto parts store that should have a vacuum diagram in it.
On the injectors, I know for sure you can check the front injectors real easy as they have a separate harness from the main harness, it plugs into the main. Just follow the wires from the front injectors and you'll find the plug that you can unplug and check their impedance (this is done with the car off). The rear injectors will be a little more difficult to do if memory serves. I don't believe they have a separate harness. If you can't get to them to remove the plugs you could try probing the rear of the connectors of the injectors and if you can't get to them you could also test them at the ECU. Its been so long since I've messed with my Maxima that I can't remember head easy or hard it was to get to the rear injectors.
As for a vacuum diagram, I can't remember if the FSM has one but you can find the FSM here, its for a 94 but will still apply. You can also pick up a manual from an auto parts store that should have a vacuum diagram in it.
On the injectors, I know for sure you can check the front injectors real easy as they have a separate harness from the main harness, it plugs into the main. Just follow the wires from the front injectors and you'll find the plug that you can unplug and check their impedance (this is done with the car off). The rear injectors will be a little more difficult to do if memory serves. I don't believe they have a separate harness. If you can't get to them to remove the plugs you could try probing the rear of the connectors of the injectors and if you can't get to them you could also test them at the ECU. Its been so long since I've messed with my Maxima that I can't remember head easy or hard it was to get to the rear injectors.