Rough idle 1992 Maxima GXE

[bdes64]

Hello, I have a problem with my 92. It idles rough, if i put it in Neutral it goes away. Car was just purchased and tuned up, supposedly? Any tips would be grateful???

[killakarebear]

Hello, I have a problem with my 92. It idles rough, if i put it in Neutral it goes away. Car was just purchased and tuned up, supposedly? Any tips would be grateful???

does it die in P or D? i would say try cleaning idle air control valve( need new gaskets about $3 or $4), check spark plugs, if that dont work seafoam in the the gas tank it cleaned my fuel injectors and helped. if that dont help hit me back and well take it from there.

[bdes64]

Thanks for your reply...I replaced the PVC valve, it was sticking some. I replaced the fuel filter, it did not seem to have good flow either. I have run two bottles of fuel injector cleaner (Johnson's and I forget the other). Put new NGK plugs in, the wires are new and I checked them.

If the car is in N it is ok, put it in gear or even leave it in park in runs rough. The idle goes up and down...It seems to do this also if you put the brakes on and have it in N. I lost...Thanks

[tigersharkdude]

my 99 did the same thing until i replaced the KS and cylindar 5 coil packi hope that may help you diagnose the problem, not sure though diff. parts

[mtcookson]

Usually if the RPM fluctuates like that it means there's a vacuum leak... but, it does sound like it could be the idle air control valve mentioned above. I would try cleaning that and go from there.

[bdes64]

Where and how do you get to the idle air control valve. The chilton's manual is not even close in it's drawing...Thanks Guys

[mtcookson]

Its the cylindrical thing on the driver's side of the intake manifold. I would go ahead and get a gasket for it before you take it off as its likely the gasket will break when you remove it.

You can kind of see what it looks like on page EF & EC-147 of ec.pdf (PDF page 145): http://www.nicoclub.com/FSM/maxima/1994/

[bdes64]

Should I just use a good carb and choke cleaner to clean it? Also, where can I find more info on the ECU, one book says their are 3 modes another says only 2 with 2 conditions each???I am truly lost here....Thanks for all of your help, I am learning a lot...Are the codes for the 240 the same as the maxima. Their is a post on here about it (zerothread?id=253912&postid=2680415Does this apply for the maxima also or not? Thanks in advance

[mtcookson]

Carb cleaner should work fine for the IACV, just don't clean any plastic or electric components with it as I don't believe carb cleaner is very good on them.

EF & EC-42 of the ec.pdf you downloaded has the codes for the Maxima. There are actually 5 diagnostics modes but to check the codes you want diagnostics mode 3. With the key in the on position, turn the screw on the ECU clockwise and it will start flashing. 1 flash for diagnostics mode 1, 2 flashes for diagnostics mode 2, etc. Wait for 3 flashes then turn the screw back counter clockwise to enter diagnostics mode 3. From there it will start to put out the codes. A red LED will blink for the 10's and a green for the 1's. So, 3 red blinks and 2 green blinks would be a code 32, which would be an EGR code.

[bdes64]

Thanks for all the help...How do I ensure that after I check the codes that I set it back to where it needs to be...Sorry so many questions...

[mtcookson]

Once you're done reading the codes you can either turn the key to the off position which should kick it out of diagnostics mode or you can go to diagnostics mode 4 then turn the key off which will clear the codes, if I remember correctly.

[bdes64]

Thanks I got a 14 and a 4. Dont see 4 in the book....The 14 could it be the reason the speedometer works intermittently? WHere is the reed switch?Man you are a good teacher Thanks Bruce

[mtcookson]

I'd go ahead and run the codes again just to double check on that second code.

The speed sensor issue I always had was with the wiring itself off of the sensor. On my GXE the wires touched the manifold and melted the plastic causing the two wires to touch and short. I just cut the bad part out and spliced in new wires to fix it. On another the wires were basically coming out of the sensor itself so I had to get a new sensor. So... check out the wiring first and go from there.

[bdes64]

Where is this sensor located? Cant find it in the books? This car is actually fun to work on compared to my Mazda 626 and Toyota Corolla and Honda Accord..Thanks once again

[mtcookson]

Not a problem.

Alright... the transmission is on the driver's side and the speed sensor should be located on the rear of the transmission (closest to the firewall), on the right side of the transmission (passenger's). You'll see a little cylinder sticking out of it with a single bolt (10mm I believe) holding it in and a wire coming out.

[bdes64]

Hi, is it located under the oil filter? Does it have a yellow gear on it. That is the only thing I could find with one wire (actually 1 black,1 green) in a sheath held on by a 10mm bolt?

[mtcookson]

Sounds right. It will have a plastic gear on it so you're probably got the right one.

[bdes64]

Thanks, it has a yellow plastic gear. The speedometer worked all the way to the junkyard and back..It is so intermittant. I checked the codes again and i got 1 red 4 green the a pause and 4 green.

[bdes64]

Thanks for all of your help this week...Have a good weekend....Bruce

[mtcookson]

Thanks, it has a yellow plastic gear. The speedometer worked all the way to the junkyard and back..It is so intermittant.

I'd say being intermittent like that its likely the wiring. Also check the the plug itself, make sure there isn't any corrosion on the connectors.

Quote »I checked the codes again and i got 1 red 4 green the a pause and 4 green.[/quote]That's very weird... I'm going to have to look into that further and see if I can figure out what could be going on.

[bdes64]

I replaced the speed sensor, same intermittent problem. What do you suggest to try next?

[mtcookson]

Ahh, I didn't know you were going to go ahead and replace it. Check for corrosion on the main plug (the plug that the speed sensor goes into) and I'd also check the wiring between the main plug and the ECU/speedometer. There's likely a short somewhere along there.

[bdes64]

I replaced the connector comming off the speed sensor. From there it appears to go into a bundle of cables that split into several directions. Am I missing something?

[bdes64]

How do you check the wire to the speedometer..Just cut those bundles open?

[mtcookson]

Hey, I'm very sorry for the delay. I completely missed your reply then didn't get on much over the weekend.

Anyway... the best thing to do would be to get a multimeter. From there you can check to see if the sensor itself is good (check for continuity between the two wires while spinning the gear on the sensor or the tires with the car jacked up, continuity should come and go), if the sensor is ok then I would check for continuity between the plug itself and the gauge cluster. The two wires are Green with an orange line and Green all of the way to the gauge cluster. They may be different on the sensor itself but from that plug should be the correct color. Testing for continuity between that plug and the gauge cluster will definitely tell you if there is a break or short between there.

[bdes64]

Thanks I will try that.