Rough Idle, 92 Maxima GSE

[DaveJ-I30]

To anyone,

You've folks have bailed me out in the past and now I need you again!

This problem is kicking our asses in our Nieces 92 Maxima!! This car rough idles and won't go faster than 35 mph. As we rev it up it seems to run smoother. We already changed 2 fuel injectors, swapped out the distributor, and coil. The catalytic conv. is fairly new. The service engine light is on, but I need to get an older OBD reader to scan it. Right now the car is my Brothers driveway and he's already down $800!!

My friend, a crack Chevy man thinks we need to start by checking the compression.

Any thoughts or sugestions ???

Thanks,

Dave

[mtcookson]

I'd go ahead and check the codes just to see what its showing as a problem. You can actually check them on the ECU itself. Its on the passenger's side behind the left kick panel. Remove the panel and you'll see the ECU with two LEDs (green and red) and a screw. With the key in the on position, turn the screw fully clockwise and it will start blinking. 1 blink for mode 1, 2 blinks for mode 2, and so on up to mode 5. We want diagnostics mode 3 so let it blink 3 times then turn the screw fully counter clockwise and you'll be in mode 3. From there it will start putting out the codes.

The first flash is the 10's and the next flash is the 1's. I can't remember which color is associated with the numbers but the first flash is always 10's. So, say you have a code 43 the first light will flash 4 times and the next light will flash 3 times.

Once you get the codes you can check them out in the EF/EC section of the FSM (ec.pdf) at http://www.nicoclub.com/FSM or you can post them up here and we can go through them for you.

[DaveJ-I30]

mtcookson, Thanks!

I agree, I'm calling my brother now and I'll e-mail your suggestion for finding out the codes.

Dave

[mtcookson]

Good deal. I modified my instructions, well actually just one word. Instead turning the key clockwise its supposed to be the screw so that it goes into diagnostics mode.

[nissanracer300zx]

Maybe your car needs a tune up.

[DaveJ-I30]

Nah,

It doesn't need a tune up. It's something stupid cuz, it all of sudden happened.

By the way, I owned a 1986 300zx 2+2, bought brand new, owned it for 11 years, it was mint, never saw winter, my ex-wife drove it mostly. Untill, after the 3rd recall for fuel injectors replacement, mind you 3rd set. 1 week later 2 of them leaked again, engine caught fire...rest is history...the body, interior was fine. But, Nissan did buy the vehicle from me and was very fair. That is why I bought an Infinty.

Dave

[DaveJ-I30]

mt,

Thanks for the correction. My Bro's performed the diagnostic sequence per your instructions and the code was 45, leaky injector. Now we've already replaced 2 injectors, the 2nd one yesterday and it still idles like ****. Should we replace them all ? Dam things are $80 each.

Thanks,Dave

[sweet3rdgen]

Have you checked the MAF?

[DaveJ-I30]

Sweet3rdgen,

Forgive my ignorance but what does MAF stand for ?

Thanks,

Dave

[mtcookson]

mt,

Thanks for the correction. My Bro's performed the diagnostic sequence per your instructions and the code was 45, leaky injector. Now we've already replaced 2 injectors, the 2nd one yesterday and it still idles like ****. Should we replace them all ? Dam things are $80 each.

Thanks,Dave

That's interesting... that must be a California car as I'm pretty sure code 45 was only California models only.

Anyway... first thing I would do is check to see if all of the injectors are opening. You can apply 12 volts to each injector and listen for each of them to click or listening to each injector with a long screw driving or similar for the clicks. You can also check the resistance of each injector to make sure they're within specs (look for between 12 and 14 ohm).

If that pans out ok then I would bet that fuel could be leaking past one of the o-rings, especially since the injectors have been replaced as it is very easy to not get them seated properly. If one is leaking past the o-rings, just pull that injector, make sure the o-ring isn't torn or damaged, and if it is ok lightly lube the o-rings before putting the injector in to help it seat properly.

Have you checked the MAF?

MAF issues will usually throw a check engine light and a code so its not likely the MAF, plus a fuel leak like what the ECU is saying is happening would most definitely cause the issues he's seeing. I actually had an injector o-ring leak so bad once that the engine actually hydro locked and filled a couple cylinders as well as the intake manifold with fuel. Overnight all of it drained to the oil pan and turned the once 10W30 oil into the viscosity of water.

Sweet3rdgen,

Forgive my ignorance but what does MAF stand for ?

Thanks,

Dave

Mass Air Flow sensor. Also know as:

MAFS - same as above with the SAFM - air flow meterMass Air Meteretc.

[DaveJ-I30]

Mt,

I can't thank you enough. We'll try anything!

Dave

[sweet3rdgen]

MAF's don't always throw a code.

When they go bad they can cause rough idle and will not let the car go above (usually) 2,000 RPM.

[DaveJ-I30]

S3G and Mt,

Thanks for your input. This weekend my Bro's will attack this. This site is just a beautiful thing!

Dave

[mtcookson]

MAF's don't always throw a code.

When they go bad they can cause rough idle and will not let the car go above (usually) 2,000 RPM.

That's true, though even in limp mode the car should be able to go faster than 35 mph. I think the rev limit is around 2,500 but regardless it should be able to do nearly 60 in limp mode so that it doesn't take forever to get back home.

Not that its not worth checking... I would take a look at the connectors at the MAF, make sure they aren't overly corroded and maybe test the MAF out going by the FSM specifications. I just don't see it being an MAF issue since its such and extreme change in the way it runs (and because of that fuel leak code as well).

[drg007]

check for air leaks, spray with a crab cleaner arounf intake manifold or air cleaner hose

[DaveJ-I30]

MT,

Well the Bro's are doing some hard time here. They measured the ohms on each injector, all good. Re-checked the compression, fine. replaced all the O-rings on each injector. Replaced the gasket under the fuel ring. Swapped out the MAF. Same rough idle.

Servis engine light still on, rechecked the ECU it is now throwing code 11, crankshaft angle sensor. I wasn't there during the ordeal, but what do you think??? Swap it out???

Thanks,Dave

[mtcookson]

The CAS is located in the distributor itself. I'd check the wiring to the distributor, make sure its not loose or corroded. I've never really heard of any VG guys having CAS issues so it should just be something simple in that area. If not, I believe I have one laying around that I could send your way. I know mine worked just fine when I pulled it.

The test procedures for the CAS are on EF-EC page 85 (pdf page 83). If after checking the connection it still throws the code I'd go through that procedure.

Also, after checking the CAS I would reset the codes which I believe is done by going to diagnostics mode 4 then turning the ignition off. When you turn the key back on the codes should be cleared so there won't be a check engine light. When you start it, the light should come back on if there's an issue. If you'd like, you can also try this first just to see if the CAS code comes back on.

[DaveJ-I30]

MT,

Thanks! You say the CAS is connected to the distributor, you know way back, we swapped out the distributor originally cuz Brother "Dodge Man" Bob thought it was that casusing the rough idle. I'll have him put the original one back in first. Then reset the ECU per you suggestion. We still might take you up on the one you have.

Thanks again and again and again........Dave

[mtcookson]

Yeah, if you pull the distributor cap off you'll see a metal plate under the rotor, the CAS is under that. Its pretty well sealed which is why I think they don't usually have many issues.

Since the distributor has been removed I'd make sure the timing is good, they can sometimes be a pain to get the teeth to mesh correctly when putting it back in though the problem seems to be worse than a timing issue so its not likely that.

[tbg3]

Had the same stupid problem on my 93 GXE! Replaced pretty much the entire top of the motor trying to fix it. The engine NEVER showed a code or had ANY of the warning lights come on, but ran like it was missing. Replaced pretty much the entire top of the motor trying to fix it. It was the voltage regulator on the alternator! Seems as though the alternators for these particular cars are not built very well. Replaced the alternator and have not had the problem since. GOOD LUCK!

[mtcookson]

Seems as though the alternators for these particular cars are not built very well.

That's the damn truth right there... the alternators for our 3rd gens are horrid, or at least all of the replacements. I did have a voltage regulator go out on my GXE but don't remember having any idling issues. Wouldn't hurt to check and is very easy, just throw a multimeter on the battery while the car is running and see what kind of voltage is going through it. If the regulator is gone it'll be high, well over 14 volts. I remember mine being 18 volts and it caused the radio to make funky noises and such.

[KurtMcCrum]

I'd go ahead and check the codes just to see what its showing as a problem. You can actually check them on the ECU itself. Its on the passenger's side behind the left kick panel. Remove the panel and you'll see the ECU with two LEDs (green and red) and a screw. With the key in the on position, turn the screw fully clockwise and it will start blinking. 1 blink for mode 1, 2 blinks for mode 2, and so on up to mode 5. We want diagnostics mode 3 so let it blink 3 times then turn the screw fully counter clockwise and you'll be in mode 3. From there it will start putting out the codes.

The first flash is the 10's and the next flash is the 1's. I can't remember which color is associated with the numbers but the first flash is always 10's. So, say you have a code 43 the first light will flash 4 times and the next light will flash 3 times.

Once you get the codes you can check them out in the EF/EC section of the FSM (ec.pdf) at http://www.nicoclub.com/FSM or you can post them up here and we can go through them for you.

I have a 91 Nissan Maxima and followed your advice, checked the code and got "51". I have had no luck trying to decode that in the EC.PDF you linked to. Any help would be appreciated. Car has a rough idle, sputters while going up to speed, but will hold a 2000+ RPM without a problem. I replaced the distributor entirely without success. Still rough idle and the engine light flashes/threw the code.

Peace,

Kurt

[mtcookson]

EF & EC-43 (pdf page 43) - code 51 comes out to injector circuit error (injector circuit is open).

Check the resistance of the injectors, at least one of them is likely toast. Look for between 12 and 14 ohms on each. If any are above or below that point, they are your culprits.

[jimmy1530]

what is crab cleaner?

[jlkunz]

hey, i own a 1992 nissan maxima SE. and i had that same problem when i first got the car. i couldn't get it over 25 mph. or 3000 rpm. for sure check compression. thats what my problem was. i had two bad injectors and compression was very very low across all cylinders. i ended up replacing the motor

[NutriaforBreakfast]

No expert here but u might;

1) Check the compression2) Check the timing3) IF the car uses camshaft position sensors or crankshaft positionsensors, see if there are ok

[pacoslaw]

This has happened to me several times. It is caused by the gunk buildup in your engine. Simply use a strong engine cleaner. It will go away in about 200 miles of driving. Best to take a long drive. Also, Shell's gasoline with nitrogen should be used.