Greetings,

I'm new to this newsgroup, but have heard really good information about this group from my friend who owns a '94 GXE, so I hope that maybe by some extreme luck, someone will have the answer for me regarding my problem with my car:

CAR:

'89 Maxima SE, 220K miles (actual mileage: appx 240K since VSS had malfunctioned for about 20k miles prior to us purchasing the car), original automatic transaxle still in the car

PROBLEM:

Engine will quit for no apparent reason while the car is in motion or even when stopped, but the problem is very intermediate and inconsistant. I would be driving at a nominal speed, and then the car engine would lurge. Putting the car into neutral, the engine quits on me (which ruled out transmission problems). Any attempt to restart it would result in the engine catching, but then stalling out again. Occasionally, when the car stalls, the "Check Engine" light comes on. Then, just as mysteriously as the stalling symptoms had showed up, they mysteriously disappear, and the car runs like nothing ever happened. Sometimes, the car would even stall while at idle, and won't restart, but then after a few minutes would restart and go on as if nothing ever happened.

Running the self-diagnosis code, I get code "12", which indicated a bad MAF sensor. So I purchase a remanufactured MAF sensor for $180, only to realize that the sensor that I received had 4 prongs while the one on my car has 5 prongs, and lo and behold, the 5-prong MAF sensor costs $430. So, I bite the bullet, and purchase this extremely over-priced sensor, only to realize that my car now runs even *WORSE* with this new MAF sensor, stalling out even more frequently than when I had my old MAF sensor in it. However, whenever my car starts to lurch while cruising, and if a check engine light does come on, this sensor's number comes up. I even checked the connector itself, cleaned the contacts, took a small screwdriver to bend the mating contacts slightly inward to improve the contact between the plug and the sensor, but again, still no luck.

The numbers I received on my voltmeter between the old sensor and the new sensor from pin "E" and "B" to ground, given the various conditions that I should be testing it at (engine not running but ignition on, engine running at idle) are almost identical in readings for both MAF sensors, while pin "C" and "D" do read ground as it should be, according to the Haynes repair manual. So, at least this test seems to verify that both my original MAF sensor and the $430 MAF sensor are working within normal specs.

Engine does not feel like it's missing at idle, though occasionally, it will dip for no apparent reason, then correct itself and start idling normally. Fuel injectors seem to be all working ... no shudder .... though I know if I jiggle one of the injector wires, the engine will start missing that one cylinder, but would disappear once the car is shut off and restarted.

Also, on another issue which may or may not be related, I've burned through almost 1/2 a tank of gasoline according to the fuel gauge, but mileage-wise, I'm at approximately 85 miles on this particular tank of gas. Supposedly, this has happened a few times in the past before, though the time when the car seems to run normally (that is, not stalling), I would be averaging about 20-22 mpg.

HISTORY:

This started happening after I tuned the car up. Brand new cap and rotor, brand new spark plug wire set, brand new spark plugs. Found one cylinder had a bad threaded hole for the spark plug, so we rethreaded that hole. Emission-wise, after the tuneup, the numbers came out much better for the smog check than before, though this problem of intermediate stalling while the car is moving showed up after the car had been tuned up. Fuel filter was changed about 45k miles ago. Oxygen sensor has never been changed as far as I know (we bought the car at 170k miles). MAF sensor has been cleaned with electrical cleaner to no avail.

When the car first experienced this stalling problem, I had gotten a code which indicated a defective cylinder head temperature sensor. However, I disconnected the battery, left the car sitting overnight, and that code plus the stalling problem never came back for about a month. Now the stalling problem has come back, the cylinder head temp sensor code has *NEVER* came back, and this MAF sensor code had replaced it. To me, I'm almost lead to believe that this MAF code only comes up because my engine is about to stall, but the car is still in motion, so the extra air passing over the sensor in relations to the car engine's RPM wasn't matching up, and thus, the ECM would generate this code.

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This problem has been driving me crazy for the last 4 months, and frankly, I think it's downright dangerous given the intermediate nature of this stalling at any car speed. I can't imagine what would happen if I was cruising on the freeway, only to have the engine suddenly cut out from under me and not restart.

Any ideas from your experience with your Maxima would be greatly appreciated, especially if you've had symptoms that were very similar to mine. I'm very close to ruling out the MAF sensor as a possible defective component, given the fact that all the numbers check out ok, whether it be with the original or the remanufactured sensor. Perhaps there's some other sensor that may be malfunctioning ...? TPS? O2?

Responses to this forum and/or via email to me would be extremely appreciated.

- Alan Quan
- '89 Maxima SE, 240K miles

 

So you are still getting the code for MAF, even afterr replacing it? Hows your fuel pump? HTe injector won't cause outright stalling, I get the same thing, if I wiggle the harness at the injector. No biggie. That's your dip in idle too.

 

Same code as before ... "12" ... which is why I suspect it may be coming up only because when the car engine stalled with the car still moving, the engine really isn't running, so the ECM expects the MAF sensor reading to be something lower than it really is.

I think the fuel pump is okay ... I don't know of any diagnosis that I can do to check it. I can hear it pressurizing the fuel lines, but that's about it. I'm tempted to swap out the old fuel filter with a new one, but even if I do that, I don't think that could explain the excessive fuel consumption problem I occasionally have.

 

Not sure how the ECM respond to stalling while moving. Your idea bout it expecting a reading makes sense. Does it run well before it stalls. If you have excessive fuel consumption, you may be running really rich, even that causing stall, but the engine would bog like mad before that happens. It's like your just cruising then nothing? Have you done a driving ECM diagnostic. I mean, you said it throws 12 when it stalls, but what about when it is running OK? I would pull the plugs and inspect them. They can tell alot about the situation by the color of the buildup oon them. I'm not ruling it out, but I think TPS would give you more consistent trouble.

 

My sister actually owns the car, so she's had more stalling experiences with it, but for me, it would be more like this: one minute, I'd be driving as if nothing's wrong (let's say at 2000RPM, 55mph), then next thing that happens is the RPM gauge drops to 1500RPM, then back up to 2000RPM when you give it more gas, but at this point, the engine feels really bogged down, note that with a "Check Engine" light on (12: MAF sensor). So I put the car in neutral (note the car is still moving at about 50mph at this point), and the engine quits on me. Any attempt to restart it fails. Eventually, leaving the car alone, I attempt to restart, and it starts right back up, and everything seems okay: no check engine light, no nothing. The code only comes up under diagnosis mode "3", but once you clear it, it doesn't come back until the car does this stall act again.

The plugs unfortunately are still relatively new since I only tuned the car up about 3 months ago because I had to get it through smog, so I honestly can't say how much soot or crud would have accumulated onto the spark plug by this point. I'm real hesistant to pull the plugs out when the car stalls because it's at this point when the engine is hot, and with the aluminum heads on this car, I could do some pretty severe damage if I start taking out / reinstalling the spark plugs on a hot cylinder head.

My uncle (a general car enthusiast) said I might want to check the O2 sensor, given that it has never been replaced before, but I can't see any correlations between a bad O2 sensor and stalling problem, especially when I haven't gotten any O2 sensor codes. However, I'm at this point where I'd try anything.

 

It's time like this when I wish the car would either be running right or be not running at all. Intermediate problems, to me, are the hardest ones to diagnose, esp those which the car's computer doesn't seem to indicate as being a problem. I've had other electrical problems with the car (temp gauge falling to "C" for no reason, even with a known good coolant temperature sensor ... then the one time where if you turned on the headlights, the rear defrost would come on, until this problem suddenly disappeared by itself ... then the other time when a short in the rear brake light bulb resulted in the parking lights coming on ever time the brakes were applied). I just hope that in this situation, it's a sensor that's bad and not the whole electrical wire harness because those are a pain to diagnose.

 

Your problem is NOT MAFS itself but it's the wiring to and from it. There's some breakage in the wiring... This would explain its intermittened nature (and why the engine shuts off after hitting rough roads or major potholes) This is what you do to find were it is. Turn your engine on... feel, move, or just plain bend the wires connecting from and to the MAFS with your hands. You will feel and hear the changes in RPMs... Eventually causing the car to shut off. Let's face it - 3rd gen is pretty old so expect wires to brittle over time. Once you find the break(s), you'll just have to replace those wires and connections. It worked for me - without having to replace the MAFS... Going on three weeks now.

 

True, especially when you talk about wiring under the hood being subjected to those cyclical thermal stresses of the engine getting cold, getting hot, etc. Other wiring problem that I have had did involve cyclical mechanical stress loads (opening/closing trunk resulted in breakage of the wiring for the 3rd brake light on the trunk-mounted spoiler), but the wiring problems within the interior were, to me, quite strange since there really isn't any cyclical stress load being applied to that bundle. I've had older cars ('77 Mercury, '83 Civic, '85 Accord) that never had these type of electrical problems, though granted those cars didn't have anywhere near as many sensors as the newer cars do.

Regarding the wiring to the MAF sensor: I have tried squeezing some of the wiring near the MAF sensor, and even took a small screwdriver to bend the mating plug connectors inward to improve its contact with the MAF sensor, but none seemed to work and the condition of stalling could not be reproduced manually. All I know is that for some reason, the car ran worse with the $500 remanufactured sensor than with the original MAF sensor. I definitely do agree with you, though, that intermediate failure usually does point to some type of wiring discontinuity, but the car has stalled under almost any road condition: whether car is moving on relatively flat road, bumpy road, or even when stopped. The wiring harness bunch on this car looks pretty bulky, so I'd hate to have to start ripping apart the plastic mesh shielding that holds all the wires together, just to start hunting down the wire that has a break in it.

Also, still not sure how this may relate to my excessive fuel consumption problem as of late, especially considering the car has a fresh set of plugs, wires, cap, rotor, and air filter. I'm basically shooting in the dark right now on trying to figure out why the car isn't running right.

 

I really suggest the o2 sensor. You are definately running rich. That's typical of bogging and stalling. If it were going lean, you would have different symptoms. Bogging wouldn't happen, you might knock like hell then shut off, but not bog and stall. Do you hear any knocking just before it stalls?. The wiring to the MAFS sounds plausible too. Then again, it could be your ECU acting stupid too. You might try a known good ECU. As stated above intermittent problems are the absolute worst. Good luck.

 

The O2 sensor was what I was thinking about trying next .... no, I did not hear any knocking prior to the car stalling. It would just be driving, then the engine bogs down and if I put the car into neutral or the car comes to a standstill, the car will stall.

I have a real far-reaching guess right now: perhaps the O2 sensor is intermediately defective, which may cause the engine to deliver more gas than usual at some intermediate interval. This in turn floods the engine with too much gasoline, which results in the car engine bogging down and eventualy stalling. However, at the same time, the engine gets close to stalling, but the MAF sensor is still expecting some "x" amount of air to be flowing over its meter in relations to the car engine RPM. When it sees that the expected reading vs. the actual reading isn't what it should be (because the car is still moving), the ECM sends out a fault code "12". But the ECM would not catch this O2 defective code because it's very intermediate, which isn't something new because it didn't catch my faulty alternator when its output was not sufficient to recharge the battery. (Any thoughts from anyone about this assumption and the logic behind it? )

That's just my wild guess right now. What I plan on doing is returning my MAF sensor (praying that Autozone will take it back since it was a special order item), then order a new Bosch O2 sensor, install that and a new fuel filter, then do what "blackonblack" suggested in jiggling the wire harness from the MAF sensor on to see whether this may cause the engine to stall. I have tapped and jiggled the MAF plug and its immediate wiring after the mating plug before to no avail, but I'll try checking further upstream within the wiring harness.

Anyone with further input, please feel free to respond. Thanks!

 

Do the 02 sensor. I don't see how it could be that bad to cause stalling but if it was totally non-functioning, I guess I could see it happening. Plus if you have over 90,000 on your stock 02, it's time for it to go. another indicator that you need one is your "running rich" statement.

 

True, if it was dumping fuel that crazy, I'd think I'd have some fuel injection problems to go with it, or at least a O2 code to show for it. But I do think the O2 sensor might need to be replaced since the smog check in September did reveal some trace amount of O2 in the exhaust, which might be saying that the O2 sensor wasn't sensitive enough anymore.

I suspect my car is running rich due to the amount of gas it's gone through this time, but I haven't been able to verify it without going through a few more tanks and checking to see whether the plugs are wet.

 

Update:

I replaced the oxygen sensor today with a Bosch oxygen sensor. The new Bosch sensor was slightly different from the original one on the car: both had two mating plugs (one with 3 pins, one with 1 pin), but on the original sensor, there was only three wires from the oxygen sensor whereas the Bosch sensor had four wires. The thing that baffled me was that the new sensor's connection made more sense to me (4 wires from oxygen sensor, 4 wires to two plugs), but why would the OEM sensor have only three wires coming from the oxygen sensor, then somewhere down the line, the "black" wire has this additional "blue" wire that is connected to it in some way? And also, why was the 1989 Maxima the *only* year where the oxygen sensor had two plugs with four wires, whereas every other model year preceding or produced aftewards only had one plug and 3 wires?

In any case, I test drove the car for about 20 miles on surface streets (stop and go) and freeway, and it seems to be fine for now. I did get a "check engine" light a few hours later when I first started up the car, which the ECM called out code "33": open circuit for the oxygen sensor. I assumed it was just because the ECM wasn't used to the new sensor yet, plus when I was test-driving the car, I was on self-diagnosis mode 5, so perhaps the ECM didn't recognize this new sensor. I reset the computer, and the code went away.

I'll post a followup reply in about a week.

 

I am having the same problem with my 89 max. Just recently I have noticed that when driving the car accelerates fine no prob, but when I begin to slow down and dis-engage the clutch the engine's idle drops down to 200 rpm's almost stalls no check lights come on but then the engine catches and the idle returns back to normal around 700 to 800 rpms? If I wiggle my injector harnesses the engine will drop because the injector isn't firing, the same thing happens to my MAF if I wiggle the wire harness but the engine will die. So i am going to change my injection leads tomorrow, and try to find a junkyard to cut me a old one off of another max. I have changed my MAF recently a remand one, also have cleaned both the MAF connector along with my injector harnesses. Car drove better but was just a short term fix!!! The main thing though is that my car doesn't stall out at any point, so what could be my prob? Let me know?

 

FYI - After finding a winning position for the wires coming out from the MAFS, my max has been on the road for officially 1 month. And last night I got a rebuilt MAFS for $80 from a friend who works at a Body shop... I installed it Monday. WOW! What a difference! Im convinced! The culprit is the MAFS.

 

Glad to hear your success!!! My situation hasn't been solved as yet!! My injector leads are old and need replacement but the car doesn't miss-fire just that pesky strange idle when dis-engaging the clutch generally from 3rd gear. the idle seems to drop down to 300 rpm's but doesn't stall!!!! Hear are my driving habits, I general don't downshift in any gear when coming to a stop. I stay in that particular gear and just brake until the car's idle drops down to like 1500 to 1000 rpm's then dis-engage the clutch and that is when i experience the drop in idle!! Any suggestions!!!

 

Well, an update from me: somehow, the new Bosch oxygen sensor is messing with my ECM; every time the car is warmed up after I've shut off the engine, the check engine light comes on and stays on for some reason. I tried resetting the ECM three times, and even did a "disconnect the battery overnight" one time, and in all cases, it didn't do squat: the check engine light still came on. Putting back my old sensor resulted in *no* check engine light. Right now, I am waiting for a replacement Bosch oxygen sensor from the parts store because I'm thinking that as rare as it may be, that sensor was defective from the box. If the check engine light comes on again with another Bosch oxygen sensor, I may just stick with the old one because the old one's mpg seems to be reasonable on the open road (right now, looking at maybe 25-26mpg on a 220K+ miles engine with a starting-to-slip-but-functional OEM auto tranny and a slightly out-of-cal speedometer)

Regarding my original problem: I ended up changing the fuel filter and ignition coil (slightly out of spec), and the car hasn't died on me on the road yet. The fuel filter had about 40k miles on it, so I'm a bit stumped as to whether that may be my true culprit because it was changing the fuel filter and oxygen sensor that cured my road stalling problem, and now that we've determined that the new oxygen sensor had been bad and the car runs fine right now with the old OEM sensor, it might have been a very clogged fuel filter all along. My MAF sensor code hasn't come back at all, (when I jiggled the wire harness, the car still ran, but if I tapped on the "electronic box" part of the MAF sensor, it would stall), and considering how bad my car ran with the remanufactured MAF sensor ($500!!!), I went back and will probably stick with my old one right now.

What I do have a problem right now is that my car will occasionally die at idle. It idles around 600-650RPM, then for no reason, the engine would stall. But unlike the past when I had the stalling problem, the car would start right back up again. I take it that this stalling at idle problem is something common among the early Gen3 cars? And if so, what was the fix, if one existed?

-Alan

 

FYI - Update

Recently I told you that I lucked out and got a used MAFS for $80 bucks from my friend who works at a body shop right? Well, upon installing it on my max and running better than ever, I decided to crack open the rectangular pin connetor box... Basically I unscrewed it to see what's the inner workings of this thing. After doing so, I found out that the process is IRREVERSIBLE! But I did see what was causing the problem. Three of the pins were just burnt... Well darker than the other two. This told me that current was not flowing as efficient as it was meant to be. The fact is that the sutter connecting the pins to the circuit box on top THE MAFS was burnt and corroded. About the five pin thing, well, actually four are actually connected - one is a ground. Just get another MAFS. Avoid the headache.

 

What do you think could be causing the burned terminals on the MAF? I am going to have to change the wire harness for my max, however I have found a junkyard selling one for 10 dollars all the others are 50!!!! So, Will get and slowly make the change and hopefully my spuratic idle will leave!!!

 

Simple! The car is about 12 years old.

 

check your TPS (Throttle Position Sensor).

it sounds like its it.

 

I was having the well known "intermittent hesitation/stall". Several suggestions were made of which due to financial constraints only a few were attempted. (Basically I didn’t have enough money to replace all sensors). I did the easier and least expensive suggestions.

1) Replaced the fuel filter.
2) Cleaned throttle body and idle speed motor/solenoid.
3) Cleaned sensor connectors and applied di-electric grease to the ones that I could easily reach.
4) Checked coils' resistance.( Distributor less system=6 coils)
5) Checked O2(Oxygen) sensor with digital voltmeter. Sensor has three wires, one is the sensors output and the other two are power to heat the sensor during warm up. Checked the voltage on the sensor output wire while the car was running the voltage should fluctuate around .5VDC. Check the following link for more info on test Oxygen sensor.

www.forparts.com/o-21.htm

The car continued to stall, it seemed to get worse and happen more frequently toward the end. In the mornings if I started the car and let it warm up I noticed that after a while the rpms would fluctuate as if the ECM was hunting trying to find itself. On a few occasions the rpm's would drop considerably nearly stalling the engine. I checked the ECM for codes and always got back a 55=system ok.

Unfortunately my car got stolen soon after trying all these things, when my car was recovered the instrument cluster had been stolen along with leather power seats, radio and other personal items. After putting a new instrument cluster, seats, and radio the check engine light came on. I checked the ECM and it gave me a Detonation Sensor (Knock) code. The car still stalled intermittently. I had not gotten a code before this I know the check engine light did work but no code was ever set before. I had heard/read (I think it was here ...) that a bad knock sensor doesn’t always set the "Check Engine" light.

I replaced the knock sensor, $184 from Nissan this past holiday weekend. After buying it from Nissan I was quoted at a local Auto parts for $120.

No stalls or hesitation in the past five days. The car feels better then ever, plenty of power great acceleration. My car is a 92SE with the VE engine 160K miles. The knock sensor is mounted UNDER the intake manifold on the "V" section of the engine block. If you have the VG engine it is supposed to be easier to replace. I took some pictures I'll try and post them tonight from home. The knock sensor had cracks in the plastic outer coating and some oxidation on one of the terminals. I also replaced the vacuum lines while I was under the hood. Some of the vacuum lines were beginning to get hard. I would say that for the average Do-It-Yourselfer it is easily and eight hour job (assuming you have all tools). Don’t skimp and try to reuse the plenum and intake manifold. You will need some high temp RTV for the water passage/tube that runs along the “V” of the engine. You need to loosen the tube to get to the Knock sensor. You’ll see what I mean after you take the manifold off.

I speculate the bad knock sensor was intermittently sending a false signal the ECM causing the ECM to retard the timing hence causing the hesitations and stalls. When ever my car would hesitate the RPM's would fluctuate between 1500-2500 rpms. When this happened if I took my foot of the accelerator for about 3 seconds then the car would be fine. I seem to remember this happening most during a deceleration/coast just as I tried to accelerate. On a couple of occasions it stalled on me during stop & go traffic. I had to put it in neutral a restart it while coasting, what a scary feeling.

A lot of info here, hope it helps.