# HELP!!! I need some professional direction!!



## Nightrain (Oct 14, 2005)

I'm fairly new to the forum but have become quite knowledgeable on the 4th generation Maxima's from google searches, forums and the Haynes manual. I have recently purchased two 1997 Maxima SE's...one with 85K and the other with 105K. The one in question is the 105K car. I bought it in good condition but of course it needed 100K routine maintanence, therefore, I had the following performed (some by Nissan & others by local reputable shop): 

Changed spark plugs with NGK platimums, air filter, oil change/filter, transmission oil change, changed PCV valve, cleaned throttle body, replaced EGR canister and repaired wiring, changed MAF sensor, replaced bad ignition single coil, and fuel injection cleaning.

I just want to experience a good, smooth ride like my wife's 85K SE has. My car with 105K idles decent but I have MAJOR problems with hesitation (especially from stop-to-go), hearing the engine louder than normal when accelerating, and piss poor acceleration. I have no CEL light on or no ghost CEL code, but I do have a code from the TCM which designates a "disconnected and/or shorted TPS circuit"!!! Could this be the culprit or does it sound like I may need a new Knock Sensor???

QUESTION #1
My car idles OK (even though I probably need adjustment because I'm currently at about 600-700 RPM). Should this probably be closer to 800-850 RPM?

QUESTION #2
I'm thinking it may be one or a combo of the following: Throttle Position Sensor (TPS), Knock Sensor or O2 sensor(s). Am I in the ballpark?

QUESTION #3
Should this fix (whatever it may be) effect the extra loud acceleration engine or transmission noise that I'm hearing? It sound like a possible problem with my air-to-fuel ratio and possibly from incorrect/inconsistent signals being sent to the TCM and/or ECU.


Please help me out! I'm not a hard driver but I do want to experience that Maxima feel and I'm not getting it at all! In the meantime, I will do some testing today with my multimeter to check circuits and sensor operation.

Thanks guys. :cheers:


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## Shenanigans pres (Oct 9, 2005)

id get on maxima.org and go to there forums and ask. your going to get much better help there than you will here. prob wonthave to wait 10 min after u post there to get a response with someone that can tell ya wats going on for sure or give you a better idea!


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## Hydrolock (Feb 18, 2005)

Air fuel ratio isn't going to make you engine louder at least not that you can hear. Your hesitation is most likely your tps sensor. You should be able to find the test prosedure fairly easy since I don't feel like typing much right now.

What makesyou think it's all these other things, Knock etc?


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## alexnds (Oct 1, 2005)

*poor acceleration and idle*



Nightrain said:


> I'm fairly new to the forum but have become quite knowledgeable on the 4th generation Maxima's from google searches, forums and the Haynes manual. I have recently purchased two 1997 Maxima SE's...one with 85K and the other with 105K. The one in question is the 105K car. I bought it in good condition but of course it needed 100K routine maintanence, therefore, I had the following performed (some by Nissan & others by local reputable shop):
> 
> Changed spark plugs with NGK platimums, air filter, oil change/filter, transmission oil change, changed PCV valve, cleaned throttle body, replaced EGR canister and repaired wiring, changed MAF sensor, replaced bad ignition single coil, and fuel injection cleaning.
> 
> ...



My answer is an educated guess. What you described above is basically a very good tuneup. However, at 100k+ miles an item you may wish to consider doing on this car is the change of the water pump and timing belt and all accessory belts. If the timing belt was to break, you'd have major piston to valve hitting and no motor. The other issue of the diaphram in the old water pump possibly failing, likewise, no motor. I know it has nothing to do with your problem, but it's not a bad idea considering the age of the car.

Now then, some things to check are as follows: take a good quality Digital Voltmeter, about $40 and check the number of ohms per fuel injector. If one of the injectors has very high ohms compared to the other ones, it may the problem of poor idle. The cleaning of the injectors via putting fuel into directly into the fuel rail, a service that typically costs $60-$100 mostly cleans the intake valves and may lodge any particles in the injector further int the injector pintle, causing the high ohm reading. If the injectors are not putting out good amount of fuel, it also explains the lack of power, poor fuel consumption, and so forth.


Another thing to check is the EGR valve system. The Exhaust Gas Recirculation valve being stuck in the open or closed position is an issue. If it's stuck in the closed position, the engine will run too rich. You usually can get away not buying a new one, but simply disconnecting it, and cleaning it out with carb cleaner. 

In terms of your noise situation, sounds exhaust related. Have the car on a lift, or on jackstands and never get under the car if it is not 100% securely supported. Check the bolts that hold the exhaust manifold to the motor. They may be loose so you're leaking out some of the exhaust and thus the very noisy sound. Also, since the exhaust gas is recirculated by the EGR system, the two problems would be connected in fact. I would check for an exhaust leak, and rule that out. 

Check engine vaccum as well. Make sure there are not vacuum leaks. A very good test for that is called the "leak down test", where the fuel pump fuse is take out temporarily, and air compressor forces air into each cylinder, one at a time, where the spark plug normally goes, as each piston is rotated to TDC (top dead center). If there is an air leak, you'll hear the hiss coming from one of the vaccum lines. Replace any vaccum hoses that may be leaking. (those with the hiss when the air rushes). This is also a good test to tell you if you have bad valves or gaskets. It basically tells you if the motor is in fairly good shape overall. 

A leak down test, combined with a compresion check, is two good tests to tell you whether you should even bother investing any more into this motor, or buy a new motor, or a new car. In other words, at 100k miles, odds are, everything is fine, but before you spend more money, and chase down your noise and performance issues, get a "zero starting point" to assess the overall health of the motor as a whole.

I doubt it is the O2 sensor. Those things last a long, long time. 

Good luck and keep us updated.


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## Hydrolock (Feb 18, 2005)

alexnds said:


> Another thing to check is the EGR valve system. The Exhaust Gas Recirculation valve being stuck in the open or closed position is an issue. If it's stuck in the closed position, the engine will run too rich. You usually can get away not buying a new one, but simply disconnecting it, and cleaning it out with carb cleaner.
> 
> Check engine vaccum as well. Make sure there are not vacuum leaks. A very good test for that is called the "leak down test", where the fuel pump fuse is take out temporarily, and air compressor forces air into each cylinder, one at a time, where the spark plug normally goes, as each piston is rotated to TDC (top dead center). If there is an air leak, you'll hear the hiss coming from one of the vaccum lines. Replace any vaccum hoses that may be leaking. (those with the hiss when the air rushes). This is also a good test to tell you if you have bad valves or gaskets. It basically tells you if the motor is in fairly good shape overall.
> 
> A leak down test, combined with a compresion check, is two good tests to tell you whether you should even bother investing any more into this motor, or buy a new motor, or a new car. In other words, at 100k miles, odds are, everything is fine, but before you spend more money, and chase down your noise and performance issues, get a "zero starting point" to assess the overall health of the motor as a whole.


EGR doesn't make a car run rich if it's stuck in any position. At idle it needs to be CLOSED, while your driving or cruising it will normally be open partially to lower combustion chamber temp. and slow the burn rate of the air fuel mixture by introducing spent (unable to support combustion) exaust gases into the cylinder.

A better way to check for vacuum leaks is with a vacuum gauge, and you ears. You should see 17-22 inches of vacuum from a live manifold source. Lower vacuum than that would indicate a leak, poor internal engine sealing, or a timing/mechanical issue. Vacuum and compression go hand in hand, your not gonna have one without the other. Propane can be a helpful tool for pinpointing where a vacuum leak is, because it you introduce the propane to where the leak is you should see the rpm come up a bit since you just richened the mixture.

Cylinder leakage test only really tells you anything when the piston is at TDC and you won't find any vacuum leaks there since both the intake and exaust valves will be closed. Good luck trying to rotate the engine while you have compressed air in the cylinder, you'll probably hurt yourself when the ratchet kicks back and rips your arm off. IF YOU SUSPECT A WEAK HEAD GASKET THE CYLINDER LEAKAGE TEST CAN TURN IT FROM A WEAK GASKET TO A BLOWN GASKET.

CHECK YOUR GOD DAMN TPS SENSOR BECASUE ITS PROBABLY YOUR PROBLEM. THE COMPUTER EVEN TOLD YOU SO. A hesitation is a EXTREMELY common symptom of a defective TPS.

By the way don't get sucked into looking for the most high tech fix you can think of when diagnosing a drivablility concern. Start with the easiest and most likely.


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## Nightrain (Oct 14, 2005)

*Thanks Hydrolock and alexnds*

You both made some very good points. Like I stated, I'm no tech or a highly knowledgeable person on cars...but I have a pretty decent grip on basic Maxima maintenance. I actually dropped it off at the Nissan dealer today and it's being thoroughly examined by a highly reputable master tech. I have recently hear something that sound like a possible exaust leak so I'm having him check that out along with the other above mentioned problems. As far as the TPS, I figured this had something to do with the issues so I did by one yesterday but did not install it...waiting until I get Nissan's full analysis. 

Thanks yall and I'll post the outcome!
:cheers:


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## Nightrain (Oct 14, 2005)

*Hey Hydrolock!*

I recently replace my knock sensor and TPS. I do notice a difference in the acceleration. I have yet to properly adjust the TPS yet and will do that as soon as our rain stops (i.e. getting a 500 ohm reading as well as a gradual ramp up based on throttle position to 4000 ohms).

I also put in some Chevron Fuel Cleaner before a full tank of 93 Octane. I still hear exhaust or engine noise which is proportional to throttle position...nothing terribly upsetting but my wife's '97 Max is much more silent. The Nissan dealer did recommend a Transmission Flush! Could this be the noise culprit? I also read that maybe the IACV needs to be cleaned so I'll do that tomorrow.


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## Hydrolock (Feb 18, 2005)

Nightrain said:


> I recently replace my knock sensor and TPS. I do notice a difference in the acceleration. I have yet to properly adjust the TPS yet and will do that as soon as our rain stops (i.e. getting a 500 ohm reading as well as a gradual ramp up based on throttle position to 4000 ohms).
> 
> I also put in some Chevron Fuel Cleaner before a full tank of 93 Octane. I still hear exhaust or engine noise which is proportional to throttle position...nothing terribly upsetting but my wife's '97 Max is much more silent. The Nissan dealer did recommend a Transmission Flush! Could this be the noise culprit? I also read that maybe the IACV needs to be cleaned so I'll do that tomorrow.


Proportional to throttle position when driving or when in park/neutral?


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## alexnds (Oct 1, 2005)

*diagnosing the problem*



Nightrain said:


> I recently replace my knock sensor and TPS. I do notice a difference in the acceleration. I have yet to properly adjust the TPS yet and will do that as soon as our rain stops (i.e. getting a 500 ohm reading as well as a gradual ramp up based on throttle position to 4000 ohms).
> 
> I also put in some Chevron Fuel Cleaner before a full tank of 93 Octane. I still hear exhaust or engine noise which is proportional to throttle position...nothing terribly upsetting but my wife's '97 Max is much more silent. The Nissan dealer did recommend a Transmission Flush! Could this be the noise culprit? I also read that maybe the IACV needs to be cleaned so I'll do that tomorrow.


Transmission flush/fill is just maintenence item and not tied to your situation. The replacement of fluids, including radiator fluid, is probably simply a good idea, but it's not tied to your specific situation. Like I mentioned previously, a good idea is to change these fluids and also water pump and timing belt, since these too would wreck major havoc if either was to break. But again, these items are not specific to your situation, just good maintenence, and good insurance.

The 97 maxima, your wife's is a 4th Gen and your car is 1993 as I recall and is a 3rd Gen. different motor: both 3 Liters, but one is a VG series, and the other is VQ series.


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## Hydrolock (Feb 18, 2005)

alexnds said:


> Transmission flush/fill is just maintenence item and not tied to your situation. The replacement of fluids, including radiator fluid, is probably simply a good idea, but it's not tied to your specific situation. Like I mentioned previously, a good idea is to change these fluids and also water pump and timing belt, since these too would wreck major havoc if either was to break. But again, these items are not specific to your situation, just good maintenence, and good insurance.
> 
> The 97 maxima, your wife's is a 4th Gen and your car is 1993 as I recall and is a 3rd Gen. different motor: both 3 Liters, but one is a VG series, and the other is VQ series.


Timing chain.


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## Nightrain (Oct 14, 2005)

*Hey Hydrolock*



Hydrolock said:


> Timing chain.


I'm hoping my tranny isn't showing small signs of possible upcoming failure. Between 1st & 2nd, at times I get a pretty hard shift but then there's times when it's relatively smooth. Also when coming to a stop, my rpm's jump up a little when just under 1K rpm. I feel like I have to push harder on the pedal (especially at low cruising speeds) then I should to get an acceleration burst. With my wife's (same year & model) Max, her pedal is much easier to push down (not as much resistance). I bought a bottle of LUCAS for the transmission oil and put it in today. We'll see if this makes a difference. I'm also thinking that it may be incorrect valve operation somewhere. I'll be cleaning the IACV tomorrow. What about troubleshooting the EGR valve? Any thoughts (anyone)? 
:wtf:


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## [email protected] (Sep 5, 2005)

QUESTION #1
My car idles OK (even though I probably need adjustment because I'm currently at about 600-700 RPM). Should this probably be closer to 800-850 RPM? 

leave it this will improve when you get car running right

QUESTION #2
I'm thinking it may be one or a combo of the following: Throttle Position Sensor (TPS), Knock Sensor or O2 sensor(s). Am I in the ballpark?

knock code o/2 code will come up if aif/fuel ratio is in correct

QUESTION #3
Should this fix (whatever it may be) effect the extra loud acceleration engine or transmission noise that I'm hearing? It sound like a possible problem with my air-to-fuel ratio and possibly from incorrect/inconsistent signals being sent to the TCM and/or ECU.

does it sound like pinging?

this is what I'd do first take it some place you can get codes read. then if you have a knock sensor code this means you a/f is incorrect. next disconnect air flow meter, and see if it improves, this will make the ecm default into a 100% a/f reading. All Maximas that come into our shop complaining of poor accel and performance this is the first thing we look at. hope this helps


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## Hydrolock (Feb 18, 2005)

Do you have an exaust leak?


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## Nightrain (Oct 14, 2005)

Hydrolock said:


> Do you have an exaust leak?


Hydrolock,
All I know is that I had the head mechanic at the Nissan dealer look over and test drive the car and there were no bad reports. Do you have to perform specialized tests for exhaust leaks? Are there any techniques I can perform myself? Currently I do not have any codes.

Thanks.


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## alexnds (Oct 1, 2005)

*time to sell and time to keep?*



Nightrain said:


> Hydrolock,
> All I know is that I had the head mechanic at the Nissan dealer look over and test drive the car and there were no bad reports. Do you have to perform specialized tests for exhaust leaks? Are there any techniques I can perform myself? Currently I do not have any codes.
> 
> Thanks.


Sounds like you have alot of problems. Motor. Transmission. There's a point in which spending money on repairs is not worth it. My advice:sell the car.


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## Nightrain (Oct 14, 2005)

alexnds said:


> Sounds like you have alot of problems. Motor. Transmission. There's a point in which spending money on repairs is not worth it. My advice:sell the car.


Actually I don't believe the problem is that major. My car rides OK as it is, but I think there is something minor that is keeping it from running great. I'll look into any possible leaks somehow and have my timing checked. Does anyone know how much a water pumps costs including the labor?

Thanks.


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## alexnds (Oct 1, 2005)

*water pump question*



Nightrain said:


> Actually I don't believe the problem is that major. My car rides OK as it is, but I think there is something minor that is keeping it from running great. I'll look into any possible leaks somehow and have my timing checked. Does anyone know how much a water pumps costs including the labor?
> 
> Thanks.


Cost is about $120 for the pump, and with labor,it's about $450.00


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## zxt (Jun 17, 2006)

alexnds said:


> Now then, some things to check are as follows: *take a good quality Digital Voltmeter, about $40 and check the number of ohms per fuel injector.* If one of the injectors has very high ohms compared to the other ones, it may the problem of poor idle. The cleaning of the injectors via putting fuel into directly into the fuel rail, a service that typically costs $60-$100 mostly cleans the intake valves and may lodge any particles in the injector further int the injector pintle, causing the high ohm reading. If the injectors are not putting out good amount of fuel, it also explains the lack of power, poor fuel consumption, and so forth.
> 
> 
> Another thing to check is the EGR valve system. The Exhaust Gas Recirculation valve being stuck in the open or closed position is an issue. If it's stuck in the closed position, the engine will run too rich. You usually can get away not buying a new one, but simply disconnecting it, and cleaning it out with carb cleaner.


Hi...how do you use Digital Voltmeter to check the number of ohms per fuel injector? Sorry I got no idea.

My 2nd question is, does EGR and PCV the same? Or at least connected to each other? I dont think my 97 B14 with GA165DNE has EGR, but I do have PCV of course.

Thanks in advance.


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