95 Nissan Maxima occasional loss of power :-(

My 95 Maxima appears to work flawlessly, well almost...

Over the last six month, the engine stopped 4 times while I was
waiting at a stop light. Every time, I was able to restart it within
10 to 20 seconds... so I did not annoy other motorists.

Recently, I felt a very short loss of power while I was driving at
about 60 km / h.

I read the error codes:
47 - Crankshaft Position Sensor (reference)
13 - Engine Coolant Temperature Sensor

I am prone to discount the Temperature Sensor because the engine
starts easily, and runs smoothy at any temperature.

Is it not the Crankshaft Position Sensor that sends a pulse to the
Engine Control Unit so that the latter ®knows¯ when to activate the
injection and fire the spark plugs. I guess this sensor is nothing
but a winding that generates a pulse when a permanent magnet linked to
the crankshaft passes in front of it. If this is so, how can it
fail? Could it be a bad contact between this sensor and the Engine
Control Unit?

It is an intermittent problem that I cannot reproduce at will. What
does your experience tell you?

Thank you very much for your help.
--
Jean Castonguay
�lectrocommande Pascal

Well, my experience tells me that it is exactly what your computer is
telling you. It is the crankshaft position sensor (CPS) going bad or
your timing is really really out, but if it were the latter you would
most likely have bent your valves by now.

Unfortunately, my experience is with a '93SE and not a '95 so there
isn't a whole lot that I can tell you about that part. The engines in
the '93 and '95 are completely different ... I think; it's hard to
remember that far back. Now, if they happen to share a similar CPS then
it is not a copper winding magnetic sort of affair. In the '93 it was
the ever popular photo light sensor. Basically, the unit ran off the
camshaft in the same position as a distributor cap would be found and
sort of looked like one. It was on the passenger side head in the front
of my car with a bundle of wires coming out of it. Inside the cap was a
metal card that would spin inside a reader element as the engine
turned. In my car it went bad because it had been dropped and dented at
the factory and rubbed against the light reader until it ate the reader
unit.

The symptoms were rough idle, and notchy acceleration when the car was
floored. As it got worse it would cough out both at idle and on the
highway. It got so bad in my car before I replaced the unit that the
car would only run on the highway for 50 seconds or so before the
engine needed to be restarted.

It was bloody easy to replace. Simply unplugged it, and removed the
bolt that held it to the engine then remove and replace. The notch in
the camshaft that it fit into was unideirectional [eg it would only
accept the key one way and not the other automatically locating the
card] then I put a timing light on it and timed the engine. Easy as
pie. However that was for a '93SE, and I make absolutely no claims that
the same thing would be true for a '95, but the symptoms are the same.
All the best - H

Jean Castonguay wrote:

My 95 Maxima appears to work flawlessly, well almost...

Over the last six month, the engine stopped 4 times while I was
waiting at a stop light. Every time, I was able to restart it within
10 to 20 seconds... so I did not annoy other motorists.

Recently, I felt a very short loss of power while I was driving at
about 60 km / h.

I read the error codes:
47 - Crankshaft Position Sensor (reference)
13 - Engine Coolant Temperature Sensor

I am prone to discount the Temperature Sensor because the engine
starts easily, and runs smoothy at any temperature.

Is it not the Crankshaft Position Sensor that sends a pulse to the
Engine Control Unit so that the latter ®knows¯ when to activate the
injection and fire the spark plugs. I guess this sensor is nothing
but a winding that generates a pulse when a permanent magnet linked to
the crankshaft passes in front of it. If this is so, how can it
fail? Could it be a bad contact between this sensor and the Engine
Control Unit?

It is an intermittent problem that I cannot reproduce at will. What
does your experience tell you?

Thank you very much for your help.
--
Jean Castonguay
�lectrocommande Pascal

Replace the temp sensor. It's a cheap part and easy diy job.When the
temp sensor goes bad;

1. The sensor fools the ECU into thinking the engine is still cold so
it keeps running rich.
2. Because you keep running rich you lose power and gas mileage goes
down.

You may be running so rich that the car may be stalling out.

After you've replaced the coolant sensor, it will take about 3 tankfuls
for the ECU to relearn its fuel maps and adjust itself accordingly. I
would wait untill then and see if the crankshaft sensor warning goes
away as well. If not, replace/fix that as well.

One last note, there are usually 2 temp sensors, 1 for the gage on your
instrument panel, and the engine one. Make sure to replace the engine
one of course. It is usually located somewhere along the top radiator
hose, where it connects to the engine.

CD

Hazey wrote:

Well, my experience tells me that it is exactly what your computer is
telling you. It is the crankshaft position sensor (CPS) going bad or
your timing is really really out, but if it were the latter you would
most likely have bent your valves by now.

Unfortunately, my experience is with a '93SE and not a '95 so there
isn't a whole lot that I can tell you about that part
.. The engines in
the '93 and '95 are completely different ... I think;
Oh yeah they're different. Inside the 95 Maxima was the birth of the now

legendary VQ motor, the VQ30DE. This evolved in to the VQ30DE-K in the
2000 and 2001 Maxima, and the VQ35DE in the 2002+ Maxima. The VQ35DE
engine was then put into so many nissan vehicles. Murano, Altima
3.5,350Z, G35, M35, Pathfinder, Quest. Finally there's the recently
introduced VQ35HR engine in the 2007 G35. The VQ motor just ROCKS. It's
won the Wards auto award for great motors so many times it aint even
funny. Long live the VQ!

Sorry, got carried away

it's hard to
remember that far back. Now, if they happen to share a similar CPS then
it is not a copper winding magnetic sort of affair. In the '93 it was
the ever popular photo light sensor. Basically, the unit ran off the
camshaft in the same position as a distributor cap would be found and
sort of looked like one. It was on the passenger side head in the front
of my car with a bundle of wires coming out of it. Inside the cap was a
metal card that would spin inside a reader element as the engine
turned. In my car it went bad because it had been dropped and dented at
the factory and rubbed against the light reader until it ate the reader
unit.

The symptoms were rough idle, and notchy acceleration when the car was
floored. As it got worse it would cough out both at idle and on the
highway. It got so bad in my car before I replaced the unit that the
car would only run on the highway for 50 seconds or so before the
engine needed to be restarted.
On the VQ motor, the crank position sensor is on the crank The sensor

sits on the tranny and reads the plate mounted on the flywheel. Quite an
elegant setup. Usually cleaning the sensor involves getting rid of metal
particles surrounding it. Easily to replace it as well, if needed.

It was bloody easy to replace. Simply unplugged it, and removed the
bolt that held it to the engine then remove and replace. The notch in
the camshaft that it fit into was unideirectional [eg it would only
accept the key one way and not the other automatically locating the
card] then I put a timing light on it and timed the engine. Easy as
pie. However that was for a '93SE, and I make absolutely no claims that
the same thing would be true for a '95, but the symptoms are the same.
All the best - H

CD

Codifus wrote:

Oh yeah they're different. Inside the 95 Maxima was the birth of the now
legendary VQ motor, the VQ30DE. This evolved in to the VQ30DE-K in the
2000 and 2001 Maxima, and the VQ35DE in the 2002+ Maxima. The VQ35DE
engine was then put into so many nissan vehicles. Murano, Altima
3.5,350Z, G35, M35, Pathfinder, Quest. Finally there's the recently
introduced VQ35HR engine in the 2007 G35. The VQ motor just ROCKS. It's
won the Wards auto award for great motors so many times it aint even
funny. Long live the VQ!

Sorry, got carried away

Actually the VQ35 series has been not lived up to the expectations and
precedence set by the VQ30DE and VQ30DE-K. Oil burning and engine
replacements are a problem on the VQ35DE series. We'll see if Nissan
has managed to correct the problems with the HR version.

On the VQ motor, the crank position sensor is on the crank The sensor
sits on the tranny and reads the plate mounted on the flywheel. Quite an
elegant setup. Usually cleaning the sensor involves getting rid of metal
particles surrounding it. Easily to replace it as well, if needed.

Actually on the VQ there are 2 crank position sensors. One on the
transmission bell housing as you suggest and another right under the
crank pulley on the passenger side of the engine bay. One is the
position sensor and the other is the reference sensor.

Cheers,
Nirav

njmodi wrote:

Codifus wrote:


Oh yeah they're different. Inside the 95 Maxima was the birth of the now
legendary VQ motor, the VQ30DE. This evolved in to the VQ30DE-K in the
2000 and 2001 Maxima, and the VQ35DE in the 2002+ Maxima. The VQ35DE
engine was then put into so many nissan vehicles. Murano, Altima
3.5,350Z, G35, M35, Pathfinder, Quest. Finally there's the recently
introduced VQ35HR engine in the 2007 G35. The VQ motor just ROCKS. It's
won the Wards auto award for great motors so many times it aint even
funny. Long live the VQ!

Sorry, got carried away


Actually the VQ35 series has been not lived up to the expectations and
precedence set by the VQ30DE and VQ30DE-K. Oil burning and engine
replacements are a problem on the VQ35DE series. We'll see if Nissan
has managed to correct the problems with the HR version.

You know, I was going to mention but I stopped myself, my favorite VQ

would be the VQ30DE-K in the 2000-2001 Maxima because I've also heard
alot of talk about how the 35s are not as refined as the 30s. The
VQ30DE-K addresses a few weaknesses in the VQ30DE, mainly the lack of a
variable intake manifold. My ultimate Maxima would be a VQ30DE-K motor
in a 99 Red SE 5-speed body. Yeah baby! I see a lot of guys on
maxima.org putting 3.5s inside 95-99 bodies with not that much
modification, so it is do-able.

On the VQ motor, the crank position sensor is on the crank The sensor
sits on the tranny and reads the plate mounted on the flywheel. Quite an
elegant setup. Usually cleaning the sensor involves getting rid of metal
particles surrounding it. Easily to replace it as well, if needed.


Actually on the VQ there are 2 crank position sensors. One on the
transmission bell housing as you suggest and another right under the
crank pulley on the passenger side of the engine bay. One is the
position sensor and the other is the reference sensor.

Good to know. Thanks

Cheers,
Nirav

CD

Codifus wrote:

You know, I was going to mention but I stopped myself, my favorite VQ
would be the VQ30DE-K in the 2000-2001 Maxima because I've also heard
alot of talk about how the 35s are not as refined as the 30s. The
VQ30DE-K addresses a few weaknesses in the VQ30DE, mainly the lack of a
variable intake manifold. My ultimate Maxima would be a VQ30DE-K motor
in a 99 Red SE 5-speed body. Yeah baby! I see a lot of guys on
maxima.org putting 3.5s inside 95-99 bodies with not that much
modification, so it is do-able.

Adding the 00-01 VI to the 95-99 3.0 is actually fairly straightforward
and a lot of guys have that modification. I know of two local Maxima
owners (in the Chicago area) who have swapped in a 3.5L into their 4th
Gens. That is much more involved and far more expensive.

I think my next Max will be an 00 or 01 SE... here in the rust belt
even a few year old car is painfully difficult to work on because of
the corrosion - so I don't think I'd pick up another 4th Gen - unless
of course I got one from a dry part of the country where cars are less
prone to corrosion.

Cheers,
Nirav

On Thu, 26 Oct 2006 15:36:46 UTC, "njmodi" <njmodi2 (AT) yahoo (DOT) com> wrote:

Actually on the VQ there are 2 crank position sensors. One on the
transmission bell housing as you suggest and another right under the
crank pulley on the passenger side of the engine bay. One is the
position sensor and the other is the reference sensor.

Could you tell which one is which?

Moreover, could you elaborate on the function of each of them?

Thank you very much.
--
Jean Castonguay
�lectrocommande Pascal

njmodi wrote:

Codifus wrote:


You know, I was going to mention but I stopped myself, my favorite VQ
would be the VQ30DE-K in the 2000-2001 Maxima because I've also heard
alot of talk about how the 35s are not as refined as the 30s. The
VQ30DE-K addresses a few weaknesses in the VQ30DE, mainly the lack of a
variable intake manifold. My ultimate Maxima would be a VQ30DE-K motor
in a 99 Red SE 5-speed body. Yeah baby! I see a lot of guys on
maxima.org putting 3.5s inside 95-99 bodies with not that much
modification, so it is do-able.



Adding the 00-01 VI to the 95-99 3.0 is actually fairly straightforward
and a lot of guys have that modification. I know of two local Maxima
owners (in the Chicago area) who have swapped in a 3.5L into their 4th
Gens. That is much more involved and far more expensive.

Doh! Of course! adding the variable intake from an 00 or 01 Maxima is a
wee bit easier than transplanting the whole engine! Sometimes I just
make things too difficult

I think my next Max will be an 00 or 01 SE... here in the rust belt
even a few year old car is painfully difficult to work on because of
the corrosion - so I don't think I'd pick up another 4th Gen - unless
of course I got one from a dry part of the country where cars are less
prone to corrosion.
I can imagine. I'm in the NYC area and for some reason, changing the

fuel filter in my car is a B*&^%CH, and its just 2 hoses. Add the
corrosion factor and it must become way more difficult.

Cheers,
Nirav

CD

My 90 GXE was doing that a while back. Turns out, it was the Engine Cont
relay. I also thought the crank position sensor was bad although I never
check for codes on the ECU.

I don't know if your 95 has an Engine Cont relay, but the 3rd gens have
them.

The test I used for the relay: take off the relay box cover and tap the
Engine Cont relay while the engine is idling. If the motor skips a beat or
just flat out quits, there is your problem.

Chris
90 & 94 GXE's
06 SE