95 Nissan Maxima occasional loss of power :-(

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

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

1=2E The sensor fools the ECU into thinking the engine is still cold so it keeps running rich. 2=2E 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

. The engines in

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:)

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.

CD

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.

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

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.

Good to know. Thanks

CD

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

Could you tell which one is which?

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

Thank you very much.

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 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.

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