wlcooper

My 95 Maxima misses badly when you stomp on it. It seems to run fine
otherwise. The check engine light is on and is giving a PO340 code. The car
has been in a Nissan repair shop to try to correct the problem. They
replaced the cam position sensor. Inspected wiring from sensor to pcm. Ran
new wire from sensor to pcm. Changed pcm (installed used one temporarily)
Nothing has helped the problem.

Here is the kicker! The car was in a different shop, (not a Nissan shop)
about 5 weeks ago to have the water pump replaced. My wife drives the car
most of the time and she didn't notice a problem at first. She cannot
positively remember if it ever missed before the water pump replacement.

I made the Nissan service manager aware of the water pump replacement and
my suspicion of a possible connection to the miss when I first took it in.
At this point they say It could be the timing or a chip in a tooth or gear
and that the next step would to pull the engine to check as they cannot
eliminate the timing issue completely with the engine in the car.

Any suggestion or comments appreciated.

Thanks

 

Matt93SE

the service manager is feeding you a load of crap... the engine doesn't need to be pulled to look at the timing chains on it, but I will admit it's much easier to do.

it's possible they got the timing chain 1 tooth off, but you would notice the engine laggy all the time. I had a timing belt off a tooth once on an old honda, and that thing ran horribly...

There are several cam position sensors on this car. there's one on the front timing cover near the crank pulley, and there's another one on the front or back of the engine that reads the teeth on the flywheel.

the P0340 code refers to the one on the timing cover specifically... I have a feeling the original shop damaged it, didn't hook it up, or didn't do something properly.

I would call them back and let them know you're having this problem and let the mechanic that replaced the water pump check things over.

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wlcooper

Thanks, for the reply Matt,
The Nissan shop did replace the sensor and ran new wire to it temporarily but it still gave the po340 code.
I'm leaning toward the 1 tooth off theory. I had a 93 626 that that happened to while replaceing the timing belt. The same shop made that mistake but they corrected it for free. The Maxima does run good except when you nail it though.
I am considering going to the original shop, but given the history am undecided.

Matt93SE

I would give them a chance to fix their mistake first, before spending $$$ elsewhere.
it wasn't having that problem when you took it to them to begin with, so they need to fix it.
you paid them to replace a water pump and they broke other stuff. that's their responsiblity.

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Redline

You can also have a mechanic check the timing with a timing light to eliminate some of the guess work.

 

wlcooper

I was told by the Nissan shop that they could not tell with a timing light if one cam drive sprocket is off 1 notch. There are diagrams showing dark and light colored chain links on the drive chain and how to align them with marks on the crank and cam drive sprockets. I am told it is not an easy task due to the lack of room and visibility. The car is back in the shop that changed the water pump. He is going to pull the cover and try to determine if that is what has happened. I'll post the results when I find out.
Thanks, WC

wlcooper

Well, I took the car back to the shop that replaced the water pump. He agreed to check to see if they got a cam sprocket off one notch and that turned out to be the problem. He corrected that and the car runs great now.
Apologized and no charge!! Thanks