Bad Crankshaft Position Sensor?? - My symptoms don't seem to jive IMO

[TheNinja]

Seems a bit odd but that's the code they tell me they were getting. I don't really trust it as these are my symptoms

1. When trying to start the 1st time quite often it just turns over and over and over for 2-3 seconds. I quit trying, turn the key back and foward to start again and it almost ALWAYS works.

2. Just lately I'm driving along the freeway and start slowing down the car just flat out dies. I can pop it into neutral and try to restart it. Sometimes I have to try 3-4 times before it'sll start but it always seems to restart.

3. I've had OK luck (but might just be coincidence) running my automatic in a "manual" mode to keep my RPMs high. It seems it doesn't die at higher RPMs.

I just had the guys replace it since they were going to charge me $120 for "diagnoses" or would waive the fee if I paid $129 to just replace it. I got a bad feeling I'm going to be stuck in traffic on my ride home tonight.

 

[Zivic]

In my humble opinion it sounds like it could be a crank sensor.

why don't you think it is?

 

[TheNinja]

In my humble opinion it sounds like it could be a crank sensor.

why don't you think it is?

Cool. Well I hope it is/was. I was just reading that it should only really affect starting and shouldn't really "kill" the car while it's running. But that's just me reading a few Internet forums. I have 0 real world experience with it.

Thanks!

 

[phucheneh]

Cool. Well I hope it is/was. I was just reading that it should only really affect starting and shouldn't really "kill" the car while it's running. But that's just me reading a few Internet forums. I have 0 real world experience with it.

Thanks!

That's the cam sensor.

cam sensor = CMP = engine position

crank sensor = CKP = engine speed

The names can be misnomers. I've seen setups with both sensors side by side monitoring the engine's flywheel.

The CKP is needed for normal running because it gives a much more detailed signal that then CMP, albeit without an indicator for the position of the engine (which lets the ECM know when to fire injectors and plugs). In addition to simply measuring RPM, the CKP is also responsible for detecting relatively minute variations in the acceleration of the crankshaft as it rotates (misfires).

 

[96Firebird]

I had a crankshaft position sensor go bad on an old Buick winter car I had. Had similar symptoms, died a few times at stop lights, would misfire like crazy when the car shifted into OD and the RPMs went low. Don't remember having any problems starting though...

 

[bamx2]

TheNinja - Just curious as the vehicle make. model and engine .

 

[SyndromeOCZ]

Sounds like a crank position sensor to me. Had a 96 grand caravan that did this. And the sensor fixed it.

 

[TheNinja]

TheNinja - Just curious as the vehicle make. model and engine .

Sorry to leave ya hanging. It's a 2006 Nissan Altima that apparently had a recall on it to reprogram the ECM or something. So that's done, but today I got the stupid service engine light again......frustrating. Maybe I need the cam shaft position changed as well.

 

[DaTT]

A bad crank sensor will kill the engine from time to time. Also, will make it not start from time to time. The actual reason it can start is the engine only stops at 1 or 2 positions. If the crank sensor is bad, it "guesses" where the engine is and fire injectors/plugs with its guess. Laws of average say it has to get it right eventually and therefore your car will start.

As for it killing the engine, I'm not exactly sure why, but my assumption would be that the sensor craps out for a second then kicks back in. At this point it has to guess again where the engine is and guesses wrong and therefore the engine dies.

 

[TheNinja]

A bad crank sensor will kill the engine from time to time. Also, will make it not start from time to time. The actual reason it can start is the engine only stops at 1 or 2 positions. If the crank sensor is bad, it "guesses" where the engine is and fire injectors/plugs with its guess. Laws of average say it has to get it right eventually and therefore your car will start.

As for it killing the engine, I'm not exactly sure why, but my assumption would be that the sensor craps out for a second then kicks back in. At this point it has to guess again where the engine is and guesses wrong and therefore the engine dies.

Recall on my car. Now don't you think part of the recall should be to fix/replace the CPS not just reprogram the ECM to ignore it?


Recall Date: 2007-11-15
Summary:
ON CERTAIN PASSENGER VEHICLES EQUIPPED WITH A 2.5L ENGINE, THE CRANKSHAFT POSITION SENSOR CAN OVERHEAT CAUSING A BRIEF INTERRUPTION IN THE SIGNAL OUTPUT FROM THE SENSOR.
Consequences:
IF THE INTERRUPTION IN THE SIGNAL FROM THE CRANKSHAFT POSITION SENSOR IS SO BRIEF THAT THE ELECTRONIC CONTROL MODULE (ECM) LOGIC DOES NOT HAVE TIME TO DIAGNOSE THE CONDITION, THE ENGINE MAY STOP RUNNING WITHOUT WARNING WHILE THE VEHICLE IS DRIVEN AT A LOW SPEED INCREASING THE RISK OF A CRASH.
Remedy:
DEALERS WILL REPROGRAM THE ECM FREE OF CHARGE. CERTAIN MY 2006 ALTIMAS WHICH HAVE BEEN PREVIOUSLY REMEDIED UNDER RECALL CAMPAIGN 06V223 (NISSAN R0606) ARE NOT INCLUDED IN THIS RECALL SINCE THE REPROGRAMMING FOR 06V223 ALSO INCLUDED THIS REPROGRAMMING. THE RECALL BEGAN ON DECEMBER 31, 2007. OWNERS MAY CONTACT NISSAN AT 1-800-647-7261.
Component Affected:
ENGINE AND ENGINE COOLING
Notes:
Nissan North America, Inc.