# '02 altima won't start when engine is warm



## mcmillan (Sep 14, 2015)

1st off I'd like to apologize if this isn't the right place to post this. I bought a used 02 altima with 100k miles, well the guy sold me a lemon and I'm trying to fix what I can. I have had to replace a head gasket (running hot), motor mount and timing chain (found during head gasket replacement). Well now the car will only crank when the engine is cool, it will just turn over and never fire up until the engine is cool a couple hours later. Whenever the engine is cool it'll fire up and runs good, I'll cut the engine off and it'll start right back up but if I try 10 minutes later it will not start. From what I've read on here I'm thinking maybe leaky injectors or possibly crank/cam sensors, please help....


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## smj999smj (Jan 1, 2006)

Cam position and crank position sensors are weak points on these engines and the aftermarket sensors have had poor quality issues. It wouldn't hurt to get a fuel pressure gauge and check fuel pressure leakdown, but, if it were mine, I would have better peace of mind replacing the sensors with new, genuine Nissan parts. You can get both of them in a "sensor kit," developed for the recall pertaining to these sensors, over the counter and it'll be cheaper than buying them individually. Be mindful that the sensors look the same, but the crank sensor will have a white paint dot on it. By the way, you posted in the correct place!


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## SPEEDO (Jun 9, 2003)

I had the same issue, replaced both cam/crank sensors and its been good ever since, as stated above..buy the(oem) kit its much cheaper


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## mcmillan (Sep 14, 2015)

I bought both, genuine oem, just waiting for them to get to my home, priced them at a local nissan dealer and they wanted about $120 apiece. Quick amazon search I got 2 sets for about 80 bucks, I'll let you guys know how it turns out, I really appreciate the help and advice.


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## SPEEDO (Jun 9, 2003)

at $120 ea, that is not the kit, its runs about $50


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## ignition4less (Sep 23, 2015)

I had the crankshaft position sensor replaced on my 2005 Altima at around 60k miles. Bought the sensor from a local auto parts store for about $40 and then paid Pep Boys another $100 to install it for me (the crankshaft sensor is much harder to get to).

The camshaft sensor I had to replace this past winter (which sucked... it was like 10 degrees outside and my car wouldn't start). For that one, picked it up at NAPA for about the same $40 and easily installed it myself in about 30 minutes, most of which was spent trying to fit my hand in to remove the old one. That one is really easy to replace.


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## mcmillan (Sep 14, 2015)

So, I replaced both sensors, wasn't really that bad as what I expected. Bad news is the car is still doing the same thing. Anybody have any ideas, I'm really hating this car, please help.


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## mcmillan (Sep 14, 2015)

Oh and they were genuine nissan parts.


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## rogoman (Dec 16, 2004)

mcmillan said:


> 1st off I'd like to apologize if this isn't the right place to post this. I bought a used 02 altima with 100k miles, well the guy sold me a lemon and I'm trying to fix what I can. I have had to replace a head gasket (running hot), motor mount and timing chain (found during head gasket replacement). Well now the car will only crank when the engine is cool, it will just turn over and never fire up until the engine is cool a couple hours later. Whenever the engine is cool it'll fire up and runs good, I'll cut the engine off and it'll start right back up but if I try 10 minutes later it will not start. From what I've read on here I'm thinking maybe leaky injectors or possibly crank/cam sensors, please help....


Since you replaced both the CMP and the CKP sensors, at this point you'll have to determine if the problem is failed ignition or failed fuel delivery.

First thing to do is perform an ECU code readout with a scan code tool; most auto parts stores can do this for free. Post the actual code here on the forum. The code starts with the letter P. If any codes are set, they can help you to pin-point the source of the problem.

After the engine is fully warmed up, so at this point, test for ignition by pulling a coil pack and grounding the base of a spark plug that's plugged into the coil pack. Now look for the presence of spark when attempting to start the engine. To test for fuel delivery, use a "noid" light probe on the signal wire at the harness connector of any fuel injector. You can also test fuel pressure by teeing in a fuel pressure gauge at the output side of the fuel filter; the pressure should be around 50 psi.


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## mcmillan (Sep 14, 2015)

Is it possible to have a code without the engine light being on. My check engine light isn't on so I'm assuming it won't throw a code, is this right?


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## mcmillan (Sep 14, 2015)

Update, not sure if this helps, I've been messing around with a haynes manual and it said my issue could be a coolant temp sensor I figured that was easy enough to check. Checked it cold and got about 290k ohms, checked it hot and got about 190 ohms not sure if this is an issue because I'm not sure the temp in my car (gauge reads normal). Also, the car will crank immediately after I cut it off but after about the 3rd or 4th time it will not crank. Sorry to ramble on guys and I really appreciate everyone's input. I'll work on the fuel pressure and ignition spark tomorrow.


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## mcmillan (Sep 14, 2015)

So I have some more info and would like to know what you guys think. Ok, so I checked spark and cylinder 1's coil had very weak spark, also did fuel pressure leak test and it was good. Finally was able to get a code reader, P0725 which haynes says engine speed signal or circuit fault, no clue what that means and also p0335 which is crankshaft position sensor or circuit fault. I just replaced that sensor so I'm not sure why it's throwing a code. Any help I would be grateful for, thanks.


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## jdg (Aug 27, 2009)

mcmillan said:


> Is it possible to have a code without the engine light being on. My check engine light isn't on so I'm assuming it won't throw a code, is this right?


Yes, you can have a code without a Check Engine Light.
It's called a "Pending Code". Usually, but not always, means the engine hasn't been run long enough to set the code or all of the conditions to set the code haven't been met. A lot of cheap code readers won't give you that info.


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## mcmillan (Sep 14, 2015)

So i pulled 2 codes from the car and they have to deal with the crankshaft position sensor. I got the car to crank normally and i changed both sensors, I have a new problem now, when i push the gas the rpm doesn't change so the hardly moves. I was able to pat the gas and that helps but it's like the throttle isn't connected or something. And it didn't do this until I changed those sensors, and the check engine late has been disabled somehow that's why I never seen a light. So to be clear the car cranks normally, while I was checking fuel pressure and spark I also changed the sensor, at which time the throttle problem began so I put the code reader on and it mentioned the sensor. Is it possible I received a new, bad sensor? And what should it look like because the new one looked different than the ones a removed. I also replaced the camshaft sensor. HELP!!!!


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