# Hard Starts When Sitting for Extended Periods



## john123086 (Jan 11, 2016)

Hi All! I'm hoping to get some feedback on a persistent problem I've been having with my Nissan Altima. First the car details and then I'll explain the problem; please be patient, it's a fairly lengthy story but I think it all may be related.

Car Details
2006 Nissan Altima
2.5L
185,000 miles

Problem
About 6-7 months ago I had some issues where my car would not start again when it was hot. I read up on the issue and checked the code. Sure enough, code read 'Camshaft Position Sensor'. I changed it out and fixed the problem. No issues for the next month or two.
A few months later, I started having issues where the car would not start when cold. If I adjusted the gas pedal while cranking, I could eventually find the sweet spot where it would crank. I read some suggestions which basically said that it could be the camshaft or crankshaft position sensors. It finally got so bad where the car would not start anymore. Unfortunately, the battery was bad and finally died while the car was sitting, so I lost all the codes and didn't know what the problem was. Finally, I had it towed to the shop.
The auto repair shop did a diagnostic and came back to tell me the camshaft and crankshaft position sensors were bad, confirming my initial concern. I told them that I already replaced the camshaft position sensor, and they told me there were two on the car (or misunderstanding and they said two sensors total. Either way they replaced both sensors). So they replace the sensors and the car starts fine. I pick it up and drove it to work. A little way into the drive the car started running really rough. I called NAPA and they told me the sensors had to relearn or something like that but I brought it back to them anyways. 
They told me nothing was wrong but I probably needed new spark plugs ($184 - nope!) and a fuel system cleaner. So I quickly bid them farewell and changed the plugs myself. Car seemed to run the same, by this time the code read 'Multiple Misfires' even after resetting the computer.
That brings us to current day: I'm still having trouble with starting the car. The longer it sits, the harder it is to get it to start, to the point where it almost wont start at all (>2 days). If I adjust the gas pedal from 1/3 down to full open a few times, I can occasionally find the right spot to get it to start, but sometimes I have to jump it while trying because it takes so long. I know it's getting fuel; I could not confirm the spark by putting a tester on the coil packs (may not be checking them right), and I was able to confirm that all coil packs have an impedance of around 1 ohm (think that's right). Once the car is hot, it starts right up and runs pretty smooth. I'm out of ideas.

Parts replaced:
2x - Camshaft Position Sensor (~3-4 months ago)
Crankshaft Position Sensor (~3-4 months ago)
Sparkplugs

Those more experienced on here may say I could have told you the problem with the last paragraph, but just wanted to be thorough. Please Help!


----------



## john123086 (Jan 11, 2016)

*BUMP*

Still looking for an answer on this one. Now it is occasionally having trouble starting even when it is hot. Same solution, just adjusting the gas pedal until I hit the right spot and it will start up. I'm going to Autozone today to get the Check Engine Light tested. I'll update when I have more information.


----------



## bozz911 (Jan 18, 2016)

I am having the same problem with my 2004 Altima 2.5. The colder the weather it doesn't want to start. It will turn over fine and hit but wont stay running. When I can get it started it runs fine after. I have changed the cam sensor and the crank sensor. Put on a new battery. Once when it did this I tried opening the butterfly on the throttle body and spraying ether in but still would not start. it would hit but not start and stay running. I am going to put on a new coolant sensor see if that fixes it. I will let the forum know. I searched this forum and there is no definitive answer. PLEASE HELP.


----------



## vince_ka24e (Aug 23, 2015)

might be a hit out of the ball park but have you thought about a fuel pressure regulator? it may not be getting enough pressure to start hence having to push the gas pedal to start it and maybe it sitting is well i can't really explain that but it might be worth a try it might explain the rough idling too.


----------



## vince_ka24e (Aug 23, 2015)

wait with the miss firing and the rough idling and hard starting it could also be a bad 02 sensor it would be the upflow not the down flow sensor because the down flow only tells the ecu that the cat is working so i think it could be worth a shot too.


----------



## rogoman (Dec 16, 2004)

john123086 said:


> Still looking for an answer on this one. Now it is occasionally having trouble starting even when it is hot. Same solution, just adjusting the gas pedal until I hit the right spot and it will start up. I'm going to Autozone today to get the Check Engine Light tested. I'll update when I have more information.


The crank/cam sensors don't relearn, either they are good or bad. When you replaced the crank/cam sensors, were they OEM from Nissan? If not, then that could be your problem; aftermarket sensors have a bad reputation for failing early or causing problems that you're experiencing. Many times they are DOA. Nissan sells the crank/cam sensors as a kit, making it cheaper then buying them individually.

You might also want to check the fuel pressure to eliminate that possibility. Tee-in a temporary fuel pressure gauge at the output side of the fuel filter. The reading at idle should be approximately 51 psi.
If the engine is unable to start, turn the ignition key to the run position but DO NOT TRY TO START THE ENGINE. The fuel pressure reading should be somewhere around 51 psi which would be a static reading.


----------

