2002 Nissan Sentra power won't turn off

Part 1 -How to Test the Ignition COP Coils (Nissan 1.8L)

troubleshootmyvehicle.com > Nissan > 1.8L

Feb 12, 2013 - What Tools Do I Need to Test the COP Coils. ... coils (most commonly known as the COP ignition coils), on your 1.8L Nissan Sentra is pretty easy. ... When one COP ignition coil fails... that cylinder goes 'dead' due to a lack of Spark and is said to be misfiring. .... 2000, 2001, 2002, 2003, 2004, 2005, 2006 ...

Part 2 -How to Troubleshoot a No Start (Nissan 1.8L)

troubleshootmyvehicle.com > Nissan > 1.8L

Jan 17, 2013 - Checking for Spark With a Spark Tester. ... Your 1.8L Nissan will either have a distributor-type ignition system or the more modern COP ... A BAD fuel pumpwill cause your 1.8L Nissan Sentra to Crank but Not Start... since the ... Still, the other method that I've used to test for a lack of fuel... is spraying starting ...

2002 Sentra 1.8, no spark, code 0505... - Nissan Sentra Forum ...

www.b15sentra.net > ... > Technical Discussion

Nov 4, 2008 - 15 posts - ‎3 authors
I have never had a problem with the car before (02 Sentra 1.8/auto), so I had no need to post ... Originally Posted by Black B15 ... Join Date: Jun 2005 ... Can you see if the coilpacks are getting spark & work back from there? how many spark plugs do i need ? - Nissan Sentra ...
7 posts
Mar 19, 2010
Spark Plug Replacement - 2002 GXE 1.8L - Nissan ...
15 posts
Oct 12, 2009
1.8s starting problems - Nissan Sentra Forum - B15 ...
15 posts
Jun 23, 2009
No start on 1.8L 02 GXE - Nissan Sentra Forum - B15 ...
15 posts
Apr 11, 2009
More results from www.b15sentra.net

Big difference between valve cover gasket and head gasket. To replace head gasket, you must dissamble top end of engine and send the head out to be resurfaced and then install new head gasket. If it is a leaking valve cover it is much easier. Simply dissasemble and then clean valve cover and top of head from all debris and remove all old gasket material. Tighten back down in sequence and do not over tighten. these small bolts can be overtightened easily so go in sequence just like when you tighten lug nuts by skipping one as you go around. 10mm bolts require about 10 pounds or less torque.

it could be your head gasket or a cracked cylinder head.

could be a bad thermostat. or a clog in coolant system.

the catalytic coverter might be cloged check o2 readings

At least a new head gasket, not sure what damage he saw, but if the block is cracked when he looked at the piston walls its possible.

Start the car up when it is cold and rev the engine up for 30 seconds,loosen up the radiator cap and see if there is pressure there..If there is you probably have a bad head gasket...Caution do not open cap if engine is warm...

Here is a diagram of the 1.8 exhaust from the service manual, you can obtain a full factory service manual for relatively cheap from Promanuals.net here.

buy a used unit from the junk yard.

Check for vaccume leaks and also you PCV valve. check the hose too. Visually inspect every vaccume hose you can find. Sounds like a leak .