Just changed to new Spal electric fans instead of the OEM setup.
2005 350Z started throwing PO300 code - random misfire.
Everything seems fine while driving.

Any chance the PO300 code is being caused by the new fan setup?
Thanks

 

I'm currently trying to troubleshoot a P0300 code myself. By reading the service manual I don't see how the electric fans could be throwing the code. I'm not familiar with the Spal setup though. Is it a direct replacement including harnesses or do you have to splice anything?

I cleared my code by doing the following off Technosquare's site:

http://www.technosquareinc.com/350reset.htm

I still have a rough idle but it's not as bad as before and so far haven't thrown a code.

Are you experiencing a rough idle or sputter or any other symptoms associated with the P0300 code?

If there are no symptoms I would just clear it and do an idle relearn and see if it comes back.

 

I did rewire (see photo) according to this thread:
https://my350z.com/forum/engine-and-...ator-fans.html

This was only the fan circuit wiring not the main harness.
No one mentioned throwing a code.
I was wondering if the extra amp load would possibly cause the PO300 code.

Car runs fine and no problem with idle.

 

I just though of something while i was trying to diagnose my P0300 code. My rough idle tends to get worse every time i roll a window up or down. So I'm guessing I have a ground fault issue somewhere.

Have you checked for proper grounds on you wiring? If its not touching bare metal its not grounded properly.

Also to accomodate for the added current draw when the fans kick on you could wire in a relay. A basic diagram for that is available at the12volt.com

 

There are MANY things that can cause the P0300 random misfire code. One cause that may apply to your situation is low voltage. Connect a multimeter to your battery and observe voltage under load, such as when the fans kick on and when rolling windows up/down. If the voltage is dropping below about 14 volts with the motor running, this may be your problem.

 

How would you go about correcting this problem? I have a brand new battery in my car and the RPMs drop at idle any time I roll the windows up/down.

 

have you fix this problem?