Jump to content

- - - - -

L16 running really rough at mid rpms but stops when under load

  • Please log in to reply
23 replies to this topic

#21 racerx


    Senior Member

  • Senior Member
  • PipPipPipPipPip
  • 5,172 posts
  • Location:NorCal
  • Cars:71 Datsun 510 and 65 Mustang Fastback

Posted 03 January 2018 - 09:14 PM

Prolly cab advance a couple before it pings, so maybe 7 or 8 degrees.

#22 banzai510(hainz)


    L motor God

  • Senior Member
  • PipPipPipPipPipPipPipPipPipPip
  • 15,343 posts

Posted 04 January 2018 - 08:01 AM

goes up hill in 3rd w/o pinging then its good.


I have never ran 5 degs my self most mine are above 10deg 12

Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#23 G8KeaPoR



  • Members
  • Pip
  • 47 posts
  • Location:Virginia
  • Cars:71 510, 93 RX7, 95 993 C2, 67 bug, 16 RAM 3500

Posted 04 January 2018 - 08:33 AM

The vacuum advance is set up, there's just that nub that looks like it could be for a ground sticming off of it, and I do have a timing light, it's set at about 9 degrees advance at idle, it ran fine for about 2 weeks after I put in the new ignition but after that is when it started acting up at mid rpms under no load. Plugs are new-ish, only a few hundred miles on them and they look healthy, valve lash though, quick rundown on what that exactly is? Heard the term but hearing it again would definitely help freshen my knowledge


My two cents.  I would go back to the last thing you did as your source of problem.  In your case that sounds like ignition and as with all things electrical the disturbing of these connections usually only leads to problems.  The same can be said for vacuum lines too. 


1 cent:  Verify that you have no vacuum leaks with a gauge under.  If you do have a leak (low vacuum) then you need to find it.  Spraying starter fluid around the manifold gasket works great.  if the idle increases then there you go.  If none of the gaskets cause a surge in idle check your lines.  If you don't have a leak then pull out your multi meter set it to Ohms and check the resistance on all aspects of the ignition system.  You should be able to get acceptable resistance ranges from the manual.

If any of those are at the edge or outside the acceptable range then they need replaced.



2 cent:  That said though from your posts it sounds like you have a bunch of other issues with the engine and personally I would say take care of all of your other known issues before you start making upgrades to the engine as you're only going to end up pissing away money in the end.  It sure makes troubleshooting a lot easier (way less messy and frustrating.) when you have taken care of all your obvious problems like leaky seals etc first.

I hate when people go cheap on repairs or modifications.  If you were just going to light your money on fire using band-aid fixes you might as well have given it to me.

#24 nl320what


    Hall Monitor

  • Members
  • PipPipPip
  • 156 posts
  • Location:Sacramento
  • Cars:63 NL320 4WD..... Member since 2008

Posted 08 January 2018 - 12:31 PM

It does sound like a vacuum leak in or around the carb and intake, symptom during cruise only.


I second trying to spray around that area carefully with Carb Cleaner, I hate the exhaust being right there for risk of fire be carefull.

63 NL320 4x4= 5SPD,PDB,PTS..... 87.51% Completed as of 3/12/2018.

Mobile Mechanic Webpage: http://actfast1234.wix.com/itsmycar

I need NL320 Doors or complete L320 Doors to use, will barter value :)