Jump to content
SAU Community

Splitfire/plugs Ignition Random Results

MikeR34GTT

By MikeR34GTT,
in General Maintenance

 Share

Recommended Posts

MikeR34GTT Collaborator

MikeR34GTT

Posted
Posted

Was hoping to find useful info or jack someone else's related thread before I made this but no luck so here goes:

Was having terrible misfires awhile back on my GTT, had it diagnosed and replaced the coils with Splitfires and also replaced the plugs and the misfire problem has gone. Which is awesome.

My question is, I barely had an instant ignition when I turned the car over, 1-2/3 chugs before it ticked over before I had splits. When I first popped the splits in, BAM, first go, which was an awesome feeling.

Now I'm back to the 2 to 3 chugs, rarely ever getting that unicorn-like first turn instant ignition feeling. Would it be worth gapping the plugs back down (0.8 before problem, 1.1 once the splits went in, using Copper NGKBCPxxES-11 or whatever) to 0.8 again or could this be attributed to something else?

MikeR34GTT Collaborator

MikeR34GTT

Posted
  • Author
Posted

Gapping the plugs down is free and worth a shot.

When did you change the battery last?

Back to 0.8 you reckon or? Just a lot of work for me to get to those plugs (I'm novice), great practice though!

Didn't even think of the battery.. can an old battery really have that kind of impact? I just figured it'd be drawing more current from the alternator and not affect the actual spark

GH05T Grand Master

GH05T

Posted
Posted

Back to 0.8 you reckon or? Just a lot of work for me to get to those plugs (I'm novice), great practice though!

Didn't even think of the battery.. can an old battery really have that kind of impact? I just figured it'd be drawing more current from the alternator and not affect the actual spark

alternator replenishes the battery but its the battery you draw on when starting.

V28VX37 Veteran

V28VX37

Posted
Posted

Yep defo check the battery mate, a new one helped with my starts.

Another thing to check is any dodgy leads off the battery, I had a really bad bodge job connector off my plus terminal that kept cutting out randomly and the car stalled in traffic (it was auto back then). It took $100's and lots of gray hair to diagnose it because it was so obvious everyone overlooked it :/

Also my misfire saga writeup is here, might have a couple of other pointers: http://www.sau.com.au/forums/topic/326043-resolved-misfire-in-r34-gtt-rb25det-neo/

Edit: How's your idle with the Splitfires, 100% no hiccups? I'm thinking of potentially replacing my current YJ's with them...

hardsteppa Grand Master

hardsteppa

Posted
Posted

give it more choke on startup.

But sizzirslsy, I get that every now and then, the turn and bam start, but most of the time it's a few chugs. Unless you put brand new plugs in every week, you might be chasing shadows?

  • Like 1
89CAL Grand Master

89CAL

Posted
Posted

Has there been a change of season since its gone back to struggling to start a bit more? Could be tune related if you have an aftermarket ECU.

I'd also recommend changing the battery if its old/unknown age

MikeR34GTT Collaborator

MikeR34GTT

Posted
  • Author
Posted

Yep defo check the battery mate, a new one helped with my starts.

Another thing to check is any dodgy leads off the battery, I had a really bad bodge job connector off my plus terminal that kept cutting out randomly and the car stalled in traffic (it was auto back then). It took $100's and lots of gray hair to diagnose it because it was so obvious everyone overlooked it :/

Edit: How's your idle with the Splitfires, 100% no hiccups? I'm thinking of potentially replacing my current YJ's with them...

Yeah pretty awesome. My whole misfire saga was a nightmare but they really saved my life, so much better performance-wise.

Will gap my plugs down to 0.8 and report back. Guessing it's the battery also but process of elimination will get me there in the end.

Cheers for the pointers guys

Kinks Grand Master

Kinks

Posted
Posted

Stock fuel pump or aftermarket?

I put a Bosch 040 in my R33, f**king thing didn't have a check valve in it. So the fuel empties out of the fuel lines back into the tank when you leave it sitting overnight. It would never start properly unless I let the pump prime for 5 seconds first.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • joshuaho96
      New R32 owner soon

      By joshuaho96 · Posted

      Hard to say, just pop the rocker covers off and have a look if you think it's cammed. You probably need to replace the valve cover gasket/half moons anyways.
    • niZmO_Man
      R32 Nostalgia

      By niZmO_Man · Posted

      From my youth: GTi-R clutch change is a massive pain. The gearboxes are fragile? But the car is super cool and I want one 😢 
    • niZmO_Man
      New R32 owner soon

      By niZmO_Man · Posted

      Remember this is 1988 tech.
    • TurboTapin
      R32 GTST - 600KW+ RB28/CD009 Build

      By TurboTapin · Posted

      Driveline vibration is resolved. I ended up loosening all my engine mount and trans mount bolts, giving it a good shake then retightening everything and it's gone... Let's just say I was surprised that fixed it.  I've been happily driving it around again but unfortunately put zero time into my direct port/constant pressure WMI setup. I'm on vacation next week, so I'll try and finalize it then.  On a different note, I spent all week fuel/ignition mapping 2x 216L V16 engines. Turbo's were burning glycol and we swapped them out for larger units. We also had planned emissions testing on site, so I figured I'd be there the same week to use their instrumentation and massage any emissions issues out if needed. This was a first for me. Fuel management is similar in certain ways to automotive (i.e air density as load variable) but very different in others. It's all PLC based and AFR's are controlled by air and not fuel. They use a control valve between the turbo and air manifold to control pressure which in turn controls AFR's. Due to this, target AFR tables supplied by the OEM are in pressures and not mass which really through me off. They use air pressure vs fuel pressure tables. I also relied on an O2 concentration sensor the emissions team had in the exhaust. Ignition timing was also all over the place and we were losing a fair bit of power. They're now happily sitting at 16-40BTDC depending on load. We were making about 1600kw at 900rpm at 90% load. Engines were running a lot smoother as well.    
    • Duncan
      1992 R32 GT-R Race Car

      By Duncan · Posted

      heh, aint no R32 ever meeting modern targa cage rules unless the driver is veeeery short OP, good luck with the sale, since its already in the land of freedom I'm sure you will find a good buyer.
×
×
  • Create New...