Help needed... Z won't start

Discussion in 'Technical' started by SIM300, Mar 11, 2010.

  1. SIM300

    SIM300 FAKE MODERAT0R

    Yes, have tried starting without AFM connected. The cars issue is intermittent, it starts every few days as if there is nothing wrong.
     
  2. hpcoolahan

    hpcoolahan back to boost ...yay

    By now id have replaced the whole wiring harness to rule a break/open circuit out....
    Feeling the pain with you mate, must be frustrating.


    Best of luck
    Patrick
     
  3. pexzed

    pexzed Forum Administrator

    Hey Jono

    Have you tried disconnecting the Vac lines from the FPR and F/Damper, just in case you are drawing fuel directly into your plenum?
     
  4. Egg

    Egg ....

    This is my guess.

    Electrical gremlin in the wiring harness somewhere.

    Hope you get it sorted soon. :zlove:
     
  5. SIM300

    SIM300 FAKE MODERAT0R

    Perhaps, though once it's started it drives fine. Time will tell, I dropped the Z off on Thursday.

    Anyone else want to take a guess haha?
     
  6. Zcar91

    Zcar91 New Member

    Hi,

    Just read this very long thread. May I suggest that if you have BOV's then you may have one or both stuck in the open position. BOV's need to be serviced at least annually as the spring inside them tend to rust and stick leaving the diaphragm in the open position. An BOV stuck in the open position will severely inhibit a cold start. Locating the BOV in the pod area (where it can be rammed with rain is not helpful).

    BOV's are easy to open and service with a (slight smear) of little silicone grease.

    Cheers and good luck
     
    Last edited: Sep 28, 2010
  7. SIM300

    SIM300 FAKE MODERAT0R

    UPDATE: 29.09.10

    The mystery slowly starts to unwind. Spoke to the workshop briefly this morning. Compression on the left bank is down when cold, around 60psi. But once warm is up around 140psi. He has done a leak down test on one cylinder on the left bank so far & found air is escaping at the valves.
     
  8. mungyz

    mungyz Well-Known Member

    So it has the crappy 30p inlet valves in it :(
    Mind you it should still have started & just run on three then picked up the other three as the temp comes up. Also worn out valves is not normally an intermittent issue, you either have all cylinders firing (warm) or you have some missing/flat (cold).

    Sounds like your troubles are getting worse :(
     
  9. Jinxed

    Jinxed Moderator

    all three on 1 bank can be a slipped timing belt or damaged cam gear pin, but im sure you aleardy know all this, just putting it out there....
     
  10. WazTTed

    WazTTed Grease Monkey

    engine out time... 60psi to 140 psi when warm far out... didnt this happen after you changed your intake cam gears twice
     
  11. mungyz

    mungyz Well-Known Member

    Normally wouldn't alter from warm to cold if it were due to damage from cam timing etc.

    Classic symptoms of the old 30P valves that wear out and loose compression when cold.
     
  12. SIM300

    SIM300 FAKE MODERAT0R

    No

    Yep, standard valves. Other cylinders still have to be checked before I know the full story. Wish I was good mates with an engine builder!
     
  13. Jinxed

    Jinxed Moderator

    i agree it does sound like the classic early valve problem, BUT, and its a dodgy but lol, why is it only happening on one side, as unless one head has different valves (unlikely unless its had new heads) then they should all be seeing the same symptoms.......shouldnt they?
     
  14. mungyz

    mungyz Well-Known Member

    From what I have seen so far (pulled about ten of the old donkeys apart) only some of the valves crap out, oddly they are normally on the same cylinders rather than one good one & one bad on the same cylinder.
     
  15. mungyz

    mungyz Well-Known Member

    Depends what ya want to do, if you just want to throw another set of valves in there then it could work out cheaper just going for a pair of second hand heads complete.

    Then there is the option of the complete engine second hand. They are worth SFA over here in NZ but then shipping would triple the price.

    I've got a good pair of heads here but then the freight ... probably not worth it.
     
  16. zedboy

    zedboy Active Member

    Didn't you do a comp test as apart of the eliminating possible problems? Also what should the comp be when cold on a good/health motor and cold on a crap motor?
     
  17. SIM300

    SIM300 FAKE MODERAT0R

    Belated update:

    As posted above, car was dropped off with mechanics who found lack of compression when cold was the issue. It was pin pointed to inlet valves not sealing & therefore head work was required.

    Well at least 6 weeks ago, I thought I'd try something else first. I added some MOREYS UPPER CYLINDER LUBRICANT & wow what a difference. The Z has started every single attempt since & the longest I've had to crank has been 3 seconds before she starts. On top of that, the idle is smooth from the get-go.

    Problem solved :D
     
  18. Cool300ZX

    Cool300ZX Tasmanian Zed

    Is it just a case of adding with engine oil?

    Good News as you have been having trouble for a while now. Is this stuff a good addition regardless of non starting. Just had a look at the website and it also mentions removing carbon deposits first?
    Q1: Did you just simply add it
    Q2: Does it add to the engine oil or fuel?

    Cheers, Pete
     
  19. SIM300

    SIM300 FAKE MODERAT0R

    Hi Pete,

    Yes the Z was giving me grief, but it was a combo of things. I checked & changed so many things she is in good shape now. You add the lubricant to the fuel:

    I wasn't expecting it to have the affect it did, but I'm not complaining! Very good stuff :)
     
  20. mungyz

    mungyz Well-Known Member

    Good to see the bitch is happy now that she got to have a munch on your finger :)

    Not enough blood sweat and tears prior to that to satisfy the old girl aye.

    The upper cylinder lube will help the valves to seal against the seat for a while and should slow the rate of wear - this might actually be a pretty practical way to mask the problem semi long term. Good thinking!!
     

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