User Tag List

Results 1 to 15 of 15

Thread: Earth Cable Off = Detonation!

  1. #1

    Exclamation Earth Cable Off = Detonation!

    Gday guys,

    Saturday arvo coming back up the Princess Freeway we were heading home and I was accelerating in 5th gear from 60kph to 100kph.

    At about 15% throttle (estimate) boost came on. Got to about 2,700rpm and then hit a wall!

    Conditions-
    -32* Temp
    -Up a hill
    -15% Throttle (bringing on boost (not full boost though) )
    -2 people in the car
    -5th gear
    -About 2,700rpm
    -Shell VPOWER fuel (35L in the tank)



    (The next few lines will describe the feelings and sounds from the car)

    -Power dropped off like you had taken your foot off the pedal completely.
    -A sound like "PING PING PING PING PING" occurred for about 2 seconds which was REALLY evident.
    - My right foot pulsated
    -Engine sounded rather 'tingy'

    I believe that all describes the term 'DETONATION' or 'Pinging'
    I was shocked and slowed down straight away.

    After that, it didnt ping again... odd.
    My wife describes the current engine noise as 'keys being dangled around lightly' - this was the case for the next 10 minutes of driving.

    Got home and found this...

    http://i11.photobucket.com/albums/a1...MG_0499red.jpg

    Any idea what this is connected to?

    Ive put the neg wire back on and it feels much better!
    Went to Mazda today, they have booked me in to take a look at it.

    Hopefully the ECU logged something... (my chances is that it didnt lol)

    So there you go, KEEP A CHECK ON THAT WIRE!

    Cheers,

    Jarreth

    EDIT - Car is completely stock
    Last edited by nissanman; 01-02-2010 at 11:59 AM. Reason: Added mod list

    Current: 2002 Nissan S15 200SX SPEC R
    Previously: 2006 Mazda 6 MPS ,MY00 WRX CLUB SPEC EVO IV Hatch ,97' Nissan S14A 200sx, Nissan R34 GT-T, Nissan S12 Silvia

  2. #2
    Join Date
    Dec 2008
    Location
    Carindale
    Age
    37
    Posts
    2,043

    Default

    wow... intresting!

  3. #3

    Default

    Interesting, I would like to hear more about this

  4. #4

    Default

    damn. hope they can pin point the event. will be intersting to hear results

  5. #5
    Join Date
    Jan 2009
    Location
    Perth, WA
    Age
    52
    Posts
    6,388

    Default

    Geez Jarreth! That does not sound good, I'll check my cable tonight. Times like these you need a Dashhawk or similar so you could have checked some of the readings! Some questions - prior to the Event, how long were you cruising at freeway speeds? How many kms on your car? Do you know if the previous owner modded then de-modded it? Have you checked spark plug condition?

    I know so may questions, but hopefully someone has some answers! Good luck with the diagnosis
    Cheers
    Chris
    R36 - Just like an MPS6 except with a growly V6

  6. #6

    Default

    I've had that cable off when I dropped the engine to gain clearance to remove the original down-pipe. It's hard to imagine how it would not be attached unless someone had been fiddling, in the course of modding, or when in service.

    But I will re-check that I re-attached mine now ;-)

  7. #7
    Join Date
    Jan 2009
    Location
    Perth, WA
    Age
    52
    Posts
    6,388

    Default

    Went out to the carpark and checked mine, it is definitely attached to the RH side engine mount and securely too!

  8. #8

    Default

    Quote Originally Posted by shakespeare View Post
    Geez Jarreth! That does not sound good, I'll check my cable tonight. Times like these you need a Dashhawk or similar so you could have checked some of the readings! Some questions - prior to the Event, how long were you cruising at freeway speeds? How many kms on your car? Do you know if the previous owner modded then de-modded it? Have you checked spark plug condition?

    I know so may questions, but hopefully someone has some answers! Good luck with the diagnosis
    Cheers
    Chris
    Yea a dashhawk would have come in handy. Perhaps someone can disconnect the wire and see what the dashhawk spits out?

    Ok so the answers

    1. Q: prior to the Event, how long were you cruising at freeway speeds?

    A:I came out of the city so wasnt really just 'cruising', just prior to the 'pinging' I had accelerated from the lights from 1st, 2nd, 3rd, 4th.. cruised at 60kph for about 3-5 seconds and then accelerated a tad, into 5th and continued to accelerate.

    2.Q: How many kms on your car? Do you know if the previous owner modded then de-modded it?

    A: 67,500kms (give or take 100-200kms) and the prevoius owner was an old guy. When i cracked the intercooler bolts, they had never been touched before. Same with the AFM and intake. Suspension bolts have never been cracked also. Therefore I about 90% certain that it has never been modified.

    3. Q: Have you checked spark plug condition?

    A: No i haven't actually. I think i may do that if Mazda come back with a 'nothing went wrong and nothing is wrong' diagnosis.

    Cheers guys.

    Current: 2002 Nissan S15 200SX SPEC R
    Previously: 2006 Mazda 6 MPS ,MY00 WRX CLUB SPEC EVO IV Hatch ,97' Nissan S14A 200sx, Nissan R34 GT-T, Nissan S12 Silvia

  9. #9

    Default

    Nissanman, Hi. Sounds like you might have got a boost spike and/or excessive load detection, your ECU detected the resulting detonation, retarded the ignition and shut off the boost, effectively killing the power.

    You were on a gradient at relatively low engine speed, in a relatively high gear and only just coming on-song at ~2700 (= 84kmh in 5th) with rapidly rising turbo spindle speed, so you have a fair amount of load on, even with light throttle application.

    These engines have such a flat torque curve and pull like there is no tomorrow from low engine speeds so that one is often tempted to pull from fairly low speeds in the upper gears. I generally use quite high gears as long as no load is on, especially on downgrades, mainly for the peace and quiet and economy, but change down if I need to pull harder and make sure the engine is spinning freely. I'm not suggesting one needs to cane the car mercilessly, but be very aware of loadings at low rpm.

    However, as I have been discussing off-line with MattMPS3, sometimes the engines perform better with higher rpm as they seem more capable of usefully and more smoothly ingesting all the boost generated when the engine is well and truly spooled up, say above 3,000rpm anyway.

    This is of interest as applying particularly to my car where the mods have added a heap of readily available boost and pussyfooting around in higher gears at low engine speed creates more boost and boost dump problems than using a few more revs.

    It will be interesting to see what you and Mazda come up with.

    BTW, I doubt your detached earth lead will have had much effect on the issue at hand, although plainly it helps to have it connected. Your red circle does show the correct connection location on the engine mount, too.
    Last edited by Doug_MPS6; 02-02-2010 at 04:07 PM.
    CP_e Standback & PNP; CP_e 3" SS Downpipe; Corksport FMIC with Top-mount K&N filter & OEM Ram CAI; Turbosmart BOV; Dashhawk; Prosport Boost Guage; JBR solid shift bushes; DBA 4000 Wiper-Slot front rotors; Hawk Ferro-Carbon HPS Street front brake pads (@ 69,000km); Sumitomo HTRZIII's in 225/45 x 18

  10. #10

    Default

    Can I share a funny story? A fella built a nice new big-HP V8 for his race car and after carefully installing his work of art hit the starter to bring it to life. Except he forgot to connect the earth lead to the block. The throttle cable took the full force of a couple of hundred cranking amps on their way back to the battery and instantly exploded into tiny bits of molten metal, starting a fuel fire in the intake and adding a few more dollars to his engine program.

    The moral to the story: Don't under estimate the importance of earth leads.

    Gone to Volvo


  11. #11

    Default

    Nissanman, on reflection, I did have a similar experience (pre-mods, about 30,000km up), when accelerating, urban environment, about 1/3 throttle and less than ~3000-3500rpm away from a stop sign. Same sensation as you experienced, same tinny rattle. It does stop you in your tracks and causes you to drive rather delicately until one "feels" it is not going to recur anytime soon.

    I never duplicated it. It was definitely power on and not compressor stall on lift-off. All I can assume is that the ECU decided it was going to have a few moments off and lost the plot altogether. The only other thing I can think of was that it might have been initiated by a fouled plug or plugs, but why would that be? My car regrettably spends too much time in urban environments being baulked by slow wallies, so has every opportunity to foul plugs, but this has been a one off. Best thing you can do is give these cars a good "open road day" from time to time. But I know that's where you were. A puzzle that demands a definitive answer...

    ---------------------------

    KMH001, Hi, good reminder. I never wear a watch with a metal band when working on engines. Working with my hands in a tight space, I shorted out the terminals at the starter once on my old 2.4 litre Jaguar. Amazingly, my wrist survived, apart from some tiny molten metal burns, but the same can't be said for the watch-strap or terminals. There is a LOT of energy stored in a 12v car battery! In some situations it can be fatal, especially if the battery explodes as a result and/or a fire is intiated.
    CP_e Standback & PNP; CP_e 3" SS Downpipe; Corksport FMIC with Top-mount K&N filter & OEM Ram CAI; Turbosmart BOV; Dashhawk; Prosport Boost Guage; JBR solid shift bushes; DBA 4000 Wiper-Slot front rotors; Hawk Ferro-Carbon HPS Street front brake pads (@ 69,000km); Sumitomo HTRZIII's in 225/45 x 18

  12. #12

    Default

    Most cars have them attached to the block, its a major earth point for the motor electronics My GTiRs one attaches to the side of the block

  13. #13
    Join Date
    Jun 2009
    Age
    59
    Posts
    8,042

    Default

    I got this on the Opel cruise I went to a month ago 2nd & 3rd lost power around 3500rpm to 4000rpm in both gears no noises though, I was told that this can happen every so offen 5 minutes and it's fixed... Need to plug the gizzmo in and reset it by mazda or who ever has the gizzmo I would assume most reliable mechanics should have one..... No leads come off mine .....

  14. #14
    Join Date
    Nov 2008
    Location
    Geelong, Victoria
    Age
    56
    Posts
    121

    Default

    My Mazda 3 mps does not seem to have this cable in that location. Either it is not on mine or I have had too much to drink!

  15. #15

    Default

    Quote Originally Posted by mymps3 View Post
    My Mazda 3 mps does not seem to have this cable in that location. Either it is not on mine or I have had too much to drink!
    They also may have upgraded it between the diff series (with age). And to keep this crucial cable away from the hands of a unknown user
    "THE PATH OF THE GTI-R IS BESET WITH PERIL BY THE INJUSTICES OF THE SPEED CAMERA AND THE TYRANNY OF OTHER DRIVERS. BLESSED IS HE WHO OVERTAKES THE EVO & STI THROUGH THE VALLEY OF HAIRPIN TURNS, FOR HE IS TRULY HIS CAR'S TUNER AND THE FINDER OF LOST HORSEPOWER. . . AND WE SHALT STRIKE DOWN WITH GREAT BOOST AND FURIOUS ACCELERATION ON WHOEVER DOTH ATTEMPT TO OBSTRUCT OR DELAY OUR OVERTAKING. . .
    BMW M3 Evo Coming to the R stable soon. . .

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •