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Not another CAS problem (hopefully)

Discussion in 'VT - VX Holden Commodore (1997 - 2002)' started by gw0071, Aug 16, 2018.

  1. gw0071

    gw0071 Member

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    On going issues with engine intermittently stalling in idle and surging/knocking while in motion. 2000 VT II 3.8l, driven just over 200k

    I have previously encountered CAS issues, generally causing failure to start and stalling after a relatively consistent timeframe (CAS failing above certain temps)

    Changed CAS on-spec with component sourced off eBay due to extended crank during start

    Defect persists - engine now intermittently failing to start. Begrudgingly employed services of a mobile mechanic who confirmed a defective fuel pump (via slapping tank during crank). Replace pump and filter

    After approx 2 weeks defect persisted. Mobile mechanic graciously interchanged DFI module with a spare unit, which from memory was the original component

    Defect persists, mechanic returned and replaced CAS at no cost with a sensor I purchased from Holden (Delco)

    After approx 2 weeks defect returned. On these occasions ‘Police mode’ reveals temp at failure as relatively normal at approx 80degC

    At other random times during failure the engine will stall when reverse selected or revs will occasionally hunt when steering inputs made or even electric windows operated

    One consolation is that the engine always restarts after failure

    Apart from this, the ignition plugs/leads are relatively new and engine runs well at all other times with a consistent fuel consumption

    So far I have calculated that my costs have reached approx half the value of the car

    Please help me keep old faithful off the scrap heap
     
  2. Not_An_Abba_Fan

    Not_An_Abba_Fan Exhaust Guru

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    I'd be looking at the cam sensor, it can cause similar issues.
     
  3. VT&VX

    VT&VX Active Member

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    Are you getting dash diag lights.
    Is the radiator fan always on?

    Have you tried unplugging the large plug in the ABS and then restarting the VX with that not connected.
    (Make sure it is tucked out of the way of the serpentine belt)
     
  4. gw0071

    gw0071 Member

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    Thank you for your responses

    I disconnected the cam angle sensor and drove approx 30km. While the engine was sluggish when making quick accelerations, it ran normally and the defect disappeared - no stalling, knocking or surging

    I reconnected the sensor and after about 5km the defect reappeared, at one time even sticking on 5k RPM while in neatral. I hope that this is conclusive and not an indication of something more sinister...

    I will replace the sensor but will drive with it disconnected in the meantime. It's easily accessible so I'll ask whether it's worth paying $90 for a Holden part? Are they Delco's like the CAS? Is Delphi a respectable compromise?

    Thank you
     
  5. z900collector

    z900collector Member

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    I've bought sensors off ebay only to have them fail quickly. Where possible buy genuine sensors, otherwise the Repco ones appear to work OK.
     
  6. gw0071

    gw0071 Member

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    I totally agree. I replaced the cam angle sensor with a Repco 'Fuelmiser' component, unfortunately the stalling continued

    It appears to occur more often while idling in P, when N selected and revved at just over 1000RPM stall can be avoided. Also stalls erratically in R from time-time

    The cam angle sensor is currently disconnected and the engine is running, albeit roughly. Stalls occasionally but always restarts

    I'm going around in circles here. My next attempt to fix is rewire the loom from the sensor to the DFI module. This run also interfaces with the crank angle sensor to some degree. It's a pretty harsh environment around this area and it does seem to be more prominent when at operating temps

    Old faithful is once more under threat of possibly not seeing the year out. Shame really, it's probably a simple fix - if I could just work out what it is...

    Thank you
     
  7. EYY

    EYY Well-Known Member

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    Cam angle sensor wouldn’t usually give those symptoms - a failed cam sensor means that all injectors are fired simultaneously. I.e. it doesn’t inject sequentially so will run a little tougher than usual, be down on power with poor fuel economy.

    Wiring damage is quite common and can cause these issues. The plug at the dfi module is the main culprit.
     
  8. gw0071

    gw0071 Member

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    Considering previous advice I probably wouldn’t agree with this observation except that the defect has now returned with the cam angle sensor disconnected

    I will consider the wiring at the DFI module however, this connector is away from the grime and heat of the sensors it is wired to. I may take a closer look at the wiring to the crank angle sensor (I had replaced an idler pulley mount sometime back)

    One thing it has done AGAIN is stick on over 5000RPM while in N and driving at speed on the freeway. N was selected at this time in an attempt to ‘rattle’ the engine after another episode of knocking/missing. The only way to take it out of this latched high rev state was to shut down the motor. Not pretty

    The cam angle is still disconnected however, it did do similar to this with it connected

    Could this be indicative of a throttle position sensor?
     
  9. gw0071

    gw0071 Member

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    Well for the thousands of you out there that are awaiting an update, it would appear that the suggestion to try the ABS module connector has so far provided a good, consistent outcome

    I feel a little cheated after changing the crank (x2) and cam angle sensors especially considering I know of the problems this module can create on account of it's poorly orientated electrical connector

    I had actually replaced the module about 8 years ago due to fault lights/cooling fan/traction control issues

    There were no such faults this time apart from those mentioned, but it has appeared to have done the trick

    Fingers crossed...
     
  10. Stef-vy

    Stef-vy New Member

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    My car is experiencing these same issues, just curious if you mean you replaced the ABS module connector or if you just cleaned it? Thanks
     
  11. gw0071

    gw0071 Member

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    The ABS electrical receptacle is facing upwards so it's the perfect water/moisture trap. I removed the electrical connector and there were signs of contamination. I cleaned the connector with isopropyl alcohol and reseated it numerous times to ensure all spades/lugs were making good contact

    It's been about 10days and the engine is showing no signs of stall/surge/knock

    Please keep in mind that if left unaddressed, the moisture in the electrical connector may transfer into the ABS module and effect the internal circuitry (solder joints) which will require its replacement. This may cause various dash warnings/aurals, high indicated engine temps, continuously running thermo fans, no TRAC/PWR and auto transmission sticking in gear

    I have previous swapped out the module with a recondition exchange unit to solve this but did not on this occasion as I was not getting any of these faults

    The module is an electrical interface with the ABS hydraulic manifold so does not require any disturbance of brake system plumbing

    A troublesome component indeed. Hope this helps you
     
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  12. Stef-vy

    Stef-vy New Member

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    Thank you, very helpful. Hopefully now I'll be able to fix this issue before it gets any worse because so far it's stalled but haven't had any knocking yet. I'll definitely be checking that as the first thing.
     

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