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Not another CAS problem (hopefully)

gw0071

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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
 

Not_An_Abba_Fan

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

VT&VX

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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)
 

gw0071

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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
 

z900collector

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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.
 

gw0071

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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
 

EYY

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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.
 

gw0071

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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?
 

gw0071

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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...
 

Stef-vy

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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...
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
 
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