VX Calais V6 Ongoing DFI/Ignition Problem?

[VFCalais2017]

Hi everyone,

I apologise in advance for this long-winded post. This problem has now got the better of me so I thought I'd throw this out there for those who like a challenge!

My second car is a 2000 VX Calais V6 (non-supercharged). It has 196,000kms on the clock and has been meticulously maintained and services since new. It was an ex GMH car from Victoria after which it was a pensioner’s car. I purchased the car in 2011 with 54,000kms on the clock.

Driving to work one morning last December, the car started struggling and would not go over 50km/h. Fuel tank was full and the engine was misfiring badly. Repco nearby so I stopped to buy 3 new coil packs (Delphi). Not the problem. Went back in and purchased new DFI module (Delphi). I didn't fit it on the spot. I tried to limp the car home (I wasn't far) so I could try some second hand DFI modules I had. Halfway home, had to call NRMA. The NRMA diagnosed coil packs until I told him these had been replaced. He then said DFI module, and to cut a long story short, we fitted the new one I purchased, after which the car ran perfectly.

A week later, the car started playing up again. When I started the car, it would idle rough and would struggle to keep running. Once the thermostat had opened and the engine reached operating temperature, the car would run fine. This happened every morning and night when I went to start the car. It wouldn't happen on a hot restart though. I tried old DFI modules and coil packs, new leads, new plugs... nothing worked.

I took it to my wife's mechanic in December who diagnosed and replaced both the crank angle and cam shaft sensors. The fault was still there. He said he couldn't resolve it and recommended I take it to an Auto Electrician. I decided to take the car to the local Holden Dealership.

Holden has the car for a week. They discovered a fault code with the crank angle sensor and so they replaced it and charged me, despite the fact it had been replaced two weeks prior. This did NOT resolve the problem. Holden checked all ignition wiring to see if there was a fault. They couldn't find anything. My car wasn't a priority for them so I took it back and left it with a local mechanic my Dad recommended.

This new mechanic checked everything. Keep in mind that this car now had brand new coil packs, DFI module, plug leads, plugs, crank and cam angle sensors. I had even replaced all 6 injectors on recommendation from a reputable source. Again, this wasn't the problem.

A week later, this mechanic found the problem to be a faulty connection in the DFI module plug. He fixed the connection and the car was running without fault (although a consistent rough idle was noticeable) from then on.

I sold the car to my Dad a month later. He was driving it to and from work until the car stopped one night with the same issue. Wouldn't start so called NRMA. He was towed home after the NRMA diagnosed crank angle sensor.

The car has now been sitting in front of the shed for a month now. It wouldn't start. We tried everything again; swap DFI, coil packs, leads, plugs, check connectors. Nothing worked.

Last weekend (June 10th) I decided to take the battery out to charge it as it had been sitting a while. I put the battery back in with a full charge and the car fired up first time! No rough idle and no struggling or stalling

I took the car for a drive I went fine. The only thing I noticed was when shifting from Park to Reverse or from Neutral into Drive, there was a loud clunk. Also, when shifting from 2nd into 3rd, the car lingers in 2nd and then ‘jolts’ into 3rd.

I’m not an expert mechanic by any means but I’ve managed to do everything to this car myself since 2011 up until now. I’ve tried everything I can and had quite a few mechanics look at it. I’m at the point where I don’t want to spend any more time or money on this unless I can guarantee a result.

I might also add that I have checked the fuel pump and filter and there are no faults. Fuel filter was replaced in January this year with no noticeable change to the problem.

Also owning several classic Holdens, I am extremely meticulous with my vehicles. This car is immaculate inside and out and probably one of the best remaining examples of VX Calais, hence my reluctance to keep it going, particularly after all the time and money I have put into it.

Like me, I know a lot of forum members like a challenge, but this one has got me beat!

Any ideas or assistance with this problem would be greatly appreciated.

Cheers

 

[VFCalais2017]

Hi everyone,

There's been a lot of looks on this one but no bites unfortunately. However, I have managed to get the problem resolved - finally!

The problem turned out to be a bad wire within the DFI Module harness (as described above) and a faulty replacement cam angle sensor.

The last mechanic who looked at the car said he wanted a challenge and advised he would only charge me for the work involved once the fault was found. The fault was found by pouring hot water over the cam angle sensor when the engine was cold. This revealed the issue.

Now with a new cam angle sensor installed, there have been no issues with the idle or performance. Car is going like a rocket now!

I hope this information helps other who have a similar issue with their car.

 

[Immortality]

That's interesting. Thanks for reporting back.

Interestingly enough, I'm sure the Holden service manual states that if the CAS shows as faulty and replacing it doesn't work to check the DFI, if that doesn't work than the fault lay with the wiring loom and needs replacement.

 

[VFCalais2017]

Thanks Immortality,

I see a lot of references to the Holden Service Manual on here. Is this available for purchase anywhere or is it just for Holden Service Departments?
I only have the Haynes manual which isn't the best but has got me out of trouble with things I've had to do.

Cheers

 

[Immortality]

There are copies of it floating around.

 

[VFCalais2017]

Hi everyone,

Just following on from my previous posts above to keep those interested updated...

Unfortunately the misfire problem returned about 2 months ago. Recently I left the car with the mechanic for diagnosis but unfortunately there has been no successful resolution for this problem

I'm led to believe that the previous remedy (new CAS and DFI wire) was not the solution.

To clarify the problem, the car displays the following symptoms;

* Car starts first crank and idles fine. It's not 100% smooth, there is a slight shudder in the idle both hot and cold.
* Take off immediately after starting, engine feels like it is "cutting out", "misfiring" or "kangaroo-ing". Only happens in Drive when cold. In Neutral, the car runs fine.
* After engine reaches operating temperature, it runs fine. No shuddering or misfire. Car has perfect performance, economy and power. Drives like a new car!
* Possibly unrelated - car jolts when shifting from Park to Reverse (all temperatures) I've been told that the rear engine/transmission mount needs replacing but not sure if this is causing the jolting or its related to the misfire.

For the record, to date the car has had the following replaced;

* Ignition leads (VDO). These were replaced a year ago but I just tested today for resistance and all OK.
* DFI Module (Delphi)
* Coil Packs (Delphi)
* Plugs (NGK with gap set at 1.3mm)
* IAC valve (Delphi)
* TPS (Delphi)
* Crank Angle Sensor (Delphi)
* Cam Angle Sensor (Delphi)
* DFI Module harness (staggered, soldered connections with heat shrink tubing)
* Inlet manifold gaskets (suspected possible vacuum leak plus oil was also entering cooling system)
* BCM and new keys (to remedy Variatronic steering assist failure)

The following items have also been addressed;

* Plenum chamber and throttle body fully cleaned
* MAF cleaned using a poprietary cleaning spray

This problem seems to have everyone beat and so I'm unsure as to what else I can check at this stage. Its strange in the fact that it only happens when cold and only when in drive and moving.

I was reading about the purge solenoid today but I'm not sure how to test this. Could this cause these symptoms? I disconnected the harness during idle but it made no difference to the running. Disconnecting the vacuum line from the solenoid however altered the idle.

As it only happens in Drive, could this also possibly be transmission related? Fluid level is fine when hot but could it possibly be losing fluid in the torque converter overnight?
Sorry, I'm no expert on auto transmissions but I'm starting to think it's transmission related based on the symptoms described above.

I'm looking at all possible avenues now given that I've exhausted the above! The car has 210,000kms but has been meticulously maintained. When something was on the way out or suspected to go, then I've replaced it without fail with high quality parts. I'm not prepared to write it off just yet given that it's now practically a new car and the body and trim are immaculate.

A mechanic friend has offered to borrow the car for a weekend and test it out to see these symptoms first hand.

In the meantime, any additional help would be greatly appreciated.

Thanks guys

 

[Immortality]

Ecotec V6 should have a 1.5mm plug gap.

So at this stage I think it's more than likely that the ignition side of the equation is not the problem but we need 3 things for good stable combustion, air, fuel and ignition. I'd start by checking the fuel pressure. Cold start is open loop (basically the pcm injects the amount of fuel specified on the cold start tables) once warm the pcm goes into closed loop mode and uses the O2 sensors in the exhaust to trim the fuel which may be masking other problems. If you mechanic mate has the right equipment I'd suggest checking what the O2 sensors and fuel trims are doing. Another reason for a stumble may be a blocked or leaking injector causing the poor idle hot or cold.

 

[VFCalais2017]

Ecotec V6 should have a 1.5mm plug gap.

So at this stage I think it's more than likely that the ignition side of the equation is not the problem but we need 3 things for good stable combustion, air, fuel and ignition. I'd start by checking the fuel pressure. Cold start is open loop (basically the pcm injects the amount of fuel specified on the cold start tables) once warm the pcm goes into closed loop mode and uses the O2 sensors in the exhaust to trim the fuel which may be masking other problems. If you mechanic mate has the right equipment I'd suggest checking what the O2 sensors and fuel trims are doing. Another reason for a stumble may be a blocked or leaking injector causing the poor idle hot or cold.

Thanks Immortality,

I set the plug gap at 1.3mm as recommended by my friend. He said it's to do with the change in fuels since the car was new. Incidentally, the mechanic who last worked on the car installed iridium plugs which had a similar gap. I reinstalled the previous NGK plugs with the 1.3mm gap last night as these plugs are practically new. The new plugs didn't make any noticeable difference.

I forgot to mention in my previous post that the car also has a brand new fuel pump installed (6 months ago). I did this in an attempt to rectify the rough idle. I've also installed brand new Bosch fuel injectors a year ago. I kept the originals so they can be cleaned and reused. One of the top retainer clips is missing from an injector. It hasn't affected the idle/missing issue but I've been told that it can blow if left for too long without it. I'll be replacing that today.

I will ask my friend to run a fuel pressure test though and see how we go from there. I've no doubt he will find the fault and he has a feeling that it's going to be something so simple that I'll be kicking myself!

The following fault codes showed last week when we connected the computer.

I thought this strange as the next day it only showed the CAM/crank sensor fault code.

I understand that fault codes do not necessarily indicate a faulty component but more so a fault that is causing that part or sensor to throw a fault code.

Thanks for the advice above, it's greatly appreciated. I'll keep you updated with the progress. The solution will be one to add to the troubleshooting files on the forum

Cheers

 

[Immortality]

Only the l67 runs a 1.3mm gap or if you run lpg otherwise 1.5mm is the go. I'd try it and I think it'll make a difference.

With those faults coming and going I'd be looking at wiring, make sure all the earth points are clean and tight on the engine, chassis and battery and then I'd check all the plugs are clean and seated properly.

Fuel filter?

 

[VFCalais2017]

Only the l67 runs a 1.3mm gap or if you run lpg otherwise 1.5mm is the go. I'd try it and I think it'll make a difference.

With those faults coming and going I'd be looking at wiring, make sure all the earth points are clean and tight on the engine, chassis and battery and then I'd check all the plugs are clean and seated properly.

Fuel filter?

Thanks again for your reply, Immortality.

Fuel filter was replaced last week at the workshop. Apparently the fuel was dirty. The tank was cleaned when I changed the pump and I only fill up at clean sites with Caltex Vortex 95 or 98. At least the filter is working!

I cleaned the battery terminals yesterday, degreased and cleaned with a battery terminal brush. No difference. I might try the negative terminal where it connects to the engine below the P/steer pump.

When you say wiring, are there are any other suspect places that I should be looking at? DFI harness was replaced but that was only a 30cm length of the harness. It was done mainly for the plug as one of the terminals had broken. Perhaps there is a fault further along that line?

Ordered a new fuel injector retainer today. I doubt it will make a difference but at least it eliminates another thing from the list.

Cheers