WH Statesman 3.8Ltr 6 cyl with a Dangerous issue

[VFSV6FORME]

The car behaved itself on Wednesday Arvo so Now I will leave the car off until Saturday Morning. Yes this was the biggest killer with poor connection as If I drive it morning and afternoon and every day the car sort of behaved itself but if you leave the car still for 1 or two days you will have issues with it.
Put it this way the statesman has been the best ever since this issue come on to us but we will know soon as the direct soldering of the wires on the TPS could have fixed this issue.
Anyhow later on if all is ok I might get a good spare wiring harness from the wreckers and cut that section off and splice/solder/heat shrink it in the statesman.

 

[VFSV6FORME]

Just a further update on this issue. The Last time I drove the car was Wednesday arvo so its Saturday today and I have just driven the car and its PERFECT!!.
Test it on Sunday and if all is ok its back to my son on Monday.

 

[VFSV6FORME]

Well the statesman past all test and my Son took the car back to where he lives. Yes it was a Wiring Harness issue that have plague this car from day one when he purchased this car as the IDLE revs were always over the place but it was acceptably as in the early days it idled from 850 to 950 and in between but in the last month of so it was not acceptable as the car Idled from 850 to 1800 RPM and that.s a NO Good

After I cut of 50 MM of the Wiring loom + the Plug itself I took the three wires out of the plug itself and found one of them to have a high resistance between the female clip and the end of the wire. Yes the cable is CRIMPED only on the Wire not soldered.
Now by this if you have issue like me and you change everything dont forget the Harness itself and if you are unlucky like me you can have a torrid time to fix the issue like this.

 

[Immortality]

Ahh that age old argument between crimping and soldering....

At least you found the problem

 

[Skylarking]

Ahh that age old argument between crimping and soldering....

What I’ve read is that vehicle manufacturers crimp connectors to wires as they are more reliable than solder, especially when vibration exists. Soldered connections can fail (fatigue) due to vibration and the resulting break can cause all sorts of intermittent problems down the tract.

Supposedly the reason solder connections fail is that solder can wick up the wire making it rigid where it fatigues at the multi strand wire/solder junction (which in some cases can fall outside the connector body). The crimped section tends to be rather short and the multi strand wire is better supported by the connector and wire bundle (loom) which act as strain relief (or so I’ve read).

At least you (VFSV6FORME) found the problem

Yeah, and if it comes back he knows where to look (female spring connectors loosing tension) and a plan to fix it (another loom?) but a good effort tracking it down

 

[VFSV6FORME]

Ahh that age old argument between crimping and soldering....

At least you found the problem

OOooH the disease is back again Yes doing the same after a good full week + of behaving itself. Yes 1200 or 1400 RPM at idle. Now if I have another bad connecting why when it stop the Engine and Quickly remove the Negative terminal and that disconnected terminal I short out with the Positive terminal on the battery then re-connect the Negative start the car and all is OK. But ( I done this first) if you just disconnect the negative, leave it off for 30-60 seconds then put it back on the battery the disease is still there (1200 RPM at idle). It seams to fix this issue quickly you must short out + and - with one leg disconnected from the battery. Could this be a corruption issue with the ECU. I read on this site that A guy was having issue with alarms and warning lights coming on and the issue was his tail lights . Hummmm

 

[VFSV6FORME]

What I’ve read is that vehicle manufacturers crimp connectors to wires as they are more reliable than solder,

What I normally do is I crimp them and solder them too.

 

[VFSV6FORME]

The car is still playing up, 1200 1000, 1400 RPM at idle so when it decided to go to 850 RPM I pulled out the Idle Control Valve harness out.
Question
What happens if the car is left with the idle control valve disconnect, Yes it will stall at the first start in the morning, more load via the alternator will make the idle to be lower, air con will be the same, power steering could be the same but how will the ECU like it with the ICV disconnected.

 

[Immortality]

I think it'll set a fault code.

 

[krusing]

As mentioned earlier in the thread, I had the similar idle issue, after I bought and installed non-genuine TPS and IACV, and had very similar issues,
I got to the point also of frustration,
It would idle fast on first start, and stay at 1100 > 1200 RPM, and would not drop to 850 > 900 rpm even when up to Temp,
In actual fact you didn't need your foot on the accelerator to drive it as 60km/h,
And it only started after I bought the non-genuine cheap parts.
So I made a mission of it, and went to the wreckers and bought 2 sets of TPS and IACV,
making sure both/set were removed from same/each car.

Got home, cleaned them up, and put the first set on,
and its started correctly [being the engine was cold] and idled as it should.

The following morning [while engine was also cold], I placed the second set on, and it also idled correctly.

I then re-fitted the first set, and it has Not Faulted since, and runs/drives perfectly,
So I have packaged the second set up, and placed them on the shelf in the garage for a rainy day.