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WH Statesman 3.8Ltr 6 cyl with a Dangerous issue

VFSV6FORME

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VFSV6FORME

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I spent all friggen day on this statesman and im just about sick of it. EGR valve blocked or not blocked, the engine revs go up to 1200-2400RPM. Change and measured the length of the idle control valve and it makes no difference. I even found one very poor hose thats about 150mm long that goes from the manifold itself and has good vacuum and this hose goes to the air cleaner side of the MAF pipe but I cannot understand this. Why would you want to have vacuum going to the front of the throttle body not the back? But anyhow I changed it because it was brittle and it made no difference. The REVS still goes up to 2400 or even 2600 or even 2700 but sometimes it goes back to the correct idling which is around 900 RPM.

Now this problem is very very very erratic. Sometimes you start the car when hot and it stays and idles at 900. Then after 5 minutes it goes up to 1000 then 1100. Before you know it, its idling at about 1800. After doing this madness all day, Im now going to change the mid LIM gasket.

See with the LIM gaskets you have the gaskets going from the bottom inlet manifold to the heads on either side then you have the mid chamber. Those gaskets are either o-ring or cardboard. Then you have the top which is the top plate. Yes its like a plate which is normally o-ring. So what happened, when I ordered the LIM gaskets, I told the guy at Autobarn very clearly that this car has a different engine in it. Not the original engine so I told him I need o ring up the top, cardboard in the middle and cardboard on the head side. But unfortunately they gave me the wrong gasket. They gave me o-ring up the top, o-ring for the middle which you cannot use on this manifold and the cardboard or whatever down the bottom where the heads are. I was not happy with the quality of the old mid gasket because it was poor and without no doubt, if a part of it has been sucked in. Well this is the problem. Because as far as im concerned. If you have a hole in the pipe, you should have high RPM all the time but not this as it starts most of the time with low RPM and when the car heats up the RPM goes up.

It could possibly be another issue. The ECU or PCM or other because i have never experienced in my entire life a stubborn car like this. A car that I told my son not to buy anything without speaking to me.

We are gonna order a new top manifold gasket set with the o-ring up the lid and the mid to have the cardboard or whatever. I think the original one has cardboard mixed with some steel around the outside to keep it in the middle. Anyhow rest from here until Monday for the Bathurst weekend. I'll let you know how it goes next week.
 

Lex

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mid to have the cardboard or whatever
The cardboard is actually metal, which is coated with something that looks like a black paint coating to me?
I was told they seal by pressure between lim & plenum & once you separate the 2 services (lim & plenum) they are throw away.

Here is a pic of my old one.
I changed it last Friday.
20191008_183035[1].jpg
 

Immortality

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It's sounds like an IAC issue and that is controlled from the PCM. changing the length of the pintle on the IAC makes no difference because it resets itself on every restart.

Logging the car may reveal an issue (if you have that capacity) otherwise I'd beg/borrow or steal another PCM to try.

edit:****. been a WM the pcm will be linked to the bcm so not a simple swap. ****.
 

lout

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so it is fine when warmed up
what if turned off and restarted when warm
try using engineering mode and check coolant temp
maybe the coolant sensor is eratic when cold. signalling maybe -20c
check coolant vs rpm from cold until warm
Hold mode and up arrow then turn key to on or start
Release buttons
then
Press Mode = Dash Part Number - e.g. 1731
Press Mode = Mode Switch Voltage - e.g. BV - - - 5.0
Press Mode = Battery Voltage - e.g. V 11.8
Press Mode = Petrol Sender Voltage - e.g. FUEL 02.6
Press Mode = LPG Sender Voltage - e.g. VL 5.0
Press Mode = Remaining Fuel - e.g. 38L
Press Mode = Instantaneous Fuel (Liters per Hour) - e.g. 12.8 L/H
Press Mode = Engine Coolant Temp - e.g. 63 C
Press Mode = Vehicle Speed - e.g. 45 KM/H
Press Mode = Tachometer - e.g. 2380
Press Mode = Park Lamps Switch - e.g. P OFF
Press Mode = Dash Trouble Codes - e.g. t 00 (Press up/down to scroll through any codes, these are not PCM, ABS, etc codes)
Press Mode = Dash Test - All gauges will move, lights will come on and buzzer will sound.
Turn key off will revert to normal dash
 

Trevor loves holden.

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Said egr not the problem, I think lout might be onto something with the temperature sender.
 

Sabbath'

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Im assuming you've checked all the hoses, including the one to the bottom of the throttle body and where it terminates by the firewall on the drivers side to ensure the hoses are properly seated and not split on the connectors?

You can carefully use brake cleaner when the engine is running to spray around intake pipes and areas to check for RPM changes, being careful of the exhaust etc.
 

_R_J_K_

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as you come to a set of lights, you put the foot on the brakes and the car wants to still go forward, so you put it in park or neutral and up the revs go from 1200 to 2500 rpm.

Random question but does it do it when you brake? As in does braking cause the issue to occur?
 

krusing

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I had a recent issue of the same on my L67, car would drive at 60km/h without the foot on the accelerator,
and had to hold it back at the lights,
the cause in my case, was a cheap/crappy after market TPS,
Ended up filing it under NFG, in the green plastic square filing cabinet.
As another member mentioned earlier, a vacuum leak can cause the same issue.

I went to the wreckers and bought a genuine S/Hand IAC Valve, and TPS, Fixed the issue.
 
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