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Choke sticks on

JBAV6Tony

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Hi all,

My JBA falcon tourer has developed an issue.

The VN 3800 engine this morning, as I took off when the engine was cold, kept cutting out momentarily for 25kms where I stopped and noticed, even though engine was warm, that it idled high say 1500 rpm and that dreaded sucking noise. I turned the engine off. I was towing my new homebuilt caravan and the previous day it towed perfectly.

Then after weighing my van at a weighbridge I started up the van and presto, the engine idled fine at normal 700rpm or so. The van was towed home up hills without issue although sometimes I could still hear some sucking noise coming from the intake somewhere but couldn't pin point it.

It would appear that turning off the engine has reset the computer or similar. I also find sometimes my economy isn't so good.
Any ideas on rectifying this?
Tony
 

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FXST01

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I wonder if the o-ring around the IAC needs replacing.
 

JBAV6Tony

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I'll check it out. thanks mate
 

MikeC

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I'd also have a look at all the hoses connected to the inlet manifold if you haven't done this already and the throttle body for good return of the butterfly. I suspect you've got an intermittent manifold air leak somewhere.
 

delcowizzid

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Or a failing throttle position sensor
 

JBAV6Tony

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I'll check it out. thanks mate
Hey grey man, you might be on the money.
Took the IAC off. The "O" ring was loose on its mount and appears too small eg old. Anyway replaced it with an aftermarkt one slightly thicker and idle from cold was around 1200rpm for about 3 minutes then settled to 700, sucking noise stopped. Whereas yesterday, sucking noise stayed even at 70kph towing.
Think it best to replace IAC which comes with new O ring. Ebay $30 Have now ordered it.

Yes, MikeC, I had a perished mini hose from fuel regulator to top of manifold intake was replaced last summer. Lost power and computer thought engine was lean hence fuel pumped in excessively the RACV guy said. Also the throttle body gasket was replaced when I renewed the thermostat, used gasket goo as well.

Delcowizzed - thanks, I did replace that 2 years ago with several other sensors.

Thanks again.
Tony
 

MikeC

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Hope your IAC works. I originally got a cheap ebay one when I had idling problems with my 5 litre. Didn't open properly when I came off high speed freeway runs and the engine kept stalling. A genuine GM (Delphi) IAC fixed the problem- these are also available on ebay but they are not the cheapest.
 

JBAV6Tony

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Thanks mike C,
Problem solved. It was the IAC o ring for sure
I went for a drive this morning, engine cold. No sucking sounds, no hesitations and smoother low down power. Must also mention quicker acceleration with less pedal.
Very happy
I paid $22 for the ebay iac Mike...think I wont install it. Better to leave alone with the thicker o ring in it now. Its obviously sealed well.

You guys are great. I live in Strathbogie and am on disanility with limited income. Your help is invaluable.
Tony
 

JBAV6Tony

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Hi Mike.
Problem fixed. It was the o ring. Started up cold this morning. No sucking. Superb, best low down grunt I've ever had, smoother, no excessive high idle. Likely more economical.
Thankyou everyone
 

MikeC

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Good to hear. I always keep original parts wherever possible. You'll need that low down grunt climbing the Bogie's. I spend a lot of time in Euroa- at the bottom of the hill.
 
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