I was wondering if anyone has had some experience with an erratic idle to the the point of stalling at times only on cold starts.After 20 secs or so it is back to normal and and no probs till next cold start.cheers..
4.8 rough idle only when cold
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Jimmycrackcorn
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Was That with a timing light or ECU cable?
Interested to see if the timing in the GUIV and later models was factory changed back to 5 degrees. I think that is when Nissan stopped advertising them as 185kw and it became 180kw. Always wanted to know where that 5kw went as I want it back.
Ok, well I'm back. Didn't measure the economy on the way up to Perth, but on the way back this is what happened.
Filled up in Maylands, full tank of LPG. Drove straight down through the tunnel and onto the freeway. Once I hit the Forrest highway I cruised a 114kph with the occasional overtake. Kept up with all the dunnydoores and Falcons at the lights in Perth and Bunbury and left the diesels for dead (as per usual).
Filled up again in Bunbury and calculated the milage. 25L per 100kms on the nose. Now considering the the last 130,000kms I have got 30L per 100kms in almost all circumstances (around town, towing, cruising etc) I think that's a 5L per 100kms gain!!!
Now of course, it's only one test so we will have to monitor but looks very exciting.
Now, down the the car itself. It actually goes into troque lock in 5th now, hasn't since I put the bigger tyres on it. It doesn't change down to 4th in cruise while going up hills AT ALL. In fact you barley notice it coming out of torque lock. It changes smoother, cruise works better (smooth and keeps speed constant) and has WAY more power.
This is possibly the best thing I have ever done to the Patrol and took 30seconds and a 12mm socket!!
Just wish I had of done this 130,000kms ago!
Filled up in Maylands, full tank of LPG. Drove straight down through the tunnel and onto the freeway. Once I hit the Forrest highway I cruised a 114kph with the occasional overtake. Kept up with all the dunnydoores and Falcons at the lights in Perth and Bunbury and left the diesels for dead (as per usual).
Filled up again in Bunbury and calculated the milage. 25L per 100kms on the nose. Now considering the the last 130,000kms I have got 30L per 100kms in almost all circumstances (around town, towing, cruising etc) I think that's a 5L per 100kms gain!!!
Now of course, it's only one test so we will have to monitor but looks very exciting.
Now, down the the car itself. It actually goes into troque lock in 5th now, hasn't since I put the bigger tyres on it. It doesn't change down to 4th in cruise while going up hills AT ALL. In fact you barley notice it coming out of torque lock. It changes smoother, cruise works better (smooth and keeps speed constant) and has WAY more power.
This is possibly the best thing I have ever done to the Patrol and took 30seconds and a 12mm socket!!
Just wish I had of done this 130,000kms ago!
ok time to report back. I just returned from Scenic Rim. Left the Redlands and filled up at McKenzie Caltex with 91 unleaded. Drove to Beaudesert with A/C off ( Again) travelled 57km's and used 8.7L of unleaded. That works out to be 15.26L/100 So Im happy with that. I wasnt babying her either!
Just about to do this to my 2010 4.8 auto. Will I need to do the throttle learn? If so how
Which way did ya tweak it mate? Gonna have a play with mine when I get home.
Anyone recommend a dyno south of Perth, WA?
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ok so the rough idle problem persists,but i have eliminated fuel or dribbling injectors. I know am thinking its actually idling so low it wont run until the iacv catches it and brings revs up.that why if you start it and it stalls then you start it again it runs fine,because the iacv has seen it idling too low and now idles it up. im thinking base idle is set too low
Ok... I have a theory on this starting issue... Have tried it on two 4.8's now and we seem to have stopped it by simply running a car charger on it over night making me believe that the rough start is somehow related to low battery voltage.
I think the culprit in both the cars I looked at was the RedArc battery isolator as it it drains both batteries down to around 12.1V overnight by drawing a parasitic load of .5 amps to keep the solenoid engaged before dropping out.
So a simple solution for this would be to unbolt the sensor wire from the main terminal on the RedArc and crimp it onto a wire that runs to your windscreen wiper motor positive (a very easily accessible ignition 12v point used on other dual battery installs).
This would mean that when you turn the ignition off, the voltage sensor wire for the red arc would get 0v and disengage immediately instead of draining the batteries down overnight but when the ignition is on it would work just the same as it did previously by only engaging the solenoid once the main battery got up to to charge.
This would also be far better for your batteries because they would not be being cycled every night by the redarc.
I'd be interested to know who is having the starting issues and what their battery voltages are in the morning before a cold start. It also explains why this only happens to 4.8's in the morning and not at the end of the day as the day is warmer so therefore there would be less voltage drop on the batteries...
I think the culprit in both the cars I looked at was the RedArc battery isolator as it it drains both batteries down to around 12.1V overnight by drawing a parasitic load of .5 amps to keep the solenoid engaged before dropping out.
So a simple solution for this would be to unbolt the sensor wire from the main terminal on the RedArc and crimp it onto a wire that runs to your windscreen wiper motor positive (a very easily accessible ignition 12v point used on other dual battery installs).
This would mean that when you turn the ignition off, the voltage sensor wire for the red arc would get 0v and disengage immediately instead of draining the batteries down overnight but when the ignition is on it would work just the same as it did previously by only engaging the solenoid once the main battery got up to to charge.
This would also be far better for your batteries because they would not be being cycled every night by the redarc.
I'd be interested to know who is having the starting issues and what their battery voltages are in the morning before a cold start. It also explains why this only happens to 4.8's in the morning and not at the end of the day as the day is warmer so therefore there would be less voltage drop on the batteries...
Could be the case with battery voltage being low, but as far as the redarc draining it, i didn't have mine connected till recently and don't have dual batteries either, so maybe something else
Have you sold your 4.8 Jeff as your signature says? Why?
Have you sold your 4.8 Jeff as your signature says? Why?
If you can check your voltages before cold starts and may let us know what they are when you have a rough start?
Seeing as I don't have mine anymore I can't do any further test other than on my friends Ti but it's a bit tricky to test cold starts as I'm not at his place first thing in the morning!
Yeah I've sold my beloved 4.8. My wife changed jobs and lost her company car. So she had to use the 4.8 and as good as it was, it was not ideal for her 1000kms a week travel!! It was going through two 90L tanks of gas a week at 99c per liter down here and that was becoming impractical. I've bought her a 2010 V6 Vitara which is perfect for her long country k's and tight shopping centre car parks. I sold my old Courier ute and bought a 2002 DX Patrol ute as I couldn't live without the ute.
Was a big change, but I think it was for the best! I am kind of getting fonder and fonder of the old slug 4.2 N/A. I couldn't live with it in a wagon I don't think, but in a ute it just seems to work. lol
Seeing as I don't have mine anymore I can't do any further test other than on my friends Ti but it's a bit tricky to test cold starts as I'm not at his place first thing in the morning!
Yeah I've sold my beloved 4.8. My wife changed jobs and lost her company car. So she had to use the 4.8 and as good as it was, it was not ideal for her 1000kms a week travel!! It was going through two 90L tanks of gas a week at 99c per liter down here and that was becoming impractical. I've bought her a 2010 V6 Vitara which is perfect for her long country k's and tight shopping centre car parks. I sold my old Courier ute and bought a 2002 DX Patrol ute as I couldn't live without the ute.
Was a big change, but I think it was for the best! I am kind of getting fonder and fonder of the old slug 4.2 N/A. I couldn't live with it in a wagon I don't think, but in a ute it just seems to work. lol
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