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Nissan Patrol 4.8
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Discussion Starter · #1 ·
Hi guys,
Hoping someone can help me sort my surging issue, when criuse is set at around 100klm the car surges or hunts for a comfortable speed all the time, only slight but noticable. I have a 2002 4.8 st patrol.... i know they had a known issue with surging and Nissan replaced (under warranty) the Module back in 2003 while the previous owner had my vechile. I have just recently bought this car and i am trying to fix this surging problem. Have had it at Nissan a couple of times and they are unable to do any more than they have. They have checked cable operation and throttle position. They suggest that it most probably the module ( again?? ) and to replace, but it costs around $750... ouch, and there is no gauratee that it is the module, no way of testing module. I tracked down 2 second hand ones from wreckers, 1 original part number and 1 updated module and both allowed the car to still surge while at 100klm.. is this a coincedance or is there another issue with my car.. stock car, not on gas, tyres are standard..

The only other thing i thought it could be was the electric motor that drives the cable for the cruise control... is this likely and how can i test???

Is there anyone in the Boronia area Melbourne that has a Gu with cruise control working correctly that is willing to swap modules for 10 mins to confim it is the module (a big ask i know... thanks in advance)

Can anyone help please as very annoying on the road... thanks Wayne
 

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nissan
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I have no idea of what a 4.8 looks like under the bonnet but have you tried backing off the cable where is connects to the throttle? On a series IV 4.2 Diesel the accelarator and cruise whilst both connecte to the diesel pump run separate cables. I found that if your cruise cable is set to tight it feels like it's surging at 100km/h. Whilst Nissan may have checked the throttle cable and position, is it possible the cruise control cable is set to tight? The extra slack may help smooth it out.
 

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nissan
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mine was doing that till i did the pcv(power control valve) mod. If you try searching '4.8 pcv mod' it should come up. Simple little mod to the inlet. My phone internet wont let me search it for you. Pete
Yep that and the cruise mod so that you can set cruise in 4th instead of 5th will both make the surging almost disappear.

The problem is that at 100kph in stock form the 4.8 is barley working so the PCV valve closes up and then it loses power and tries to compensate which it does and the valve opens again giving the motor heaps of power (surge) then backs of and repeats.
 

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Nissan Patrol 4.8
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Discussion Starter · #6 ·
Thanks lads thats all awsome.. have already done cruise mod... that was easy and a really useful mod.. i am about to do pvc mod so will look forward to the results. At the moment the truck is a the panel shop getting the back of wagon cut off into a space cab..(wanted a 4..8 ute with extra leg room for i am tall). so when its back i will do pvc mod.... i have put it into a automatic shop in Dandenong area who really knows 4.8 and he is fitting the vale body upgrade (amoung other things) to firm up shifts and increase clutch pressure, i am reall y looking forward to seeing the results of each mod so i am doing each one in sequence to see how each mod affects the truck... will keep you posted on the results if you like, not sure if i am allowed to refer to business names and costs of mods on the Forum???
Anyway thanks for the advice.. Wayne
 

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ive done the mod and since i have swapped to 3.9 diff ratio mine is now surging. didnt have any surge before with or with out the mod. can be a little annoying on longer trips
 
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