YD25tdi rough idle

[likemike88]

I have an '08 D40 with the 2.5 turbo diesel that is running rough at idle. It is an automatic with the EGR still in place, I have fitted a 3" exhaust and new DPF fitted (the rough idle was present before the exhaust was fitted)
The car has just over 200 000km and has been dealer serviced up till 185 000. The car doesn't blow smoke, still has plenty of power, loaded and unloaded, still getting over 650km to a tank
I have so far checked the following
-replaced air filter
-replaced fuel filter
- cleaned MAF sensor
-cleaned throttle body
-run injector cleaner (I have only just done this so waiting to see the results over the next few tanks)

If anybody has any other hints or ideas it would be muchly appreciated

 

[Cobez]

Undo the negative terminal on the battery, turn the ignition on and leave for about 20 seconds, turn ignition off, then reconnect. This does an ECU reset. I had a tiny shudder on idle after doing exhaust etc, this fixed it perfect.

 

[likemike88]

Thanks, I'll give it a go!!!

 

[doc]

Yep, in addition to what Cobez said, when the neg terminal is disconnected, try cranking the vehicle using the ignition key. Will completely drain any residual current. ECU will be reset.

 

[nathand22]

My 2010 had an issue with fluctuating idle only when cold and it turned out to be the suction control valve, once it was replaced no probs at all.

 

[likemike88]

Thanks guys I'll give it a go!!!

 

[4BYFOR]

Thanks guys I'll give it a go!!!

Matey I would try doing the pedal reset it solved my rough idle issues before you buy anything else.
Have the car in park or neutral and switch it from the off position to ignition and wait 3 seconds as soon as you see some of the dash lights disappear press the accelerator pedal 5 times really fast then wait with your foot off the pedal for 7 seconds then press and hold it down for up to 10 seconds then the engine light should start flashing (you may need to try it a few times but you will get it) once you have it flashing let go of the pedal wait a few seconds then hold it down for about 10 seconds ( this will clear the ecu and reset the fuel curve and values) then start it without switching it back to off then go for a good 5 to 10min drive come back home switch it off. Then you can see in the morning if it has solved your issue.

 

[Cobez]

What's the difference between that and disconnecting the negative terminal?

 

[4BYFOR]

What's the difference between that and disconnecting the negative terminal?

We'll I tried doing that when I had issues and it didn't do anything.. But the pedal reset worked a treat. It's always good to have other options when 1 might not work for you like in my case

 

[bennyv]

Is the rough idle a indication of anything? I feel that resetting it might be a band aid fix for the car screaming for love?

Mines due for a service and the idle is rough as guts, so any further information would be awesome.

 

[4BYFOR]

Is the rough idle a indication of anything? I feel that resetting it might be a band aid fix for the car screaming for love? Mines due for a service and the idle is rough as guts, so any further information would be awesome.

We'll if it fixes the issue then I doubt that there is anything majorly wrong with it. If it doesn't fix it then you can say that it needs some love and attention in some area.. It will most likely be the SCV that is key to regulating the fuel pump.

 

[sportfish]

Hi guys, my 2011dies manual with 55k has been doing this for 20,000kms but has got worse the last few months, nissan have had the car for the last 2 days and it has idled rough for them as well but they cant find the fault because it hasnt thrown an error code?? They want to give the car back but i want it fixed because warranty runs out in 3 or 4 weeks, i am worried it is something serious like timing chain etc.. Any ideas of what i should do, the car has been nissan serviced since new, cheers col.

 

[nathand22]

Hi guys, my 2011dies manual with 55k has been doing this for 20,000kms but has got worse the last few months, nissan have had the car for the last 2 days and it has idled rough for them as well but they cant find the fault because it hasnt thrown an error code?? They want to give the car back but i want it fixed because warranty runs out in 3 or 4 weeks, i am worried it is something serious like timing chain etc.. Any ideas of what i should do, the car has been nissan serviced since new, cheers col.

As i have said before, the suction control valve can and will cause issues with idle as it did with my 2010 ST, It wont necessarily throw a fault code (well it didnt with mine)
Nissan could not find the fault at first and had the "tech line" opened for days, they even replaced the timing chain as they WRONGLY believed it was the cause of the idle issue.
I Asked them from the strat if it could be the SCV and they said no, no very unlikely, lol only to cal me up after replacing the timing chain to say they had found the problem and it was the SCV!! well what do you know im sure they told me "NO NO very unlikely"

Anyway it may not be but it is a good point to bring up with Nissan and let them know you know of others that had the problem fixed by replacing the SCV.

 

[sportfish]

Thanks for that il ring em in the morning and mention it, although you would think they would know the d40's inside out by now! Il let u know how i go thanks.

 

[sportfish]

Hey there, got the car back from nissan today, they replaced the suction contol valve, so hopefully that was the problem, il find out in the next few mornings!

 

[Diesel Marks]

Id replace the Vacume control valve too, (suction Control valve etc) Regulating Valve Kit is what nissans box has on it.
Thai 2010 25mm unit is #A6860-EC09A
http://t3.gstatic.com/images?q=tbn:ANd9GcSzg1NwOYF0n15Xv_PtIBHsKu5Ex7-vR-0BdrWu-snQBFeI8l5C

Car would stall at lights after warming up and revs dropped below 1000rpm. restart then conk again. Could still drive it but needed to keep the revs up. Was very very annoying.
I cleaned MAf, Cleaned Throttle Body, Reset ECU, Fuel rail re learn also, Changed out this part ($350 non trade/ $270 trade) and it hasn't faulted in 4 days now! Cheering. Took 20 minutes to do Nissan wanted to charge me 2.5 hours. Part is avail on ebay for $130 but I needed it now.
Apparently Nissan superseded the original part with this new one so they must be aware of the fault.
Its 2 allen Key bolts on the injector pump at the back. There are two types. Measure yours and tell the dealer. Mine 2010 Thai is the 25mm one there is also a 45 mm one.
I have pics but not hosted.

 

[sportfish]

Well its been a week since nissan changed the scv and there has been not one sign of any rough idle or stalling, happy days, i must say though this is my 3rd navara and its the first time ive had a problem in any of them so i cant complain too much, cheers col.

 

[nathand22]

Well its been a week since nissan changed the scv and there has been not one sign of any rough idle or stalling, happy days, i must say though this is my 3rd navara and its the first time ive had a problem in any of them so i cant complain too much, cheers col.

Great outcome, and im also pleased my guess was on the money,,

 

[Diesel Marks]

Happy Days

 

[Stevo_d40_05]

I've got the same problem. To the point it will stall occasionally.
Everything used to go fine till I took it to a bloke for a service.
He used all aftermarket filters and belts.
Now belts are squealing like bitches and it's idling rough as guts.
At first it went into limp mode when I got it back but that has been solved due to the reset described above by 4BYFOR.
My particular model has two fuel filters on it so I'm thinking it's the one I have not replaced by myself yet. I already replaced the one the dodgy mechanic put in.