Fluctuating Idle & surge under acceleration

[nathand22]

Ok guys i have been reading through heaps of posts trying to find ones with similar sounding problems to what my ute is doing but cant find the posts i know i have read.
I would not have worried about it if i was trading my car in on the new one but my brother inlaw is buying it and i would like to get it sorted first.

So in the mornings and only then when i start it up and let it idle while loading tools ect, the idle starts to fluctuate from normal RPM to a few hundred RPM lower and back up again, It will return to normal idle after a few kms of driving.

That was all it was doing until the other day when it started to surge or miss under acceleration. It seems to be once it is hot and has been driven for OVER 15 or 20minutes, I can make it do it more noticeably if i have been driving then stop and let it idle for a few minutes then go to drive of and it surges and inbetween gear changes it almost feels like it will stall and isnt smooth letting the clutch out going into the next gear.
Once your in top gear and cruising its all fine, but change down and give it some and you can feel it not revving out cleanly.

Any ideas??

Thanks Guys,
Nath

 

[d22dave]

trade it in, Anything been done with the fuel system lately, Filters or disconnecting of fuel lines

 

[nathand22]

Cant Trade it Dave my brother has bought it, I did disconnect the pre filter, but that was only done to try and fix the problem.

 

[Old.Tony]

I'd suspect turbocharger actuator, particularly given the model that you've got.

 

[nathand22]

Thanks Tony, i will get nissan to check it out. Is there any simple ways you know of to test the little bugger my self??

 

[nathand22]

I did read this in another thread, But the problem and subsequent fix is been explained by a third party so i dont know who he is referring to and also the parts he describes dont quite make sense.

This problem sounds exactly like another thread on here....just can't seem to find it. The thread outlined the same problem and how the author went to Nissan and was diagnosed as needing a new fuel pump and rail. The author didn't agree with that assessment as the issue was intermitent.

After much investigation the issue turned out to be the fuel regulator and/or pressure sensor which are both independent parts on the fuel pump. You can source them from Denso if Nissan won't do them. The issue was something to do with the above mentioned parts sending the wrong signal to the ECM (either too high pressure of too low). The author changed out the parts and the car hasn't missed a beat since.



Anyone know the thread he is talking about??
Or what he means by "FUEL REGULATOR / PRESSURE SENSOR" ?? Spoke with a Denso supplier today and he new nothing of those parts...............

 

[Old.Tony]

If you watch it, the actuator arm should move freely at idle, almost vibrating (slowly, 1-2 pulses per second) over a 3-5mm range.

 

[nathand22]

If you watch it, the actuator arm should move freely at idle, almost vibrating (slowly, 1-2 pulses per second) over a 3-5mm range.

It does seem to do that, But i will check it again in the morning.
Cheers,
Nath

 

[nathand22]

Tony I just received my "scangauge" today, is there a setting i should look at that may help diagnose the problem??

 

[Old.Tony]

I guess you could stick it at the bottom of a steep hill in first and climb up holding a relatively low pace. The turbo should provide around 14-15psi for a decent hill and it should hold that fairly steady.

If your actuator is behaving fairly normal, it could be something else. Could there be air getting in the line, just before the fuel pump? It could be a dirty MAFS, too, come to think of it. I removed mine today and gave it a spray with contact cleaner. You could try that too, see what happens.

 

[nathand22]

Thanks Tony, I will plug the scangauge in and have a play. The actuator did seem to be pulsing normally this morning but it wasnt doing the irregular idle so i will have to check it when its doing it, It did surge as soon as i took off down the road. Its just strange how inconsistently it does it.

The MAFS got a spray the other day when i first noticed the surge, But no difference to speak of, might be worth another try though.

It could be a leak in the lines, so i will check all the fuel lines and clamps for any noticeable leaks as well.

 

[nathand22]

OK i sprayed the MAFS again but no real difference,
took out K&N and put in a brand new genuine Nissan filter no difference and checked all the fuel lines to make sure the clamps were tight and they all seemed fine.

What i did notice was when i first started the car the actuator was moving up and down, but once i drove the car to drop my daughter off i checked it again and it wasnt moving at all, BUT the idle was normal..........
Should the actuator stop moving up and down on idle once the engine is at normal operating temp??
Can someone have a look at theres when the engine is hot and get back to me please??

 

[Old.Tony]

I'll take a squiz next time mine's hot. I think it still moves - but I'll make sure and will let you know.

 

[nathand22]

That would be great, Thanks again

 

[nathand22]

Ok so thought I would post a bit of an update, the idle problem is getting looked at again tomorrow at my local Nissan dealer so don't really have any answers yet, BUT the surge that was there when accelerating has just disappeared???
It was doing it on Saturday just before I give the whole car a big clean which included pressure washing under the car and in the engine bay.
The strange bit is as soon as it was all finished I needed to drive it to go pick some stuff up and the "SURGE" was gone!!
I thought it was just a fluke, BUT after 4 more days of driving it hasn't done it at all
I know it's good to clean the car but when it maraculesly fixes stuff it's bloody amazing.... Seriously have no real clue as to what has done it but I like it.....

 

[longy509]

Might have to give mine a clean tomorrow

 

[nathand22]

Do it mate!! It cures all ailments!! It's better the. Adding two stroke to diesel

 

[longy509]

Ha clean ute is now priority one for weekend and on the scanguage go to default reset and start from scratch it will be a lot quicker then trying to recalibrate in a new ute

 

[nathand22]

Thanks for the tip longy. I didn't end up putting it in the old ute, i will just wait for the new one and figure it out then but I am bloody hopeless with these new fangeled gadgets so I could be back asking for more tips.... Besides Krafty loves when I don't bother to learn shit for my self and just go pestering everyone else..

 

[longy509]

Thats what the forums for isn't it and also Krafty can u help me out with what sort of lift i need to fit 265/75/r16 tyres on my ute