Slight Miss/Surge Problem with RB25DET

[Lone]

Ive just recently purchased a Nissan Stagea RS4 with a 4WD RB25DET as standard for those who dont know them, practically its a R33 RB25DET system.

The problem Im encountering is when cruising on flat generally at 100km/h with about 1/5 throttle continuious the car will start to surge/miss very minor, but you can feel it in the car kind of spluttering and just makes you shake back and forth in the car, nothing overlly noticeable, but if I take off overdrive it will be more noticeable shaking and you can just see the tacho slightly (like 100rpm) dropping revs and going back up. This problem I notice can occur at even 60km/h, it seems to be at any speed that I hold the throttle continously.

Ive done a quick searhc on here not to find any solutions/common problems.

My theorys are that it could be maybe the O2 sensor gone as the car is doing when I keep the throttle at the same point (cruising) and it starts doign the shaking about 5-10 seconds after holding the same position which would be aroudn the point the O2 sensor goes into closed loop?

The only other theory is a TPS but I doubt that there woudl be many problems with these?

Hope some people can give me some ideas or past experiences, and also I must also mention its a great forum here and great setup and proud to be a member

[aKTiVE]

hmm thats really strange...

i have had a 'similar' problem but not as extreme in 2 of my cars.. when doing a relatively high speed, if i held the throttle in one position, to maintain a certain speed the car would seem to get confused between cruising at speed and being in the torque curve and where boost comes in with a punch.. if i then stabbed the throttle it would accelerate fine, if i let off it would be fine too.

It was extremely strange... i put it down to ECU getting a bit temperamental, i changed my fuel filters as well just incase.

Yours seems a bit more severe though because its doing it at 60kmh...

I dont know whether it could be starving of fuel or what, but it sort of seems like fuel surge. Could you change your fuel filters and have your fuel pump checked out?

Does this happen 100% all the time? Or is there an instance where it happens?

i.e.

In hot weather?

Low on fuel?

etc..

[Lone]

I haven't changed the fuel filter, was going to hope to do them this weekend, but would imagine more to be a continual problem throught hte whole rev range, be interesting to see the fuel pressue when its happening and that could more narrow it down to fuel pump/filter but at the moment im doubting that could be the problem.

At 60km/h its only very slightly noticeable, I dont think a passenger would even notice it though, at 100km/h they do and at 60km/h it would have to be on a very flat road as it feels almost like going over a set of minor bumps or even a slightly corrungated road.

It has happened the past two days of me owning the car in both during the day and night so outside temperatures dont seem to play a factor. I might even if I get the chance try and extract some codes on the weekend, but dont think ill have too much luck.

Hopefully someone here has also had a past experience and been able to fix it.

[Lone]

Anyone else here have any idea what coudl be causing this problem?

[BHDave]

If it has an aftermarket ecu the light load tuning could be out.

[Lone]

No it doesn't have an aftermarket ecu, no mods at all standard as :|

[x2shy]

coil packs shot?

[mattR33]

my skyline r33 does that....... at about 4500rpm flat in 3rd gear it starts to feel like its missing

[blind_elk]

I've recently put one of those engines into a R32 GTS4. I'm running Wolf 3D, and I get a really bad surging at low throttle running (like creeping in traffic). We've figured the problem is a wear spot in the TPS, because when you "calibrate" the Wolf for the TPS, it starts at 0, goes to around 10, drops back to 0 then climbs to 100. Makes it virtually impossible to tune for "injection overrun"

Could be a similar thing happening in yours. Disconnect the TPS and measure the ohms across pins 1 & 2 (?) as you run (slowly) from closed to open throttle, and see what sort of readings you get.

[Lone]

Update: I have now tried many other solutions to this problem still with no luck, the following are the things I have done to the car since I last posted in this thread..

* Replaced spark plugs with ngk 0.8mm gap

* Electrical tape on coils as a temporary measure

* Cleaned throttle body

* Replaced O2 sensor with new one

And just now adjusted the throttle position sensor placement to increase the voltage at idle (incase it still thought throttle was shut and doing injector cut too early when throttle was slightly open as this is when the problem occurs.) The voltage at idle was 0.45 then went in .05 increments to 0.70 still with no change other then higher idle which shows it was making a change but not fixing the problem. Also checked the voltage was increasing with turning the throttle..

Argh, im starting to run out of ideas, anyone can help at all??

[Bobby^]

my r33 does it too. seems to be a common problem.

[Lone]

Judging by other threads it does seem to be occuring every no and again, out of interest was yours an auto?

Certainly with this many people having this problem someone must have some solutions?

[MYS013]

I tried the electrical tape on the coil packs trick with my RB25DET, didnt seem to make any difference. I bought 4 working ones and it fixed my problem. I would see if you can borrow some known good ones and give them a try.

[tigerleo62]

Sounds a bit like what my car has been experiencing ever since my weird pulsing then 4WD warning light thing:

http://www.skylinesaustralia.com/forums/sh...ead.php?t=63842

I have been experiencing minor surging/missing - sometimes feels as if the drive is transfered to the front wheels more for just a second or so then back again... however my car seems to feel much better on new smooth roads - unless the new 'smooth' road isn't that smooth - then I feel as if I need new shocks!

I was hoping that a full tune/service would sort the problem out (with the surging, not the shocks) - they would hopefully read anything wrong in the ECU and know what to do, but perhaps I am too hopeful - or perhaps I have become hyper-sensitive to what the car is doing after the weird experience I linked to above.

[Enterthestagea]

Why wouldn't it be the torque converter trying to lock up. My stag does it in every gear once you start idling along the road. The revs drop and it cruises along until you touch the throttle again and it kicks back like half a gear, but stays in which ever gear it was in. Maybe the torque converter / filter is effecting the revs.

You can run a fault check on the auto easy enough just by turning the key on and off and going through the auto gears gears.

Or maybe I wouldn't have a clue either!

[natho]

throttle position sensor?

[tigerleo62]

You can run a fault check on the auto easy enough just by turning the key on and off and going through the auto gears gears.

How's that? What do you do and what tells you the fault(s)? Is there a link to this, or is this 'common' knowledge that the total lack of anything mechanical stored in my head has neglected me to be aware of?

[skylinegal]

my r33 gtst does something similar but when going at higher speeds (accelerating from about 110-120k and in 4th gear) It was happening regularly until had safcII installed, which seemed to fix it. It has done it twice just recently so next service I will get the mechanics to check it out again. It is quite a severe miss and feels like the car is kangaroo hopping, which is a bit scary when it happens.

[The Dan]

Cmon people. Think outside the box for a second....well think about the box actually.

If it is while cruising along it kinda feels like your bunnyhopping on a really small scale.

It get's worse.

The first thing you need to try is change the transmission oil. It should get better.

If it does not get better, you have to replace the 4WD pump which SHOULD be located above the rear diff. What a prick to get to. This, ofcourse, is after you have had the 4WD pump tested. Anyhow, if I was a gambling man, I would bet both arms, a leg and my left nut that is your problem. I am very attached to my left nut, however, so I won't be putting it on the table if you know what I mean.

Do it!

[The Dan]

I must also mention that this will only effect the 4WD vehicles and it took 3 of us 5 weeks to find out what the problem was. So it is kinda privilaged information until now.

Some WRX rally cars have the same issue. That's how we stumbled upon it. We found that an oil change made it slightly better for a while but it kept coming back and getting worse and worse. You could definately see it in the tacho and feel it in the car. It wasn't anything like a missfire coz the engine note didn't change that much. With a missfire you can hear the engine skip a beat.

Hope you sort it out.