Weird 'pulsing' then 4WD warning light

[tigerleo62]

On the way home through peak hour traffic, as I was stopped in the traffic I felt a low pulsing sort of vibration at around 50Hz or so...

I turned off the radio to make certain it wasn't the stereo, but the pulsing was still there - almost like the enging was hunting. I looked at the tacho, and it was fluttering ever so slightly, so I figured the car must need a service etc...

Further along the road I noticed the 4WD warning light had come on and the car seemed to be lurching every so often - like the 4WD was cutting in and out or something - so I thought, bugger, the car really does need a service AND something isn't right.

Closer to home the tacho started going berko - it would rise to about 2500 and then drop to about 1000 RPM, but the car didn't feel it was revving that hard or that low - there was a definate feeling of change of power, but not to the extreme that the tacho was indicating. Oh sh*t, I thought to myself - this was something serious and I thought the car was going to die on me at any moment.

So I pulled into a deli that I was heading for on the way home and decided to pull out the 10 AMP fuse for the 4WD/ABS - the fuse looked fine, but I replaced it anyway with a new one and drove home with no problems...

So, what do you reckon? An intermittent fuse on its way out that was freaking out the ECU or whatever? Admittedly I didn't need to drive to far home after I replaced the fuse, but the 4WD warning light had stopped coming on and the tacho wasn't fluctuating strangely after that...

Any ideas or similar experiences??

[Terminal]

I've had exeriences where fuses look fine but either don't work at all or the connection is dodgy. Sounds lucky to me that you didn't have something worse happen.

I've learned not to trust a fuse by looking at it, i always test for continuity

[tigerleo62]

Yeah I know what you mean about not judging a fuse by its looks, that's why I changed it - glad I have a box of fuses in the car...

The car has warranty - just a pain in the arse when the car yard is on the other side of the city/river from where I am and I am so damn busy at work at the moment... I want to take the car in to be checked out, but it's a real hassle at the moment to find time.

[Sydneykid]

I did a bit of testing yesterday and when I turn the boost up to ~1 bar, the ECU seems like it does its usual "rich & retard" strategy based on the excessive readings from the AFM. At the same time the "Power" light comes on, at the tranmission selector on the console. This appears to foul the plugs and the engine goes very sluggish and misses on one or more cylinders. If I turn the car off, the ECU seems to reset itself and it runs fine again. Until the next excessive airflow event.

Does this sound like other's experiences?

[tigerleo62]

Hmmm, "the engine goes very sluggish and misses on one or more cylinders" could describe what I experienced and am still experiencing to a much reduced degree...

My power light doesn't work, so I can't tell whether that came on the other day while the car was freaking out, and the only 'performance mod' I have done to the car is replace the rubber strip around the air intake

Driving today the car had moments of what would be described as 'sluggish' and then seemed to be fine - like something was cutting out momentarily - perhaps electrical or fuel, but I guess that could mean absolutely anything could be wrong...

I had a car once that started cutting out all the time - I thought it was electrical as the tacho would do strange things and the the car would cut out like the ignition had been turned off - turned out to be crap in the fuel tank clogging up the fuel filter...

Must take my stagea in for a full service & inspection now that I've had the car almost two months - hopefully that will find out what's going on. Damn I hate driving when I find I am questioning the reliability of the vehicle.

[Lone]

Id try it for you, but dont know how well the stock turbo will hack the 1bar pressue?

[Stagea_RS4]

I've had the some problem with the 4WD warning light coming on.

The Dealers mechanic found the 4WD tranfer case stuff.

The mechanic said alot of the GTRs have the some problem which happens in japan where the cars have big wheels on the back and small wheels on the front which changes the 4WD ratio.

I'm lucky the car is under WTY, because the damage comes to $3000.

I hope this helps?

[Tangles]

TigerLeo62 - where was this 10amp fuse located? Ive got a similar problem (4wd and Abs not working), and dont have a list of fuses that sit under the dash.......

Cheers - Brendan

[boomtheroom]

I've had the some problem with the 4WD warning light coming on.

The Dealers mechanic found the 4WD tranfer case stuff.

The mechanic said alot of the GTRs have the some problem which happens in japan where the cars have big wheels on the back and small wheels on the front which changes the 4WD ratio.

I'm lucky the car is under WTY, because the damage comes to $3000.

I hope this helps?

so what was actually wrong? just diffferent size tyres?

[Duncan]

different tyre sizes (smaller on the rear) make ATTESSA think the rear wheels are spinning, which makes it run front torque all the time, which burns out the clutch packs pretty quickly.

difference in diameter of front and rear tyres of about 3% is all it allows for, some people have even had trouble with same size and brand of tyres front and rear as they wear out

[66yostagea]

I've had Nissans since 1978.

One problem I've had with them is the fuel pressure relief valve. It ceases to bypass excess fuel back to the fuel tank. This makes the engine seem like its flooded. Idles great to about 2000 then dies in the arse. The other problem I've found is the three connections that feed temperature info to the ecu. A

loose, dirty connection can cause rev fluctuations caus the ecu is confused as to what temperature the engine is really at. The ecu sort of goes hot cold hot cold etc.

The R30 I just bought had both these problems and so did the 30 hatch I got new in 1984.

Maybe its a fault of factory #5.

I dont know how this could affect the 4wd system. I've not had any problems (touch wood) with my S1.

[boomtheroom]

anyone willing to do a write up with pictures of points of interest, step by step of the entire procedure bleeding the altessa system?

[Duncan]

Well its pretty straightforward.

Fill up the ATTESSA resoviour in the back.

Put the rear of the car up on car stands, start the car and get underneath.

Take a 10mm ring spanner and a bleeder pipe and bottle under the car with you

Open the bleeder nipple on the rear of the transfer case....it will bleed fluid straight out when the car is running. When the bubbles stop (if there are any) close it off.

Make sure there is still plenty of fluid in the boot

Now for the tricky one....there is a second bleeder above the driver's side rear driveshaft right up on the chasis....nasty to get to.

Same thing, bleed it until there are no bubbles then lock it off.

Done!