4wd Is Still Not Working & Some Other Problems

[omega36]

Hello! I hope you guys can shed some light on this for me...

#1 - 4WD is still not working:

I have a 1990 BNR32 GTR that I bought in February, and as far as I am guessing, the 4WD has not worked since way before then...

I found out that the 4WD meter wasn't moving a bit when the back end was spinning one rainy day, and I though to myself: WTF.

Anyway, could anyone give me some advice as to where I should start looking? The 4WD system does not work at all. There is NO 4WD light on the dash whatsoever, not on start, not on running, never - and if this is the case I believe the 4WD computer isn't even giving fault codes at the back. All fuses are fine. I have a Mines ECU.

I was sold this car as a car with 'minor mods' and "only a exhaust and airfilter"... anyways, my mechanic found a BURNT OUT Tomei HICAS lockbox under the engine recently, and so I imagine there's other stuff that's effed up? He removed the Tomei box. He then said the wiring to the ECU was shitty as well. The fluid resevoir was also topped up...

Where can I find the ATTESSA signal lights? Is it obvious to see the flashing lights? How do I start the diagnosis sequence?

#2 - Leaking differential

The rear differential is leaking on my GTR, it's only obvious when the car is at an angle, ie, it's pooling inside the case... what would cause this? I have never drifted this car or hit any hard bumps.. could this lead up to the problems with the 4WD? Or have nothing to do with it?

#3 - Not so great compression

A recent compression test revealed scores of roughly 120-123 across all cylinders. There are no vacuum leaks, what should I start to prepare for or what could be the main reason for this? All I know is that this generally means an engine rebuild will be needed in the not so distant future?

#4 - Black smoke

When I push the car a bit hard I see some smoke out the back, not lots, but enough to make it evident, is this normal? I watch lots of drag racing videos and see cars sputtering out smoke on shifts.. is this normal?

I really appreciate all your help and input with my issues... all I'm trying to do is to get my GTR to decent standards but I am struggling to do so with all these problems. If anyone in Melbourne could offer any assistance that would be cool too.

Cheers

[djr81]

First peace of advice: Sell the car & get a good example. Sorry if that sounds harsh but it will almost certainly cost you more to bring it up to spec than turning it over & finding a better one. But anyway:

1: Check the error codes (if any) on the ATTESSA unit. The light is under the ATTESSA unit & can be seen easilly if you park the car in the shed.

A Tomei HICAS unit under the engine? Um, eh?

2: If the diff is leaking then get the seals fixed. Also check the backlash & the "tightness" of the LSD function whilst you are about it.

3: That sort of compression is symptomatic of a tired motor. So yes, start saving.

4: Is it normal? Yes. Get the AFR's checked on a dyno as you may well just be wasting fuel & money with an over rich mixture.

[blind_elk]

...There is NO 4WD light on the dash whatsoever, not on start, not on running, never

Then the globe is probably blown.

Check the fluid level in the ATTESSA reservoir in the boot.

GT-Rs (Skylines in general) run RICH on boost - it's quite normal to see black smoke under those conditions.

[GeeTR]

Oh dear, this R sounds used and abused. Who ever did the mechanical check for you, needs a zip tie around the neck.

[arbess]

Um dudes...

since you have said the AWD meter doesnt move at all, the first thing i would of done is check to fuse in the engine bay. Its in english.

To me it sounds like someone sold you a lemon. if your AWD light isnt on when you turn your car to to "ACC" position then that means your bulb is out.

By doing these first you could save yourself a huge headache and lots of money.

Having compression that... usually a healthy gtr sees 140+ and I have seen averages around the 160 mark. (I quote these figures from many skyliners here on SAU).

Honestly I think you were taken for a ride when you purchased this car. I would do what others say and sell, that engine doesnt sound happy, but please get a 3rd opinion from a DECENT mechanic, i mean that with a big emphysis on the decent part if you havent noticed.

For you my friend, check that AWD bulb in the dash, replace that FIRST so that you can use that to see if AWD is busted when you start your car, after you have re-installed the cluster.

Then if, when your car is started, the AWD is on, turn your car off and inspect the fuse in the engine bay (in the little black box), it should be a 30A fuse, mine is green of colour. If that isnt in there, get one asap. If it is in there, test it to see if it is busted, use a multimeter (i cant remember if you can visually inspect it to determine if it busted). If it isnt there go buy yourself one that will fit, put this in, hope to god it fixes your problem.

If all else failes, then further determination of your problem is needed.

I think this is your essential first steps to save you lots of time and money.

Keep us all posted on your progress.

Edited May 20, 2008 by arbess

[R34GTFOUR]

if some one has gone to the effort to rip out the awd bulb then its more than likely something major was wrong with the system and they just covered it up to sell it.

It may have a buggered attessa pump

Edited May 20, 2008 by R34GTFOUR