Hey everyone,

The day was going quite good today until I lost power on the motorway all of a sudden. Mine is a jap spec and the stock boost guage is not reading past 0 and there is no power at all. After reading a few threads here I believe its the passenger turbo seized. Now the symptom of this that I can think of is my oil pump. I always check my oil and water before taking the Z on the road and them both are always fine. But while driving every now and then, the stock oil guage would show really low readings. Now I have read here that the stock oil pressure guages are poo. So I did ignore it all this time but obviously, it was reading right. Just wanted to confirm that it did mean that the oil pump wasn't doing its job properly at all times or could it be anything else due to which the oil didn't reach the turbo much??? There is no smoke what so ever..

I'm looking to get this fixed in the next few days so wanted to know what else I should get looked at regarding this. Any help and advice greatly appreciated guys..:)

Best regards,

Zee..

The general cause for this is oil starvation to the bearing, the passenger side turbo oil feed can become blocked at the feed point just after the oil pressure gauge sensor where it narrows.

Most times its just bad luck and does not mean the oil pump has a problem, changing the turbo, cleaning the oil lines out and making sure you have fresh oil every 3k to 4k miles will sort it.

 

Jeff TT

Edited March 27, 200916 yr by JeffTT

The general cause for this is oil starvation to the bearing, the passenger side turbo oil feed can become blocked at the feed point just after the oil pressure gauge sensor wher it narrows.

Most times its just bad luck and does not mean the oil pump has a problem, changing the turbo, cleaning the oil lines out and making sure you have fresh oil every 3k to 4k miles will sort it.

 

Jeff TT

 

Thanks Jeff. I suppose my luck was quite bad here as the gauge reading when showing low did then rise again back to normal everytime. Perhaps you are right about the blockage then which opened up everytime. Me being an idiot, just thought that the gauge was talking rubbish with the high and low readings all the time due to it supposedly being crap but should've been extra careful I suppose and got it checked out. I just checked it out for any oil leakages underneath and again oil pressure is reading fine. Tut..

Have you tested to see which turbo is seized for sure?

 

Jeff TT

I haven't yet tested it..Am going to get that done tomorrow hopefully..But what I noticed was that my dump valves used to kick in at 4K revs. Now just the driver side one dumps and not as loud..

Also you can feel slight power at 4K+ revs which has got to be the 2nd turbo which I think is the driver side too so..

i had this problem when i first got my car, no boost at all so i tested which turbo by attaching a boost gauge to the little nipple coming off the turbo hard pipes next to the rad. quickly realised it was passenger side so got another engine with turbos as my oil pressure was reading very low. pulled the engine all out only to discover that the last tit to service my car had left the plastic wrapper on the top of the oil filter, with only a small slit to allow oil past. I thought that must be the reason so cleared all my oil lines through and put new turbos on it only to discover it was still very low followed by another fried turbo (thinking it will be ok - big mistake lol).

Ended up having to change the engine (i'd already bought a spare to rebuild anyway) and turbos again.

Anyway, make sure you definately find the cause otherwise you might end up like me and having to pull the engine twice and looking like a right idiot! Although on the plus side i can get the engine out in 5 hours with no help at all now :D Still haven't started stripping it down yet though to find the cause but its most likely a bit of that plastic floating about in the feed on the passenger side of the block as the lines are completely clear!

Edited March 28, 200916 yr by damo-f
missed some parts

i had this problem when i first got my car, no boost at all so i tested which turbo by attaching a boost gauge to the little nipple coming off the turbo hard pipes next to the rad. quickly realised it was passenger side so got another engine with turbos as my oil pressure was reading very low. pulled the engine all out only to discover that the last tit to service my car had left the plastic wrapper on the top of the oil filter, with only a small slit to allow oil past. I thought that must be the reason so cleared all my oil lines through and put new turbos on it only to discover it was still very low followed by another fried turbo (thinking it will be ok - big mistake lol).

Ended up having to change the engine (i'd already bought a spare to rebuild anyway) and turbos again.

Anyway, make sure you definately find the cause otherwise you might end up like me and having to pull the engine twice and looking like a right idiot! Although on the plus side i can get the engine out in 5 hours with no help at all now :D Still haven't started stripping it down yet though to find the cause but its most likely a bit of that plastic floating about in the feed on the passenger side of the block as the lines are completely clear!

 

Thanks for your input buddy. Much appreciated and I will get the feed checked out and get all the oil lines cleared. Defo don't want a same problem occurring twice. Its so hard to digest a situation where something with the car goes wrong due to something really silly when we are trying to be a couple of steps ahead taking care of these cars..

Right...Did alot of fiddling around with the car and not come up and to any good result but just found out a couple of things that I wanted to ask about. Would any of the dump valves dump if any turbo is seized?? As both mine seem to be dumping fine..The springs in the dump valves are really hard and long..This shouldn't be a problem for the turbos right?? Also the pipes that go on the dump valve still is giving out air..Not sure if thats from the turbo.. Any views on these anyone??

where are your dumpvalves sited? in the engine bay or under the air filter?

 

What do you mean by you can feel power at 4k revs it must be the second turbo? the turbos in the 300zx are not sequential, they both boost at the same time and are the same size, if one is siezed, none will boost.

 

and if you can hear the dump valves then your car must be boosting.

where are your dumpvalves sited? in the engine bay or under the air filter?

 

What do you mean by you can feel power at 4k revs it must be the second turbo? the turbos in the 300zx are not sequential, they both boost at the same time and are the same size, if one is siezed, none will boost.

 

and if you can hear the dump valves then your car must be boosting.

 

Another Z owner quite sometime ago mentioned to me that one turbo kicks in between 2-3k revs and the other 4k. Maybe that's wrong. But now as there is no proper boost, while driving if I give it the foot, I definately feel a slight pull over around 2k revs and a little more around 4k revs. And the dump valves are definately dumping but are not as loud as they should be. These are sitting under the air filter. Upon check up I did get the 6th coilpack and injector to work as they weren't working and now the car is smoother. The plugs defo need changing too. But don't think these have got anything to do with boost. But now I'm thinking that maybe the turbos aren't seized as the dumps are dumping...:confused: But a little more fiddling around in the next few days would show the result though..

have you removed your balance bar lately if so then maybe its not on propperly ??

Just did this morning while getting to the coilpack under it on the right and the injector. Thats definately fine. What I did however put on just recently was a new Apexi induction and Pace Side Mounts. Checked the piping from under the car on the coolers but they seemsed fine. I will check properly with the bumper off..

well whoever that was, was miss informed.

 

Doesn't sound to me like your turbos are busted, have you checked for error codes?

ah, chances are its a boost leak then, remove the bumper and check those intercoolers

Just did this morning while getting to the coilpack under it on the right and the injector. Thats definately fine. What I did however put on just recently was a new Apexi induction and Pace Side Mounts. Checked the piping from under the car on the coolers but they seemsed fine. I will check properly with the bumper off..

 

well if you was thrashing it and one of the clips wasnt on properly these your problem

 

the same thing happend to me id just fitted sumit and drove it down the road and booted it and it went blerrrrrrrrrrr and stopped lol

 

coz one of my pipes had blew off :) so yea check all the pipes first and do a boost leak test ;)

 

and like pete said make sure ur getting a 55

Thanks guys..:) I will look into all this thoroughly and hope for the best and if still its the worst case then so be it. Will keep you posted..:)

When this happened to mine you could identify the side quite easily. Find a clear quiet road - floor it for 10 seconds - it won't be that fast - then stop open the bonnet and have a smell on both sides. The siezed side will have a very hot exhaust manifold due to the restriction placed by the siezed turbo. My engine would smoke a little on the siezed side as oil and muck was baked off the very hot manifold. You could also smell hot rubber! On mine it was the drivers side one that died after 140k miles.

When this happened to mine you could identify the side quite easily. Find a clear quiet road - floor it for 10 seconds - it won't be that fast - then stop open the bonnet and have a smell on both sides. The siezed side will have a very hot exhaust manifold due to the restriction placed by the siezed turbo. My engine would smoke a little on the siezed side as oil and muck was baked off the very hot manifold. You could also smell hot rubber! On mine it was the drivers side one that died after 140k miles.

 

Yes it is the driver side which seems dead. Just don't understand why the car would be dumping if tubs ain't working..

Incase the turbo has gone, and my pocket doesn't allow me to fix it for the time being, would driving it without the turbos working do any other harm to the car?? As there is no smoke or any unwanted noises and the drive is smooth..

Hi Zee, there is a very simple fool proof method to determine if a turbo is seized or not.

 

But firstly if you have zero boost on the gauge and no associated noise from escaping boost it will almost certainly be a seized turbo, however remember as the inlet uses the balancer bar to equal the pressure to both sides of the engine then it also means any boost been produced from the good turbo can more easily channel down the stalled turbo, in fact due to the exhaust exiting past the small impeller it actually causes a vacuum effect drawing the boost from the other turbo*

 

The method of checking this out will also demonstrate this very well, of course when you shut the throttle very quickly there is a sharp change in the turbo equalisation and some will exit the dump valves anyway albeit much quieter than normal.

 

1) Ok start by disconnecting the air flow meter.

2) loosen all four jubilee clips to the large intake pipes to the throttles

3) Choose a side and remove the large pipe completely

4) Start the engine ( yes it will run as it is ignoring the disconnected afm )

5) Take a latex glove and secure it over the steel pipe coming from the intercooler.NOT THE THROTTLE

6) Rev the engine and observe the glove.

What happened?

 

A) If it blows up then that`s boost from the turbo and that side is ok.

B) If it fails to inflate and looks like it is sucking in then that is the possible seized turbo *(remember the exhaust sucking issue)

C) Do the same test on the other side regardless of result, the engine may be a little unsteady with both pipes off and it helps if an assistant can keep the revs up a little for you.

 

7) Once established which side it is, switch off engine and remove the outer large rubber pipe from turbo to intercooler

 

8)Restart the engine and again secure the glove over the steel pipe this time the one directly from the turbo.

 

What happened?

 

A) Same result no boost? if so then that`s it confirmed defo a seized turbo.

 

OR

 

B) Better result boost now ok? then that means the intercooler or pipework to or from it is leaking.

 

Well thats about it, with a definitive answer you can then make a better informed decision on what to do next.

 

Hope that helps,

 

 

Jeff TT

Golden.......is all i can say. Good write up Jeff!!

Hi Zee, there is a very simple fool proof method to determine if a turbo is seized or not.

 

But firstly if you have zero boost on the gauge and no associated noise from escaping boost it will almost certainly be a seized turbo, however remember as the inlet uses the balancer bar to equal the pressure to both sides of the engine then it also means any boost been produced from the good turbo can more easily channel down the stalled turbo, in fact due to the exhaust exiting past the small impeller it actually causes a vacuum effect drawing the boost from the other turbo*

 

The method of checking this out will also demonstrate this very well, of course when you shut the throttle very quickly there is a sharp change in the turbo equalisation and some will exit the dump valves anyway albeit much quieter than normal.

 

1) Ok start by disconnecting the air flow meter.

2) loosen all four jubilee clips to the large intake pipes to the throttles

3) Choose a side and remove the large pipe completely

4) Start the engine ( yes it will run as it is ignoring the disconnected afm )

5) Take a latex glove and secure it over the steel pipe coming from the intercooler.NOT THE THROTTLE

6) Rev the engine and observe the glove.

What happened?

 

A) If it blows up then that`s boost from the turbo and that side is ok.

B) If it fails to inflate and looks like it is sucking in then that is the possible seized turbo *(remember the exhaust sucking issue)

C) Do the same test on the other side regardless of result, the engine may be a little unsteady with both pipes off and it helps if an assistant can keep the revs up a little for you.

 

7) Once established which side it is, switch off engine and remove the outer large rubber pipe from turbo to intercooler

 

8)Restart the engine and again secure the glove over the steel pipe this time the one directly from the turbo.

 

What happened?

 

A) Same result no boost? if so then that`s it confirmed defo a seized turbo.

 

OR

 

B) Better result boost now ok? then that means the intercooler or pipework to or from it is leaking.

 

Well thats about it, with a definitive answer you can then make a better informed decision on what to do next.

 

Hope that helps,

 

 

Jeff TT

 

A VERY BIG THANKYOU to you Jeff TT. That sure as hell has broken it down to what I should do and very simple. It has been said many times before and I'm gona add to it. YOU DEFO ARE A STAR..:) Best regards and will keep you updated on how it goes..

cool

Cool..... I`ll say was on the last line of that and my laptop battery started failing had to get the mains lead super quick before it I lost it.:hyper:

 

 

Jeff

Stupid turbos......who hates them....seems like everyones having trouble with them