Any advice or past experiences are appreciated, first time posting on the forum.

 

So I purchased a 1990 automatic Z32 twin turbo from the family of the previous owner who unfortunately passed away, and sold the car as a non runner. Lots of receipts etc, well serviced, custom exhaust and a few other small mods, car needs a lot of work (respray, front windshield to start off with) but I want to get it running first.

 

History:

• Engine replacement and either new turbos or new turbo seals in 2003 (108k miles)
  
• Latest timing belt done in 2005 at 122k miles, still has no cracks and rotates nicely.
  
• New head gaskets in 2006 (
• SORN from 2011 at 132k miles.
  

 

Fuel tank was nearly empty and obviously very old fuel, put 10L of fresh fuel in so I don't think old fuel is the problem.

 

The car turns over no problem, I've only ran it for upto 10 minutes at a time in park but the symptoms don't change:

• White smoke from both exhaust outlets
  
• Standard turbo gauge sitting at about -11 psi
  
• Custom turbo gauge sits at 0 psi even at 6k revs, sounds like there is an air leak at the gauge though, not sure if thats normal? (First time with a custom gauge).
  
• Rattling from front of engine, sounds like it's coming from under the left casing for timing belt, maybe a belt that needs tightened? (power steering groans when steering wheel is touched also)
  
• After a few minutes at idle, the smoke out the back begins to splutter. Can clearly see it and hear it.
  
• Also from observation, there is a not so thin film of oil in both exhaust outlets, and all over the subframe/pipework at the front of the car by the radiator/intercoolers etc
  

 

Blown turbos seems the obvious solution given the evidence, but the smoke is quite clearly white/grey, and the spluttering suggests the main problem is with the engine itself such as the valve seals or fuel injectors?

 

Oil looks clean, coolant level has always been near the max

 

Any help is appreciated!

 

Thanks

First things you need to do, and honestly you need to do them all

 

Establish the exact problems

 

Does it idle smoothly, does it misfire, what is the idle speed

 

Check/ replace plugs- do a compression check while you are doing this

Oil change

Check every electrical connector on the engine- there will be green corrosion- remove it, there are lots of guides on here/ the net

Get a consult cable- £15 off eBay and will help hugely

Set timing- 15 btdc up to temp with ac off

Remove pas and alternator belt and see if the noise goes

If it doesn't- it's probably a timing belt bearing

If it's been 10 years on that timing belt, get it changed

Boost/air leak test

 

These cars require a bit of knowledge to get going properly, maybe you have a friendly local member that can help you out. Even with experience and all the right bits to hand it sounds like there is a long weekends work on the car.

 

With reference to the fuel, sitting in there for a long time could have gummed up the injectors, an injector flush may help

Oh and welcome to the club:thumbup:

Good advice above and welcome to the club Colin :thumbup1:

Thanks for your responses guys

 

I'm a DIY mechanic for basics but have never worked on a turbo before, thought I'd start big haha. Maybe not the best on a student budget but got it for a good price, will be working with my dad (>25 years working on cars every night) on it.

 

Compression check will be the first thing yeah, and will run it for a bit longer with some revs and fuel cleaner to hopefully clean out the injectors.

Found a guide for adjusting the CAS for timing so will get that sorted too.

 

Is there software available online for the cable? Found one cable for around £55 from australia. I have diagnostics software for OBDs.

As Dougal says, connectors and compression and boost leak. Is also add it would be worth ohming the injectors, one may have failed open and be dumping fuel in.

The fact it's habits belt done ten years ago is reason to change it imo. They can deteriorate quite well unnoticed. The head gasket replacement rings bells to, why was it done? They arnt prone to it, unless they oveheat. They are prone to warping when the head though in that scenario.

Hi, in case no one mentioned or you didn't know you must do the timing with a timing light/gun not via the software (it will lie)..

 

there are plenty of posts in the tech section about working on these old beasts, you can also find good info here:

 

http://www.pexcom.com.au/z32cms/e107_plugins/content/content.php?cat.8

 

http://www.twinturbo.net/nissan/300zx/tech/tech.aspx

 

https://z32.wikispaces.com/

 

A free version of Conzult can be found here:

 

http://300zx-twinturbo.com/conzult/downloads.htm

 

and here are some tips on the info....

 

Right, so the free version of Conzult should show you:

These values are only valid at idle and the values are linked.

The engine should be fully warmed up.

 

>Throttle Position (good reading TPS 0.44-0.46)

> Timing ( will show set at 15 Deg, best to check with timing light)

> IACV-AAC/V ( ideally 15% but a little out is OK)

> Mas Air Flow 1.30v (may vary slightly)

> Injector Pulse (2.2 msec, for std car)

> Injector Duty (.61% for standard setup as well)

> Water Temp (80 Deg C-84 Deg C)

> Fuel Temp (25 Deg C-35 Deg C)

> A/F Alpha 109%

this is an average value and only works if you have fully functional O2-sensors and ideally you want this value to be close to 100%.

any value over or under 100% means the ECU has to compensate with less or extra fuel to get the mixture right.

Extreme compensations (> +/- 15%) usually mean something is wrong with either air (air-leaks) or fuel (injectors/fuel pressure)

 

>On the free version there is only one readout for the O2, it should fluctuate up and down.

 

Timing may show 25 BTDC if the P/N position switch is OFF (may be the case for a malfunctioning neutral switch or an auto to manual conversion.)

 

the fuel temp values are ignored by the ECU for the most part, so not really important in respect to getting the car running better.

another important one is battery voltage: should be between 13.7 and 14.3 Volt (at any rpm)

If the value is off, it may indicate (future) problems with the alternator

the timing should always be verified with a timing light.

Also the later Zeds don't follow the 15 BTDC at idle rule.

They work quite different and use a variable ignition timing system to get better emissions ratios.

Because of this the timing hovers between 5-10BTDC at idle.

 

And obviously autos idle higher than manuals (in neutral).

 

 

 

I don't know how well conzult works with software newer than XP.. however I'm sure there are others on here than can offer more advise on diagnostics.

 

best of luck.

I'll be replacing the timing belt/tensioners/power steering pump/waterpump and other belts after engine tests, waiting on parts arriving now.

 

Thanks very much for the info and detail, still waiting for my cable to arrive but will hopefully get started on that soon.

Have you ascertained the cause of your issue yet? It's very admirable that your getting on with the service items but I don't think they will cure your initial issue.

I personally would be thinking of rebuilding the engine, which would be the better option at saving you time and even more money in the future.

Hi and welcome to the cub what part of edinburger are you in??