Hi all!

 

First off I'm new to this great forum so 'Howdy Every1!' 8-)

I drive a jap '90 Z32 2+2 TT Auto that is stock (62k miles on clock) and have been thru the wars in the last few days! *lol*

 

About 10 days ago I was driving from Poole to London (~130miles) and 120 miles into the journey, she lost all power and I had to pull onto the hard shoulder (M25 j22-23). Immediately as I came to a stop the car died and has not started since. It was about 40degrees road temp that day and the engine was roasting, indeed because the engine was so hot and she didn't have her 3-4mins 'spin down' time the oil started to fry on the turbos and produced light blue smoke under the bonnet (which s**t me up!)

 

After a lot of waiting I finally managed to get the car towed back to Poole and the very next day went to work on it as my local Nissan Dealer (Westover) said they wouldn't touch the 300ZX as it was "too complicated for them..." after they said that I told them the only way they'd get my keys is if they killed me first - the only people that I'll let touch my Z is Zedworld as I have heard some very good things about them.

 

So at this point in time I am left with a very sick Z :( that fires it's starter but won't start.... Here's what I have checked and I hope someone can suggest what else I can try!:

 

Check ECU - Code 55 (surprise, surprise) all clear
Checked Battery
Checked Fuel pump / Fuel Filter / Fuel Pressure / Fuel Pump Controller
Checked Crank Angle Sensor
Checked Air Intake system for blockages/abnormalities
Checked Temp Sensor/Sender
Checked Knock Sensor
Checked TPS - needs slight recalibration (shouldn't stop the Z from starting!)
Checked easiest coil packs (front 4) all within tolerences
Checked all belts were still there inc. cam belt ;-)
Checked PTU by cutting open and running a continuity check on all components within - checked out OK!
Pulled coil pack #1 attached new plug and tried to see spark -
NO SPARK!

*When above components were checked all harnesses were cleaned and di-elec greased*

 

Checked 300ZX service Manual, which points everything back to the PTU!!!

 

Is there anyway I can test my PTU further other than ordering another one?

 

I noticed 'check' connectors for the PTU on the Engine loom and in the service manual, does anyone know how to read this info?

 

Does any Z owner live near to Poole/Bournemouth with a series 1 PTU that is good I can run a comparison with my 'suspect' one?

 

Any help would be greatly appreciated - as this is driving me mad and all I do is worry about my Z - I have tried everything I can think of and have spent about 24 solid hours reading everything I can on the net about the Z32 TTs, the only problem is that the majority of the stuff is written by yanks so they don't bother testing the PTU they go get it replaced under the recall :((((.

 

Sorry for the long post and thanks for hanging in there! :-)

 

~Nibbler~

Sounds like your PTU m8, maybe someone on here lives near you and can lend you a working one to try?

 

Just dont get a new one over here, £318 plus its the old seres 1 model!

If you get stuck I could send you one to try. Let me know ;)

 

CheerZ,

 

Andy

Hi guyZ,

 

Back again (not so long a post this time *lol*)!

 

Does anyone know exactly how a PTU works, or have a breakdown of all the components are and what they do etc?

 

I'm just wondering if I had my PTU out, some wires, a bulb, a 12V battery and multimeter if there is anyway I can test it?

 

I have to do something to keep busy cos sitting here staring out the window at the Z not going anywhere is making me dribble, and it just *aint* healthy!!!

 

Thanks in advance :)

Look at your engine and on the left on the back cambelt covers you will see a metal square with a plug on either side.

 

That is your PTU.

 

Its a little bit like a speaker amp, but it amplifies electric currents to the spark plugs.

 

You can try take it off and clean the contacts. It worked for me.

 

You probably can use a circut tester to see if that is the problem but I dont know what to do.

 

However the cars Self Diagnostics will be able to tell you if it is the PTU.

 

Do you know now to do a diag on your ECU? Its really easy.

 

Stuart

:D :D

 

SRRAE - he's already checked for ECU codes and even opened up the PTU to check the internals so I reckon he knows where it is

 

:D :D

 

Sorry, couldn't help myself:p

I've already got the PTU off, and stripped the black casing off so I can see the PCB, thinking that it would be in a similar state as in the tech notes on PTU repairs but on the tech docs you can see the physical damage and the separation of the ground soldered wires due to heat and vibration.

 

I thought when I'd taken mine apart I'd be faced with a similar situation only to find that things inside the PTU actually looked in pretty good nick! Surprising really considering the amount of trouble these little boxes can cause...

 

Although I'm capable of using a multimeter and soldering iron my knowledge of electronics is very basic and the most i'd ever really done was chipping playstations and resoldering duff resistors on hard disks.

 

Thanks to the help of many tech docs I was able to check the components mentioned at the start of this thread were within tolerences using the multimeter.

 

My ECU diags keep coming up 55 with the PTU in place, and if I removed the PTU and ran the diags it would come up code 21 so I know the ECU is 'seeing' as far as the PTU.

After disconnecting the Battery -'ve for 30mins and replacing the PTU, the ECU diags come up as 55 again.... and yet still no spark... Weird, no?

When is SRRAE going to learn how to read???? And then engage his brain, just a bit?

Originally posted by markstevens

When is SRRAE going to learn how to read???? And then engage his brain, just a bit?

 

**** u

Originally posted by SRRAE

**** u

 

Don't tell me the swear filter now filters PTU too? :D:D:D

See this re PTU; seems typical prob on that age Zed.

 

http://www.twinturbo.net/ttnetfaq/appendixz.aspx#Power%20Transistor

 

You would have thought that you would get a fault code showing.

 

Don't know whether you can have a sick transistor unit and not a fault code.

Have you checked all the earth points? There's some at the back of the plenum - make sure they are secure and clean.

Have checked all earth points I know of, but will double check there positions and give them a clean up anyway just to be on the safe side.

 

Maybe I am attacking this problem from the wrong angle....

 

Would a problem with Vacuum and/or Compression actually stop the engine from creating a spark?

 

Those are the only other things I can think maybe the problem, and may not give any warnings to the ECU....

 

Maybe I'm testing for a spark the wrong way, I pulled coil #1, attached a new spark plug that I had spare (can't get the ones out of the engine cos I don't have the right wrench) reconnected the coil pack harness and layed the plug on it's side loose on the engine near where the coil is bolted in so the 'nut' part of the plug was in contact with the grounded engine, so if all things were working I should have seen a spark right?

 

What do ya think guyz?

You said

 

she lost all power and I had to pull onto the hard shoulder (M25 j22-23). Immediately as I came to a stop the car died and has not started since. It was about 40degrees road temp that day and the engine was roasting, indeed because the engine was so hot and she didn't have her 3-4mins 'spin down' time the oil started to fry on the turbos and produced light blue smoke under the bonnet (which s**t me up!)...

 

Electrics such as one or two of the transistors in the PTU failing would give a misfire and rough running. Loss of the 12 V power supply or earth to the PTU would be like turning the ignition off.

 

Fuel vapour lock might give the power loss symptoms you describe - goes with the temperatures - have you taken a fuel hose off the fuel filter to see if the pressure is there - watch for a face ful of petrol!

 

Also the light blue smoke under the bonnet - I dont think that should be there unless oil was burning off something. Even if the oil was burning on the turbo shafts any smoke can only get to the crankcase and shouldnt be seen. Hope you still have compression - you didnt totally overheat it did you?

 

On seeing sparks it can be hard to see on a plug - if you are really brave and dont have a pacemaker use a bare lead and hang on while you crank it - you'll know if there's volts! Or get one of those old type neon timing lights and put it in series with the plug.

Hi m8 thnx for the reply...

 

about 90secs before I pulled onto the hard shoulder, the temp gauge started to rise, and when it hit 3/4 I started to pull over, I didn't let the car overheat and wanted to just let it idle on the hard shoulder to let it all cool down and let the turbos spin down, unforunately the car just shut itself off as soon as I came to a stop, but the car never over-heated ie: It didn't hit the red marker on the temp gauge + didn't lose any coolant and didn't emit any steam, I didn't have any blue/black/white smoke coming out of the exhaust and I had plenty of oil and water when I checked after the car had a little time to cool down.

 

* I've learnt the lesson to always be wary if the temp gauge starts going lala after having a BHG on one of my old cars *

 

When I mentioned about the light wafts of blue smoke coming from the back of the engine bay the tow truck guy said it was probably a little spilt oil burning off the hot components, which sounded reasonable as I had only just had an oil change a month b4 but not driven the car much so it wouldn't have got that hot.

 

A day after the car got back, I took the petrol cap off overnight (but left the petrol cover closed) to relieve as much pressure as I could, then pulled the hose that goes into the engine from the fuel filter got a buddy to hold it into a bottle and cranked the car sure enough a big jet of fuel sprayed into the bottle, also stuck my finger over the end of the fuel hose and cranked again only to have petrol blast my finger off the end of the pipe, so I assume there is enough pressure there to at least start my Z?

 

Also tried using some of the fuel now in the bottle in the Thrott. Bodies to see if I could get her to at least turn over, but nothing...

 

I really want to get the plugs out, and try a compression test now, but can u do this without a compression tester? I was hoping maybe the condition of the spark plugs may give me a clue?

SRAAE Wrote **** u

 

I take it thats Never then? Just asking. Lol