Hey everyone,

 

Need some input with my issue.

 

Here it comes....

 

My idling recently got lumpy. I suspected this to be a breathing issue and gave my twin HKS induction, new filters/elements. This didn't solve the lumpy idling, so I then suspected the problem being due to the MAF. I took the MAF off and gave it a clean and connected it all back up. This led to the air flow being all over the place. The gear changes weren't right and upon putting the foot down, the Z seemed to rev up high and engine got loud and power not up to standards. Just didn't boost correctly. I then got hold of a perfectly working MAF and an Apexi induction. This completely cured the idling issue and everything else got back to normal. However, as soon as I sorted this out, I noticed a puff of smoke behind the car. Turns out the drivers side exhaust is smoking slightly. It's not smoking heavy or thick but slightly. On cold start its fine when idling and as car gets warms up, the drivers side exhaust starts puffing out smoke. Its starts of slightly from white/grey to grey/light blue.

 

Now I know the turbo seals is the worst case scenario as I have divorced downpipes and decats so complete straight through exhaust. But I'm trying to be positive and hope the problem hasn't got that far due to the MAF failing and air ratio being all over the place. I read somewhere that the PCVs were linked to the intake system so have ordered a whole new set. Valves and hoses which I have received and am looking to change them.

 

So..

 

1. Could I please get some tips on what I need to do to change the PCVs and hoses.. I kind of have an idea from the bits and bobs I have read up here. Just if I could get pin point info on what needs doing.

 

2. What else should I look at which could have got effected by the encounter above that can be an issue??

 

Any ideas and heads up would be great guys. The car is boosting/running fine otherwise. I have given it an oil change since but smoking still there. And before the MAF issue there definitely was never any smoking. I keep an eye on the exhausts like a hawk checking for smoke so I know there definitely wasn't anything before.

 

The smoke is smelling of oil burn.

 

Many thanks,

Zee..

???

PCV info on here mate http://www.ttzd.com/tech/pcvtech.html Sorry I cant help on other points and hope other members will help you out.

May have been that the car was overfueling due to the maf issues, once your getting warm your burning off the shit in the exhaust. Have a search through my posts and you will see a classic video of turbo rear oil seal failure. Try putting your aircon on, this raises the load on the engine slightly and often stops the smoke. Personally what id do is get it hooked up to consult or similar check everything is running right then take it for a long but gentle drive, motorway speeds etc with very few full throttle runs. and try leaving it to idle again. I can take a fair whle to clear the stuff out the exhaust.

If you have a pcv problem, you will normally see lots of oil in the plenum, but nowhere else in the induction system. The pcvs can clearly be seen about halfway along the undersides of the side face of the plenum. If your car still has the original pipework for the breathers, then I would expect them to be a pain in the ass. Purchase the pcv hose kit from sfs this will make refitting so much easier. Soaking the pcvs in petrol overnight often does the trick, replacements re pretty cheap from mjp. They should be free moving.

Looking further on you can really only diagnose what it isn't, ie the engine has good compression the breather system is correct etc.

But yeah just try giving it a gentle run to clear the crud through.

Just in case you weren't aware turbo replacement is an engine out job really, rebuilds are ok but a replacement brand new core is a better bet long term. Beautiful car that mate.

May have been that the car was overfueling due to the maf issues, once your getting warm your burning off the shit in the exhaust. Have a search through my posts and you will see a classic video of turbo rear oil seal failure. Try putting your aircon on, this raises the load on the engine slightly and often stops the smoke. Personally what id do is get it hooked up to consult or similar check everything is running right then take it for a long but gentle drive, motorway speeds etc with very few full throttle runs. and try leaving it to idle again. I can take a fair whle to clear the stuff out the exhaust.

If you have a pcv problem, you will normally see lots of oil in the plenum, but nowhere else in the induction system. The pcvs can clearly be seen about halfway along the undersides of the side face of the plenum. If your car still has the original pipework for the breathers, then I would expect them to be a pain in the ass. Purchase the pcv hose kit from sfs this will make refitting so much easier. Soaking the pcvs in petrol overnight often does the trick, replacements re pretty cheap from mjp. They should be free moving.

Looking further on you can really only diagnose what it isn't, ie the engine has good compression the breather system is correct etc.

But yeah just try giving it a gentle run to clear the crud through.

Just in case you weren't aware turbo replacement is an engine out job really, rebuilds are ok but a replacement brand new core is a better bet long term. Beautiful car that mate.

 

Many thanks for your time and expertise there mate. I do have the full brand new PCV kit that I'm looking to get on with and hoping that is the issue. I did have a read of that PCV link a few times and still finding it hard to locate the damn things on the engine lol. Perhaps should look closely. It's just bizarre how you work on these to fix something and instead it comes out worse. Cleaning the induction and maf led to dodgy running and gear changes which led to smoke. Could even be seal somewhere as due to funny gear changes when foot was down which had the car redlining for tad longer than normal that made me think hold on, that wasn't right. But keeping positive.

There should be pictures in the manual. Stand at the side of the car on the passenger side. Looking from the the battery follow the engine left towards the front of the car, roughly level with where the fuel lines cross over and connect from the inner wing to the engine, you will see a thick 20mm odd diameter hose on the underside of the plenum. This connects to a threaded stud in the plenum. That will be it.

Google 300zx PVC valve you will soon find labeled pictures :)

Google 300zx PVC valve you will soon find labeled pictures :)

 

Get better results googling PCV mate...lol

Your a star mate. I'll give that a go tomorrow morning. Hope I manage. Thanks again mate.

Right guys, the issue of my gear changes being all over the place has somehow returned. Gear changes got funny at the first when I attempted to clean the induction and MAF. The sensor inside the MAF wasn't touched as each end is netted. However, this was cured when the MAF and induction kit was changed and gearbox wise, everything got back to normal.

 

However, I drove the car a couple of days ago and the issue with gear changes seems to have returned.

 

In detail,

 

Whats happening is, on normal driving, my reverse, 1, 2 and 3 are fine and smoothhhh but, it stays in 3. Overdrive is not kicking in. When I put my foot down, from 1st, the car flies but then redlines for a little longer than normal, then changes to 2nd (here its fine) and then to 3rd and it stays in 3rd. Overdrive doesn't kick in at all.

 

Now again, this has happened before with the first MAF when I took it off for the first time to clean up but then ended up changing which cured this issue but now out of no where it has returned...

 

Any thoughts???

Right guys, the issue of my gear changes being all over the place has somehow returned. Gear changes got funny at the first when I attempted to clean the induction and MAF. The sensor inside the MAF wasn't touched as each end is netted. However, this was cured when the MAF and induction kit was changed and gearbox wise, everything got back to normal.

 

However, I drove the car a couple of days ago and the issue with gear changes seems to have returned.

 

In detail,

 

Whats happening is, on normal driving, my reverse, 1, 2 and 3 are fine and smoothhhh but, it stays in 3. Overdrive is not kicking in. When I put my foot down, from 1st, the car flies but then redlines for a little longer than normal, then changes to 2nd (here its fine) and then to 3rd and it stays in 3rd. Overdrive doesn't kick in at all.

 

Now again, this has happened before with the first MAF when I took it off for the first time to clean up but then ended up changing which cured this issue but now out of no where it has returned...

 

Any thoughts???

 

Have you checked or changed your TPS...this iff faulty can cause a big issue with shift points on your autobox

Did you do the PCV's?

Have you had the air on a computer yet?

Could be worth looking at things like the TPS, or checking its set right at least

 

Might sound daft but have you drove the car in the rain?

One answer to all those points.. NO..

 

PCVs I have worked out how I'm going to get to them but then other commitments took my time. So the next chance I'm going to get to work on it is the weekend. Going to do the whole cleaning TBs and connections and checking as much electrical stuff as possible.

I don't have access to conzult or anything that I can hook up to the car to get readings.

 

Anyone in the London area got this stuff??

There will be people that have it mate. Might be worth putting a thread up in the local area

Hey guys,

 

I managed to do the PCVs and all 5 hoses. Not that bad of a job really. With some patience and common sense, everyone can do them from home. Definitely get new hoses if someone is looking to change PCVs. Old hoses will definitely rip.

 

Anyway, changing them hasn't stopped my Z problems. Which I'm explaining again as follows: -

 

1. Smoke on idle. On cold start up, the car is fine idling. Then as the temperature rises, the smoking starts. Just the drivers side exhaust. Starts off with white smoke then slowly turns into blue. Definitely smells of oil burn. With this, there is smoke coming from behind the engine too. In the autobox dipstick area. I can't make out where its coming from when I look into that area. I can see my divorced downpipes and they are spotless and no oil residue anywhere in that area. They both definitely start off together when temperature rises.

 

2. My autobox. I am sure I noticed not long ago, that there was smoke coming from underneath the car but at further inspection it had gone so thought maybe it was just me. Upon normal driving, the gear changes are perfect except for going into 4th. It doesn't go into 4th on normal driving. A couple of times it has gone into 4th and then jumped right out of it and gone back into 3rd. Upon putting the foot down in 1st, the car picks up fine but then just revs up redlining which makes me ease off and then right away it goes into 2nd. If in 2nd, it drops to 1st fine when foot is down and then again, redlining and engine or intake screaming loud. If in 3rd and foot is put down, there isn't what we'd call a kickdown but like a real slow gear change which gives time to the engine to rev up a little and then it picks up speed fine and changes to 3rd fine and then just stays in 3rd reving up and picking speed. There are no noises from the autobox and never felt any funny jolts or anything that could've indicated to me at the time that something has gone pop with the box. But, everything was fine up until a couple of months ago when I decided to take the induction apart for clean up.

 

So in order,

 

Car fine but oddly used to get lumpy on idle so took the induction apart for new HKS elements and gave maf an over clean as inside mesh looked clean anyway.

Once all was put back, the gears started doing right away all I've mentioned about autobox above.

And the redlining I believe has led to the smoking.

 

The smoke behind the engine, you can clearly see the gearbox from that area.

 

All seem linked???

 

The autobox fluid looks clear yellow and I know its meant to be redish/pinkish. The smell of it is different to do the smell that actually comes from exhausts and behind engine though. A popped autobox I can understand smoking from behind engine but would it smoke from exhaust too? Or do I have more than one problem there....

 

Bloody annoyed with this thing.

???