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I was going through photos of 2 TT engine bays, and i think i'm about to ask some daft questions, but if i don't ask i'll not kind out.

Below are 4 photos i picked out.

The black car is a 91 TT manual and the blue one is 95 TT auto.

In these first 2, what are the items circled in red? Where is that vacuum pipe going to, thats connected to the balance pipe (arrow pointing to it).

The black car doesn't have these things, and i can't seem to see a vacuum pipe connected to the balance pipe, theres nothing theres, shouldn't it be at least capped?

engine1_zpsdf62666a.jpg

 

engine2_zps69cc67cb.jpg

 

Same goes for the power steering stuff in these 2 photos, is it something to do with HICAS? And why has the blue car got those 3 connectors connected up and the black one doesn't?

I'd say yous are probably rolling your eyes asking yourself, 'is this guy for real' lol

engine4_zps1833110d.jpg

 

engine3_zps24cc8919.jpg

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First 2, cruise control. 2nd 2, difference between the earlier hydraulic HICAS units fitted to all TT cars and the electrical ones fitted to later cars which did away with the modulator.

You should not have any open vacumm lines or ports. It would appear it's been removed or that's popped off, check around that area for a loose one. I can't remember what that take off is for and mines long since changed, referance it against the other engine. It would also appear both those engines have automatic balance bars, that's the thick black steel the on the top rear of the plenum. There are also some redundant electrical pick ups on the drivers wing on the black one and the 2nd clutch bleed point is gone, I would suggest it's highly likely this car was orginally automatic. Nothing wrong with that simply an observation.

That vacum pipe is for the stock boost gauge,

Where the brake master cylinder and small fuse box is hiding in the corner is a little black box with a vacuum pipe the other end of that goes on your balance bar...

Ithe vacum pipe normally drops down so may be hard to spot so will probably be easier to find the end on the black box and follow it...

  • Author

I was only testing you guys, i knew all that stuff lol, only messing, who needs a mechanic when i have you guys, thanks, i now know what to research and read up on.

 

First 2, cruise control. 2nd 2, difference between the earlier hydraulic HICAS units fitted to all TT cars and the electrical ones fitted to later cars which did away with the modulator.

Thanks Si, hadn't a clue about the cruise control. I had doubts about the second photos being the HICAS because both cars have HICAS, didn't think about the switch-over to electronic. Funny how in 1991 the wiring loom was there for the 1995 electrical HICAS switch-over. I guess i don't have to install a NA power steering pump when i do a NA rear subframe swop, will it now be a lot easier?

 

You should not have any open vacumm lines or ports. It would appear it's been removed or that's popped off, check around that area for a loose one. I can't remember what that take off is for and mines long since changed, referance it against the other engine. It would also appear both those engines have automatic balance bars, that's the thick black steel the on the top rear of the plenum. There are also some redundant electrical pick ups on the drivers wing on the black one and the 2nd clutch bleed point is gone, I would suggest it's highly likely this car was orginally automatic. Nothing wrong with that simply an observation.

Thanks Stephen, i think you's may have solved a small problem with my idling. Ever since i had the car i was always meaning to adjust the idle down to just below 1000rpm, it sits around 1500rpm, now i think it has nothing to do with idle adjustment but that open vacuum port.

Nice to know i'm driving a manual conversion, i was worrying about the clutch pedal being too stiff when i do a manual conversion on that blue TT, it goes to show i hadn't a clue i was driving manual conversion already lol.

 

That vacum pipe is for the stock boost gauge,

Where the brake master cylinder and small fuse box is hiding in the corner is a little black box with a vacuum pipe the other end of that goes on your balance bar...

Ithe vacum pipe normally drops down so may be hard to spot so will probably be easier to find the end on the black box and follow it...

Thanks Terry, the cars are at a friends house, i'll investigate in the next couple of days. A few weeks ago i took photos of the engine bays to study, below are photos around the area you describe and i can't see a misplaced vacuum pipe. Do you think it's deleted, will i have to replace and reconnect it?

 

Screenshot2_zps34a6333c.jpg

 

IMG_0647_zps2fe39dd4.jpg

Check to see if there's a vac connection not attached on the clutch servo, it may not be connected.

Check under the black box circled and follow the vacum line the other end of it will go on that nipple the idle will be high because its sucking in air,

 

2014-11-03%2010.02.21_zpsxiygtiqw.jpg

  • Author

I'll take a look on Thursday and let you's know :thumbup:

Have a research on boost leak testing. You could do with doing one of these to ensure no other loose ends or clamps are present. Often with auto cars the idle is higher post conversion and the idle needs adjusting down, that may of not ever been done. However you need to check that it's not another issue such as the boost leak above first.

  • Author
Have a research on boost leak testing. You could do with doing one of these to ensure no other loose ends or clamps are present. Often with auto cars the idle is higher post conversion and the idle needs adjusting down, that may of not ever been done. However you need to check that it's not another issue such as the boost leak above first.

 

Thanks Stephen, i found the loose pipe which is capped, it's connected to where the red arrow is on the photo. The diagram below shows that that vacuum pipe is for a boost controller and boost sensor (on the passenger side of the engine). What is that vacuum pipe for (blue arrow)? Should i reconnect it to where i capped the pipe coming from the balance bar (yellow arrow)?

 

300zx1_zps26c138da.jpg

 

TT_Vac_BoostController_zpsa278d881.png

 

I was wrong, when engine was warm it was idling near 2000rpm, and when i capped the vacuum leak it went down to 1500rpm and sounds much better.

I don't think it sound as high as 1500rpm, below i've uploaded a video of the idle rpm sound, i assure you that the engine doesn't have that rattle which sounds in the video, i don't know how the recording picked that up, it sounds like a bloody tractor lol.

The photo below shows my instrument cluster, see how my speedo sits at 10mph, would my rev counter also be giving a false reading? My boost gauge doesn't work when i rev the car, it must be that loose capped pipe from the balance bar. I'm thinking would someone have removed an aftermarket boost controller from the car before i bought it, and forgot to cap that balance bar. I bought the car from a car dealer.

I purposely emptied the fuel tank to store the car, but i have read that that is a bad idea, i need to have a full fuel tank to stop condensation building up in it, i'll fill it when i get a chance.

 

300zx2_zps3309ca61.jpg

https://www.youtube.com/watch?v=cfO8ZO_5qOE&feature=youtu.be

 

Stephen I've took your advice about the vacuum test, I did some research and pulled the nose panel off to measure the MAF diameter (80mm), i'll make a tester in the next few days and let you know the outcome, If there is no more vacuum/boost leaks i will adjust the idle, thanks again for your help, and if you think of anything else please let me know.

 

300zx3_zps66785420.jpg

 

300zx4_zps96c33c65.jpg

That vac picture you've got there is the simplified version with an electronic boost controller. The thing pictured red arrow is either an sub solenoid or egr. I would highly recommend deleting the aiv in any event. Google robos 300zx page. It contains lots of step by step useful bits such as deleting SUV etc and shows the various breakdowns on the vac diagrams.

The blue arrow tube is that going to the black solenoid marked with the red arrow? Once you start tracing them to delete stuff you will realise what theyvall are.

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