FIXED - THANKS - Xantia 155bhp/2.0/16v ACAV question

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sbraud
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FIXED - THANKS - Xantia 155bhp/2.0/16v ACAV question

Post by sbraud »

Xantia 155bhp/2.0/16v air intake DIAPHRAGME question :?:

Guys,

Anyone know what the purpose of the two DIAPHRAGMES (like two UFOs) that sit at both ends of the Air Distributor box & intake manifold on 2.0 16v 155bhp XU10J4 unit (1994)?

I realise they work by vacuum action and should work together. Only ask as I’ve just noticed mine have stopped moving when excerptor is revved. The pistons that project out of the bottom of two DIAPHRAGMES used to move in and out together with accelerator. :(

Cheers
Steve
Last edited by sbraud on 10 Aug 2006, 13:00, edited 3 times in total.
95 Xantia 20/16v 155 bhp VSX 210k
97 Saxo 1.1 SX 100k
03 S-Type Jag (sorry!)
``Only standing on the shoulders of giants - The more I know, the less I understand?? Ignorance is bliss! ''
PowerLee
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My Cars: Current - Slightly modified 2016 Pug 308 Puretech 130 Allure
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2003 - 206 GLX TU3JP & 206 SE ET3JP4
1995 - 405 Executive XU10J2
1996 - 406 GLX XU10J4R
1994 - 405 GTX XU10J2
x 1

Post by PowerLee »

They work the variable inlet manifold.

There are 2 tracts through the manifold per cylinder, One for more low down torque & when the second one opens up you get more air flow into the engine & hence more power.

Thats how PSA got 155 bhp out of a low tech 2 litre engine without fancy VVT technology.
deian
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Post by deian »

thats why the call you power lee? lol
sbraud
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Post by sbraud »

Thanks PowerLee,

I though some horses has left the stable :lol:

Guess I now need to work out why :?: :?:

Cheers
Steve
95 Xantia 20/16v 155 bhp VSX 210k
97 Saxo 1.1 SX 100k
03 S-Type Jag (sorry!)
``Only standing on the shoulders of giants - The more I know, the less I understand?? Ignorance is bliss! ''
PowerLee
Posts: 1260
Joined: 01 May 2004, 19:49
Location: United Kingdom
My Cars: Current - Slightly modified 2016 Pug 308 Puretech 130 Allure
Past:
2003 - 206 GLX TU3JP & 206 SE ET3JP4
1995 - 405 Executive XU10J2
1996 - 406 GLX XU10J4R
1994 - 405 GTX XU10J2
x 1

Post by PowerLee »

These units have been known to fail, There is a test you can do in the Haynes 405 book of lies that pin points where the fault could be.

I dont have a copy though.

Someone on here will know how to test them.

Its the AVAC system :wink:

Have you checked the pipes are all ok? Also are the push rods free to move in & out?
sbraud
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Post by sbraud »

Thanks again PowerLee,

Didn't know about Pug 504 sharing same unit. I'll check out Haynes 504 manual. :wink:

Cheers
Steve

Ps. Any idea what AVAC stands for ?
95 Xantia 20/16v 155 bhp VSX 210k
97 Saxo 1.1 SX 100k
03 S-Type Jag (sorry!)
``Only standing on the shoulders of giants - The more I know, the less I understand?? Ignorance is bliss! ''
KevMayer
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Post by KevMayer »

405.......

He said 405.... 405..405..


lol

cheers,
Cheers, Kev

02 plate C5 2.2 Hdi Exclusive SE (now 170k miles 03/21).

Used to have:- Xantia 1.9 TurboD SX. 1996 Blue & 1998 Silver Activa. + 1992 BX TZD Turbo.
PowerLee
Posts: 1260
Joined: 01 May 2004, 19:49
Location: United Kingdom
My Cars: Current - Slightly modified 2016 Pug 308 Puretech 130 Allure
Past:
2003 - 206 GLX TU3JP & 206 SE ET3JP4
1995 - 405 Executive XU10J2
1996 - 406 GLX XU10J4R
1994 - 405 GTX XU10J2
x 1

Post by PowerLee »

Ive no idea what AVAC stands for.

Get hold of a Haynes book of lies for a 405 / 306 or other PSA car that has this lump in & it should tell you in there.
wheeler
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Post by wheeler »

sbraud wrote:
Ps. Any idea what AVAC stands for ?
Its actually ACAV & it stands for Admission Characteristics Acoustic Variable :wink:
sbraud
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Post by sbraud »

Last edited by sbraud on 15 Jul 2006, 08:20, edited 1 time in total.
95 Xantia 20/16v 155 bhp VSX 210k
97 Saxo 1.1 SX 100k
03 S-Type Jag (sorry!)
``Only standing on the shoulders of giants - The more I know, the less I understand?? Ignorance is bliss! ''
sbraud
Posts: 158
Joined: 04 Nov 2004, 20:46
Location: United Kingdom
My Cars:

Post by sbraud »

A Big Thank You to PowerLee, wheeler and all you guys! :D

I don’t want to get all emotional on you, but I just want to say THANK YOU!! This forum never ceases to amaze me with it’s knowledge and wisdom, time after time. :wink: 8)

In tracking down one problem, above, I’ve (You’ve) found two others I posted some time ago and never quite got round to sorting.

http://www.frenchcarforum.co.uk/forum/v ... highlight=

http://www.frenchcarforum.co.uk/forum/v ... highlight=

Anyone know if ACAV electro-valve is readily available or is it Cit dealer only?

Cheers
Steve

Ps. I had forgotten what 155bhp felt like, as I left this unresolved for too long and boy does she shift now. 11 years in and still having FUN !!
95 Xantia 20/16v 155 bhp VSX 210k
97 Saxo 1.1 SX 100k
03 S-Type Jag (sorry!)
``Only standing on the shoulders of giants - The more I know, the less I understand?? Ignorance is bliss! ''
andybsmith
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What were the symptoms?

Post by andybsmith »

I too have the 2.0l VSX and mine seems to be doing the same as yours as in the diaphragm thingys dont seem to move much if at all. I posted some pics of them last year but got no response as to what they were. How much did yours cost (AVAC) cos my car aint got as many horses as it should have. Other than that what a great car.
andybsmith
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What were the symptoms?

Post by andybsmith »

I too have the 2.0l VSX and mine seems to be doing the same as yours as in the diaphragm thingys dont seem to move much if at all. I posted some pics of them last year but got no response as to what they were. How much did yours cost (AVAC) cos my car aint got as many horses as it should have. Other than that what a great car.
andybsmith
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Same problem

Post by andybsmith »

My vsx does the same thing how much do the AVAC things cost?
sbraud
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Post by sbraud »

Sorry for late reply Andy... In my defence I was on holiday 8) :lol:
I’ve not had to replace ACAV air intake units as my problem is ACAV electro-valve. I’m still waiting to pick one up from my local friendly Cit dealer :( :(

I tied them open to track down problem and it made a huge difference to performance. Can’t wait to get thing working properly as it should.

I would say if both units are not working there’s a good change your electro-valve is shot/blocked.

There is a good thread on here http://www.frenchcarforum.co.uk/forum/v ... light=acav

I’ve got a diagram of set-up I can email if you send address.

Cheers
Steve
Last edited by sbraud on 14 Aug 2006, 08:12, edited 1 time in total.
95 Xantia 20/16v 155 bhp VSX 210k
97 Saxo 1.1 SX 100k
03 S-Type Jag (sorry!)
``Only standing on the shoulders of giants - The more I know, the less I understand?? Ignorance is bliss! ''
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