Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

CIS Rebuild

 
Post new topic   Reply to topic    924Board.org Forum Index -> How-To
View previous topic :: View next topic  
Author Message
Ozzie  



Joined: 12 Mar 2005
Posts: 4413
Location: Townsville, Qld. Australia

PostPosted: Thu May 29, 2014 3:54 pm    Post subject: CIS Rebuild Reply with quote

Erratic Idle, Injectors spraying without the engine running, unequal flow from injectors usually means an overhaul is required.
Kits are available to match the part number on the CIS or if you prefer, get the parts individually.
I bought a kit and it comes with different seals for variants and not all are used.
A new metal diaphragm is also included in a kit.

So you have it on the bench and ready to start.


1. remove ‘O’ ring
2. straighten lock tab and undo 19mm nut
3. check orientation of notch in piston housing
4. undo 8 screws
5. separate gently the two halves,

*do not twist, use any levers or damage the mating surfaces, a few light taps on the outside with a hammer should be all that is needed.

You should now be at this stage.



Pull off the centre cylinder and remove the piston if it has not already been removed.



There are 6 ‘O’ rings here to be replaced, check the small fuel filter and remove and clean if necessary.
Check movement of piston in the cylinder and very lightly sand if necessary.


There is an ‘O’ ring in the base, a bit tricky this one.


And one final ‘O’ ring in the pressure relief valve (may be different for USA models)
Shims may be needed to adjust system pressure later.
System pressure should be between 65-75 psi.


Insert the piston back in the top section, using plenty of lube, wd40 or oil, aligning the mark with one of the outlets.
Fit the new diaphragm and reassemble.


There you have it, a lot simpler to do than expected; on a scale of 1-10 I’d give it a 5.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance
Back to top
View user's profile Send private message Send e-mail
Ozzie  



Joined: 12 Mar 2005
Posts: 4413
Location: Townsville, Qld. Australia

PostPosted: Thu May 29, 2014 4:10 pm    Post subject: Reply with quote

Result after setting the a/f mix -
smooth idle, easy start, no misfire, pulls well.
I think this is the best it has run since I bought it.
Still have a hot start problem but can live with that.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance
Back to top
View user's profile Send private message Send e-mail
Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11354
Location: PacNW

PostPosted: Fri May 30, 2014 1:50 am    Post subject: Reply with quote

Wow, good work. I haven't tried it, but I understand these can be a bear to reseal.
_________________
Toofah King Bad
  • Shaggy (1980 931) - Got Boost?
  • Red (1987 924S) - Pro44/Spec944
  • Weiße Scheiße (1987 924S) - In Progress
Back to top
View user's profile Send private message Visit poster's website
Ozzie  



Joined: 12 Mar 2005
Posts: 4413
Location: Townsville, Qld. Australia

PostPosted: Fri May 30, 2014 7:54 am    Post subject: Reply with quote

maybe a fluke but haven't had any problems.
Make sure everything is clean especially the mating surfaces.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance
Back to top
View user's profile Send private message Send e-mail
musicalannette  



Joined: 21 Feb 2012
Posts: 412
Location: UK

PostPosted: Sat May 31, 2014 11:41 pm    Post subject: Reply with quote

Would you recommend scotchbrite as a surface cleaner if its needed?
_________________
I KNEW white wall tyres were invented by Americans .....just not at Boeing.... to be fitted on the 737.....
Back to top
View user's profile Send private message AIM Address Yahoo Messenger MSN Messenger
Ozzie  



Joined: 12 Mar 2005
Posts: 4413
Location: Townsville, Qld. Australia

PostPosted: Sun Jun 01, 2014 10:33 pm    Post subject: Reply with quote

probably 1200 wet and dry.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance
Back to top
View user's profile Send private message Send e-mail
MikeJinCO  



Joined: 08 Jun 2010
Posts: 726
Location: Maysville, Colorado

PostPosted: Tue Jun 03, 2014 12:26 am    Post subject: Reply with quote

If you're going to use 1200 paper. Way back when we had to repair industrial piston type air compressor valves(called reed valves I think) the technique was to put the paper on a sheet of plate glass. then take the valve part with a little oil on it and sand it using a figure 8 motion. The figure 8 motion tends to equalize all the little natural pressure variations from pushing it around. I'd practice first using some Prussian Blue on a chunk of steel. It was pretty tricky to do correctly, but got a surface better than a surface grinder.

This really dates me.
_________________
Mike
Poco a Poco, '80 future track car
'77 924
cricketdesigns.com
Back to top
View user's profile Send private message Visit poster's website
Ozzie  



Joined: 12 Mar 2005
Posts: 4413
Location: Townsville, Qld. Australia

PostPosted: Tue Jun 03, 2014 10:44 am    Post subject: Reply with quote

Yes- definitely the best way
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> How-To All times are GMT + 11 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group