Man teaches chimp to remove CIS in 90 minutes with partial drop.

[clevy70911T]

Actually man with chimp sized brain teaches self to remove entire CIS induction
system in 90 minutes with a partial engine drop. I dont really have questions
and this is more of a informative post than anything. Definately open to
suggestions and questions. I've been fighting a high idle (1500-1800) for months
now and have removed, cleaned and inspected the fuel dist (FD) 2 times along
with the throttle body with a partial drop which is a standard procedure now
days. Each time digging deeper into the system in search of my air leak.

First off, all my fuel pressures are in order and ignition timing is right on.
My mixture is ball park at a few turns back from rich and the idle oscillations.
I have removed and plugged the Decel valve (DV) and the AAV. By taking off a
hose and blocking it with plastic and reconnecting the hose, you can easily find
extra air sneaking past these components if the idle slows down. Anyway, the AAR
is working well after adjusting it and closes fine. Basically I've taken
everything off and made sure I have no leaks in that air circuit that bypasses
the throttle. The idle screw is closed fully to the right also. I have replaced
the injector sleeves and o-rings. I also have de-leaked all the vaccumm lines.
So I'm thinking, having the throttle plate closed and no air bypassing the
throttle plate, why is the engine idling at 1500 rpm? There has to be another
leak and someone has richened it to compensate. That's when I decided to drop it
again and remove everything including the intake runners. The leak has to be
either a crack in the airbox, the rubber sleeves that attach the runners to the
airbox or the little o-ring under the throttle body.

Sunday as I lay on the couch, the clock ticks past 2pm and I decide to drop
it again. At 3:30, it's done and everything on the induction system is laying on
the garage floor. I retreat to the couch to let my back rest.

Inspecting the rubber runner sleeves, they all look fine and are soft and
pliable enough I can easily turn them inside out to inspect for cracks. I didnt
find any gaskets under the cold start valve (CSV) so I fabricated one and used
non-hardning sealant. I used JB weld to seal the seam where the 2 halves on the
airbox meet. I used some permatex sealant to help the throttle body o ring seal.
Maybe overkill, but maybe if I had done this the first time, I wouldnt be doing
this again.

Re-assembly took more like 4 hours, but I got all done in a day with several
long rests. Anyone wondering if you can replace any item on the CIS without
removing the engine, it can be done and it wasnt that hard at all. My partial
drop was about 4-5 inches and alittle more to reconnect the cold start valve.
What a pain to connect the CSV!

Link to pelicanparts partial drop procedure:
http://www.pelicanparts.com/techarticles/911_partial_engine_drop/911_partial_engine_drop.htm

My partial drop procedure is simpler as many things have plenty of clearance and
need not to be disconnected.

1) Disconnect the multi-connector engine harness on the driver side fuse/relay
cluster.
2) Disconnect the shift linkage inside the car under the cover, making sure to
have the car in first gear and paint mark the positions before disconnecting.
3) Chock the front wheels to keep the car from rolling forward.
4) Jack car up under engine sump plate using an old math book as a cushion.
Place jack stands under the rear using the ends of the torsion bars at the
spring plates and lower the car until it rests on the jack stands
completely.
4) Place jack under engine in same spot and place a concrete block and another
book or soft wood just in front of the jacking spot on the sump plate to rest
the engine on when lowered. Using the block a peice of wood and the book, I can
tell that the engine will drop about 4-5 inches before it comes to rest.
5)Supporting the weight of the engine with the jack, loosen the 2 rear motor
mount bolts until you feel them let go.
6) Slowly lower the jack/engine, watching all other hoses and oil lines. Luckily
none of mine ever get tight or kinked. Once you remove the rubber air boot,
you have alot more clearence to work. It really is an easy procedure as long as you can remember or note where everyting goes.
Hopefully this can help others. I'll update my results later today if anyone is curious.

I love my cars.

[Paulporsche]

Scott,

Thanks for the informative writeup!

BTW, when you say your mixture is a few turns shy of oscilation, you don't really mean FULL TURNS do you (!?)
I am assuming you have turned your idle screw clockwise to get the revs down.
Have you checked your fuel injector seals? The oil breather hose?

Let the rest of us chimps know what you find.

[clevy70911T]

Another CIS problem conquered for mankind! On my fuel leak test I had a fuel dist connection leak and had to lower back down to get back there and tighten more. Geez. Found out my jack leaks now too. Double geez.
Anyway, it started up rich and I leaned alittle for a good enough idle to warm up. Once there, I set the mixture and the idle speed. I use the freq valve dwell method to set the mixture also. Now I think I ready for a gas tester.
It might have been the cold start valve not having a gasket. The first time I was in there, the PO's shop that did the rebuild didnt have it tightened on completely.

Paul, I meant a few 1/8 turns back from rich. The idle screw was completely in clockwise and I replaced the injector seals a few months ago on the first attempt.

Thanks for the suggestions.

[teewhy1311]

Scott, did you have to drain the oil? will have to do a partial drop, was trying to loosen the lock nut to adjust the sensor plate and it broke off,no luck trying to get out the broken adjusting screw,any ideas. thanks for the great post!

Tom

[patkeefe]

Scott:
Very nice work and documentation! Go get yourself a banana.
Pat

[Bob's Flat-Six]

[clevy70911T]

Tom
No oil drain required for me and I didnt have to disconnect any oil lines. That will be easier to repair once you have the fuel dist out. Trying to fix that in the car would be a challenge.