sc distibutor advance and mentaly challenged vacuum lines

tony77targa · 04-30-2006, 08:28 AM

suspect ... 83 911 sc
crime.... poor acceleration
findings... retard vacuum line OK.. advance vac line gives good vac on slow acceleration about 22 in but on full opening of throttle vac only about 6 in and engine is def doggy let off on the throttle and bring rpms down and vac jumps back up to 22 in jump on the throtlwe and back down to 6 in slowlly throttle up the rpms and vac stays at 22 in.. retard vac is great and cuts out the moment you throttle up the rpms..

I have been wading through vacuum diagrams and digging through the arcives of ign. dist. with the two vacuum ports on either side ... the advance and the retard...
the advance vacuum on the 83 seems to be tied in to a vacuum booster could this be the problem ?

Gunter · Gunter's Garage

Looking at the Bentley SC Manual, I don't see a vacuum booster, just the advance line to the rear of TB and the retard line to the front of the TB.
It is my understanding that the retard only works on deceleration for emmission control.
Is the vac. line for your advance good? No leak? Open the cap, remove the line from the rear of the TB, suck on it hard. Do you see the advance inside the distributor move? Full range?
Does the vacuum hold?
Any play in the distributor shaft? Did you maintain it by putting a few drops of oil under the felt-plug periodically?
If you suspect that the parts/weights/springs inside are not working correctly, there are threads on this board to refurbish the distributor.

tony77targa · 04-30-2006, 11:28 AM

fThanks for your reply DR..Iread quite a few of your replies in other posts helping others with CIS probs... I had my dist apart and cleaned and lubed it up ... but i will do the suck test to see if I am getting good movement on the vac advance plate.. the problem seems to me to be more vac related ... which could very well be the prob ... if I had preconcieved ideas as to what the prob is then I may be overlooking the obvious something else>>.
below is the diagram I have been using fopr reference... in actuality it doesnt seem to be the same as my system... but it looks good on paper as they say...thats where I see the vac booster.. I also unplugged my DME and the car ran the exact same as plugged in is that nowrmal?

Gunter · Gunter's Garage

SC's don't have DME, it's called Bosch K-Jetronic CIS.
What did you unplug? The OX sensor plug in the engine compartment?
Or the relay under the passenger seat connected to the Lambda brain?
To check if your frequency valve works, carefully unplug the relay under the pass. seat. The idle becomes very rough. Put dielectric grease (Or Vaseline) on the connectors. The relay/brain is often neglected and becomes rusty. The '83 also has an Acceleration Enrichment Control Unit attached to the Lambda unit. There are also several additional micro-switches on the throttle plate. Altogether too much to play with unless you have the knowledge.
To learn more about your '83, get a Bentley and read, read.

Number 14 on the diagram is just a dual connection for the vacuum booster (Brakes). Tighten the clamps and check these lines which can leak. The Servo booster is up front attached to the MC.
So, what exactly did you disconnect?

emcon5 · emcon5's Garage

Do your dome lights work?

Tom

tony77targa · 05-01-2006, 02:42 PM

Gunter ... I unplugged the the I dont know what is it an 8 or 10 pin plug that is on the firewall right above and to the left of the clutch which I think goes to the Lamda brain ... acceleration enrichment control unit...hmmm that would surley slow down accelaration if that wasnt working properly...
dielectric grease comming rioght up!

Tom .... no .... why????

emcon5 · emcon5's Garage

Quote:

Originally posted by tony77targa

Tom .... no .... why????

The Lamda system gets power from the dome light fuse. If that fuse is blown, the O2 system won't work, and the car will run like crap.

Is the frequency valve working(buzzing)?

Tom

vizail · 05-01-2006, 04:24 PM

Tony
I'm glad that Gunter is aboard.He is a great source . My contribution is that you have to listen to the FV to see if it is working .You probably misplaced the two connectors. You have (3) diferent connectors back there C Start, FV and Flow Sensor.
You can also use the following for the Vacum Lines route

Vic

tony77targa · 05-01-2006, 04:56 PM

Thanks everyone I will do some more checking 2 morow FV and AECU and brain ....

vizail · 05-02-2006, 05:18 AM

Check this One Out Too

<http://www.pelicanparts.com/techarticles/rice_ramblings/rice_ramblings-3.htm>

Vic

Gunter · Gunter's Garage

tony: What you unplugged is the 6-pin connector for the fuel system.
When you get the dielectric grease, carefully pry open the 14-pin connector to the left in the engine bay. A screwdriver will do it.
Disconnect the neg. battery terminal before you do this.
Make it a habit to maintain the electrical stuff with dielectric grease to prevent corrosion.
Groundstraps are very important; check all of them, especially in front where the neg. battery cable connects to the body. Disconnect the straps, clean up any rust/corrosion. Underneath, do the strap from the transmission to body.
With engine running, reach in the back and feel the FV vibrating.
It uses the same fuse as the dome lights as Tom says.
Is your OX sensor still connected to the CAT? That's the plug underneath the Bosch CDI module in the engine compartment.

tony77targa · 05-02-2006, 03:09 PM

Hey guys ... started the engine and unplugged the relay under the passenger seat that goes to the lambda.... engine ran the same ... plugged in a spare relay that I have and the engine cuts out imeadeatly
... if I hold the rpms up and plug in the relay engine smooths out a little
but would say I have tuned the engine to run without the lambda working
should I lean out the mixture or enrichen it ? Im leaning towards leaning
he he...

tony77targa · 05-03-2006, 03:38 AM

gunter ... yes my ox sensor was and is still connected to the cat and plugged in and new....installed by a PO... I basically bought the car in this state of not running correct and PO or his wrench tuned the car to run without the brain working so I am working backwards here not knowing what square one was ....my only other CIS experience is with the 77 and 79.... and I ahve been trying to get all the info I need from the net ... mostly here... and mostly YOU and your past posts...
I def need a good ref book ... unwittingly bought a Hanes ... found a use for it when jacking the car it makes a nice cushion between the engine and the jack... def need a good book...