txhokie4life

Yeah I know there's a topic on an 85 -- but I have CIS :-)

Running 12-14PSI vacuum at brake boost and at WUR.

If I put a mighty vac on the WUR -- I can get to 20psi --
then watch it slowly bleed off. Down to 5psi maybe
lower if I was patient.

Maybe 1 psi every seconds or so, until 10psi then it slows some.

My detection that is rich is that my eye are watering every time I fire
it up in an open garage -- and the wife bitches about the smell.

It hasn't been driven a ton -- but it does hit the road every now and then.

Pulled the intake plenum and double checked all the connections
and replaced a couple rubber seals (for good measure)

How do you check the WUR? Is that likely the cause.

I haven't checked it after a long run - but I'm pretty sure it's been rich for
ever since I've owned it (2.5 years)

thanks,

Mike

NordicSaab

Hey Mike,

I just went through an extensive education on the CIS in the process ow working on my '81 Euro S.

There are a handful of things that could be making the car run rich and other items you have the ability to adjust. A vacuum leak is your first and most likely culprit. I would inspect every vacuum line you can find. There are many helpful diagram on the forum if you search as well.

As far as adjustment. There is a 3 MM spring loaded allen screw that is the located near the air metering plate which adjusts fuel mixture either lean or rich. This screw will adjust the mixture across the entire range... If i remember correctly left will lean out the car and right will rich-en the mixture.

The other adjustment is on the bottom of the WUR. There is a copper plate covering the adjustment screw so you will need to drill the plate to have access. This screw will control how mixture is modified with vacuum. i.e. off idle enrichment.

I would recommend you get a couple of books on CIS. I cannot even tell you how valuable they were for me. I am still learning, but this can maybe give you a place to start.

txhokie4life

I've been hunting down vacuum lines and have replaced nearly all of them.
I've got 12-14psi at the brake booster as well as at the bottom of the WUR.

Might expect a little better -- but shouldn't that be good enough?

Yeah -- I've got a buddy with a CIS on a 911 -- I'll see if he's got a few books to lend.

Mike

NordicSaab

According to the WSM:

Possible causes for too rich a mixture
System pressure too high
No partial vacuum at the pressure regulator
Injection valve does not close
Blockage in the return line to the fuel tank
Misfiring
Short-circuit to positive, Lambda probe

I attempted to find a vacuum specification, but am unable to locate. The only thing in the manual is it does suggest removing the hose at the break booster that pressurizing the system. If you have a compressor that might be the way to go. I know when I replacing lines some of the cracks and holes were very difficult to see.

txhokie4life

will need to check system pressure.

will check the blockage in the return line -- Is there a known good test?

No misfiring

Not sure I have a Lambda probe -- will have to check.

Note if I have the same pressure at the brake booster lines
as at the WUR -- and I am 12-14psi at idle, can I rule out vacuum
at this point?

thanks,

mike

NordicSaab

A blockage in the return line will greatly increase your system pressure. There is a sequence in the WSM about disconnecting the fuel return and testing the volume, but I would avoid doing that if possible.

Did you try the 3 mm allen screw? That is where I would start...

You may be able to accomplish your goal with just this mechanism. Just be aware that it will affect your idle.

AirtekHVAC

Make very small adjustments...mine stank forever.....it would burn my eyes and permeate my clothing in a matter of seconds....poured some cleaner (a lot, actually) into the tank...just take it slow and make a little adjustment at a time.....let her run about 15 min, and turn a little more....worked for me....

Dennis Wilson

A bad thermotime switch can cause the cold start valve to inject continuously. Try unplugging the injector after a cold start to see if the rich running goes away. If it leans it out, replace the switch. If it still runs rich, adjust the A/F mixture.

Dennis

txhokie4life

Thanks -- next time I'm cleared for Hazmat duty by the wife -- I'll do some testing :-)

Mike

txhokie4life

Couple quick updates.

measured the heater on the WUR -- 18 ohms.

Tried pulling the cold start fuel injector connector.
Harder to start as expected -- but still ran rich, maybe a tad less
but still brought tears to my eyes pretty quick.

I get the idea of leaning my mixture -- but I'm trying to figure out if there is
something that has gone south --

I don't remember being this rich maybe a year ago -- but I have not driven
it much as it has been going through various stages of renovations.

I'd rather not start messing with things until I've checked most things out.

thx,

Mike

Dennis Wilson

It is possible the A/F mixture was previously richened to compensate for a vacuum leak. Now that you have replaced the lines, the mixture may need reset. A basic running adjustment may be made by slowly leaning (turning CCW) the mixture until the engine starts to cut out. Mark that point then slowly turn to rich until the engine starts to cut out then mark that point. Next turn the mixture back to lean until you are halfway between the two marks. That should put it close to the final setting. BTW the adjustment screw is spring loaded. You will need to push downward on the adjuster but not so far that it pushes the air sensor plate down.

Dennis

txhokie4life

Dennis -- I think you might have nailed it --

I was trying to think when this rich running all started and while I can't pin point it for sure,
one of the things I had done was to redo all the vacuum lines -- and what the mech's missed
I completed.

So -- I'm going to try make the suggested adjustments and see how it goes.

Then I have to finish off my dash, finish the rebuild of my AC and start enjoying the car.

Mike

txhokie4life

Adjusted the CIS mixture screw.

Dropped idle down about 200RPM to just over 600RPM.
I think the richness is a tad less -- but still stinky as hell and eye watering.

Took it for a drive. Even when warmed up -- it seemed to still be rich --

I have a friend who has some CIS Meters -- will borrow them and
do some more testing next week.

M

NordicSaab

I'm glad your making progress in the right direction. Remember that you also have the idle (basically air) adjustment on the throttle body.

I suspect that if you open the throttle body screw a little bit your idle will go up, but the burn will be cleaner (i.e. more air)

It is a balancing act. Mixture screw = Fuel. Throttle Body screw = Air.

txhokie4life

Is the throttle body screw accessible without taking the intake plenum off?

thanks,

Mike