Looking for Tech info on euro "S"

[rich]

My engine is a 5.0 Hybrid, 1980 M28/11 top end. I have it running but have a small issue with my CIS.

The engine is running rich. I tested the AAV. It checks out fine.

I have an appointment to have the control pressure checked next week but I wanted to check to be sure I don't have some other simple issues like vacum leaks or a bad diaphram. (the thing on the side of the throttle body with the two hoses on it)

The other thing with the rich condition is a high idle. The engine is idling at 1200 rpm's warm. I attempted to lower the idle by turning in the air screw on the throttle body but it made no change.

So, on to my question. I looked through my manual and couldn't find a base setting for the air screw on the throttle body.

Anyone have a clue?

[devilinblack]

I've not seen a base setting for the mixture and idle screws either but I don't see how turning the idle screw could not make any changes unless the plate is stuck open. It should move freely up and down and return to the up (closed) position at idle. If that's okay, then vacuum leaks would be my next guess, but wouldn't that make the idle high and lean since un-metered air would be getting in? Have you tried turning the mixture screw lean just a little (always finishing by turning lean to rich, iirc) to see if that makes a difference?

I know there's been times where I thought my car was running rich, but richening things up has actually improved idle. If it's too rich it should be hunting by changing RPM's up and down in a cycle as it idles, lean won't do that.

[Danglerb]

Idle means air is going in, find out where.

Isn't there a mixture adjustment on the air meter seesaw catapult thing?

[rhjames]

Rich-

the vacuum limiter on the side of the throttle body was put on there to limit how fast the engine decelerates while changing gears through the neutral gate. it was eliminated in later MY cars. If you remove and plug the outlets, you have eliminated an area of vacuum leak concern. Other vacuum leaks can be checked with a Mighty VAC, or just plug the offending line individually-- test for throttle response or use a vacuum gauge to see if there is any change.

The idle screw--on the front of the throttle body--is not really an idle screw. it is an idle mixture screw, not an rpm regulating adjustment (although it will change the rpm idle--I know, this doesn't sound like it makes sense). You will find a screw on the linkage (driver's) side of the throttle body. This screw, is actually for adjusting idle rpm's. Problem is, it's facing upside down and it is usually loctite-d or lock nut-ed. You can adjust it by using an allen wrench of the appropriate size, but this requires some fineness, or removing the throttle body-adjust-and then re-install.

I looked through the FWMs and there is really no guidance as to where the base settings for CIS should be, other than pressures and O2 settings.




--Russ

[Normy]

Uh oh~

[devilinblack]

You've probably seen these already, but they helped me a lot to understand how the CIS works.

http://forums.pelicanparts.com/showthread.php?t=185926&pp=20&highlight=cis+mixture+idle
http://forums.pelicanparts.com/showthread.php?t=232089&highlight=cis

I do need to get my junk into a shop with a CO meter and get it properly adjusted though instead of just playing it by ear.

[rhjames]

Originally Posted by devilinblack

You've probably seen these already, but they helped me a lot to understand how the CIS works.

http://forums.pelicanparts.com/showthread.php?t=185926&pp=20&highlight=cis+mixture+idle
http://forums.pelicanparts.com/showthread.php?t=232089&highlight=cis

I do need to get my junk into a shop with a CO meter and get it properly adjusted though instead of just playing it by ear.

this guy souk is well versed with CIS, both of these threads are a valuable read....




--Russ

[rhjames]

Originally Posted by Danglerb

Idle means air is going in, find out where.

Isn't there a mixture adjustment on the air meter seesaw catapult thing?

Yes there is.

As I understand that adjustment--

you can press the air valve lever (sometimes called the barn door) down --at idle-- and it will richen the mixture. if you press it far enough to cause the engine to stumble, it is at it's too rich point. adjust the allen screw adjuster counterclockwise (a little at a time) until you can just barely press the lever down making the engine stumble. you're at a correct mixture level then, but not too rich. (If you bring the adjustment back clockwise, it will cause the engine to run lean.)




--Russ

[rich]

Oh ya, I forgot to mention, it has a low idle when I start it up in the morning and hunts for a little while. Then when it warms up it high idles. It's rich all the time.

Thanks for the links. I'll read all the posts. I have an appointment with a very saavy mechanic next week. He worked in Fla. at an import shop. Lots of ferrari's, Jag race cars, Lots of CIS Volvo's back in the day.

Kind of funny I can build a franken car like the Alien and can't tune the CIS myself. Well I probably could but I have no experience with it except to turn a could screws with no result.

Anywho, Thanks. I'll read up on it.

[devilinblack]

Let us know what the resolution is.

[MPDano]

Originally Posted by rich

Oh ya, I forgot to mention, it has a low idle when I start it up in the morning and hunts for a little while. Then when it warms up it high idles. It's rich all the time.

Thanks for the links. I'll read all the posts. I have an appointment with a very saavy mechanic next week. He worked in Fla. at an import shop. Lots of ferrari's, Jag race cars, Lots of CIS Volvo's back in the day.

Kind of funny I can build a franken car like the Alien and can't tune the CIS myself. Well I probably could but I have no experience with it except to turn a could screws with no result.

Anywho, Thanks. I'll read up on it.

I know you checked your AAV, which is exactly what was wrong with mine with high idle and richness. Did you try and remove that large screw and give it a good cleaning (inside hole and screw), I heard that this can also be a problem. Gunk clogging. It's a free thing to try anyways.

[rich]

Originally Posted by MPDano

I know you checked your AAV, which is exactly what was wrong with mine with high idle and richness. Did you try and remove that large screw and give it a good cleaning (inside hole and screw), I heard that this can also be a problem. Gunk clogging. It's a free thing to try anyways.

Thanks for the tip. No, I didn't. Maybe that's why nothing happens when I turn it.

[MPDano]

No prob, I hope this helps. BTW, that avatar freaks me out every time

[rich]

Originally Posted by MPDano

No prob, I hope this helps. BTW, that avatar freaks me out every time

That's my oldest son when he was a toddler. When he was a teen he scanned that photo and tweeked it. So, he's a real Alien experiment just like my car.