CIS question - can't seem to hit the screw

SCWDP911 · SCWDP911's Garage

1983 cab with mostly stock 3.0 and CIS - hole to mixture adj. screw is already open...

OK, I just filled out my application for CIS Loser Gruppe. I cannot for the life of me and my car, seem to get a good hit on the top of the mixture screw with my newly acquired CIS mixture adjustment wrench. Should it really be this hard? I am not a complete mechanical idiot, but this is really bringing me down... Any hints, tips, etc? The screw is straight down, and not angled off at all is it?

Thanks,
Shane the CIS loser

Porsche_monkey · 06-29-2007, 07:10 AM

What size key are you using?

If it's any consolation I think I had a few problems gettingit to engage.

SCWDP911 · SCWDP911's Garage

3mm

Porsche_monkey · 06-29-2007, 07:22 AM

It might be 2.5?

SCWDP911 · SCWDP911's Garage

The one I have is the one sold by our host, however, it was purchased from another party. When I got it, it turned out to be about 2-3 inches too long as far as bing able to get it in place and through the access hole. So, someone said there were two different ones and that the 83 should use the shorter one. So I cut mine off to the short size (from someone elses measurements - 4 7/8" I think. I will go get my Bentley and double check the required size (3 or 2.5mm)

JK-81SC · 06-29-2007, 08:13 AM

The screw is definitely a 3 mm, straight down from the hole. Have you adjusted it lately? It may have some gunk in the hex socket of the screw, which is preventing the tool from seating. Maybe try and take a sharp ended pick and clean out the screw socket.

SCWDP911 · SCWDP911's Garage

I am a little reluctant to stick the sharp object in there... showing my timid ways I guess. Is there anyone reading this that is anywhere close to Memphis or Nashville, that has done this before and would not mind looking over my shoulder. With the car running, and sticking my verified 3mm wrench in there, I can feel what MIGHT be the head of a screw, but I cannot really feel it turn at all when attempted in either direction. It does push idle down briefly until I let off of the wrench. I am not pusching very hard mind you as I would rather not screw it up. I was going to just try the basic method of adjustment (for now) that Souk describes in one of his threads. I have read enough to think that a lot of you think he is very CIS knowledgeable. Are there any dissenting opinions as to the adjust by sound method, so to speak...

Jeff · 06-29-2007, 08:37 AM

It does take a bit of fiddleing to get it seated in the allen head. I remember I was barely able to get the wrench in the hole, because of the angle and the length of the wrench. If I used a shorter one it wouldn't seat in the allen head. Just remember to only turn it a little pull the wrench out and rev the motor to let everything "seat".
If you have Harbor Freight near you they sell longer 3mm aleen wrenches, just in case you cut yours too short.
Keep at it, you will get it.

74er · 06-29-2007, 08:44 AM

I'll vote for gunk in the hole.

SCWDP911 · SCWDP911's Garage

Looking at that last piuc, it makes me feel a little more confident about using a pic maybe to try toclean out the "hole" on the screw. Just to verify, is there any way I can do damage if I am slow and methodical about it?

Thanks for all the help guys. I know CIS gets covered a lot, but sometimes it is hard to find that one little piece of info YOU needed by reading through several long threads.

Cheers...

holtjv · 06-29-2007, 08:54 AM

Make sure to do the adjustment with the car NOT running. Get a strong light and angle mirror to look down there.

Take the air filter cover off and hold down the main lever for the sensor plate (you barely see this on the right side of the upper part of the airbox) when you extract the wrench from the hole. You should hear the sensor plate thunk a bit if you pull it up while pulling out the wrench.

I'd just put it down there and wiggle it around until you find the....never mind.

Jack

Sunroof · 06-29-2007, 09:17 AM

I had the same issue with the mixture screw. The previous owners wrench put locktite on top of the screw!! I was totally unaware of this as the mixture adjustment tool would not get in the groove to set the mixture.

What I did was to take the air filter cover off and held up the sensor plate with my hand while I placed the tool in the hole with the other. I pushed down on the tool and felt it get in the adjustment hole just a bit, but not enough of a good bite for adjustment. I then used a dental pick to clean it out while holding up the sensor plate because of the downward force on the dental pick. I got most of the crap out, but still use the same method as a precaution when I adjust mixture. Sounds a bit crazy, but it works just fine.

You can try this to see if the indeed the adjustment hole is gunked up. Use some type of pick to lightly check the screw.

Bob
73.5T Sepia of Course

Sunroof · 06-29-2007, 09:19 AM

OH!!!!!!!.............DO NOT DO THIS WHILE THE ENGINE IS RUNNING!!!!!!!

SAFETY FIRST

BOB

Gunter · Gunter's Garage

Adjusting with engine not running?????????
Clean the hex in the adjusting screw as described above.
Fit the 3mm Allen key.
Remove Allen key.
Replace the filter.
Start the engine.
Insert the 3mm Allen key into the adjustment screw.
Adjust mixture by ear with small movements. Richer is cw.
Remove the key before revving!
Instead of the fancy and costly "Official" Allen tool, buy a LONG Allen key from any tool supplier for much less. In fact, buy 2!
Also, mix adjust is the LAST thing to do when tuning your engine:
Valve-adjust, ignition timing, mixture adjustment.

SCWDP911 · SCWDP911's Garage

For those that read this later and will be new, take the airbox cover off like just mentioned, and you can see much easier what was just mentioned. Thanks Gunter.