Should the injectors "wiggle" a bit ?

[prebordao]

While searching for vacuum leaks, I noticed that I can wiggle a bit the injectors from side to side and also up and own, while inserted in the runners.

Is this ok, or does it points to worn sleeves and o-rings ?

[kodioneill]

Normal for the most part. Spray a little wd 40 around each injector while the motor is running if you have a vacuum leak the idle will rise. You can use brake clean or carb clean but have an extinguisher handy.

[prebordao]

tnks, will try.

[Bob Kontak]

Been using the carb cleaner/starting fluid for years without incident. Not saying it's fool proof but the extinguisher nearby is for common sense reasons vs for a high risk of losing your eyebrows.

Also, the rubber o-rings are pretty easy to replace. They get hard and don't seal that well depending on age. I am assuming you injectors are similar to mine on my 81 w/CIS.

[aigel]

"A bit"?

While the O rings are all that hold the injectors in on the CIS these should be sitting pretty tight, especially sideways. They are not easy to come by and often stubborn to pull due to hardened rubber, so if you do not have any lean running symptoms on any of the cylinders, I'd wait until you are in there deeply (or the engine is out) anyways.

G

[prebordao]

I suspect a lean condition, but I'm looking at the airbox first.
Anyway, how to get them out ? Just by pulling?

[Josh D]

The O rings that tend to be loose are the injector sleeve to manifold. The injector to sleeves are usually tight.

When the engine is running, engine vaccum tends to pull the injector sleeve and injector tight. Try wiggling the injector with engine running and you'll see what I mean.

[aigel]

Unless all injector o-rings leak air at the same rate, you should be able to tell a "hot" cylinder from the look of the spark plug.

Yes, you just pull - but it generally takes considerable force. As mentioned above by Josh, there are two sets of o-rings: injector to sleeve and sleeve to intake runner.

This thread holds some good images showing it all apart:
CIS Injector Sleeve w/Backfire Damage??

Good Luck

G

[VFR750]

The injectors should not wiggle or move in and out. They are loose and leaking, causing a lean condition. You should replace both sets of o-rings. An acceptable, but ugly fix, is to apply black RTV sealant and glue the injector into the manifold. This will seal the leak effectively.

The basic message is: CIS systems hate vacuum leaks. You have found a typical one. Fix it now, and take it off the list of contributors. I did, and it was a huge improvement on cold start.

[porsche930dude]

to get the sleve out whats the standard procedure of removing the crimps from the manifold? dremel? then how do you reset them?

[boyt911sc]

Originally Posted by prebordao

While searching for vacuum leaks, I noticed that I can wiggle a bit the injectors from side to side and also up and own, while inserted in the runners.

Is this ok, or does it points to worn sleeves and o-rings ?

PJR,

Don't worry too much about the slight movement of the CIS injectors. They all move slightly up/down and side-to-side directions. The important thing is that they should not be leaking air!!!! Even newly rebuilt runners with new sleeves and O-rings do not keep the fuel injectors rigid. Reasons: The sleeve's inside diameter is slightly bigger than the outside diameter of the injector body. The fit is not snug but slightly loose. Lastly, the injector rubber O-ring does the sealing but does not prevent the slight up/down movement of the injector/s.

The sleeves seldom go bad unless cracked or chipped. The o-rings (sleeve and injector) do the good job of sealing the air from coming inside the engine. Discard or replace those hard and brittle O-rings if you want your CIS engines to run much better. Air/vacuum leak is the Achilles' heel of CIS (K-Jetronic). Keep us posted.