K-Jetronic Injector O-Ring Question

Hello,
My '78 245 runs a little rough, even after the standard tune-up stuff. I
tried a few different test for the injector o-rings, and they all failed.
I decided to pull the injectors, soak them in Techron over night to clean
them up a bit, and then install them with the new o-rings. All of the
plastic injector holder/insulators were in terrible shape, so I ordered a
new set. I'm left with two questions though.

The first of which is how do you get the holders off the injectors? The
injector turns around freely in the holder but it does not slide out.

The second is where do the o-rings go? It seems like the larger one goes
on the injector holder, but I seen no place for the smaller one. This
car's previous owners seem to have taken very poor care of it (I've seen
some very stupid mistakes all over the car), so I am beginning to wonder
if they even had the smaller rings in there.

Thanks in advance.

 

Would you say runs rough, or just idles rough?

Do you mean that all the tests indicated bad o-rings?

The real test of a properly functioning injector is the spray pattern.
The spray pattern is affected by the cleanliness of the injector inside
as well as outside. Many properly equipped Volvo shops have a tool that
can force a cleaner through the injectors whilst off the car and can
observe the spray pattern of liquid from the injectors. Soaking the
injectors in Techron may not clear a dirty injector if it is dirty
inside. Running with Techron additive in the tank could help clean the
intectors inside, but the real verification is cleaning and spray
pattern inspection.

Install the injector holders back onto the head with the injectors
inserted. Use a small prybar between the bottom of the injector and the
screw that holds the injector holder onto the head to pry out the
injector. Then remove the injector holder.

This is a pretty good indication of a worn o-ring between the injector
and the inside of the injector holder, which will suck air and lean out
the mixture, mostly at idle.

The smaller one is on the injector inside the injector holder and is
what is holding the injector in place inside the holder. Its purpose is
to form an airtight seal between the injector and the inside of the
injector holder. The larger o-ring forms an airtight seal between the
holder and the head. Both are important.

If the smaller o-rints were missing, you would be able to easily remove
the injectors from the holder because there would be nothing to keep the
injector in the holder. When you pry the injector out of the holder, you
are compressing this o-ring to get the injector out.

 

The fat oring is holding the injector and holder together. They will
pull out, but since you have new holders, you can just break your old
ones. The skinny orings go in the slot on the outside of the holder to
seal the holder to the head.

--
Mike F.
Thornhill (near Toronto), Ont.

NOTE: new address!!
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)