karl ruiter

CIS injectors are the garbage dumps of early fuel systems. Most of the crud in the system after the fuel filter either ends up in the FD strainer or in the injectors. Ideally, when overhauling a CIS system you would start with the tank and replace or clean every line in the system plus the WUR and the FD and replace the injectors. I often don't have that kind of time so I take short cuts. This leads to the new injectors getting crud in them again. Roger has injectors for around $200 a set, which is a smoking deal and a good idea. The first time. But by the second or third time it starts to feel a little pricy. So I have been searching for an easy way to clean them. This is it.

First, here are the guts of the injector. Not much to it, just the keeper, the spring, the valve, and the seat. No little passage ways or secret sauce. There is also i screen before this assembly, that is really hard to remove intact.



The problem is that the spring keeps the valve closed and you cannot clean, soak, or back flush the injectors. You can buy a fixture to pump fluid through them in the forward direction, but it does not clean the screen and it costs about the same as a set of injectors. That's pretty cheap, but unless you are doing it a lot, the injectors are probably the better choice.

Here's how you do it.

1) Take a piece of thread. This is high tech UV resistant marine thread, but probably anything would do.



2) Pry the valve up with a pair of fine tipped tweezers and pull the thread under it.


You will want to wrap the thread a full 360 around the valve, otherwise it will tent to pop off.

3) Once you have the thread in place you can use it to pull the valve up and to one side and hold the injector open. The world is your oyster. You can back flush, soak, and generally clean to your heats content. I find that a quick puff of air backwards pretty much does the trick, but I also squirt some carb cleaner in the forward direction and then blow both ways.



This is so easy to do that I will be doing it any time I'm changing plugs or wires as part of a general tune up. Make sure you put some anti-seize on where the injector holder threads into the manifold so they will come out easily next time.


I've been meaning to write up a post called the total bottom feeders guide to a full overhaul of the CIS system for around $200 (including the pump) in a day. Hopefully I'll get around to that at some point, but in the meantime I think this is the biggest missing piece.

Callum_GT

that is awesome & so simple. thank you

The Deputy

Thank you, for sharing. Looking forward to the rest of your CIS information.

Brian.

hlee96

I was lazy and put all my CIS injectors into a tub of simple green in the ultrasonic cleaner and let it zap for 10-15 min with some heat. Afterwards, I used an air compressor to blow dry the injectors with what a rookie like me seemed "proper" misting during blow off.

Thank you for uploading what you did and I will certainly do this if my old injectors don't work!