Backflushing CIS injectors

[grantsmells]

I just used this method on my injectors from my '82 SC and the backflush went well, but using the can of brake cleaner I couldn't get my injectors to open and spray. But they do open and spray just fine when hooked up in the car. I noticed mine look different to yours, with an indent for the o-ring that yours don't have. Could it be that these injectors have a higher opening pressure?
I'm not worried as they work in the car, but thought this would be handy info for anyone else who may be worried when the spray can doesn't work.
I also had to put some tape around the squirt nozzle thingie to get a good seal in the injector. So possibly a different sized hole there too?

[JFairman]

Glad you found my post on cleaning and flushing these things useful.

I used a can of generic carb cleaner instead of brake clean to spray through the injectors. They are different and maybe carb cleaner is at higher pressure inside the can so it's able to crack open the injectors better.

My injectors are from a 930 or 911 turbo and they look different than your SC injectors because they thread into the intake manifold instead of press in with an o-ring like in most or maybe all normally aspirated motors with CIS.
930 injectors thread in so they don't get blown out when the manifold is pressurized by the turbocharger.
Healthy 930 injectors should crack open around 35psi at sea level ambient pressure. I don't know pressure is required to open SC injectors.

Good luck with your injector cleaning.

[grantsmells]

Thanks Jim! I actually didn't realise until after I'd posted that I was in the 930 forum as I was linked here from a thread in the 911 tech forum, my mistake!
I then theorised pretty much exactly what you just said that obviously they needed to thread in rather than just be held in with friction, and also that the opening pressure would be slightly lower to accommodate for the higher pressure in the manifold of the turbo engine. The difference may be just either side of the pressure in a spray can. Or again you could be right about different pressure inside different cans, which may be why your heckler early on also swore that it wouldn't work.

[bpu699]

Originally Posted by grantsmells

I just used this method on my injectors from my '82 SC and the backflush went well, but using the can of brake cleaner I couldn't get my injectors to open and spray. But they do open and spray just fine when hooked up in the car. I noticed mine look different to yours, with an indent for the o-ring that yours don't have. Could it be that these injectors have a higher opening pressure?
I'm not worried as they work in the car, but thought this would be handy info for anyone else who may be worried when the spray can doesn't work.
I also had to put some tape around the squirt nozzle thingie to get a good seal in the injector. So possibly a different sized hole there too?

Brake cleaner or carb cleaner should have enough pressure to open the fuelinjector... If it doesn't, gently heat up the can in hot water to boost the pressure. If it still doesn't open, thats unusual.

I spent a lot of effort trying to backflush my 930 injectors... Can't say it did much. I tied a piece of copper on the little spindle to gently pull it out slightly. then slipped fuel hose over that end and clamped it on. Then flushed with pressurized fuel running it backwards using an extra fuel pump...

Good luck...

[T77911S]

i messed around with this a little on one of my injectors. then i sent them to larry for testing. one of the pintles came out when he was testing it. would not be good if it happened on the car.
i was very careful with it but i cant help but think it was my fault.