1983 SC - How to clean injectors?

[wachuko]

Getting the RSR Tribute to run again... need to clean the injectors. How much air pressure to clean them without damaging the internals of the injectors??

[wachuko]

Yes, I took them out, cleaned them on the outside, running some carb cleaner, dipped in gas while I type this... would like to run some air through them to make sure the internals are working before I put them back.

And yes, installing a new fuel filter as well

[larrym]

you can buy a inexpensive device called an "injector inspector" which pulses the injector, (i don't recall the brand - it's not on the gizmo)

then set up a fuel pump with a hose connected to the injector nose and pressurize it,

(i use a late 914/vw "bullet style" that has one inlet & one outlet - it produces 100psi unregulated)

turn on the tester & it will backflush

this is especially necessary if you ever get fine rust or dirt into your system

.

[Joe Bob]

Bottle of Techron, Sea Foam or other gas additive after re-installation.

[wachuko]

Originally Posted by larrym

you can buy a inexpensive device called an "injector inspector" which pulses the injector, (i don't recall the brand - it's not on the gizmo)

then set up a fuel pump with a hose connected to the injector nose and pressurize it,

(i use a late 914/vw "bullet style" that has one inlet & one outlet - it produces 100psi unregulated)

turn on the tester & it will backflush

this is especially necessary if you ever get fine rust or dirt into your system

.

Ok... I did it manually with 75psi and they are cleaning well and working... I just want to get it started. New booths, o-rings, etc. after I drop the engine for cleaning, going over the top seals, and other small stuff.

Thank you all!!

[wachuko]

Originally Posted by Joe Bob

Bottle of Techron, Sea Foam or other gas additive after re-installation.

Techron, absolutely!!

[Bob Kontak]

Originally Posted by larrym

"injector inspector" which pulses the injector

Ain't no pulsin' on them injectors. Pressure only.

[spuggy]

I scored some 930 injectors in a box of 930 CIS parts. I wired the pintles open, ran the ultrasonic cleaner for two weeks solid with the heater on and changing the cleaning fluid as often necessary - like whenever I could no longer see the injectors getting cleaner.

Some of the stuff that looked like rust turned out - after about a week - to be fuel varnish... I backflushed (from the manifold/pintle end against the direction of fuel flow, to lift anything off the internal screen) several times.

Any Porsche or MB place that works on CIS cars should have a CIS injector tester that lets you measure the crack pressure and observe the spray pattern. I junked two out of six - which, at $140 a pop for RoW 930 injectors, I thought was kind of a result....

[Marc Bixen]

Yes a Bosch CIS injector tester and some mineral spirits will fix a lot of injectors. We use our tester ALL the time. We still replace injectors but many times you can clean them. If your going to store them, put a little ATF through them before you put them on the shelf.

[Laneco]

We usually send our CIS injectors to a local diesel repair shop - might check that option. For the newer 911's with the electronic injectors, we send those to Witchunter in Seattle.

angela

[RWebb]

yes, any Cummins shop can do it - Or. Fuel Inj. is the local go to place here

[Walt Fricke]

Some day I'm going to use one of several spare brake master cylinders to make an injection tester. Mount with a lever, put in a pressure gauge, and find the fittings needed to screw onto the injector. Use any old container as a reservoir for the fluid.

some day.

[boyt911sc]

Originally Posted by wachuko

Yes, I took them out, cleaned them on the outside, running some carb cleaner, dipped in gas while I type this... would like to run some air through them to make sure the internals are working before I put them back.

And yes, installing a new fuel filter as well

Check the opening pressure. I segregate or classify the CIS fuel injectors according to the value by which it starts to spray uniform mist pattern. Group I (35 - 39 psi.), group II (40 - 45 psi.), and group III (46 plus psi.). They should not drip at standby and produce uniform mist spray pattern to pass the test. Group I is classified as VERY GOOD, group II as GOOD or ACCEPTABLE, and group III as REJECT. While group III fuel injectors could still make the engine run, I avoid using them.

Tony

[Aurel]

I cleaned mine in an ultrasonic bath of IPA. They came out as new.

[wachuko]

Originally Posted by boyt911sc

Check the opening pressure. I segregate or classify the CIS fuel injectors according to the value by which it starts to spray uniform mist pattern. Group I (35 - 39 psi.), group II (40 - 45 psi.), and group III (46 plus psi.). They should not drip at standby and produce uniform mist spray pattern to pass the test. Group I is classified as VERY GOOD, group II as GOOD or ACCEPTABLE, and group III as REJECT. While group III fuel injectors could still make the engine run, I avoid using them.

Tony

Tony, I have a new set just standing by (that I was going to use in the RS project) in case I need to trash the ones in the car. Those were the pressure values that I needed. When I get back home I will remove them again and test with 35-39 psi.

Right now I think I have a fuel pump issue... but I did not have the time to check everything well before getting on a plane... I will spend Sunday troubleshooting the fuel system. Car used too run fine but the rust in the original tank took out two pumps before I figured out what it was... a new tank later... I need to go over the system again.

Thanks

[Bob Kontak]

Originally Posted by Aurel

I cleaned mine in an ultrasonic bath of IPA. They came out as new.

Was it the beer or the ultrasonic that did it?