tj90

OK, Ive been reading good articles about cleaning the fuel injectors using ultrasonic cleaner and techron. The DIY article can be found here:

http://www.rowand.net/Shop/Tech/DIYF...orCleaning.htm

question for you guys - does anyone know what the proper electrical voltage to momentarly actuate the injector? Is it as simple as 12v? Any resistor needed?

Garth S

For the high impedance Bosch injectors (~14.5 ohms), I've used +12V with a low wattage fuse on the + side: pulse thei njector open to introduce the cleaning solution for an overnight soak .... carb cleaner, or an aerosol can of GM's "Cleens" works great.
Blow clear with air and WD-40, then fill a tube connected to the injector with a ml or so of the WD, pressurize with ~40psi air .... and pulse the switch on the test rig.
If the injector blows a perfect conical mist pattern ( for the single pintle type), it is a good sign that it is clean - oh, and no dripping from the tip with pressure applied and power off is also a good sign

tj90

Excellent - this is the information I was looking for!

North Coast Cab

I was going to do this myself, but I ended up shipping to Witch Hunter. For $120 round trip they were tested, cleaned, re-tested and had new seals installed. I though it was well worth it considering the cost of th eengine rebuild I'm involved in.

JoeMag

Marren Fuel injectors is another place that does them. ...they provide data on spray pattern and flow rate also (before and after I believe)

geolab

In the ultrasonic bassin, diluted water works best, the other stuff might goo, and I don't like. Used (for a friend's car) injector cleaner that you add in tank, next day it was stuck like candy
The battery you can use, is the 9 volt flat square torchlight battery (the one the size of a hand palm), works very well,
ps: you can trigger the injector even with 4.5 volts.
Only thing you need (practical), is the electric plug that connects to injector.
Any 964 guy has a spare one, it has a rubber surround, there is one in the 964 mirrors I think.

tj90

Wow - 9v battery? Easy as that! I ordered a FI rebuild kit and the guy told me that the Bosch injectors are initiated with a 12V pulse for a few milliseconds then the injector is held open during a spray cycle by 1-2 volts. An oscilliscope will show the initial voltage spike before dwelling low during a spray cycle.

My injectors have been soaking in an ultrasonic bath overnight with 30% techron (basically what I had left iin the bottle and 70% berrymans chemdip cleaner. Hopefully nothing is gummed. What do you mean by diluted water? My concern with water is that Ive been told that the pintle internals can corrode. Maybe not an issue with these Bosch Type 1 injectors?

I did notice during initial cleaning that the FI black body paint came off with the gunk. I guess Ill be repainting those. I presume that exposed metal may not be good in regards to corrosion.

NineMeister

Can you tell us how to dilute water??

chris walrod

Like Steven Wright said, what do you add to powdered water?

Akerlie

geolab probably ment destilled water . . .

. . . shaken, not stirred . . .

Garth S

The French, being of impeccable taste, likely dilute water as we do here ..... with a good single malt. Strange though, to use it for injector cleaning

geolab

oxymoron, I meant water mixed with a little of the cleaning stuff (techron, lubro moly etc), and not the cleaning stuff by itself, my mistake
Yes akerlie, in the ultrsonic cleaner user manual, they advise distilled water

TJ bosch injectors are aluminium, and nozzle, pintle, etc are chromed iron aluminide, no rust. mine were serviced at bosch stuttgart, and they were sent back with some dielectric grease. put some if you have on the + / - socket

Yes the palm sized 9 volt battery is very handy.
The battery has two metallic pole tabs about an inch each.
twist the wires from the injector on two paper clips.
This way you can slide the battery tab in the paper clip when you want to
keep the injector open, and pull the paper clip for closed position.
the battey is practical next to an ultrasonic bassin.

chris walrod

Personally, I would send them out for cleaning, flow pattern verification, rebuilding.

axl911

If you DIY, you would have to buy new seals and the little plastic spray tip for the injectors? Priced from Porsche, combined, they cost almost as much as sending them out.

geolab

on bay, search bosch efi injector kit and the whole seals, nozzles, filters, kit for 7 injectors (+1 spare) is at $10-15