TheSamba.com :: View topic

Wed Apr 13, 2011 1:53 pm

OK, I'm an aircooled guy and know very little about the CIS fuel system. The injector seals were leaking, sucking air and a rough idle so I've got new seals.

On the CIS injector nozzles should I apply any lubricant to the seals or install them dry?

If I should apply a lubricant, what lubricant is suggested?
Silicone?
Oil?
Grease?
?????

Thanks for any advice!

Dave

Wed Apr 13, 2011 2:13 pm

Vaseline! Very thin layer... I usually stick them in my mouth and roll them on with a little spit on them. They are easy and they don't tear easy. Do you already have the seals?

Wed Apr 13, 2011 2:23 pm

Yes, I have the seals, I didn't think of Vasoline! I did a bit of looking and found this site, they say a drop of oil .........

http://www.passat32b.hu/olvasnivalo/kezikonyvek/sz...on_ECI.pdf

On page 15 it says this.......

" FUEL INJECTORS
1) Clean area around valves. Hold valve securely and remove
fuel line fitting. DO NOT allow valve to turn as damage may result.
2) Remove retaining plate if present, and pull valves out
carefully. DO NOT remove insulator sleeve.
3) To install, reverse removal procedure. Replace "O" rings
and lubricate with a drop of oil. Place injectors in sleeve and press
until seated. Tighten fuel lines and check for leaks."

I also found this statement on another site, granted, talking about Bosch CIS in a Toyota but....

"According to Bosch, the o-rings should be installed dry and rolled over the injector barrels. Silicone may help, since new o-rings fail upon repeated removal and installation. Normally, o-rings come out with injectors. Green (nitrile) aftermarket o-rings appear to give better service than the OEM black rings."

Thanks for the advice!

Dave

Wed Apr 13, 2011 3:05 pm

Best of luck Dave... Let us know how it works out.

Thu Apr 14, 2011 1:47 pm

I hope it's not too late to add my piece here. A buddy who is a 20-year Audi master tech gave me a tip for lubing injector seals a few years back, and it worked like a charm.

He recommended installing the seals on the injectors dry, making sure they are warm enough to be pliable; I did my 16v Jetta's on a cold day, so I kept them in my pocket until each one was needed. Once each injector had its seals in place, give a quick shot of aerosol carb cleaner in the hole and on the injector and slide it in. Any of the excess solvent that drips down inside the cylinder will burn when the engine is fired, and any surplus on the outside will evaporate.

As the injectors in nearly all watercooled VW & Audi engines are a press fit(no hold-down hardware), silicone or petroleum-based lubricants are not recommended; there is a slight chance that the pressure developed within the cylinder can dislodge the injector if it has been lubed....and that is a bad thing to have happen. Unlike Vaseline or silicone lubes, any trace of the carb cleaner is gone after the install.

Thu Apr 14, 2011 2:38 pm

CIS injectors have a hold down clamp. Motronic injectors have a clamps. Digifant uses injector clamps. Newer cars have a fuel rail that bolts down on the injectores. Pressure that builds up in the cylinders is called compression and it's inevitable. I have never had a issue with an injector popping out from a thin coat of Vaseline.