Cleaning the Lower DME on 964

[964C2]

I disassembled the DME on my C2 to inspect and clean parts in prep to putting it back on my newly Top-end rebuilt engine (thanks Walt!). When I removed the rubber sleeves that connect the Connector Tube to the Right and Left Intake Distributors, I noticed that there is some kind of adhesive used to seal the rubber sleeves. Does anybody know what the adhesive used here and how it is applied?

Also, I want to clean the fuel injector jets and replace the O-rings but had a hard time removing it from the manifold...is there a trick to this? How do you clean the Jets?

One more thing, does anybody know if the O-ring on top of the fuel injector, the one that seals the connection to the Fuel Rail is a replacement part or do I need to buy a new fuel injector?

[ChrisBennet]

The DME is just the engine computer part of the injection system.
You can soak the injectors in some B12 Chemtool or have them cleaned and flow matched by someone like Marin or EBS. You can't mechanically clean them
I know the lower injector O-ring is replaceable. I'm pretty sure the O-ring at the top of the injector is replaceable but I don't see it listed in the Porsche parts fiche.
-Chris

[rcwaldo]

has anyone had their fuel injectors cleaned and balanced? Notice a difference? Recomend a good place to do so?

Thanks!

[964C2]

So I found this place, Pacific Fuel Injection in South SF,that specializes in mechanical Fuel Injections, and Kugelfischer Injection pumps. He said he can do the Hydrosonic cleaning and Flow matching on EFIs for $18.00@. This is cheaper than EBS' $30.00 a pop deal!

Also, with a little muscle I got the injector out of the manifold. Looking at it carefully, I'm convinced that the o-rings for the bottom is the same for the top. The top ones all show sign of age while the bottom ones were ok but I've decided to replace both since it'll be awhile till I open it again.

[964C2]

When I picked up my injectors from Pacific Fuel Injection, Gus Pfister, the owner gave me a tour of the shop. He showed me how ultrasonic cleaning works and how flow matching is done.

Ultrasonic cleaning is basically dipping the lower half of the injectors in this tray full of special cleaning fluid with an ultrasonic frequency generator. The concept is simple, vibrations caused by the sound removes any dirt from the injectors.

For the Flow-matching, Gus installed the 6 injectors on a test fuel rail with a measuring cylinder at the end of each injector. The special fluid is then pump into the injectors using different frequencies and the amount of fluid is measured afterwards. According to Gus, 10% difference is acceptable between all injectors. Mine came out to be about less than 5% difference, so I was pretty stoked!

Gus also replaced all the O-rings (the lower and upper are the same) for $1.60 @.

Lastly, Gus gave me a tour of an MFI from a 930 he was working on...fascinating! If you ever need a Bosch fuel injection rebuild, Gus is your man.