Opticalfuel, here are my remarks:

Yes, copper is better for your car. Lose the platinums.

Ignition wires should be roughly 4000 ohms. The large spark plug connectors should have about 3000 ohms resistance, and the smaller connectors at the distributor have about 1000. The numbers you posted look good. With new wires and plugs, and a new cap and rotor, you are perfectly positioned to adjust your CIS system, which is necessary once in a while but not often. You can also watch your fuel pressures during warmup, once the CIS system has been adjusted at running temperature, and troubleshoot any cold running problems you might be having.

The solvent to use in cleaning the injectors is Berryman's B-12 Chemtool. Trust me on this. Usually they are back-flushed but if you think an ultrasonic cleaner is enough.....

I think 1997 was the last air-cooled year. The 1997 993-S is going to be a keeper, much like the '73 RS is.

Andras: Don't know why your backfiring condition would go away at temperature, but burbling in the exhaust during decel, or popping during decel ("over-run") almost always is an exhaust leak. A place where oxygen can get into the exhaust system, such as a gasket leak. The oxygen provides the missing ingredient for explosions. The other two are already there (unburned hydrocarbons, and heat).

I know you're right about the platinums. I'll never run them again.

Copper NGKs are the good unit.

Interesting about the popping during decel. I have that same effect sometime, but not badly. Just on quick decel, right off large throttle. I also have a by-pass (the original cat's guts got clogged and subsequently removed) therefore any gasses that escape un burned are probably going to pop in the hot exaust pipe, if it goes all the way to the tip without being burned.

I am going to run B-12. I just wanted to be sure there was no way to harm the injectors, and I trust you about that.

Thanks, and I'll post after I clean them out.

ONE QUESTION: in your opinion, if I have been running with the same set of injectors for over two years, is it proabably time to clean them, considering the way it was running for a while? (having mixuture problems related to the fuel distributor, and so forth.)

Thanks.

As we are showing off our motors:

Pelican Parts has a nice looking intake. Sounds only slightly more throaty. Not a real noticable change. But as for the looks, well, if you aren't REALLY old school, you might agree - it pops...

http://www.opticalfuel.com/motor.jpg

Looks like Warren beat me to the Chemtool tip. Always listen to Warren. When Warren and I disagree, Warren is correct.

If your injectors are just two years old, then I think you're wasting your time cleaning them. Techron is a good injector cleaner. Wait until you have less than a quarter tank, put one whole bottle of Techron in, drive for a while and park the car overnight. Next day, drive some more and before you run out of gas, stop and fill up, putting a second bottle in. When that tank runs out, change your oil. Techron does not burn. It just gets into your oil and it's pretty icky stuff.

Chevron gas is reputed to be the best gasoline on several measures, including and especially keeping injectors clean.

And last but not least, as long as we're showing off pictures....


http://forums.pelicanparts.com/uploa...1109290628.jpg

Nice looking engine. I used to have a fan that was red. It was a smaller fan and when I replaced it with the 9.5 Inch (Carrera late model) it came silver.

I am working on making it run perfect, and later I will work on pimping it out.

Thanks for the pics! I will try cleaning the injectors the 'easy' way.

From what your telling me it sounds like I am already doing the right stuff. I placed a big bottle of the Techron in the tank. I should have clean injectors after the weekend.

You think it is overkill to remove the injectors and clean with the ultrasonic? I really don't mind doing it if it will really clean better.

QUESTION:

Are there screens in the injectors or the connectors that screw on the tops of the injectors that could foul up the flow of fuel ?