How do you adjust idle on 1975 1.8L l-jetronic Options

[steveneashcraft]

Assuming that everything is right. Where is the idle adjustment on a 1975 Porsche 914 with a 1.8L engine with l-jetronic. Car is absolutely stock.

[Cap'n Krusty]

OK. If you can't get it right with the air bleed screw, it's REALLY likely you have a vacuum leak. Unlike most induction systems where a vacuum leak will make the engine run faster, a vacuum leak on an L-jet car will make it not idle at all. Pull the oil filler cap and make sure BOTH gaskets, the flat one AND the o-ring, are there and in good condition, and that the cap is screwed on straight and tight. If fixing that doesn't do it, check all the vacuum lines, look for any place where a hose might go but doesn't, check the intake boots (hoses) and the nuts holding the manifolds to the heads, and finally, the valve cover gaskets. BTW, how did you set the timing if you couldn't make it idle? Holding the throttle steady isn't the best way to get it right, and it's 800, not 900RPM.

Besides all that, the valves need to be set at .006" or looser, and they need to all be pretty much the same setting. I say "or looser" because the car will actually run cleaner at .012-.016, something we "could" do for smog testing purposes where appropriate. Of course we wouldn't really do that, 'cause it would be illegal.

As to the appropriateness of my post, you CANNOT set the idle with the timing off, so setting the timing is the first step. You can't set the timing with the idle off, either. The car obviously doesn't run fine except for it dies at idle, because the idle is a critical part of running fine.

In closing, I think you may have misinterpreted my answer as being irrelelvant. For that, I'm sorry. However, I supposed you knew what an air bleed screw is, and it appears your idea of an air bleed screw was more in the line of that they use on many (but not all) carburetors. Go back and look at the things I've outlined, and get back to us. The Cap'n