Need Help De-Loping a 280i Idle

[Grady]

We have a strict annual pollution test for which I'm ultimately exempt. But you still have to play the game and let them mess with your car.

So after some well intended "fine tuning", my 280 is running badly, way rich with a very lopey idle - lopey to the point of almost stalling on the low side (1200-400 rpm).

What is the best source for DYI tuning & adjusting tuning instructions? I read though the Bible, the Epistles and the Bosch reprint and they have more on the principles and/or on V-8s.

I seem to recall a good Porsche CIS link but can't find it searching. Thanks Grady

[grahamw48]

Search out some UK Ford Capri sites...2.8i of course...same engine.
Emissions stuff will differ slightly, as we have the full 160horses of course.
Lots of clubs and enthusiasts here

Edited by grahamw48 on Friday 20th June 22:55

[Comadis]

there should be a red plug at the fuel dizzy. underneath is a hex-bolt (4mm key?) where you can adjust the mixture.

attention: do not accelerate when the hex-key is still inserted.

airfilter is new i guess?

more or less thats all what you can do.

check also the valve clearances, ignition timing and often a new rotor-arm and cap, incl. new spark-plugs will improve the engine running too.

[jeff m]

Grady said:

I seem to recall a good Porsche CIS link but can't find it searching. Thanks Grady

http://www.pelicanparts.com/911/911tech_articles.htm

1974 was the the first full year that 911s had CIS

To tune CIS properly you really need a CIS fuel pressure guage, the one with the T fitting. (so the control pressure can be measured)

BUT, you may not need it one. CIS is all about air flow. I doubt you would get those revs with just high fuel pressure. I would check first the three way air can get to lift your plate.
Correct seating and correct return of main butterfly.
AAD (not openning)
Main butterfly by pass. (if malajusted, but probably not as it's only small)

You do have your 02 sensor connectted? The WUR thinks it is

Edited by jeff m on Monday 23 June 00:44