rawwarden

Does a 82 928 S Euro have an idle speed regulator? What would cause the idle to go up high and return back slow after giving it gas. (It hovers at 2,000 and slowly over a minute or so returns back to idle)

Rich9928p

No, Euros didn't get idle speed regulation until the S4 in 1987 (US spec 928s got it in 1985).

A typical symptom of a slightly over-rich air/fuel mixture is for the engine to "hunt" around the target idle speed - go a little faster then drop down below the desired speed - over and over again. If you adjust your base idle mixture just a bit leaner, it will idle smoothly.

rawwarden

If you rev it up, the idle stays up high and comes slow. It also sometimes struggles to reach idle when turning on, it starts at 200 and raises slowly to the idle. It used to work fine a month ago, would the fuel/air mixture create this problem?

Rich9928p

You may have a combination of issues - some clogged passages in the fuel distributor, the metering piston could be slightly dragging on crud, your WUR (warm up regulator) could be off. Also, if you've never had your fuel injectors cleaned they may not be flowing right. The CIS injectors have screens inside that can get blocked up. CIS fuel injectors are less expensive then their electrical brothers, so it may be time to install a new set. Also, if replacing or removing the fuel injectors, replace the rubber grommets.

If you'd like to learn more about the CIS system, I wrote a lengthy paper about the work that I did on my '79 Euro. Drop me a note at info@electronikrepair.com