GerritD

Hi 928-friends,

I know this topic has been often posted but I can't exactly identify the problem since it concerns more than 1 issue :

1. when starting my 1980 928S with warm engine, I need to push my gaspedal
fully to start my car, but it always start this way.
When engine cold, I don't have this problem and just
need to turn key to start

2. idle is fluctuating from 400 to 800 rpm in P or N. in D this doesn't occur

3. when cruising for 5 till 10 min at high speed (> 100Mph), the idle doesn't
fluctuate anymore and remains stable (800rpm)

4. sometimes idle suddenly rises till 1300 rpm

5. some of my spark plugs are rather black instead of brown (especially the
ones at back of the engine)
6. acceleration and normal driving of my 928 seems to be OK, it is only during
idle or start that I have these issues.

Where should I look, first ?
Is it my Warm-Up regulator that causes all these problems ?
If so, is there a repairkit avaliable ?


thanks


Gerrit

WallyP

Obviously an early car, but it ALWAYS is a good idea to give complete info on the car - model year, transmission, RoW/USA, etc., etc.

GerritD

It is a Euro 928S of 1980 (chasis nr 92A0820833) , 3sp Automatic, but original engine (4.7L 300Hp M28.12) has been replaced by one of the former owners by a 4.4L 240HP (engine M28.01)
It is a K-jectronic with 1 distributor

Jadz928

Aux air valve? Pull it, inspect it, put it in the freezer to see if it actuates.

GerritD

Alright Jim,

I'll give a try....thanks

Gerrit