Rough High Idle 1989 420 SEL
 

I have a slight high idle, 800 rpm, and sometimes a rough warm idle. I have changed the injectors(inlcuding the cold start), FD, wires, coil, plugs, idle controller. 3 plugs were dark. I'm thinking the dark plugs are getting too much fuel, or maybe not enough air.

Could the air distribution hose leading to the injectors be blocked or clogged? Any other ideas?

I would change out the rubber it is easy and it does get brittle with age. I would replace all the rubber on mine, I did it with the injectors. But I don't think that is your problem. Is the high idle at P or in D or both.
m

The high idle only seems to be in P. In D it is 500 rpm, which I believe just about right.

800 rpm
 

Isn't 800rpm about right on P or N for that car. My idle is about 550-600 in drive and about 800 in park or N. I have injector issues also on my 126. What kind of change did you get when you changed your injectors??

Dunno about the idle, 800 seems a bit high in gear. Make sure the linkage aint binding. Also, I'd check the base CO and look for a injector seat or bucket leaking vacuum.


Joe

In Idle in drive 550 =/- 50 rpm
In P or N should be 650 rpm - 50 rpm +100 rpm

CO?
 

How do I check the base CO?

The injector buckets were changed with the injectors. Maybe one or two were not seated properly as Joe P. suggests. To get them seated, can I just tap them in lightly or push them down, or do I have to remove the fuel lines, etc.? What's the best way to get them seated properly?

It sounds like I should probably replace those air distribution tubes. I might as well replace the hose to the idle control valve too.

The air distribution hoses connected to the injecters, should I just pull-up on the tube to get it off?

depends on how brittle they are. If very hard cut them off. I would also replace the 2 air distribution hoses under the fuel/air flow unit. Ypu can do this with out removing it.
and yes you should replace the rubber by the idle valve both pieces.
m

Re: Rough High Idle 1989 420 SEL
 

Interested in a parts car? Very reasonable.

I have other posts here which describe it, Monday its donated. I do not have time to fix.

Shame to let it go to waste...

email offlist at spw1@optonline.net

base co needs tobe done with a gas analyzer.
m