[W126 Coupe] 89 560 sec with engine miss and rich, poor idle

[Al Hollis]

My chrome is coming off the grille near the star (89 560SEC). Does anyone 
have a fix for this or knowledge where to find another grille?

Laurie

----- Original Message ----- 
From: "Rick Granlund" <rickard681 at cox.net>
To: <mbcoupes at mbcoupes.com>
Sent: Thursday, July 19, 2007 1:28 PM
Subject: [W126 Coupe] 89 560 sec with engine miss and rich, poor idle



> HI-

> I don't mean to bother the list, but I have qa rather sever problem with 

> my '89 SEC.  I tried earlier but did't get any takers in trying to 

> diagnose the problem.  Hoping someone will chime in with the solution to 

> my problem.

> thanks in advance.

> Here is the problem:

>    The car

> does not appear to have any enrichment when first started, but acts like

> more than one injector is running wide open.  When it is first started,

> cold, it will stall unless you give it enough gas (1000rpm or more.

> After about 30 seconds you can let it try to find idle, but it hunts

> between ~500rpm and ~800-900rpm or stalls.  The exhaust is VERY rich (it 

> stinks

> with fuel). I bought the car with a broken ( front vacuum

> tube nipple)fuel pressure regulator and the idle was erratic and had 

> bumped up to

> 1000 - to 1400 rpm isong the throttle linkage (the one link down under the 

> front of

> the throttle body, just behind the cruise linkage. It would still stall

> and hunt up to 1400rpm. I replaced the fuel pressure regulator.....no

> change!  So I replaced the Idle control valve....no change! I seems to

> have a severe miss....running on seven, but it does that well above idle 

> too.

>   The miss is it running very 'rich'.  I replaced the distributor cap

> and rotor and the plug wires thinking it was an electrical miss.....no

> change. It appears just to be a very rich condition....all the time.  It

> will not idle, just hunts 400 to ~900 rpm and stalls.  After stopping, it 

> is very hard to start...like leaking injectors.

>     I am thinking this rich condition is controlled by some electronics,

> rather than a faulty injector....it just runs too rich.

>     Could someone guide me through the logical troubleshooting steps to 

> get

> to the bottom of this problem? How do I check if the cold start injector 

> is 'open' all the time.  Removing the electrical leads to it does nothing.

> I think if I can find the reason for the ery rich idle and run condition, 

> it will solve the idle and 'miss' the car has at idle and in running.

> Rick

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