Hey guys,


So as of a week now, the 560SEL has been doing a really weird thing when I start it up when 'warm'.

It'll start right up, and then after maybe 4 seconds, the economy gauge reaches the mid point, the rpm's drop below 500, and the oil pressure drops to 2.

It sort of rumbles, so I'm guessing this isn't something I should just let happen, but what could be causing such a thing? After letting the car do its thing, it generally goes away after 20 seconds, revving itself up to about 1100, and then back down to 950.


Thanks,


Carlen

Forgot to mention that also on occasion when warm, I'll turn the key, it'll start, and the rpm will climb to 1200, and when on it's descent back to where it would idle, it just continues downward and dies.

I then can restart it, and it'll do that whole weird thing it decides to do.

After driving her the past two days, the thermostat gauge is acting realllly strange ALL the time; It'll start reading at the bottom, and then work its way up to the 80 degree mark, but usually at that point, it'll JUMP to over 120 degrees, and while highway driving, it'll move anywhere between 80 and 120, and I have to hit the dash to make it unstick from the 120 degree mark.

I guess I need a new Thermostat? Probably a coolant flush while I'm at it.

Could just be a bad ground on the gauges too.

If you can get it running, and stay running... check your idle vacuum.

Also verify your engine/body grounds and the battery ground. That can cause issues too.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Oh the idle vacuum is as low as possible; she runs after one or two start-up attempts.

I have the work manual, but where do I check for these grounds?

My battery ground is pretty chewed up; I'll take a picture sometime tomorrow.

Thanks,


Carlen

Well a bad battery ground is never good, one of my BMWs would not even start with semi loose battery connections. I am not sure how sensitive these cars are to charging systems, but verify the alt connections and its output.

I know one of the body grounds is from the steering pump bracket to the fender area.

Well consider this also: the newest M116/7 here in the US was built in 1991. That was 19 years ago, maybe 20 depending on build date. The early ones should have come out late 1985 which is 25 years ago! So most of the rubber under there is in dire need of replacement.

Pull the air cleaner assy off and nose around. Just touch and squeeze all the stuff to see if it is pliable, if not... well that would be a good place to start before attempting to further fix issues. Do not forget, the intake manifold is a two piece... so the eight o-ring looking seals need to be replaced also. This is a real PITA. Also the fuel distributor boot to throttle body shrinks with age.

Four and three way connectors go bad too. Any oil leaks are vac leaks...

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]