300sd rough idle loss of power
 

I have been working on my 85 300 sd Cali and encountered another issue that I could use some expertise.

About two months ago the AC starting shutting off and then would come back on, real intermittent then the ignition key started sticking and one day left me locked out ,in front of my house thank goodness. I had already been searching this form and knew it could happen and how to fix.

So since it's my daily driver I pulled the cluster and dropped the wheel and removed the steering lock,then cut off the pin and drilled a hole through it and set a screw in place.
Then I ordered a new lock and ignition from here Pelican Parts installed the unit. The old ignition was really worn and I immediately noticed the difference and to my surprise as mentioned on another forum the AC was back to normal NO issues.
However I noticed on the first crank that the car would turnover but not
start:confused:so I would reset the key and second time no problem. It seem quirky to me but I was willing to see if it went away.... But it has not and now it is almost every start I have to do twice.:confused:

This is also followed by a start that sometimes leads to rough idle and no power ,car just sits there,so I just shut it off and then wait a few seconds then restart and whamo it runs the first crank and off I go.

What do you guys think?
Puzzled in St. Louis

On the Steering Colum Lock is a Vacuum Switch/Valve. When it malfunctions it can fail top bleed the Vacuum off to the Vacuum in the Vacuum Shutoff Valve on the Fuel Injection Pump.
Also getting the Vacuum Lines reversed on the Vacuum Swith/Valve causes it not wot work prperly.

It is also possible there is some internal issue in the Steering Colum Lock.

To check this as the cause before your first start open the Hood and disconnect the Vacuum Line that goes to the Vacuum Shutoff on the Fuel Injection Pump.
If it always starts the first time like that then it could be that Valve that is on the Vacuum Swith/Valve Stering Colum Lock.

I was wondering if hooking up the vacuum lines wrong on the vacuum switch on the back of the ignition part might also have a funny effect. You would have had to have them off for this to have any possibility at all. They are not interchangeable.

A simple test might be to have someone turn the ignition key on the first time. Watch to see if the lever on the injection pump is in the run position. I suspect it will remain in the no run position until someone turns off the ignition key and turns it on again. This could also cause all of your related issues.

Other than the wrong hookup to the vacuum switch. The switch itself may be not activating internally properly or the drive connection is seriously worn. Or just pull the vaccum line from the stop device on the pump. Everything normal you will have established where to look. You can just shut the engine down with the shutoff lever during the testing. No expertise here but generally with any new fault after any form of repair. You critically examine the repair.

Are the glow plugs functioning properly?

The third try indicates that is when the shutoff is fully disengaged at last to me. Each time you cycled the switch vaccum was being decreased to the shutoff.

Yes , I just replaced last year and replaced the relay this week from eBay they are fine.

Tomorrow I will pop out the cluster and check lines. I was taught that if the lines are rev then the motor won't shut down without manually doing so.
Is that correct?:confused:
Thx

:DToday I pulled the cluster and reversed the vacuum lines and problem solved.
I guess it's pretty easy to do that when you R/R cluster and steering lock 2-3 times in August.

Thx for the help:P