hard starting, rough idling, stall loving 560SL - PeachParts Mercedes-Benz Forum

nonextant · #1 10-02-2006, 09:23 PM

Hi,
I just got back from Iraq and am attending the Armor master gunner course in Kentucky. My wife decided to surprise me by getting my 560SL all tuned up and having the steering components all replaced while I was gone so I could drive it to school.
The car runs great on the freeway, but when first started it turns over but doesn't catch until about the 4th crank... then It loves to stall but start right back up. once I get it running, it idles rough and will stall when I put it in gear. If I put my foot on the brake and give it enough gas to idle at around 1200 rpm it will drive and smoothes out after a block or two. Then it runs just fine. If I shut it down it will start right back up, unless I leave it for about 20 minutes, then I have to go through the whole procedure again.
Does anyone have any idea about how to go about troubleshooting this? I have my service cds but the first disc got damaged and now I can't install the cd's on my laptop. So far I have checked the OVP relay fuse and have started looking for a vacuum leak with negligable results so far. I also started it up this afternoon and noticed a puff of white smoke from under the air cleaner when the car died then surged back to life again before finally stalling. It could be the injectors maybe. I don't know. I would appreciate any advice you guys may have...

Thanks,

SSG Mark Beazley
C Co 1-8 Infantry

jaoshea · #2 10-03-2006, 01:01 AM

Almost sounds as if the cold start valve is not working. Just a thought.
Good luck.
John

david s poole · #3 10-03-2006, 10:04 AM

sounds like you have a bad ovp relay as though car is trying to start in limp home mode.for sure the main ecu is not getting power. ps cold start valve will not operate until engine temp is around 30f.

nonextant · #4 10-03-2006, 07:25 PM

Well, I got out of class early enough to go buy some tools and take another crack at my 560. I cleaned out the Idle Control Valve with carb cleaner and checked over the vacuum lines in the area. I also pulled the Cold start injector and made sure it was pushing fuel. While I was at it I did took a look at the temperature sensor, but I'm not sure how to go about testing it. I now have to wait until the engine cools back down so I can go out and see if it starts easier. Here hoping

psfred · #5 10-03-2006, 10:08 PM

Check condition of idle control valve hoses -- if hard, replace, and also check the boot between fuel distributor and air flow meter horn. Leaks here will drive you nuts, car stalls and won't start, won't start hot, won't stay running, etc. Im almost certain you have a serious air leak (make sure the idle control valve hose is actually attached to the boot between air horn and throttle body! -- this is the only way you could get a puff of anything under the air filter housing.

You probably should also check the injector seals, as leaks here will also make it idle badly and cause starting problems -- just spray a quick squirt of brake parts cleaner on the injectors while it's idling. If the idle smooths out, that seal is leaking.

Just did this on the TE, it runs properly for the first time since I got is 5 years ago!

Glad you survived Iraq, thanks for serving over there. If you take a Geology course at Austin Peay you will likely have my brother for a prof!

Pete

nonextant · #6 10-03-2006, 11:10 PM

Well, it's gotten a little easier to start. I called my mechanic today and he suggested changing the temp sensor. That's one part I don't mind throwing at the problem as I know it doesn't always switch on my aux fan while stuck in traffic so the engine gets hotter than I'm comfortable with. Fortunately the autozone here can get for me. I hate dealing with them, but I have not seen mercedes one here at fort knox, so my parts options are somewhat limited.
He also suggested that I check the fuel pressure. without my service cds I'm kind of operating blind. I did not notice anyting major with the fuel accumulator. I did notice oil on the lower edges of the hoses coming off the valve covers. the one that ends just near the ICV and the one that goes into the bottom of the air cleaner on the passenger side. I think that may be the cause of my white smoke. now i just need to figure out what is causing that too. One thing I did find while checking the ICV... the vacuum hose to it's left rear was brittle. I broke off one of the nipples while pulling the ICV. I had to macguiver it back together using a coffee stir straw and some epoxy. hopefully that will hold until I can order a new one. In fact I might as well replace them all.
The spark plug order seemed a little odd. the firing order is listed on the valve cover but I'm not sure which piston is which, so I am trying to find a diagram online without much success.
Again thanks for all the help. I'll keep plugging away at it, and updating my progress online. Hopefully I'll solve it and the thread can help someone else down the road.

zcc · #7 02-06-2007, 04:32 PM

I'm having almost the same problem with my 560SEL 1989 and no one could fix it!