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.

psfred · #7 10-04-2006, 12:35 AM

Gee, I can never remember this stuff --

#1 is passenger side front, where the oil filler cap is.

Out of order spark plug wires will produce all the symptoms noted -- I thought of that while eating dinner this evening.

Peter

nonextant · #8 10-05-2006, 04:35 PM

Alright I found out.. autozone of all places.. putting it here incase anyone else ever needs to know. from the front passenger side it's 1,2,3,4 from the front driver's side 5,6,7,8.

or from the top looking in from the front

....4 8
...3.. 7
..2 o ..6
.1. ^ ..5
.....|......
pesky ICV right there in the middle

nonextant · #9 10-05-2006, 09:31 PM

Well I ordered a coolant temp sensor as my mech. suggested. I need one anyway, it doesn't turn on the aux fan, so stop and go traffic is a harrowing experience. I'm not sure how to adjust the idle mixture on the 560... my service cds are desilvered? I don't know what to call it. that data part somehow came off the disk. wierd, huh?
I put injector cleaner in at every fill up on the way to kentucky from colorado. small improvement.. still hard to start from cold. It has gotten easier since pulling all the relays, cleaning the idle speed valve and reseating the vacuum lines, but still takes about 20-30 cranks and I can't drive until the engine warms up past 80 degrees centigrade. I did find that someone had jammed a bb into one of the hoses which attaches to some component on the drivers side down next to the wheel well. looks to be attached to the exhaust header. With out my discs I have no Idea what this componant is or why some one would have blocked the line to it.

dpetryk · #10 10-07-2006, 07:53 AM

Sounds like they plugged the line going to the EGR valve. Doing so will improve engine power and gas mileage, also the emissions will increase.

nonextant · #11 10-07-2006, 06:42 PM

Put in some work today. I recleaned the Idle control valve and in the process managed to chip the lip on the plunger inside... guess I need to order a new one. I also removed the fuel distributor and cleaned that out some. While I was at it I pulled the OVP relay and a few others down there. the OVP showed some corrosion which I cleaned off with a wire brush then resoldered all the connections. I also adjusted the mix a tad richer to bring the idle up a hair to around 7-800 rpm. net result: car is still hard to start, now it still takes about 10-20 good cranks to start cold and about five to start warm. I noticed some leaking around the fuel line on the side of the distributor and tightened it down. (the thick line closest to the front of the vehicle) it's possible I may have bent the line a little trying to line it back up. (didn't notice the 10mm bolt holding it in place) so tomorrow I will pull the air cleaner and make sure it's sealed up real good. The stalling when put in gear has diminished considerably. I did notice a new symptom that first showed up a couple of days ago but is more pronounced now. While driving at around 50 MPH the engine will bog down for 2 seconds then let up then repeat. It is pretty intermittant but a little disconcerting. Any ideas?

86560SEL · #12 10-07-2006, 10:10 PM

Join the club... my 380 does the same thing. Seems to be a very common issue on these cars. They need a recall.

dpetryk · #13 10-08-2006, 01:49 PM

I have no idea of how many miles are on the car but it could be the fuel distributor itself. I have had 2 go bad in my fleet so far. Each time it happened the car was hard to start, rough idle and there was hesitation during acceleration. I took the fuel distributor apart and found the diaphram had holes in it.

nonextant · #14 10-17-2006, 07:26 AM

Hopefully the video might provide some clues, could the starter be going bad?

http://web.mac.com/mark.beazley/iWeb/Site/560SL.html

Alright, the 560SL has become very hard to start when cold. recently it has also become harder to start when warm. I have noticed if I dribble water on the injectors the one in cylinder 3 will cause the engine to bog down some, indicating a leaky injector. I am posting a video of a typical start up to hopefully get some ideas of what else I should be checking for.
Actions taken: The battery fuel filter and coolant temp sensor are brand new, The pump was replaced last year. I have cleaned the Idle control valve. I could not find any vacuum leaks, but it does run worse when it rains. I have cleaned the fuel distributor.
Symptoms: extremely difficult to start when cold. If shut down and restarted when warm will fire right up. the longer it sits the more difficult it is to start. When Cold, idle hunts from about 1100 to 500 RPMs. When the engine temp reaches around 82 degrees it settles down to about 750-800 RPM at idle. When warm running above 40 MPH the engine will occasionally enter a pattern of power loss. (like a draw on the engine lasting 2 seconds then back to normal for 2 seconds, pattern repeats for about 45 seconds then goes away) Things I have noticed: then starter will occasionally drop in pitch and speed as though it is under a heavier load, you can hear it in the video. When this happens the car is more likely to start. I can also hear what sounds like a relay clicking in the passenger footwell and can hear what sounds like fuel sloshing around in the tank while trying to start. I never noticed it before, but I wasn’t listening so It may be normal.
I would appreciate any advice you may have.
Thank you

psfred · #15 10-17-2006, 11:07 AM

Use brake parts cleaner spray to check for vac leaks, not water -- you risk damage sucking water around leaks into the intake, carb or brake parts cleaner spray will cause the idle to improve (and clean everything off for the replacement of the bad part!).

I would replace all the injector seals, and if there are plastic sleeves the injectors fit in, check that they are tight and don't leak as well. On the M103, these also have an o-ring seal, and they do go bad and leak.

Verify that you do not have a vac leak -- this includes checking the transmission vac modulator ACC system for serious leaks (and brake booster!) -- all the symptoms you describe sound a lot like a vac leak to me except the noise from the tank.

I would also check the cap and rotor again -- funny running in damp weather sounds a whole lot like a damp cap with carbon traces...

Verify that the plug wires recently installed (and plugs) are correct, and have the correct resistance. Using platinum plugs with resistor wires and resistor ends can cause starting and idle problems.

Run a whole bottle of Techron or RedLine injector cleaner in a tank of gas through it -- this will clean off any varnish accumulated while sitting.

Finally, if nothing else helps, you should find someone who knows how K-Jet works and test the system pressures. The fuel distributor has a tendency to corrode when sitting unused for extended periods, and will cause very rich running problems, starting problems, etc. Hopefully this is something else.

You did check the firing order, right?

Peter