E300 intermittent no start - Page 2 - PeachParts Mercedes-Benz Forum

nhdoc · #16 08-22-2009, 11:30 AM

Quote:

Originally Posted by TMAllison

On gassers, the CPS provides critical reference timing for spark and fuel delivery and causes intermittent cutout/no starts when it begins to fail.

On our diesels, that sensor provides some emissions data and the input to the tach. I don't remember anyone replacing it? Mines OEM at 272k.....

There are actually a couple of posts from people who have replaced them on the diesel models. I reckon they must also provide the "start signal" which tells the ECU to stop cranking and even are responsible for idle control since the ECU needs RPM information to set idle speed.

I just don't like the fact that he says the car starts fine after it cools...that tells me it is not a fuel issue based upon my gut.

http://www.peachparts.com/shopforum/showthread.php?t=242730&highlight=cps

http://www.peachparts.com/shopforum/showthread.php?t=88304&highlight=cps

http://www.peachparts.com/shopforum/showthread.php?t=196190&highlight=cps

I suppose you could easily test my theory by unplugging it and seeing what happens. If it stalls out and won't restart you will probably have answered the question as to whether a failing one can cause the symptoms described.

TMAllison · #17 08-22-2009, 02:01 PM

Another quick test - Fire it up, reach under the manifold, put your thumb on the SOV electrical connector and wiggle it around firmly. If it cuts out the plugs cracked or the wiring is faulty. Mine did this hot; would invariably restart cold when the fitting contracted.

nhdoc · #18 08-22-2009, 03:24 PM

Quote:

Originally Posted by TMAllison

Another quick test - Fire it up, reach under the manifold, put your thumb on the SOV electrical connector and wiggle it around firmly. If it cuts out the plugs cracked or the wiring is faulty. Mine did this hot; would invariably restart cold when the fitting contracted.

That's another possibility!

TMAllison · #19 08-22-2009, 04:11 PM

It doesnt resolve the air in the fuel lines though; I prefer to resolve that first and then work on whatever other problem remains.

nhdoc · #20 09-08-2009, 07:50 AM

Did the OP ever resolve the problem??

e300nocash · #21 09-08-2009, 10:35 PM

I think the main problem has been resolved, and your suspicions about the crankshaft position sensor were correct. The CPS has been replaced, and the car has not stalled or failed to restart in three days of use. I was planning to give it a while longer before declaring victory, but I am happy about the results so far. Before changing the CPS, I had some adventures. Once I coasted 1/2 mile to my driveway, and another time I was not so lucky and had to be towed.

I am still fighting air in the fuel line after the prefilter (even though I have replaced the lines going to and coming from the prefilter, replaced two prefilters in the last week (with o-rings), and even covered the top of the prefilter with wheel bearing grease to try to isolate the leak). There is still a steady stream of small bubbles in the line coming from the bottom of the prefilter. The good news is it does not seem to be enough to kill the engine.

Troubleshooting is especially challenging when you have more than one problem. This one was odd because the engine usually sounded like it was about to run on its own most of the time the problem occurred, and sometimes it would start after a few attempts. It really sounded like a loss of prime. Only a few times did it sound like no fuel at all was getting in. The problem eventually worsened to the point that only walking away for a few hours would cure it.

The other odd thing about it was on two occasions I put my fingers on the SOV after the engine stalled and wouldn't restart and had my wife turn the key. In both cases I felt and heard the SOV actuate, so I kept thinking it couldn't be electrical. Perhaps the SOV was initially actuating but then closing if the CPS didn't sense rotation. I may never know the answer to that, but the car is working now, and I am grateful to all who responded.

Mr.Billyd · #22 09-09-2009, 12:13 AM

I am fighting air leaks as well, like people may have seen in my other post.
Terry set me up with a fuel flow diagram on a blog. It seems when I was out on vacation in Ca, starting out in AZ with a full tank of B100 was not a good idea. The car ran great, but the next day, leaks everywhere.
I had to have an indie shop replace all of my lines and o-rings.
Did this DIP S it swap my lines? 5 and 6/8. Are they keyed so you can't swap them? I am installing all my viton o-rings on the weekend.
IF they are indeed swapped. Can someone give me an idea how this car still runs?
Bill

TMAllison · #23 09-09-2009, 12:18 AM

E300no$$$ - Glad you resolved it.

Try crimping the prefilter holddown washer so that it provides a little more pressure. Dont tighten the bolt too much or the plastic filter can crack or distort,

Also check every connection upstream of air. Exiting lower prefilter to SOV, prefilter, prefilter to fuel thermo. Its got to be one of those.

TMAllison · #24 09-09-2009, 12:23 AM

Quote:

Originally Posted by Mr.Billyd

I am fighting air leaks as well, like people may have seen in my other post.
Terry set me up with a fuel flow diagram on a blog. It seems when I was out on vacation in Ca, starting out in AZ with a full tank of B100 was not a good idea. The car ran great, but the next day, leaks everywhere.
I had to have an indie shop replace all of my lines and o-rings.
Did this DIP S it swap my lines? 5 and 6/8. Are they keyed so you can't swap them? I am installing all my viton o-rings on the weekend.
IF they are indeed swapped. Can someone give me an idea how this car still runs?
Bill

Your left and center lines ARE swapped. You'll need to use the diagram I sent you to see if the lower conections of those lines were swapped too???? The balck fuel line is the return line.
*edit*
The left line on yours goes straight down to teh SOV, that should be the middle line. Cant see anything else.

http://bp3.blogger.com/_p71v9ofBM6w/R5ZR4hrNUFI/AAAAAAAAAIQ/XCBQ40qtPDQ/s1600-h/fuelflow.JPG

Mr.Billyd · #25 09-09-2009, 01:01 AM

I checked all my lines to the diagram. The two they swapped that you pointed out are the only ones.
What is the result in the function of the flow path having these two swapped? Was I driving on non filtered fuel the past 25K miles?
When I have it all apart this weekend, seeing the inards might explain it better. Walking my head thru the flow path > it would seem to me that with my current set up the indie shop in HB Ca, had me running on un-Pre filtered, and un-main filtered fuel ???? Am I wrong? any opinions anyone?

Thanks for your comments,

Bill

Mr.Billyd · #26 09-09-2009, 01:10 AM

moving the left and center lines connections back at the Filter manifold, my car will match the drawing.
I though my last post could be confusing.

Mr.Billyd · #27 09-09-2009, 02:28 AM

WOW, Ive lost 2 years of driving a nice car.
I never had the car long enough before I put B100 in the tank.
If I had the issue at home I would of replace the lines myself from my massive leak issue I got from the B100. So the indie shop wrecked 25k miles of driving experience.
My wife hated driving the car. It would be fine on CC at 65mph.
Off the line this car was a piece of SH.
Now > Thanks to Terry> I just swapped my lines and went for a ride.
WOW! It feels like I just installed a turbo.
I have had the feeling that buying a 96-97 Non turbo was a very bad mistake.
I was use to driving E320 CDI's in europe. So, I prefer the turbo, but this car is now awesome.
I don't know how I feel, Happy and Angry i guess

I wont be able to get the wife out of this car now.
I still need to know how I was getting 450- 500 miles per tank with these lines swapped.
As asked earlier, was my fuel being filtered? It was being choked off for sure.
My god, in comparision, it feels like an AMG now
If I did not hear all the post about these being a dog, and I would of had more time with this car before the new lines being installed, I would not have made it 500miles,
Wow 25k miles in a dog, im gonna slam my head into the wall a few times

I might not even have air bubles in my lines any more. They could have been coming from my line swap?

Bill

nhdoc · #28 09-09-2009, 06:56 AM

Quote:

Originally Posted by e300nocash

I think the main problem has been resolved, and your suspicions about the crankshaft position sensor were correct. The CPS has been replaced, and the car has not stalled or failed to restart in three days of use...

Good to hear that you're making progress and maybe the CPS fixed it after all.

As for your air in the fuel system problems, I would start at the beginning...check all of the connections between the fuel tank and lift pump. Make sure everything is connected exactly as the fuel diagram says and if necessary replace every o-ring again. Even the pros can reverse a line or you could have a defective o-ring.

One thing I discovered recently is that a clogged tank screen CAN CAUSE AIR BUBBLES. I found this out in my old wagon. It has to do with the way the tank screen works and will do so only when the fuel level in the tank is below the top of the screen, so, below about 1/2 tank. If the screen is clogged with slimy crud it will pull air from the top of the screen into the sump because it is easier for air to pass through the slime than fuel. If you get air bubbles when the tank is full it is probably not that but if it happens primarily when the tank is less than half full you might have a clogged tank screen.