Car is stumbling and running VERY rough. - Page 3 - PeachParts Mercedes-Benz Forum

lsmalley · #31 03-25-2014, 11:42 AM

Quote:

Originally Posted by ps2cho

Those snake oils do nothing at all. Switch to a good diesel oil to help clean that crap out whatever it is. Delo 400 15-40 you can get it at Walmart cheap.

You need to address that check engine code. There's a reason why it's coming on.

I just changed my oil the other day. I may have too switch to something with more detergents in it, but I'm trying to avoid getting a leak since the engine has over 340k on it. And yes, that damn CEL code 11 is like a ghost, sometimes it will be gone for months then it will come on and I'll reset it and it goes away again for a long while. I don't even know what is meant by air injection system. I replaced all the components related to the air pump and I know the pump is working. But like I said, that code will clear up and be gone for months. It's strange. I'm certain it has nothing to do with my current situation, though I can't be 100% this time because the code won't stay away now.

lsmalley · #32 03-26-2014, 01:53 AM

Not sure what this means, but I just realized that if I am sitting in my car with the ****er in either position( P, R, N, D, 2, 3) the roughness in the idle that I feel, magnifies x 10 if I turn the steering wheel in either direction. Even if the car is idling smooth and I am stopped, when I turn the wheel the car shakes hard while turning. I lifted the hood and there is fluid, but upon listening to the engine I did notice that I can definitely here a hissing sound. Is there a vacuum line that goes to the power steering? Would this cause rough idling?

JamesDean · #33 03-26-2014, 09:48 AM

A vacuum leak could cause that I believe. Our 420SEL had a number of vacuum leaks that cause some stumbling on acceleration. Are you sure the hissing sound if coming from power steering system?

Side question, why 20w50 oil? I run 0w40 in my 190E. However its only got <120k miles on the motor.

lorainfurniture · #34 03-26-2014, 10:45 AM

Dude, quit guessing and check your vacuum with a mity vac. Then check your duty cycle.

Vacuum should be more than 10hg, ideal is 12-15.
If you have any voltage tester you can just check to see if you get 6ish volts at you x11 port.

These engines are very crude, and uncomplicated

lsmalley · #35 03-26-2014, 12:50 PM

Quote:

Originally Posted by lorainfurniture

Dude, quit guessing and check your vacuum with a mity vac. Then check your duty cycle.

Vacuum should be more than 10hg, ideal is 12-15.
If you have any voltage tester you can just check to see if you get 6ish volts at you x11 port.

These engines are very crude, and uncomplicated

I used a vacuum tester and I got between 15hg and 18hg at the intake and also I checked all vacuum hose with a vacuum tester. Everything was good and held vacuum except for 2 things: 1 was a red hose that terminated into the passenger wheel well into this black bouy-type ball and the other was the line going to the vacuum modulator of the transmission which had an extremely slow leak, but also no transmission fluid was coming through the line so the integrity of the diaphragm is still good. I also did the duty-cycle using that landiss_ke jetronic write up. The write up states I should be getting volts between 4.6 and 6.1 which I am getting. It fluctuates and jumps around, but it jumps around within that number ranger as indicated and mine is a California version.

Quote:

Originally Posted by JamesDean

A vacuum leak could cause that I believe. Our 420SEL had a number of vacuum leaks that cause some stumbling on acceleration. Are you sure the hissing sound if coming from power steering system?

Side question, why 20w50 oil? I run 0w40 in my 190E. However its only got <120k miles on the motor.

I am 90% sure it is coming from the power steering if that has any type of vacuum to it, if not then I guess it could be normal intake manifold air, but its definitely hissing. Sprayed carb cleaner around the entire intake manifold gasket, fuel injectors, and IACV while the air cleaner housing was off and got no change/surge/drop in idle. Sprayed some on the throttle plate and the idle dropped as if to stall then shot back up and evened out. Is there a hose that goes anywhere to the power steering that carries vacuum? If so, please advise where it is located and I will check it out. As for the reason I use 20w-50 oil, the owner's manual that came with my MB states that 20w-50/20w-40 is acceptable if the ambient outside temp is constantly +32°F and above +86°F, where I live its usually in the mid 70's to the mid 80's year round....except the summers which reach 110°+. But yes, please advise of he PS vacuum infomation. I tried looking it up, but only got issues pertaining to PS fluid leaks. Thanks

JamesDean · #36 03-26-2014, 12:57 PM

As far as I know there is no vacuum related to the operations of the power steering system.

A pump, two lines and the steering gear box.

ps2cho · #37 03-26-2014, 02:12 PM

When you turn the wheel it briefly lowers the rpm at idle...if its already stumbling, its going to make it stumble more, so that is typical. Nothing wrong with the steering.

15-40 shouldn't make anything leak more than 20-50. How much are you topping up each week/month currently with 20-50? regardless of being burnt, or leaking out.

lsmalley · #38 03-26-2014, 02:26 PM

I put maybe about 1700 miles a month and I only add a quart in between my oil changes which is usually every 4k - 5k miles. Everything seems sealed up pretty tight.

lorainfurniture · #39 03-26-2014, 07:57 PM

Did you get 18hg at idle?

lsmalley · #40 03-27-2014, 02:09 AM

Quote:

Originally Posted by lorainfurniture

Did you get 18hg at idle?

it was between 15hg & 18hg. why, is 18 bad?

lorainfurniture · #41 03-27-2014, 10:40 AM

Quote:

Originally Posted by lsmalley

it was between 15hg & 18hg. why, is 18 bad?

No, but at 18hg you have the tightest vacuum system I have ever seen. The very best I ever got my car was 15hg after replacing every rubber bit under ther hood.

What are you idling at? 650?