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S320W
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602 Posts
Discussion Starter · #1 ·
Alright,
when i press gas and revs go high, i feel the engine shake. It feels like as if there is no gas in the tank, although there is plenty. RPM remains normal.

As soon as it starts shaking, i turn the engine off and turn it back on, and its fine.

Only happens if i press the accelerator unexpectedly. Any ideas..? could it be the fuel pump? or anything fuel related?

Please help i want to get this issue resolved as soon as i can..

[:(]
 

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W140 S class, E31 850Ci, XC90 Exec AWD geartronic
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444 Posts
Alright,
when i press gas and revs go high, i feel the engine shake. It feels like as if there is no gas in the tank, although there is plenty. RPM remains normal.

As soon as it starts shaking, i turn the engine off and turn it back on, and its fine.

Only happens if i press the accelerator unexpectedly. Any ideas..? could it be the fuel pump? or anything fuel related?

Please help i want to get this issue resolved as soon as i can..

[:(]
Hi ///S320

sounds like one of the following
(1) Bad plug (or loose lead)
(2) Bad coil (or loose lead going to coil)
(3) Worn engine wiring harness

start with the top of the list as thats the cheapest.
Good luck
 

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S320W
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602 Posts
Discussion Starter · #3 ·
Re: Re: Mechanical Problem

Hi ///S320

sounds like one of the following
(1) Bad plug (or loose lead)
(2) Bad coil (or loose lead going to coil)
(3) Worn engine wiring harness

start with the top of the list as thats the cheapest.
Good luck
Thanks for the advice Gill. Here are few silly questions:

1) Which plug or loose lead
2) Where is the coil. I mean, where do i look for?
3) Have u ever changed the wiring harness, if so, how much does it cost and how long does it take. Have you ever done it yourself? (You may have told us in one of your postings, but i dont remember)

[:(][:(]
 

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1997 S600 - Bentley Turbo R (black/black)
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313 Posts
Hmmm...


check out this...or this site...it may help, and as w140 suggested , start ...


Hmmm...


check out this...or this site...it may help, and as w140 suggested , start with the lowest least expensive diagnosis.

http://www.autosite.com/garage/symptoms/s115.asp


ghost
 

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BMW E36, MB W140
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179 Posts
i had that exact same problem

Hi ///S320,

I had that EXACT same problem on my W140 when i bought it a few months ago. Often when I drove the car hard (ie. flooring the gas), the engine would end up in a state where it shook like mad, as if it was running out of gas... The engine would only return to normal after I turned off the engine and restarted it...

I suspected engine misfire, so I replaced all the sparkplugs, and guess what, the problem went away!!! And it went away for good, I tried gunning the gas, driving the car hard in the following months, but could never get the problem to return...

When you change the sparkplugs, you have to pull the ignition coils off the plugs (they are mounted directly on top the sparkplug)... i don't know if it was the new plugs, or the fact that I jiggled the ignition coils/spark wires connections during the install process, that solved the problem...

cheers
 

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S320W
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602 Posts
Discussion Starter · #6 ·
Re: i had that exact same problem

Hi ///S320,

I had that EXACT same problem on my W140 when i bought it a few months ago. Often when I drove the car hard (ie. flooring the gas), the engine would end up in a state where it shook like mad, as if it was running out of gas... The engine would only return to normal after I turned off the engine and restarted it...

I suspected engine misfire, so I replaced all the sparkplugs, and guess what, the problem went away!!! And it went away for good, I tried gunning the gas, driving the car hard in the following months, but could never get the problem to return...

When you change the sparkplugs, you have to pull the ignition coils off the plugs (they are mounted directly on top the sparkplug)... i don't know if it was the new plugs, or the fact that I jiggled the ignition coils/spark wires connections during the install process, that solved the problem...

cheers
Hi Rainmaker,
Exactly the same problem..
Hey, could you tell me where the spark plugs are located? I know you have all those cool pics of things you do, if u have a pic, could you please post it. I dont want to accidently change something else and end up calling 911.

Also, are these Bosch Spark Plugs, correct? Are ignition coils easy to replace?

(Imagine this: On my C280, i got my ignition coils changed plus the spark plugs and the dealer gave me a bill of $600.00 something, 3 years ago!)

Thanks a lot


[:(]
 

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BMW E36, MB W140
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179 Posts
Hi ///s320, yes I bought Bosch spark plugs. I did not buy them from the dealership. I ...

Hi ///s320, yes I bought Bosch spark plugs. I did not buy them from the dealership. I bought them from a small local oem parts store (they sell the same stuff as www.thepartsbin.com). I compared it with my original spark plugs, and the Bosch part number matched exactly. They were about $3 cdn each.

To access the sparkplugs:
1. Flip latches to free the top of the airbox (highlighted in Green in attached pic)
2. Remove two bolts holding air intake in place (blue in pic)
3. Loosen wire out of the wire guide (yellow in pic)
4. twist the air-intake out of the way. The point where it is attached is shown by the purple circle in the pic. In my case, when I twisted the air-intake out of the way, it eventually fell free.
5. Remove 6 hex bolts shown in red in the pic. (one is not shown but is under the air intake), and pull the plastic cover off.
6. Underneath, you will see where the inline 6 cylinders are. There are "black boxes" on top of 3 of the cylinders. These are the ignition coils, and each one of them handles two cylinders. I pulled the 3 ignition coils off (pull straight up, might need to jiggle it a bit to loosen it). These gave me access to 3 of the sparkplugs.

The remaining 3 cylinders simply have an ignition wire on top, I pulled these off. Note, in my case, the sparkwires seemed stuck and wouldn't come out. But after I twisted them (rotated them), I was able to pull them out using only my hands.

7. To access the sparkplug, you need an extension on your ratchet, and a standard sparkplug socket. When you put the new sparkplug in, the torque is stated on the packaging. It was well below the bottom range of my torque wrench, so I just hand tightened it (not very tight).

8. Put everything back together. To put the airbox back on (purple circle in diagram), just thump it a few times... it will hold tight...

Cheers
 

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W140 S class, E31 850Ci, XC90 Exec AWD geartronic
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444 Posts
Re: Re: Re: Mechanical Problem

Hi ///S320

sounds like one of the following
(1) Bad plug (or loose lead)
(2) Bad coil (or loose lead going to coil)
(3) Worn engine wiring harness

start with the top of the list as thats the cheapest.
Good luck
Thanks for the advice Gill. Here are few silly questions:

1) Which plug or loose lead
2) Where is the coil. I mean, where do i look for?
3) Have u ever changed the wiring harness, if so, how much does it cost and how long does it take. Have you ever done it yourself? (You may have told us in one of your postings, but i dont remember)

[:(][:(]
I think Rainmaker has already answered your questions....Thanks Rainmaker, your pictures are an invaluable resource!!! [:)][:)][:)]
To answer the third question you are looking at about $750US to supply and fit a new harness. Check to see if your leads are crumbling under the engine top cover.
 

· Registered
1995 S420
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553 Posts
Alright,
when i press gas and revs go high, i feel the engine shake. It feels like as if there is no gas in the tank, although there is plenty. RPM remains normal.

As soon as it starts shaking, i turn the engine off and turn it back on, and its fine.

Only happens if i press the accelerator unexpectedly. Any ideas..? could it be the fuel pump? or anything fuel related?

Please help i want to get this issue resolved as soon as i can..

[:(]
S320, buddy, I feel your pain. Changing plugs to Bosch platinum +4 will give you quick starts. no doubt. But beware of changing them yourself. The procedure on my S420 was quite complex, S320 maybe easier. It takes time and patience, and you don't wanna do it again. Go with Bosch +4, and forget about changing plugs for 100k miles.

One of the things that is possible is that you power-washed this car or it rained hard? Or bad gas with water in the tank? This happened to me once, and the car died on me. Yes I was $hitting. I finally got it started, but it shuddered and died on me all the time. That's when I put 2 x 16 oz bottles of Ethanol (C2H5OH), which dissolves water in fuel system, whilst dissolving in gas itself, and I fired up the car, and let it idle for about 30 mins, revving it to 3k rpm occasionally, until the shudder went away, and revvs were abso smooth. (Damn MBs never rev as silkily smoothly as a LS400 though). If it feels like it is going to die, back off on throttle, and resume idle for 3 mins, and try again. See if that helps, and let us know. IMPORTANT: Do not use Methanol (CH3OH) type additive, as it will corrode your gas lines, and also foul your Cat system.
If this works, hand wash your car hence forth, and keep it covered in garage or with a car cover when not in use. Good luck, I bet you'll be surprised.
 

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S320W
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602 Posts
Discussion Starter · #10 ·
re:

Ok..
Iam going on a solo mission to change the plugs now. Wish me luck. I will buy Bosch+4 plugs and all necessary tools i need.

(I will write a detailed post of how it went, or didnt went anywhere..)
 

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92 400SE, 93 400E, 01 CLK320, 01 ML320, 98 Land Rover Discovery
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201 Posts
//S320,

You might want to review/search for information surrounding the use of Bosch+...


//S320,

You might want to review/search for information surrounding the use of Bosch+4 plugs in your MB. After reading MANY posts about the +4, I decided to go with original MB specs.

Russell
 

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W140 S class, E31 850Ci, XC90 Exec AWD geartronic
Joined
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444 Posts
Re: //S320,You might want to review/search for information surrounding the use of Bosch+

//S320,

You might want to review/search for information surrounding the use of Bosch+4 plugs in your MB. After reading MANY posts about the +4, I decided to go with original MB specs.

Russell
The Bosch +4's cause more trouble than they are worth. Steer clear of them
 

· Registered
1995 S420
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553 Posts
Re: Re: //S320,You might want to review/search for information surrounding the use of Bosch+

//S320,

You might want to review/search for information surrounding the use of Bosch+4 plugs in your MB. After reading MANY posts about the +4, I decided to go with original MB specs.

Russell
The Bosch +4's cause more trouble than they are worth. Steer clear of them
I have used the Bosch +4 in my MB S420, my Lexus LS400, and also previously in my Infiniti G20 without ANY problems. I replaced the ones in my Infiniti after 60,000 miles with another set, and no problems there. I can't tell you for sure if the performance improved or not, or the mileage improved or not, but the starts on all 3 cars have been on the very first crank, every single time. I would recommend them for sure, but to each his/her own.
 

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S320W
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602 Posts
Discussion Starter · #14 ·
re:

OK guys,
so i went out and tried to get my plugs changed yesterday. Cold Chicago winds and rain messed my brain up. I became lazy and thought i would pay the dealer a hundered bucks and let him change em.

The moral of the story is, Loeber Motors in Lincolnwood, Illinois changed my plugs to factory specified Bosch Plugs. The mechanic there told me to return my Bosch +4s as they cause problems in some vehicles. So i did that. I drove the car for about 50 miles so far with gas padel pressed hard on beautiful Lake Shore Drive in Chicago. So far no signs of the problem.

Rainmaker: Buddy i owe you one. When you come to Chicago, let me know ill take you out for drinks and honeys.

Gill, Ghost, Russell and Chachad: Thanks for all your input... if you guys ever come here, let me know..

[}:)]

///S320
 

· Registered
1995 S420
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553 Posts
Re: re:

///S320,
Glad your car is back running normally again. I was in South Bend, IN (1.5 hrs away), but now I have moved to the Pittsburgh, PA area. Factory specification Bosch spark plugs (non-platinum) have a lifespan of about 15 to 20k miles on them. Be sure to change them religiously at that interval. That's why I went with the Bosch +4s.
 

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BMW E36, MB W140
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179 Posts
Re: re:

OK guys,
so i went out and tried to get my plugs changed yesterday. Cold Chicago winds and rain messed my brain up. I became lazy and thought i would pay the dealer a hundered bucks and let him change em.

The moral of the story is, Loeber Motors in Lincolnwood, Illinois changed my plugs to factory specified Bosch Plugs. The mechanic there told me to return my Bosch +4s as they cause problems in some vehicles. So i did that. I drove the car for about 50 miles so far with gas padel pressed hard on beautiful Lake Shore Drive in Chicago. So far no signs of the problem.

Rainmaker: Buddy i owe you one. When you come to Chicago, let me know ill take you out for drinks and honeys.

Gill, Ghost, Russell and Chachad: Thanks for all your input... if you guys ever come here, let me know..

[}:)]

///S320
hey ///s320, no prob... its odd how the sparkplugs made so much of a difference, cuz when I pulled my old ones out, they looked fine... other than that they looked dirty, the spark gap looks the same as the new ones...

too bad that the dealership charged so much for a 15 minute job!... if only you were in Vancouver / Los Angeles, I would have been glad to do it for free!
(I enjoy working on MB and BMW vehicles)

I guess it goes to show its important to keep up with the maintenance schedule...

Rainmaker
 
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