M119 Rough Running / Stumble (1992 400E)

[link]

Hello all,

First my sincere thanks to those who have contributed to this thread! I’ve read at many MB web sites about this issue over the last few years but have not come across many who have the M119 engine and have reported about the same problems as my car appears to have. I have come across nowhere else where some have made a comprehensive reporting of their results.

I have a ’92 400e and am having what sounds like the same problem as mentioned in this thread. I’ve owned the car for about 14 years. In the last roughly 5 years or so, if I use the car daily it will typically run fine. Sometimes there is a slight misfire after stopping for a stop light. If the car sits for ~ 3 days to about a week it will start okay and run okay for about 10 to 15 minutes. After that it idles very roughly and has an obvious misfire, well actually many of them. If I can gently get the rpms above about 1500, the misfire problem goes away until it gets back to idle or the next stop. The typical fix for this problem is to park the car and run it at about 1500 to 2000 rpm for a while. Eventually it will idle okay and after that it runs fine. Another solution is to park the car and go away for about an hour or more. Sometimes it runs okay after that and other times I have to run it for a while after.

I have taken it in for diagnosis 3 times to 2 dealers and one inde. I’ll spare the readers detailed results as no one has been able to solve the issue. The short version was to replace the upper wiring harness, caps, plugs, rotors. The best short term solution was when the caps and rotors were replaced, which solved the problem for a couple of months.

I understand from reading this thread that 2 likely solutions are 1) the “distributor dust shields” part # 1191580188 for the 1992 400e (one for each distributor) and in the case of the user bendover, the solution was replacing one of the rotors after replacing and testing a lot of other parts including the previously replacing the rotors.

For those who have done so, has replacing the distributor dust shield or replacing the rotor(s) proven to be long term solutions in the cases where they were implemented?

Thanks again!

 

[gerryvz]

Re: Misfire/rough after sitting

What about your plug wires and connectors? You should test out the resistance of the wires and connectors to ensure they are OK.

 

[gsxr]

Re: Misfire/rough after sitting

+1. Specifically, you are testing the resistance of the spark plug boot, as the wires themselves are non-resistor type (many American cars have resistor wires, which are very different).

Also - what spark plugs are you using? Are they the correct Bosch F8DC4 non-resistor plugs? I'd consider replacing the coils as well, if the car has ~200kmi or more.

You also need to clear all error codes, from all powertrain modules, with a hand-held blink code reader... then check all codes again after driving a few hundred miles. Any codes which come back quickly need to be addressed.

You also didn't state if you replaced the upper harness, or if that was recommended and not done. If the harness is original (see forum Wiki to learn how to check date code), replace that ASAP.

 

[link]

Re: Misfire/rough after sitting

Thanks for the nice welcome and thoughtful comments. This thread covers the details very well and I don’t feel a need to cover what has already been detailed above. My 400e has been dealer maintained during the time I’ve owned it and many of the parts noted above have already been tested or replaced.

I’m interested in the long term results of the rotor re-replacement and the “distributor dust shields” replacement from those who have done this as a solution for the intermittent rough idle after sitting for some days. One of the techs recently said he saw condensation inside the caps, and this was with new caps. I asked how it could get in and didn't get an answer....I’m pretty sure the dust shields have never been replaced as the part does not appear to have a typical service interval, and that would make it essentially invisible to the vast majority of mechanics....

 

[emerydc8]

Re: Misfire/rough after sitting

Welcome to the forum. FYI, there are three distributor dust shields currently available on Ebay for $30 each. Just type in Mercedes 1191580188. The part is not available at parts.com. The EPC lists the aforementioned number as a Bosch part. It also lists a Doduco part 1191580288. The seal ring is available at parts.com for $4.31, but from the picture on Ebay, it looks like the seal comes with it. The seal is part 0209970548.

I have never experienced a problem with these dust shields and I'm on my third W124/M119 since January 1998. Maybe the harsh winter weather or high humidity has more of a tendency to deteriorate them, but out here in Arizona they seem to hold up well. I would be careful to presume that the dealer installed the correct plugs, or that the parts they installed are still good. I think that's why GVZ and GSXR are steering you towards checking these first.

http://www.ebay.com/itm/BOSCH-DISTR...Parts_Accessories&hash=item5d4a311337&vxp=mtr

 

[gsxr]

Re: Misfire/rough after sitting

It looks like there is an error in the parts.com catalog... 119-158-01-88 shows up at other Trademotion vendors, like MBFL:
http://www.parts.com/parts/index.cf...hText=1191580188&action=oePartSearch&siteid=2

Technically these are not dust shields, they are high voltage insulators. If they were not present, the spark would short out to the cylinder head behind the rotor, as that would be a lower resistance path than through the spark plug. As noted in the PDF files elsewhere in these threads, which I assume you have read, in some cases the insulators can start to fail where they allow current to pass through to the head, causing a misfire. It's pretty rare AFAICT. I've never had to replace one of these except when they were physically broken (from previous muppet mechanics).

I'll second Jon's caution that it is not a wise thing to assume the dealership did all their work correctly and installed correct parts.

 

[link]

Re: Misfire/rough after sitting

Welcome to the forum. FYI, there are three distributor dust shields currently available on Ebay for $30 each. Just type in Mercedes 1191580188.

I tried before and a moment ago but didn't find any for $30. Best i've seen is $84 here: http://www.importecwarehouse.com/Mercedes-Distributor-Cover-1191580188-p/119-158-01-88-bos.htm

The part is not available at parts.com. The EPC lists the aforementioned number as a Bosch part. It also lists a Doduco part 1191580288. The seal ring is available at parts.com for $4.31, but from the picture on Ebay, it looks like the seal comes with it. The seal is part 0209970548.

I didnt find it at parts.com either.

I have never experienced a problem with these dust shields and I'm on my third W124/M119 since January 1998. Maybe the harsh winter weather or high humidity has more of a tendency to deteriorate them, but out here in Arizona they seem to hold up well.

There is a lot of humidity in Seattle. Before i owned the car it was in Toronto. Anywho, after so many years, changing it probably wouldn't hurt. Unless, of course, i damage something along the way...

I would be careful to presume that the dealer installed the correct plugs, or that the parts they installed are still good. I think that's why GVZ and GSXR are steering you towards checking these first.

It is always good to be skeptical, but i'll look at things which have not already been gone over by multiple wrenches before i re-cover their tracks.

http://www.ebay.com/itm/BOSCH-DISTR...Parts_Accessories&hash=item5d4a311337&vxp=mtr

Thanks! Unfortunately for me they are sold.

 

[link]

Re: Misfire/rough after sitting

It looks like there is an error in the parts.com catalog... 119-158-01-88 shows up at other Trademotion vendors, like MBFL:
http://www.parts.com/parts/index.cf...hText=1191580188&action=oePartSearch&siteid=2

Technically these are not dust shields, they are high voltage insulators. If they were not present, the spark would short out to the cylinder head behind the rotor, as that would be a lower resistance path than through the spark plug. As noted in the PDF files elsewhere in these threads, which I assume you have read, in some cases the insulators can start to fail where they allow current to pass through to the head, causing a misfire. It's pretty rare AFAICT. I've never had to replace one of these except when they were physically broken (from previous muppet mechanics).

I'll second Jon's caution that it is not a wise thing to assume the dealership did all their work correctly and installed correct parts.

I understand that they are high voltage insulators primarily, and also serve as a moisture barrier. I did read a.PDF above from the Star mag., as well as comments by bendover and that is what has lead me to seeing if these did provide a long term solution.

I’ll even 3[SUP]rd[/SUP] that double checking others work, when there is a chronic problem, is not a bad idea. But having had 3 or more different mechanics look into this problem, with the key anomaly reported being moisture inside the distributor cap, my inclination is to look where they haven’t looked before re-covering their tracks.

 

[gerryvz]

Re: Misfire/rough after sitting

A LOT of mechanics aren't specialists in the M119, so may not know the idiosyncracies specific to that motor. Unless the mechanics are knowledgeable about the M119 (and most dealer mechanics are not, nowadays, given that the motor was last used in the 1998 time frame) I would check and re-check any work they've done.

I don't trust any MB dealer with an M119 as far as I can throw them ... and even indy shops, I would only trust their M119 knowledge after a long conversation.

There are five things that YOU should do (or explicitly confirm yourself), before proceeding further, just to ensure things are baselined as appropriate:

a) Ensure that your upper wiring harness has been replaced. You did not confirm this in your earlier posts, unless I missed it. There is information in the Wiki as to how to identify and translate the date code on the label attached near the head-end of the harness.

b) Ensure that all codes have been checked, and cleared, and the car has been driven to see what codes re-appear. Again, you did not confirm you'd done this, unless I missed it.

c) Ensure that the caps and rotors have been replaced with quality (Bosch or Bremi) units.

d) Check the resistance of your plug wires and spark plug connectors. If the wires or connectors don't ohm out correctly, then I'd replace them out of hand.

e) Ensure that you have the proper plugs (Bosch F8DC4) installed, and gapped correctly. If the plugs have more than 15-20K on them, I'd replace them out of hand.

ONLY after confirming all these items have been checked, confirmed and/or changed if necessarily, then you should suspect the insulators.

To answer your question -- I have not seen any report from anyone who has replaced the moisture barrier/insulators on the distributors (and I only remember 1-2 people having done this) that it has definitively solved the occasional minor hiccup/stumbling issue at idle.

Your rough idle issue definitely sounds like an ignition issue, no question. Only with a methodical approach will you solve it. This doesn't necessarily mean throwing parts at it, but rather testing each component carefully to insure integrity. But before doing that, baseline the car by making sure your upper harness is known-good and clearing codes.

Cheers,
Gerry

 

[samiam44]

Re: Misfire/rough after sitting

I think the star article,

The mechanic said he had it always missed on a particular cylinder(s) and then he check the cap/rotor condition- and the offending cylinders changed which was his sign that the insulator had burn marks. I think if you have the orange ones(bosch), then you can inspect them closely if removed. My car has black ones- which I thought were Beru, which would be nearly impossible to inspect.

I have yet to witness a tech using an oscilloscope in my years.

Michael

 

[gerryvz]

Re: Misfire/rough after sitting

I have yet to witness a tech using an oscilloscope in my years.

About 10 years ago, I was coming home from work in the Portland suburb of Hillsboro (about 20 miles west of PDX) in my 560SEC, when it started running rough, particularly when I slowed down or was at a stoplight. I drove straight into my mechanic shop at MBI Motors near downtown Portland, about 2 miles from my house at the time. It was just before the end of the day.

I told Rich Helzer, the shop foreman, as I drove in about the issue, and he directed me over to one of the service bays, and proceeded to connect an ancient Sun oscilloscope to the car. It took all of 1 minute to determine that cylinder #6 was shorting out (to the block). The culprit was a bad insulator, which is a ceramic piece that is attached to the end of the plug wire. What was happening was that the spark wasn't reaching the plug, but rather finding the easiest path which led to the engine block.

He pulled the plug wire, removed the connector, and knocked the insulator against the block to break it off the end of the plug wire. The he walked over to the parts department, grabbed a new one, and re-installed everything. I was on my way in less than 15 minutes, out only the $19 for the new insulator, and no labor charge.

I have always advocated putting cars on an oscilloscope (a handheld Fluke Automotive ScopeMeter is an excellent example of such a device in a modern format) so that one can see what is happening (electrically) in each cylinder.

Cheers,
Gerry

 

[clarkz71]

Re: Misfire/rough after sitting

I have yet to witness a tech using an oscilloscope in my years.

Michael

.

I told Rich Helzer, the shop foreman, as I drove in about the issue, and he directed me over to one of the service bays, and proceeded to connect an ancient Sun oscilloscope to the car. It took all of 1 minute to determine that cylinder #6 was shorting out (to the block). The culprit was a bad insulator, which is a ceramic piece that is attached to the end of the plug wire. What was happening was that the spark wasn't reaching the plug, but rather finding the easiest path which led to the engine block.


I have always advocated putting cars on an oscilloscope (a handheld Fluke Automotive ScopeMeter is an excellent example of such a device in a modern format) so that one can see what is happening (electrically) in each cylinder.

Cheers,
Gerry

That's what I leaned on, an old school Sun scope.

We used it at the dealer until the early/mid 90's, then Fluke came out with the multi meter with a built in scope.

I believe that was around 1997, and the Fluke was announced in a service bulletin as an approved service tool.

Now the SDS has all that information built in with miss fire counter, injector pulse duration, and coil output per cylinder.

 

[gerryvz]

Those Fluke Automotive ScopeMeters were/are the shizz. Are you selling yours?

By the way, I'm a bit confused. If we have Clark Vader and El Beik, both of whom are Sith Lords .... which one of you is the Master and the other the Apprentice?

 

[clarkz71]

I'm a heavy breather so I have to go with Anakin Skywalker

I recently sold elbeik a burl wood console sliding door he was very happy with, by the way.

My first package sent to the Middle East.

.

 

[link]

Re: Misfire/rough after sitting

A LOT of mechanics aren't specialists in the M119, so may not know the idiosyncracies specific to that motor. Unless the mechanics are knowledgeable about the M119 (and most dealer mechanics are not, nowadays, given that the motor was last used in the 1998 time frame) I would check and re-check any work they've done.

I don't trust any MB dealer with an M119 as far as I can throw them ... and even indy shops, I would only trust their M119 knowledge after a long conversation.

There are five things that YOU should do (or explicitly confirm yourself), before proceeding further, just to ensure things are baselined as appropriate:

a) Ensure that your upper wiring harness has been replaced. You did not confirm this in your earlier posts, unless I missed it. There is information in the Wiki as to how to identify and translate the date code on the label attached near the head-end of the harness.

b) Ensure that all codes have been checked, and cleared, and the car has been driven to see what codes re-appear. Again, you did not confirm you'd done this, unless I missed it.

c) Ensure that the caps and rotors have been replaced with quality (Bosch or Bremi) units.

d) Check the resistance of your plug wires and spark plug connectors. If the wires or connectors don't ohm out correctly, then I'd replace them out of hand.

e) Ensure that you have the proper plugs (Bosch F8DC4) installed, and gapped correctly. If the plugs have more than 15-20K on them, I'd replace them out of hand.

ONLY after confirming all these items have been checked, confirmed and/or changed if necessarily, then you should suspect the insulators.

To answer your question -- I have not seen any report from anyone who has replaced the moisture barrier/insulators on the distributors (and I only remember 1-2 people having done this) that it has definitively solved the occasional minor hiccup/stumbling issue at idle.

Your rough idle issue definitely sounds like an ignition issue, no question. Only with a methodical approach will you solve it. This doesn't necessarily mean throwing parts at it, but rather testing each component carefully to insure integrity. But before doing that, baseline the car by making sure your upper harness is known-good and clearing codes.

Cheers,
Gerry

Thanks for the detailed comments. You should make a sticky of that post.

It’s all been covered, replaced, and recovered and re-recovered. I agree being methodical with any troubleshooting is the only route to success.

To answer your question -- I have not seen any report from anyone who has replaced the moisture barrier/insulators on the distributors (and I only remember 1-2 people having done this) that it has definitively solved the occasional minor hiccup/stumbling issue at idle.

The user bendover stated that was the solution, in this thread. And that is why i posted requesting a follow-up. I wish the problem was only minor or occasional.

 

[clarkz71]

Re: Misfire/rough after sitting

A LOT of mechanics aren't specialists in the M119, so may not know the idiosyncracies specific to that motor. Unless the mechanics are knowledgeable about the M119 (and most dealer mechanics are not, nowadays, given that the motor was last used in the 1998 time frame) I would check and re-check any work they've done.
Cheers,
Gerry

Very true.

The last dealer I worked at until April 2012 had 3 techs, myself included that actually worked for
MB when the M119 was introduced in 1990

The rest of the tech's in the shop had 10 years or less experience.

I was the only one that would work on them, as the other 2 wanted to stick with the new models

So I got any M119 cars that came in, including a 1994 500E, bad EZL.
The guy bought a new one at full pop $3000 or so. Then another 1.5 hours labor @ $135 or whatever it was then.

 

[gerryvz]

The Portland, OR MB dealer used to only have one mechanic on site who could work on anything from the 126 or earlier. That was 5-7 years ago !

My understanding is that the MB Houston North dealer (one of the larger of the 5 in Houston) only has one tech who knows the E500E.

 

[clarkz71]

I started in 1982, second year of the 126.

Worked on many of the D-Jetronic W108 cars and W113 M130 with mechanical injection.

I was apprentice to a (at the time) 25 year MB veteran shop foreman. Guy was unreal with knowlege and a great teacher.

 

[Maui]

The Portland, OR MB dealer used to only have one mechanic on site who could work on anything from the 126 or earlier. That was 5-7 years ago !

My understanding is that the MB Houston North dealer (one of the larger of the 5 in Houston) only has one tech who knows the E500E.

I don't know about Portland MB, but the Beaverton MB dealership does not have anyone with much W124 experience. They told me they had to "dust" off the books the last time they to do major work on one. That is one area where the independents have an advantage.

 

[gerryvz]

When I lived there, it was only Rasmussen down on Front St. and Rasmussen / MB Wilsonville.

I didn't darken the doorway of either for many years before I moved. I darkened the doorway of MBI Motors 2-3 times per week from 2000-2008. Between watching mechanics work there, and Robert Fenton in the Bay Area, and subscribing to the trade mechanics' service called LMVinfo for some years, I learned one heck of a lot of practical stuff about MBs.

 

[Maui]

When I lived there, it was only Rasmussen down on Front St. and Rasmussen / MB Wilsonville.

I didn't darken the doorway of either for many years before I moved. I darkened the doorway of MBI Motors 2-3 times per week from 2000-2008. Between watching mechanics work there, and Robert Fenton in the Bay Area, and subscribing to the trade mechanics' service called LMVinfo for some years, I learned one heck of a lot of practical stuff about MBs.

They are owned by Lithia now. Portland, Beaverton and Wilsonville. Lithia is headquartered in Medford and owns almost 100 dealerships in 13 states. I have project at their Mini store in Beaverton that should be starting up soon.

MBI is a good place. They've done nice work for me and opened the shop for the MB club a few weeks ago.

 

[samiam44]

I've heard that many times with dealerships.

I see 60's and 70's cars in the bays occasionally at our local dealers, but then I talk to a M103 guy whom said the only one whom would touch his 300E was the shop foreman.. ended up with a 7k bill as nearly everything was replaced. When I was there, he was the only knowledgeable M119 guy in service.

I think this is the same problem everywhere. The older techs generally go to independents to make more $$. Just think of the issues when you try and get a mechanical fuel injection pump rebuilt after Gus from Pacific Fuel injection retires.


Michael

 

[gerryvz]

There are other good sources for mechanical injection pump rebuids other than Gus Pfister at Pacific Fuel Injection in South San Francisco. Robert Fairchild up at Jerry Fairchild Industries in Redding is an excellent source. I've visited his shop several times personally (he's redone several 300SEL 6.3 mechanical pumps for me over the years) and there are a couple of rebuilders on the East Coast too. PFI's work isn't what it used to be when Gus ran things and did most of the work himself. Their work has slid over the past 10 years, according to knowledgeable sources......

 

[samiam44]

Yep,

That's exactly the experience transfer problem. Gus would build a pump and you could install it with minimal adjustment. I remember Ritter saying some of the other rebuilders took quite a bit of adjustment to get them adjusted right. At least the adjustment is all in the TDM!



Michael

 

[DerFuror]

That's what I leaned on, an old school Sun scope.

Those Fluke Automotive ScopeMeters were/are the shizz.

That Fluke sure looks a lot easier to move around the shop with, let alone tuck inside your coverall’s cargo pocket! Ah, the benefits of modern-day micro-electronics…

 

[gerryvz]

Derf, that is the EXACT Sun machine that we connected my SEC to per what i mentioned above. If I could get one of those used for my garage shop, I'd be ALL over it.....

Sun also made a special distributor testing machine. It was almost a REQUIREMENT for the 300SEL 6.3, which required such a machine to coordinate and adjust its dual contact-points distributor setup.

Cheers,
Gerry

 

[DerFuror]

Derf, that is the EXACT Sun machine that we connected my SEC to per what i mentioned above. If I could get one of those used for my garage shop, I'd be ALL over it.....

It's a very handy piece of equipment.

My Father was arguably the best overall Independent in his locale. He bought this Sun machine brand new back in the day. Perfect for diagnostics on older vehicles.

It has a bunch of handy peripheral equipment, but not the distributor tester...at least I don't think so; I would have tripped over it by now.

I'll keep you in mind when I finally decide to exodus this Northeast bastion of Bolshevism. I'll probably be unloading quite a few things while I can walk before they make me run like the last two generations of my family had to.

 

[gerryvz]

You should come to Texas. Life is simpler and significantly cheaper here. And you have more liberty to enjoy it.

 

[DerFuror]

You should come to Texas. Life is simpler and significantly cheaper here. And you have more liberty to enjoy it.

It's part of the overall plan.