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Engine still skipping a beat every few seconds

Jelmer

I'm "special"!
Member
With most, if not all, mechanical issues sorted, this is becoming my most annoying "problem". When the engine is warm and running idle, sometimes I feel the whole car shake, much like it skips a cylinder. But this is only every few seconds, sometimes twice in a row, sometimes nothing for a few seconds. It NEVER happens (or at least, I don't feel it) while driving.

We (well, Christian) checked the caps & rotors, I just got new sparkplugs (the right ones) and there are no codes.

Christian came with the suggestion to replace the ignition cables, as a precaution. Mine are (most likely) still from the factory, so it's high time.

Basically, two questions.
1) What's the best brand to get at the moment? Christian used Beru (http://www.daparto.de/Teilenummernsuche/Beru/0300890635?categoryId=672&kbaTypeId=5176) since people are having good experience with those.
2) Are there any other things I can check?

It's time to enjoy the silky smooth rumble of my V8 - also at idle :)
 
Hi Jelmer.

It reminds me about the article I've enclosed, but we don't have that type backing plate on our distributors. But have you checked item 14?
Old ignition cables could be a reason.

Cheers
 

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No no no. You are going the same path I went to: no where!

This is the 500E symptom I and many others could never solve. Smooth Idle with an occasional "hiccup" or Skip.

I changed rotors, correct spark plugs, cleaned caps, changed spark plug cables (Complete Set- Beru) and the result: Still there !

On the HHT, the readings a PERFECT! you can't detect the skip on the diagnostics readings from the LH nor EZL unit

Try Number 14 as Arnt mentioned, it least you won't do something that others tried.
 
Hi Jelmer.

It reminds me about the article I've enclosed, but we don't have that type backing plate on our distributors. But have you checked item 14?
Old ignition cables could be a reason.

Cheers
Item 14 is the insulator which is basically the same as mentioned in the article. If your HT/ignition cables are still original (which i'm surprised considering you went through just about everything with your car, JB) I would replace them as well as the insulators. And Beru is what I had fitted and seem fine. These insulators are not cheap , I remember being shocked at the price when i replaced mine at £70each!,,and ideally should be changed when renewing caps and rotors. But I guess a lot owners skip these insulators coz of the silly price.

I was experiencing quite a bit of stumble at idle till I replaced these overlooked item. It was significantly better ,99% after this. However it will never be 100% as it's really the characteristic or something that E500E owners have to live with. Think Uncle Gerry mentioned this before - the occasional stumble but not frequent to irritate.
 
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Smooth Idle with an occasional "hiccup" or Skip.
It's pretty smooth normally, but I wouldn't call it a hiccup. It's a rather violent shake, and it "feels" like the engine has to work hard to recover. It's quite good to feel inside the cabin, which I don't like at all.

Thanks for the replies, I'll order both the insulation caps and the cables.
 
Yes Jelmer, the cables from Beru are the best you can get and are only ~20% of what MB charges you for a fresh made set they do for you at the dealer/shop (they use cables from 500m roles and attach/crimp the boots manually), and people having had issues with in german Forums. Bernard ONLY suggest this Beru set with Silicone cables as they last veeeeeery long time.

Well my car (as it ran haha) had no hiccups. What i did before installing the engine was to replace EVERYTHING in the ignition-system (besides EZL). That means: Insulation-caps (Bosch), caps (Bosch), rotors (Bosch), cables (Beru ZEF635), plugs (Beru from MB Dealer), coils (Bosch) and both Crankshaft Position Sensor as well as Camshaft position sensor (not that the last one has something to do with ignition, but just as precaution).
The car had a SUPERB Idle i never witnessed in any M119 before.

Also Jelmer, your engine mounts are broken, thats why you can feel "anything" inside from your engine in the cabin even though you shouldnt. With stock new engine and gearbox mounts, you can't tell inside from your butt-feelings if the engine is running or not. I remember that the hiccups got a little better after i "cleaned" your contacts inside the caps and the rotors with Grid 2000 sandpaper and removing the corrosion/residues that way + cleaning them afterwards with compressed air and a rag with solvent.
So i think this will be a ignition-issue.

EDIT: Are you using Resistor Sparkplugs?
 
Jelmer- so this hiccup even only happens at idle?

Christian, do you know the Beru p/n for the set of ignition wires. All I see state side is Bosch wire sets. I'm sure with the Beru number, it will pop up in the mailorder places computers. Hate it, but that seems to be the trick most of the time.

I noticed in Bernard's rebuild on the W140 german website, he was using some 4 wire electrodes in the 6.0 liter AMG motor rebuild. What the heck were those plugs?
 
The hiccups appear to only happen at idle, but even if they happen at higher RPMs I would have no way of noticing that.

Christian, the engine mounts are for later. Don't know when, but I've heard and read that it's NOT a fun (or short) job. Maybe later ;) If I were to replace the cables and insulation caps I think I have the same stuff replaced as you had. All them sensors (as they'd say in Texas, right? :p) have been replaced already.

And I'm pretty sure I have the right sparkplugs. This is done at a proper shop, with guys who love these cars and do the work because they like it, not because they have to.
 
Yes Jelmer, the cables from Beru are the best you can get and are only ~20% of what MB charges you for a fresh made set they do for you at the dealer/shop (they use cables from 500m roles and attach/crimp the boots manually), and people having had issues with in german Forums. Bernard ONLY suggest this Beru set with Silicone cables as they last veeeeeery long time.

Well my car (as it ran haha) had no hiccups. What i did before installing the engine was to replace EVERYTHING in the ignition-system (besides EZL). That means: Insulation-caps (Bosch), caps (Bosch), rotors (Bosch), cables (Beru ZEF635), plugs (Beru from MB Dealer), coils (Bosch) and both Crankshaft Position Sensor as well as Camshaft position sensor (not that the last one has something to do with ignition, but just as precaution).
The car had a SUPERB Idle i never witnessed in any M119 before.

Also Jelmer, your engine mounts are broken, thats why you can feel "anything" inside from your engine in the cabin even though you shouldnt. With stock new engine and gearbox mounts, you can't tell inside from your butt-feelings if the engine is running or not. I remember that the hiccups got a little better after i "cleaned" your contacts inside the caps and the rotors with Grid 2000 sandpaper and removing the corrosion/residues that way + cleaning them afterwards with compressed air and a rag with solvent.
So i think this will be a ignition-issue.

EDIT: Are you using Resistor Sparkplugs?

Aha - an appropriate note for parts recommendation on the maintenance list. The corrosion does in fact build up quite quick on the pick-up points in the distr.cover, I've cleaned it several times. The distr.cover has went/drain slots in the bottom, but the moisture is entrapped because it's no airflow through the cover. Maybe I should try to make slots in top of the covers too? That will give access for water to enter, but I never flush or soak the engine anyway.

Cheers
 
The hiccups appear to only happen at idle, but even if they happen at higher RPMs I would have no way of noticing that.

Christian, the engine mounts are for later. Don't know when, but I've heard and read that it's NOT a fun (or short) job. Maybe later ;) If I were to replace the cables and insulation caps I think I have the same stuff replaced as you had. All them sensors (as they'd say in Texas, right? :p) have been replaced already.

And I'm pretty sure I have the right sparkplugs. This is done at a proper shop, with guys who love these cars and do the work because they like it, not because they have to.

Jelmer, youre lucky having enthusiasts for assistance. It's hard to dig up any enthusiastic M119 experts here in Morepay. I guess there may be some left at the "LEGO workshops", which replaces parts only :D. But it's too costly, guess what - the hour rates are now over 140 Euro ($173) at some shops here!

Ciao
 
Christian, do you know the Beru p/n for the set of ignition wires. All I see state side is Bosch wire sets. I'm sure with the Beru number, it will pop up in the mailorder places computers. Hate it, but that seems to be the trick most of the time.

I noticed in Bernard's rebuild on the W140 german website, he was using some 4 wire electrodes in the 6.0 liter AMG motor rebuild. What the heck were those plugs?

Beru 0300890635 or also known as ZEF 635 Set

Bernard used a 4 Electrode Beru Ultra-X or some sort of that plugs. IIRC they are also available from Bosch.
The hiccups appear to only happen at idle, but even if they happen at higher RPMs I would have no way of noticing that.

Christian, the engine mounts are for later. Don't know when, but I've heard and read that it's NOT a fun (or short) job. Maybe later ;) If I were to replace the cables and insulation caps I think I have the same stuff replaced as you had. All them sensors (as they'd say in Texas, right? :p) have been replaced already.

And I'm pretty sure I have the right sparkplugs. This is done at a proper shop, with guys who love these cars and do the work because they like it, not because they have to.
Well Jelmer, remember your shop also did the gearbox and it had a wrong amount of fluid in there. I still would remove one plug on my own and check if its the right one. Also check the boots if they sit properly on the plugs,etc.
Yes but your coils havent been replaced as you told me here. Dont forget them.

Aha - an appropriate note for parts recommendation on the maintenance list. The corrosion does in fact build up quite quick on the pick-up points in the distr.cover, I've cleaned it several times. The distr.cover has went/drain slots in the bottom, but the moisture is entrapped because it's no airflow through the cover. Maybe I should try to make slots in top of the covers too? That will give access for water to enter, but I never flush or soak the engine anyway.

Cheers
No dont drill anything in there. Please dont.

Jelmer, youre lucky having enthusiasts for assistance. It's hard to dig up any enthusiastic M119 experts here in Morepay. I guess there may be some left at the "LEGO workshops", which replaces parts only :D. But it's too costly, guess what - the hour rates are now over 140 Euro ($173) at some shops here!

Ciao
Yes i agree. Hard to find such guys here in Germany either. They are just a Handfull if not less that have really some deep inside knowledge of our babies. This, the insane labor costs these days, and the tendency that on the 500E everything gets broken over time, is making the 500E for a non-DIY guy only affordable if he is a "better earner".
 
How pricey are those coils? And, have a part number handy? Just trying to get a total picture of what I can replace soon, since I'm pwetty sure they'll come up sooner or later.
 
How pricey are those coils? And, have a part number handy? Just trying to get a total picture of what I can replace soon, since I'm pwetty sure they'll come up sooner or later.
below 80€/piece.
There ya go:
http://www.daparto.de/Zuendspule/Me...sse-Stufenheck-W124/2-1236-638?kbaTypeId=5176

I would go for the Bosch ones. Or the Berus.... "Herth & Buss Elparts" is also a very well respected high-quality manufacturer of sensors and all kind of electronic automotive stuff. But since the Boschs are only 4€ more expensive its not worth doing experiments here (Experiments on the 500E are rather my area haha)

EDIT: But be aware it lists some as "up to engine number" and some "as of engine number". Also the part Number might be different for left/right ones. I will try to find the correct ones.
 
Hi,
About the hiccup, I remenber a test of the Volkswagen golf VR6 made by a famous French magazine and talking about the engine "hiccupping" after the "effort". The car was almost new and it was doing it...
It would be interesting to know if the owners of the new 500 E and E 500 experienced this when they first got their cars.
Alex
 
Hi,
About the hiccup, I remenber a test of the Volkswagen golf VR6 made by a famous French magazine and talking about the engine "hiccupping" after the "effort". The car was almost new and it was doing it...
It would be interesting to know if the owners of the new 500 E and E 500 experienced this when they first got their cars.
Alex

+1 , maybe its a characteristic of the 036...need to find a 1 owner car to ask.
 
My car is a 2-owner car, and I got it at 57K miles. It has always hicupped, both in the moderate Portland climate as well as the hot/humid Houston clime. Seems to be a bit happier overall here in Houston, though it runs somewhat hotter here. It's never been a MAJOR problem, and seems to happen in bunches.

I only experience it at idle, and only when the car is fully warmed up, FYI.

Cheers,
Gerry
 
Hiccup, miss, skip, stumble :banger:. Descriptions and severity vary of course. My personal experience it rarely did it but was there. So rare that it can go thru the day without a hiccup. Think the only time that I would notice it was after highway driving then suddenly hit stationary traffic, but even then it was just a slight flick on the tacho and then it would sit in traffic smoothly all day long. So, as with Gerry's it wasn't an issue, so for me it's characteristic.

BUT Jelmer just threw another symptom !:hammerhead: Mate, Change those leads and check the plugs before Christian diss' you again!
 
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My car is a 2-owner car, and I got it at 57K miles. It has always hicupped, both in the moderate Portland climate as well as the hot/humid Houston clime. Seems to be a bit happier overall here in Houston, though it runs somewhat hotter here. It's never been a MAJOR problem, and seems to happen in bunches.

I only experience it at idle, and only when the car is fully warmed up, FYI.

Cheers,
Gerry

Aha good point. It was more apparent in colder weather and after highway driving when the engine "cleans up". only in P position fully warmed up, more subtle at D position.
 
With me it's the other way around. At P it stumbles rarely, but in D you feel the engine shake. Heck, you even see the oil gauge taking a dive!
[youtube]Wx-YnTAH_1g[/youtube]
 
When the car is put in drive, doesn't it shift the loading/weight distribution on the engine mounts? Maybe that would make the miss more noticeable. Also, when you put it in drive, isn't it normal to see a drop in RPM and consequently a drop in oil pressure?

I had a 400E that missed badly when I put it in reverse. It turned out to be the neutral safety switch. I have no idea why, but it fixed the problem.

For what it's worth, my E420 has always hicupped occasionally at idle. I just attributed it to some emission device introducing unburnt gas fumes back into the engine.
 
For what it's worth, my E420 has always hicupped occasionally at idle. I just attributed it to some emission device introducing unburnt gas fumes back into the engine.
This is a BRILLIANT point. And matches to what Gerry told, only hiccups when warm, because also the EGR and/or the fuel-fume recirculation thing does it only when warm. And the fume-thingy has a "duty cycle", so it opens/closes every xy seconds for some milliseconds or so.

Still, my car didn't have it, so maybe my fuel-fumes-recirculation thingy was broken, who knows...We need to check that further.
 
Yes, putting it in D does drop the RPM and thus the oil pressure. But it should be constant. The movie I posted shows me sitting in front of a traffic light, standing still in D. It shouldn't bounce up and down.

The fume-thingie is opening in a rhythmic way, and not at all synchronized with the engine stumbling. Wasn't that simply to relieve gas pressure in the fuel system?
 
I thought the video was showing when you moved it from park to drive. Sorry about that. As for the fume issue, I think I remember a little black part on the driver's side fender well next to the ignition module that made a continuous clicking noise. Maybe that's what you were referring to and I suppose it would be easy to verify that the continuous clicking would not be synched with the engine missing. Could the EGR come into play here?
 
EGR?!? To much tinker doodads to maintain on these cars, I hope it can be taken off, just as the air pump.
 

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Mine hiccups also. Had a chance to experience extended idling last week when caught in a traffic jam of epic proportions as they say, I was stopped for up to 30 minutes at a time and creeping at idle for about 3 hours worth, all told. When I was stopped I found that my car idled a hair above 500 rpm, which seems a tad low because it hiccups, if I hold it up at 650 rpm or so it stays steady. But interestingly, if I put the AC on when idling in drive with my foot on the brake, even though the idle speed barely changed, it stopped hiccuping. Seems like a small load was enough to keep it smooth.

(I did shut it down if the stoppage was more than a few minutes)

I wish it idled faster, because the oil pressure is sitting down at ~1.2 - 1.3 bar when idling hot like that. I know this is normal, and it climbs instantly when revved, but I still wish it was about 600 - 650 or so.

Rgds,
Chris
 
This sounds like a different "issue". Your idle rpm is a tad low; it should be between 600-650rpm and keep steady. Only in P or R it can drop slightly to ~500rpm.

Oil pressure is 1.0 bar in gear with my, still quite OK, don't worry about it.
 
Just got an idea regarded to the overheated engine bay.

Jelmer, you mentioned it happened when the car was in traffic jam, just as Allgo's experience, also when turning in from highway driving when the car was at full working temp. Could the fuel lines get overheated, causing the fuel to evaporate/boil prior to atomization giving a random and bad A/F mix? I don't recall whether it's preheated fuel on these engines, I think it is.

I had these problem on a motorbike many years back. I had a transparent filter unit on the fuel line, hanging under the carbs behing the engine, a hot place on a motorbike in fact. When the engine shuddered and also stopped, the filter was empty for fuel! I rerouted the fuel line and filter unit a bit and the problem was gone.

-a-
 
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Did I mention that? Then I must have misspoke. I haven't been in a real traffic jam recently, thankfully. A few posts back I mentioned at a traffic light, so yes, that was standing still for a short time. But that was on my way to work, only minutes after the engine had reached operating temperatures, no overheating engine bay. Also, when we drove home from Christian and pulled up to a parking place the engine seemed to have "moments of clarity": it ran very, very smooth. And that's *with* a very hot engine bay.

I'll just wait a few weeks and then order all bits and pieces (except EZL) mentioned in this topic. I'll report back when I have it all installed.
 
I have exactly the same hiccups. They happen only 1/day at the most. I had issue with my spark plug connectors being dirty from what someone put in there which was not a dielectric grease, but crusty crap. My car would lose power at high rpm before I cleaned the connectors. Now it all seems fine but the hiccups are still there.

I have had everything in the ignition system replaced by me and the PO mostly, including the EZL with a correct one. Plugs are also non-resistor ones.

the only things that I have not replaced are the cam and the crank sensors which christian is saying he changed.

I am just thinking here that he is the only one without the problem. Sounds like one of those sensors may be the issue.

Is there a way to test them?

Any thoughts?
 
I did the coils last week - all cables look great. I also redid the caps and rotors as you mentioned: no difference.
 
ivanned, maybe you can explain a bit more. This thread is called "engine skipping a beat every few seconds", yet you speak of once per day. Even after all the repairs I've been through, I notice my engine STILL does this, but it's not as noticeable as before.

What exactly do you experience? Even thought my caps and rotors were in ok-ish shape, replacing them changed a lot. As did the wiring, and especially the insulators behind the caps.
 
I saw your video and I get exactly the same thing although just rarely. The car just skips a beat especially after highway driving at a light for example. I inspected the insulators and seemed to show no black marks at all. Passenger side had yellow spots on the back side of it. I am wondering what that means. there was small amount of oil from the seal behind, but minor indeed.

You said everything has got a lot better, but do you still have problems?

Did your insulators have marks on them?
 
I'd love to hear- what's Jono's take on this?

He's driven and repaired many of these cars. My 500e seems to do but not my 420e. The 500e definately needs motor mounts and the 420e has new ones. Perhaps it happens on both cars, yet is not noticeable with fresh mounts.


Michael
 
+1 to what Jelmer, Gerry and Christian have said here. These things must all occur at the same time on these cars, because apparently it's "time" to do mine again.

The symptoms just started showing -- warm start hesitation, slight miss + shudder at idle thereafter, smooth as ice once the car starts running. It all made me start thinking of the fuel pump or a fuel relay or something. Like, Gerry, I've never thought too much about the occasional flutter at idle, thinking it characteristic of the car, based on my experience with these and 560 SEC's, per the Star Mag article. But when the shudder that Jelmer described showed up, well that caught my attention.

My mechanic says the fuel pressure regulator is the warm start / shudder problem, so they replace the fuel pressure regulator, which is further to Christian's point. The idle issue is well documented -- caps, rotors and insulator. Mine was last done almost exactly 10 years ago (which I find a strange coincidence), along with the fuel pressure regulator. The only thing that wasn't done on mine is the wires. Maybe I'll have them do that this time.

Hopefully this helps someone. I'm likely to consider this a package service every time the symptoms show up.

Cheers, Gents.

maw
 
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My 93' has had the same problem for years. I have replaced the caps, rotors, insulator, wires and plugs.
I have just been living with occasional hiccups at idle.
The 92'Renntech is smooth as silk and has never had a hiccup since I have had the car.
 
I measured the fuel pressure during hiccups and it holds steady.
My whole ignition system is new
crank and cam sensors are the only think I can think of

Having said that, my problems are very minor and very occasional. I know for a fact that I have at least a few vac leaks - pods - upshift so I want to solve the obvious first before I jump into the unknowns.
 
Ok so here is an update. I just got a pretty significant misfire back and again no codes. Skipping at idle has got much worse. All of this happens after aggressive driving, but when the car starts missing it can miss severely at any RPM at any time, even during light acceleration. The symptoms do not happen all the time, but are pretty severe. Everything on my ignition system is new, so I was suspecting a cam and/or crank sensor problem developing, but aren't these supposed to throw a CEL?

I hope is we solve it we can solve the idle misfire problem.
 
Do you think the camshaft position sensor can be the culprit?
I seriously doubt it. I was getting an intermittent error code for the cam sensor, and I could tell when it was acting up, as midrange power went flat. There was no misfire though.


Also what about the crankshaft position sensor? Are there 2 of those? one to the EZL and one they call TDC?
There are two on pre-1994 models, but the forward sensor is not connected to anything... it only goes to the 11-pin diagnostic connector, for easy access to diagnostic tools. The important one is on the rear of the engine and connects to the EZL. Again, when this sensor acts up, there is usually an error code on the EZL. And, it shouldn't cause a misfire.


Could a cam solenoid cause something like that if it has leaked through and failed.
Nope... a bad cam solenoid would cause a lack of midrange power, but it should not cause a misfire.


I am trying to determine what a partial failure of these sensors looks like.
Partial (intermittent) failure of any of these sensors should trigger DTC's.


I would love to test the units rather than throwing parts, but I am not sure how or where. Any ideas?
A scanner capable of showing live data would be required, AND you would need to know how to interpret the data (i.e., compare to another M119 with LH injection).


I'm starting to wonder if you may have a defective cap, rotor, or insulator even though these parts are nearly new. I would at least inspect them again. A very long shot would be the O2 sensor reading abnormally lean, causing a lean misfire, but I doubt it.


:scratchchin:
 
Thanks this is great info. I got up early today and went for a ride to reproduce the symptoms again. They of course came back again worse than ever.

Finally I got codes!!

Pin 4 code 4 - MAF

Pin 7 code 14 - closed throttle position switch.

Some time ago I disconnected the MAF and that did not alleviate the symptoms. so are we looking at the throttle position switch? Could my symptoms be caused by S29/3 switch?

http://500eboard.com/forums/showthread.php?742-Idle-speed-contact-switch
 
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CODES!!!! FINALLY! I'd replace S29/3 first. The MAF code is worrisome, it points to either a bad MAF, or engine harness.

If a new S29/3 switch doesn't help, I'd do the MAF next. Hendy might have a good used one you can try. They are not a common failure. As noted in Benzer's thread, the MAF can be proved bad by viewing the live data, if the kg/hr numbers are way off you'll see it on the scanner. This wouldn't help if the erroneous reading is intermittent though.

:duff:
 
Jelmer,

I think I read that you replaced the distributor insulators (round yellow disc behind the rotor arm)...so this may not be for you but others reading this thread...

Have a look at the insulator discs with a (powerful) magnifing glass to see if there are circumferential hair line mark(s). Also look where the yellow discolouration is...you/someone mentioned it earlier in the thread.
 
I already ordered the switch. I hope that is the issue. Harness looks good and has been replaced. Today symptoms worsened more. It starts as smooth loss of power during acceleration. Then it deteriorates to rough running at acceleration with loss of power and even in neutral with the MAF disconnected it has hard time revving up - it stumbles.

Jim,Dave- I did have yellow spots in the back of the insulation disks. They seemed like crusty droplets of something. I was able to wipe most of them. I have a microscope at my office. Are these carbon spots that small or are they visible with a naked eye?

I already see myself stuck at the side of the highway :pissed:
 
Just drove around a bit but nice and easy and very few stumbles. The moment I start driving more aggressive this is when things start happening.
I have to go to MB and get someone who can do the life data if the switch does not work.
 

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