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Misfire/rough after sitting

My best piece of advice for you -- with those rubber "donut" rings that mate the two halves of the intake manifold together. MAKE SURE that these are installed correctly and none of them are pinched. After you have installed the rings and put the two halves of the intake together .... take a small flashlight and inspect around each of the 8 rings with 360 degrees, carefully inspecting even the inside with the flashlight.

I had a small section of one of my rings pinched on my M117 and it made a HUGE vacuum leak which caused the engine to idle quite high (900-1000 RPM). To fix it I had to remove the intake and re-do it -- not my favorite job :)

See the photos on this post: http://500eboard.com/forums/showthread.php?564-560SEC-top-end-rebuild&p=2555&viewfull=1#post2555

Cheers,
Gerry
 
Thanks for that advice!

Can I smear a SMALL amount of vaseline on to them? I think that could help decrease the friction (should be harder to pinch them then). Is it a good or bad idea??
 
Hello (again),

I know understand what you mean Gerry. I did not need the extra vaseline :)

I replaced the intake manifold gasket last Friday. Did it solve the problem with misfiring? NO!
But the enginge does not respond to starting gas now. So one problem is deleted and I succeded with my work :)
And one more good thing. I got a chance to clean everything and that was very necessery!

The car is at the workshop now for further troubleshooting. To be continued....
 

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I drove the car to the workshop Sunday (I know them so there is no problem to park the car at the workshop on the weekends).
They started to work (same mechanic, one of the owners of the workshop) on the car yesterday.

After ~1 h he found a new VERY interesting error. One rotor (passenger side) doesent work as it should. The spark continues directly into the metal behind it (hope you guys understand what I mean)!!
I did not check/think of the rotor or distributorcaps as a possible cause of failure because they are new and installed last season. But this sounds really reasonable!

I called the place where I bought the rotors (Beru, did not buy them at MB) and told them about my issue. He told me that they have a 3 year spare part warranty.
So he ordered two new rotors for free AND Mercedes here in Arvika will replace them and charge Mekonomen (the company where I bought the spares from).
They will also pay for the trouble shooting at Mercedes! So this is probably the end of the story. And I´m happy like a child on Christmas Eve :)

Trust me, you will know if this does or doesn´t solve the missfire issue for me!

Thanks for your support!
 
It certainly sounds reasonable.

A friend of mine had a 260E that gave problems with the ignition system (replaced the rotor and cap) and in that case the problem returned within a short period of time (months) and we replaced the rotor and distributor cap again to fix the problem. On that basis I would replace the distributor cap as well, just to be sure.

Best of luck
 
PROBLEM SOLVED, I repeat PROBLEM SOLVED!

It was the rotor (passenger side) and everything runs great without any misfire at all.
- No misfire at idle (probably because of the gasket and the new rotor)
- The Idle is perfect (probably becasue of the gasket and the new rotor)
- No misfire what so ever even on higher rpm´s (>1000)

I´m happy and thanks for your support!
 
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On a side note, I experienced a variation of this issue on my one E420. It happened after the car sat for several weeks. It started and ran fine for about 10-15 minutes of driving at 30-60mph. Then when stopped at a traffic light, it would misfire badly, and when trying to accelerate, it would barely move the car at all. Once gradually coaxed up to speed (sputtering the whole time), it would smooth out at light load while cruising at ~55mph, and it would also run ok at WOT to redline, but accelerating off idle it was terrible. It did this several times after the car was parked for days or weeks. The bizarre part? After driving it several days in a row, the problem disappeared completely. So, I was never able to diagnose it. :( The main difference compared to the original issue in this thread is that my car did not act up until shortly after it reached full operating temp. It was fine when cold.

UPDATE:

Although I have not experienced the scenario described above in many months, that same car (E420) recently acted up in a different way - instead of sputtering and running rough, it just had no power intermittently. I mean trying to take off from a stop and it felt like there was a lawnmower engine under the hood... squeeze the gas and the car would barely move forward, took a very long time to reach 55mph. It felt a lot like fuel starvation. There were NO codes afterwards.

So I hooked up an external AutoMeter mechanical fuel pressure gauge and did some test driving. In 5-10 minute test drives, the problem would not occur. I let it cool down an hour or two and tried again (several times), but the problem didn't reoccur. Drove it to work today, and FINALLY, after 20-25 minutes, it choked when I slowed to make a turn. Made the turn and the car just wouldn't get going! And guess what - the fuel pressure gauge was reading ~20psi (normal is 40-50psi). Normally when you accelerate the pressure increases from low 40's to about 50, but when the problem occured, the pressure would go from low 40's down to 30 or 20.

Verdict: Bad fuel pump(s). To be replaced ASAP. Nice to get some official confirmation from instrumentation to back up the ol' butt dyno. I expect this could also be the cause of the sputtering / stumbling which happened earlier this year, but time will tell...


NOTE: The bad fuel pumps caused a power loss, but with a smooth running engine. The other issue described in post #8 earlier in this thread was separate, that power loss came with a severe misfire (due to one distributor cap cross-firing). Although both scenarios have a similar low-power symptom, the smooth vs rough running clearly differentiates the two.

:rugby:
 
May be a good time to replace your FPR as well. I think our ethanogas is killing fuel pumps.
 
I thought about it, but the FPR on this car is working perfectly... pressure is dead on spec. I'll probably skip that for the moment but in general it would be a good idea, especially if you have no way to check it. I'm 99% certain the issue is due to the pumps, but swapping 'em out should validate that theory.

I agree - the E10 is at least somewhat responsible. I fill up with non-ethanol gas now that I know which stations in my area carry it, but for the past few years I wasn't doing that... oooops.


:hornets:
 
Dang those pumps are spendy. $300 list price? Really? And there are TWO of them. Lowest price for aftermarket (sssssh, don't tell Gerry) Bosch is at Amazon.com of all places, $125/ea, undercutting Autohaus's $133/ea (both have free shipping). Maybe I'll ask Léo if he could spare some change from the $35M he pulled down the last 11 months...

:spend:
 
I got mine locally at O'Reilly. Paid a bit more ($140ish) but had them in hand so I could replace them right then. They were re-boxed Bosch pumps, same part numbers and everything (see my thread in the 126 section).
 
At $82/ea I should pick up a couple spares!

Update on the problem: The fuel pump cured the pressure issues, and when driven regularly, the car would run perfectly. However if it would sit for 2+ weeks, it would start fine and drive fine for about 10-15 minutes, then it would hesitate & misfire. Except this time the fuel pressure was normal. Although the spark plugs looked ok (electrodes just slightly worn, I've seen MUCH worse in other cars which ran fine), I changed them anyway with F8DC4's. Haven't had a single hiccup since then, even parked the car for a month to test it out... no problems. Pretty bizarre.


UPDATE: The issue described above was later pinpointed as defective insulators behind the distributor caps; possibly related to liquid on the back of the insulators, however cleaning the liquid does not cure the problem permanently. Replacing the insulators with new Bosch cured the problem permanently. This has been discussed at great length in more recent threads on this forum Click here for one of the epic threads..

:seesaw:
 
FYI, those Bosch fuel pumps are available on Amazon right now for $82 apiece.
I documented this some time back on this thread -- quoted $92 from AHAZ and later on $87 from Amazon .. so it looks like they've dumped the price another $5 a pop. Excellent price, everyone should get a pair of spares..
 
To replace insulator #14, you only need to remove the rotor bracket #5, which is held in place by a single bolt #8. That's it - very simple. When re-installing, I would recommend using a very small amount of BLUE Loc-Tite on the threads of bolt #8, and also on the threads of the three small bolts which fasten the rotor to the bracket.


On a side note, I experienced a variation of this issue on my one E420. It happened after the car sat for several weeks. It started and ran fine for about 10-15 minutes of driving at 30-60mph. Then when stopped at a traffic light, it would misfire badly, and when trying to accelerate, it would barely move the car at all. Once gradually coaxed up to speed (sputtering the whole time), it would smooth out at light load while cruising at ~55mph, and it would also run ok at WOT to redline, but accelerating off idle it was terrible. It did this several times after the car was parked for days or weeks. The bizarre part? After driving it several days in a row, the problem disappeared completely. So, I was never able to diagnose it. :( The main difference compared to the original issue in this thread is that my car did not act up until shortly after it reached full operating temp. It was fine when cold.

:detective:

I am experiencing a similar problem on my E420. After returning from a 10 day trip the car started fine but ran rough. Between 2550-3500 rpm it can't get out of its own way. The first time I drove it the exhaust had a distinct rotten egg smell but that has not repeated.Last weekend I had a chance to look around and pulled the distributor caps off, they and the rotors looked ok. There was a "sheen" inside the caps like a light film of moisture. I took some very fine emery paper to the caps and rotors and wiped the inside off. I was getting code 10 at pin 7 and code 6 at pin 8. Cleared them both. At that time the car ran worse when it was warned up. I did not drive it again until today. Symptoms are there but are worse when it is cold. Again between 2500-3500 rpm the engine bogs. Also I have always had an occasional rough idle, now it's worse although if I put the car in neutral it smooths out. No codes tonight although I get nothing at pin 13. I have new caps, rotors and plugs ready to go but I hate to just throw things at the car. Fuel filter was changed about 6 weeks ago, air filters are also new. I am running the enhanced LH module but thanks to Dave's help I have not had a CEL since I reset the adaptations. Car has about 62K, newer harness and ETA although it's a non-ASR.

A while ago I pulled a couple of the plugs but they looked fine. It won't hurt to change them since I can't tell their age. The caps look pretty new. Also I have a new O2 sensor ready to install but I don't think that's the issue. Thoughts? I only have the blink code reader, anxiously awaiting to read which Chinese Clone C3 to buy.
 
Pull all 8 plug and inspect. Make sure you use the correct F8DC4 plugs (not FR8DC or other resistor plugs). New O2 would be a good idea but make sure you reset adaptation afterwards. Are any codes coming back regularly...?

:strawberry:
 
Pull all 8 plug and inspect. Make sure you use the correct F8DC4 plugs (not FR8DC or other resistor plugs). New O2 would be a good idea but make sure you reset adaptation afterwards. Are any codes coming back regularly...?

:strawberry:
Thanks.
That's my plan for this weekend. I do have the correct non-resistor plugs. Other than the codes I pulled last weekend no codes and those did not return after a day of driving.
 
Pull all 8 plug and inspect. Make sure you use the correct F8DC4 plugs (not FR8DC or other resistor plugs). New O2 would be a good idea but make sure you reset adaptation afterwards. Are any codes coming back regularly...?

:strawberry:

Once again the thing U Americans have against the R plugs I don't understand, this is nothing personal to you Dave or others that speak for the non resistor plugs. I have had problem in the past, slight missfireing some unsteady idle and
problem w emission at car inspection wich failed. When I got the car going this summer all I did apart from fixing the exhaust system was rotors and caps it already had Bosch Yttrium plugs since last it was on the road, I didn't change them,
I did not even change the upper harness, one is waiting to be mounted, also I have a new set of sparkplug leads, I didn't change thoose either. The car sailed through the car inspection not a singel missfire idle steady as a rock, performance so smooth from whafting along to highway runs at around 160- 200 km/h.

It shouldn't perform this well from what I read about this and what I thought myself, how can that be?
Two of my 500E buddies does run Bosch Iridium plugs, no issues at all car insp. and emission tests, no problemo, it can be said, they also have new caps and rotors. Well I'm wondering is it just us or are there others w same experience,,Roger
 
I don't think anyone(including the yanks) are against R plugs. This has been covered over and over. For some, so it would seem, have no issues using the F8RDC plugs. So much so that some owners have installed stock F8DC4 and HAD running issues, then replaced with R all is fine. Quite bizarre ! I don't think anyone here ever got to the bottom of this as to why this is so. Fact is though, F8DC4 is what the Factory says.
 
Don't shoot the messenger. The FSM specifically says the high voltage side of the coils should not have additional resistance added. Screen shot below from FSM at this link. Typical resistor plugs are 5k ohms, IIRC. If MB specifically says not to add 5k rotor arms, why would be be ok to add 5k plugs instead? Just because it's working fine now, doesn't mean your EZL will go belly-up down the road...

:oldman:
 

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Last night I decided that since I was pulling the plugs to inspect them I'd might as well replace them since I had 8 new ones ready to go. So far so good. The stumbling appears to be gone. No more shaking at idle. Oddly I noticed that for one of the plugs the connector was black, the others are dark red. One of the POs mechanics must have switched it out.

The plugs I removed did not look too bad, I can post pics. They were made in Spain. The new ones were made in Russia.
The car is running much much better.
 
The honeymoon did not last. After not driving the car for a few days the stumble/hesitation returned. More pronounced when the car is cold and first driven. Also the idle would pulsate. Much less pronounced when warm. I pulled code 4 on pin 19 yesterday and cleared it. No CEL. Today I decided to inspect the cover behind the rotors. They did no look too bad. Pics of one attached. I did try and clean them with electrical cleaner. There was some green fuzz inside but I could not see any cracks. The back of the rotors look good. Put it back together and drove it. Better but still a slight hesitation between 1700 and about 2200 rpm. Idle was not pulsating. My car has always had an occasional pulsating idle. So I don't think it's caps or rotors. We won't talk about the clod (me) that stripped one of those stupid rotor screw

G]
proxy.php
 
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These insulators are commonly overlooked ! They may have hairline cracks that's not visible to the eye, I would replace them if you're not aware of them being replaced before. Here's an article from Dave's archive about it : http://www.w124performance.com/docs/mb/other/ignition_misfiring_STAR.pdf
This article was originally identified and posted on this forum (well, when it was 500Espot.com).

The original thread is here:
http://www.500eboard.com/forums/showthread.php?146-ignition-problem

Dave just snagged & archived the article from 500Espot....

Cheers,
Gerry
 
Yanking GSXR's chain on a near-daily basis has become one of my favorite things in life.

500Espot was da bomb.... :nast:
 
So far today I have drove the car on 3 short trips. Idle is lumpy even when the car is warm. One other interesting and possibly related development, when I turned on the a/c on the second trip I was getting warm air as if the compressor was not engaging. One the third trip the a/c worked fine. Isn't there a speed sensor that talks to the compressor or vice versa? I don't see how this would have an affect on the idle when the a/c is off but at this point I am trying to look at every symptom. I have no reason to believe the insulators were replaced so I will put them on the list.


I should add it was about 75 degrees when I first drove it this am and it's about 83 now.
 
Hello everyone
First of all sorry for my english :) second i dont have w124 400/500E but i am the owner of w140 500SE 92. with m119.970 engine so comparable to 500E.
My question is: Is this thread are solved ? I have very similiar issues. Car when is cold run like a charm. Perfectly ! Idle are stable, no missfire, i feel much power when accelerate. But when reach 80C runs like a crap. Missfire, then finalyy die and cant run it. It crank but backfire, detonate fuel in exhaust. After few hours i can normaly run it.

What i did:

- New caps and rotors BERU
- New ignioton coils BERU
- New ignition wires BERU
- NEw spark plugs NGK (no resistors)
- New Cranskshaft position sensor Bosch
- New Camshaft position sensor EPS
- New timing chain and rails
- All new temperauter sensors 4,2,1 pin
- New lambda (o2) sensor bosch
- New crankshaft ventilaton hoses
- New intake maniflod gaskets
- New intake manifols plastic rings between 2parts intake manifold
- Cleanes throttle body
- New/Used EZL with the same part numbers
- New wiring harness engine/lower/throttle body, rewiered with silicone cables
- New fuel pressue regulator bosch
- Checked fuel pressuer on fuel pumps, 3 baron idle, 4 bars when accelerate.
And many more little things. but the problem is still unsolved. What left is MAF but is reaaly expensive part and hard to find, and computers (ECU, E-gas, etc.)

Errors:

Pin 4 (ECU) - No errors
Pin 17 (EZL) - 18 blinks - crankshaft position sensor L5 magnets not recognised

Pleashe help.
 
Wow - you've replaced a lot of parts already! Sounds like a lean misfire. :scratchchin:

Have you replaced the insulator behind the distributor cap/rotor?

Have you measured the resistance of all 8 spark plug boots (also, are these new, or old?)

Can you try a different MAF (used is ok), or different computers?

At this point you really need a good technician and a digital scanner that can read live data. There may be clues in the live data to indicate what the possible cause may be. Continuing to throw parts at it will get expensive...

:spend:
 
Thx for your reply.

I didn't replace insulators behind rotors, seems to be ok ,no cracks. But i think i will replace them in future. I dont try different mafs and computers already. I know the only good computer to diagnose MB is SD but i dont have any technican with SD in my town. Is BOSCH KTS can read live data from MB also ?
 
SDS/HHT can read live data, and the Snap-On MT2500 with Mercedes 2003 cartridge. There may be others that work too. I'm not familiar with the Bosch KTS, sorry.

The Chinese SDS is available fairly cheap, search the forum for more info on that...

:matrix:
 
Moon, your issue sounds like a broken CPS (Crankshaft Position Sensor) to me. Not only by the codes, as #18 is a fluke that always shows up when the engine is not running under "current codes" (digital readout)
However i know of a 500E car that had exactly that very same issue and it was a broken CPS. Stalled when hot and no restart possible until cooled for some time.
I would give it a try, cheap fixed from Bosch via the Aftermarket. Removal/Install is also quite easy if you have prober extensions for your ratched and IF the old CPS had a plastic case, not metal one. The Metal ones will corrode/seize over time and are a PITA to remove then. Ask me how i know LOL.
 
Hi Christian
CPS was my firs thought. I have orginal OEM CPS with plastic core and new one bosch with the same numbers with metal core. I replaced them both and no change. I also did reset ECU adaptation using led scanner. I suspect MAF becouse when i disconnect plug i can normally run the car when is hot and reach 90C and no missfires then. I have to go to star diagnosis to be sure becouse MAF to LH-jetronic is very expensive.
 
I suspect MAF becouse when i disconnect plug i can normally run the car when is hot and reach 90C and no missfires then. I have to go to star diagnosis to be sure becouse MAF to LH-jetronic is very expensive.
If the car runs normally with MAF disconnected, and runs poorly (misfire, etc) with it connected, it's VERY likely the MAF is bad.

You can get them used for much less than new, they show up on eBay frequently. I'd get either used, or a rebuilt MAF, not new...

:wormhole:
 
What Dave said :-)
Bosch Germany recently started to remanufacture them. I bought a "new" one of Ebay.de as a bargain. It came new in a Mercedes Box, but showed to be Bosch Remanufactured on a large white sticker. I dont know if thats the normal practice these days if your order them from Mercedes?
Aftermarket Dealers quoted me prices in the ballpark of 250-300€ here in germany for a remanufactured unit + core charge. New price at the dealer would be much higher i believe (600-800€???)
 
Trying to learn here.

Would a faulty MAF throw a code that could be read with a blink code reader?
 
Trying to learn here.

Would a faulty MAF throw a code that could be read with a blink code reader?
I believe there would be a code only if the MAF was completely dead. The MAF could be reading inaccurately and there would not be a code.

:cel:
 
Christian can you give me a link when i can buy remanufactured unit ? can be ebay or web shop where i can pay by credit card online.
Thx for help guys, i will post for updates.
 
Update
I was in garage run the car, ofcourse run great without problems, idle stable, quick trip, good power under accelearation. Engine reach 80C return to garage, give him little time to work on idle, everything seems to be ok (with maf disconnect) 10 minutes later starting missfire then died, ofcourse i cant run it. But i have new error code on pin 8 (base module)
LH-SFI control module (N3/1) voltage supply, open circuit.
Could be related to my problem ?
Also have 30 and 32 blinks on pin 6 something related to can communication i think.
 
gsxr thx for this post. It is very helpful. The problem is similiar or almost the same as mine. I checked this fuses before but replace base module is good advice.
 

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