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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Yes it does. Check out the pics with the misfire data. When there are multiple misfires, they're consistently on bank 1. 1-6 have higher misfire data compared to 7-12.

Plus these V12's are so stupid sensitive that its hard to tell. It would be significantly nicer (and easier) if this engine was split into four banks, with four of everything....but then the prices would quadruple. Good thing MB didn't do it that way.
 

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2006 S600
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243 Posts
The V12TT uses MAP, not MAF, sensors.

The most important one is on the intake manifold, and reads MAP for ALL cylinders.

I think OP calls this the post throttle MAP.

Nick
 

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2003 S500
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2,512 Posts
Extremely unlikely in this case (providing the car has the correct oil, changed as required), but one cause for occasional idle misfire is a sticking intake valve. I'm not an expert, but I don't remember ever hearing of a sticking valve on a newer Mercedes.

I agree that a small air leak very close to cylinder four seems to be a possible cause. Doesn't the computer sense misfires by measuring the voltage of the discharge tail thru the plugs? If so, wouldn't that make a lean mix in that cylinder the most likely cause for the error code?
 

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2005 S600
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533 Posts
At your car's age, the injectors themselves are also suspect. A sticking injector that doesn't pulse long enough can cause a lean misfire...

IF you determine that you need to address the injectors, then I recommend this guy:

For a fraction of what new injectors cost (and you've got 12), Paul will clean, rebuild, flow test and balance your injectors. He's done injectors on two of my Volvos and the results are impressive.

Even a few % difference in flow causes a bit of flutter at idle, and less power overall as some cylinders are a bit lean and some a bit rich (the fuel trim is based on O2 sensor readings, and applied across all injectors evenly.)
 

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2000 S430, 2003 S430, 2000 S500, 2003 S600 TT, and 2005 E320 CDI
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Discussion Starter #46 (Edited)
Hmm...from the sounds of things, we have two possibilities, and it could be both.

1.) air leak, at least at cylinder #4
2.) injectors need some love

And indeed, this engine does use MAP's vs. MAF's. All MAP's have been replaced at some point recently, and the new post-throttle MAP is about a week and a half old. Currently the original one is in there, just so I could do a comparison test (readings are virtually identical).

If it is #1, i. e. an air leak, am I looking at replacing the intake manifold gaskets here? I haven't yet tried a smoke test, and that sounds like a good idea to do. Time to buy a pack o' cigarettes for the first time (no, I don't smoke)....

I also called up Paul over at Hurst Injector Service. He suggested something interesting. If an injector's flowing a bit rich, the fuel controller for that bank will lean-out the fuel-air mixture for the other cylinders...thus causing them to run lean, and thus possibly causing misfires. Given that I have often seen Cylinders 1, 2, 3, 5, and 6 go down, including in the most recent picture set...those symptoms would also correlate with Paul's idea here. He mentioned this before I told him about Cylinders 1, 2, 3, 5, and 6. When I then mentioned this observation to him, he said, "hmm...it's possible...that does fit what you're seeing."

So, all 12 injectors are going to get sent to Paul for cleaning. He agrees with @Astro14 in that they probably need it at this age. For $203 including shipping, I'd say that's not bad money at all. At least it eliminates one potential cause. If it's not that...then I keep troubleshooting.
 

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W164 GL450, W221 S550, R230 SL600TT, R170 SLK230, W140 S500, More
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I hope that fresh clean injectors will solve this and make it run happy!! I did my spark plugs and one coilpack earlier this year, and my V12TT couldn't be happier. Thank God!
 

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am I looking at replacing the intake manifold gaskets here?
Hi T,

It could be around # 4 Cyl Port yes, but you do want to verify with smoke generator before buying any more parts, tearing down Manifolds or going for Injectors etc ;)

If you think it may be Injector, swap it with another Cyl first then see if that one becomes highest misfire count ;)

Bearing in mind this one Bank has higher Misfire Count than the other, it does look like an Air Leak, and likely in the area of # 4 Cylinders Manifold Runner, or maybe some remotely placed Vac Component / Lines to it if there is a direct Connection nearest to # 4 Port

HTH,
 

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2000 S430, 2003 S430, 2000 S500, 2003 S600 TT, and 2005 E320 CDI
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Discussion Starter #49
Thanks, Dave. I'll do the smoke test this weekend.
 

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Discussion Starter #50
Couldn't do the smoke test due to too much wind. So, I got the fuel injectors out of there. The #9 injector broke while getting them out, but all the others came out OK. Apparently they're made by Siemens, though they don't have any Siemens marks on them, but both Paul and Google said this, so I trust that this is correct. Anyway, they're getting sent to Paul for maintenance, and the #9 one that broke, that'll be $85 for a new one from MBOemParts.com.
 

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Discussion Starter #51
Just heard from Paul at Hurst Injector Service today. He reports that the internal filters in all 11 injectors were so bad that if you touch those filters, they would crumble. The spray patterns were horrible, all over the place. I guess that's what happens after 175,000 miles of usage. He cleaned 'em all and put new, more durable stainless-steel filters in 'em, and they're now all flowing 92 cc's, plus-or-minus half a cc. Just like brand-new. He's going to ship them back tomorrow.

The replacement new injector for broken one out of Cylinder #9 is getting ordered today as well.
 

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Discussion Starter #53
OK, got all the injectors back, as well as the new one for cylinder #9. One of the little clips that holds the injector in place got lost, so I just went ahead and ordered 12 new Genuine-MB ones. Not that the other 11 were broken or even "bad", but the older ones had a little rust on 'em, and the new ones are not expensive, so why not? Da Benz, you know. Anyway, the fuel injector rail is now reassembled and ready for reinstallation.

While I was at it, though, I noticed something else. There's all sorts of gunk and stuff in the nooks, crannies, and valleys where the intake manifold sits. Yecch. But this is expected after 175,000 miles in a natural woodlands area where the trees lose their leaves every year. Also, one of the vacuum hoses--you know the ones, the translucent white/blue ones that turn yellow with age--runs under the intake manifold. That thing looks like it's all of 175,000 miles old, too, and it's the one that I couldn't get to.

So, last night, off came the intake manifold. It's actually rather easy to get off, once the fuel rail is off. It's 14 easily-accessible Torx bolts. Lifts right off. Torque is fairly light on these bolts, though I noticed that some of the manifold bolts weren't as tough to get off as others, so perhaps, after all those miles and between 16 and 17 years, clamping force had gone from factory tightness to somewhere a little looser. Perhaps this allowed for that tiny bit of leakage that I was thinking may have happened, or maybe there's no leakage and I'm smoking crack. Either way, we will make sure that's squared away as well.

New Genuine-MB intake manifold gaskets for either side were ordered last night from MBOemParts. Same goes for the little rubber connectors for those translucent vacuum hoses. Grabbed a good, strong vacuum cleaner and vacuumed out all the gunk from the nooks and crannies. There is a towel covering the now-exposed cylinder intake ports, to keep any debris from falling in while waiting for parts to arrive.

Removed the temperature and pressure sensors from the manifold and got to scrubbing it with a toothbrush and some kerosene. Washed it with hot, soapy water after that and let it dry overnight. The intake manifold is now clean, dry, and likewise ready for re-installation once the manifold gaskets arrive.

This rabbit-hole just keeps getting deeper and deeper, but hopefully doing all this will really sort this car out.
 

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2005 S600
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533 Posts
I look forward to hearing your results/observations when this is all done! Thanks!
 

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2009 E350 4M Avant Garde, My Mistress 2002 S600, Wife 2014 C300 4M Avant Garde with AMG
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The intake manifold shank type bolts on this engine are yield torqued, and should be replaced when removing/reinstalling.
Been there, done that.
 

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2000 S430, 2003 S430, 2000 S500, 2003 S600 TT, and 2005 E320 CDI
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Discussion Starter #57 (Edited)
Oh, really? Thanks for the heads-up. Hopefully I'll be able to pick those up on Monday from the local dealership reasonably, and hopefully they have 'em in stock.

Just got through looking on several MB dealer sites. I can find the intake manifold. But the only bolt I'm seeing is for the 2013-2019 6.0L (M279) motors. That part # is 000000007064. My guess is that they'll fit, but I'm not sure if there's a change in the M279 engine with the intake manifolds where the bolts would be different from the M275. Any ideas?
 

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Discussion Starter #58
OK, I'd ordered all 14 bolts. The dealership did put in the order correctly (they showed me). The order was indeed for 14 bolts.

Good thing I counted, though. Turns out that only 13 got sent from the supply depot to the dealership! I counted 'em up in the sealed bag before I left, and I had the guy at the parts counter verify, just to make sure my eyes weren't fooling me. So, the 14th is on the way and should arrive by Tuesday.

In the meantime, the intake manifold is on, with the brand-new gaskets. The 13 bolts that I got are gently hand-tightened on, just to hold the manifold in place. The empty bolt hole is (if you're facing the front of the car) at the left front, where the location's easiest to get to. I'll torque it all down when the 14th arrives. Things look so much better when they're cleaned up. By the way, all of those translucent vacuum hoses have now been replaced, every last one, along with whatever rubber connectors also needed replacing.

And now it's just a matter of putting the jigsaw puzzle back together. I can only do this on the weekends, due to the sun setting far too soon at night these days. But we're slowly making progress.
 

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2000 S430, 2003 S430, 2000 S500, 2003 S600 TT, and 2005 E320 CDI
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Discussion Starter #59 (Edited)
Per WIS, the part # for the M275 intake manifold bolts is 000000001424 (that's 8 zeros, followed by 1424), and its torque specification is 8 N-m. Doesn't take much. The M275 engine takes 14 of these bolts.

Just torqued it all down. Also got the fuel rail in. The plastic thingamabob that channels the wiring harness cracked in a couple of places, and I know it doesn't matter too much, but a new one of those is now also on the way. Also doing this maintenance item preemptively, since I'm in there already.


And the adventure continues....
 

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2005 SL65 plus 13 other non MB toys
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713 Posts
It has been a while but don鈥檛 torque to yield bolts get tightened to a torque value then turned a certain degree? In the past, I always replaced torque to yield bolts with ARP fasteners.
 
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