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W212 E350 CDI rev needle wobble

Mancstar

Mancstar

Active Member
Joined
Sep 18, 2019
Messages
163
Location
Manchester
Car
W212 E350 CDI
<div class="bbWrapper">Hi. I have a W212 E350 CDI 2009.<br /> Have an issue with the rev needle bouncing/wobbling ever so slightly (around 50 to 100 rpm) when car is both idle and when driving at a constant speed.<br /> The engine does not rev up/down when the needle bounces.<br /> This does effect the performance at all and car is a dream to drive, pulls nicely and on demand.<br /> If the accelerator is tapped very quickly when the needle settles back down it is fine for a few seconds then starts the bounce again.<br /> Does seem to stop when revving at over 3000rpm although it could be its hard to keep a constant enough speed when over revving the car..<br /> Car idles fine and no issues whatsoever with engine etc.<br /> Any help or pointers will be appreciated am very ocd with keeping the car in tip top condition. Have located a post from the past but seems there was no resolution.<br /> <br /> Have attached video to post to show.. <form action="/misc/cookies?update=1&amp;add=1" method="post" class="bbMediaJustifier" data-xf-init="cookie-consent-form ajax-submit" data-redirect="off" data-media-site-id="youtube" data-media-key="5ixB_OrlaNs" > <input type="hidden" name="_xfToken" value="1741942817,eeccbf2c976e1da1c56998b29c4a3dd9" /> <div class="block-rowMessage block-rowMessage--alt"> <div class="u-dimmed u-smaller"> To view this content we will need your consent to set third party cookies.<br> For more detailed information, see our <a href="/help/cookies">cookies page</a>. </div> <div class="u-inputSpacer"> <button type="submit" class="button button--small"><span class="button-text">Accept third party cookies</span></button> </div> <input type="hidden" name="consent[_third_party]" value="1" /> <input type="hidden" name="_xfRedirect" value="" /> </div> <template class="js-embedHtml"><span data-s9e-mediaembed="youtube"><span><iframe allowfullscreen="" scrolling="no" style="background:url(https://i.ytimg.com/vi/5ixB_OrlaNs/hqdefault.jpg) 50% 50% / cover" src="https://www.youtube.com/embed/5ixB_OrlaNs"></iframe></span></span></template> </form></div>
 
<div class="bbWrapper">Most decent code readers or STAR will tell you what the exact RPM is which would be a start to determine if it is the engine or an electronics issue.</div>
 
<div class="bbWrapper">Done that already engine rpm does not increase/decrease in line with 'the wobble'. <br /> An old post on another forum has suggested better quality fuel from BP/Shell which ill be trying once my tank runs low.</div>
 
<div class="bbWrapper">If the engine revs are stable then the wobble is being generated somewhere in the electronics, changing your fuel will have absolutely no effect on the tacho needle or it's associated electronics. <br /> <br /> I would talk to someone like these guys<br /> <a href="https://cartronix.co.uk/" target="_blank" class="link link--external" rel="nofollow ugc noopener">Speedo Repair | Instrument Cluster Repair | Dashpod Repair | Cartronix</a><br /> <a href="http://www.clusterrepairsuk.co.uk/" target="_blank" class="link link--external" rel="nofollow ugc noopener">The Instrument Cluster Repair Specialist, Cluster Repairs UK</a></div>
 
<div class="bbWrapper"><blockquote data-attributes="member: 148902" data-quote="Mancstar" data-source="post: 2800739" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/goto/post?id=2800739" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2800739">Mancstar said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> Hi. I have a W212 E350 CDI 2009.<br /> Have an issue with the rev needle bouncing/wobbling ever so slightly (around 50 to 100 rpm) when car is both idle and when driving at a constant speed. </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote>My 2011 W212 E350 CDI tacho did exactly the same thing from new. I sold it with 35,000 miles on the clock and it was still doing it - no more and no less. I concluded that it was a characteristic of the model, and suggest you ignore it too.</div>
 
<div class="bbWrapper">Look closely at the needle and the markings. 50 would be a movement from one marking to the middle towards the next marking.<br /> <br /> Looking at this it seems the variance is much less than 50, I would wager a variance of about 20-30 which corresponds to an engine rpm +- 10-15rpm which is entirely normal.<br /> <br /> If however you notice it fluctuating more sometimes then this could be the issue: <a href="https://workshop-manuals.com/mercedesbenz/c_350_(204.056)/v6-3.5l_(272.961)/instrument_panel_gauges_and_warning_indicators/tachometer/component_information/technical_service_bulletins/all_technical_service_bulletins_for_tachometer/li54-30_p-049068/mar/10/instruments_tachometer_fluctuates_by_approx._100rpm/" target="_blank" class="link link--external" rel="nofollow ugc noopener">Mercedes Benz Workshop Manuals &gt; C 350 (204.056) V6-3.5L (272.961) (2008) &gt; Instrument Panel, Gauges and Warning Indicators &gt; Tachometer &gt; Component Information &gt; Technical Service Bulletins &gt; All Technical Service Bulletins for Tachometer: &gt; LI54-30_P-049068 &gt; Mar &gt; 10 &gt; Instruments - Tachometer Fluctuates By Approx. 100rpm</a></div>
 
<div class="bbWrapper">Thanks pillow for the work manual and your thoughts.<br /> St13phil - I dont wanna sell my baby!!<br /> Have been observing more today and you are correct with it being a variance of less than 30 rpm. <br /> Should an obd scanner show the 10/15 rpm normal variance as this wasn't the case when it was checked - have ordered the icarsoft scanner so gonna double check this.<br /> Im thinking as the worksheet suggests 'dirt stuck in the stepper motor' this could be the beginning of that specific problem. Cars booked in at Mercedes next week so will keep yall updated with any news.</div>
 
<div class="bbWrapper"><blockquote data-attributes="member: 148902" data-quote="Mancstar" data-source="post: 2801131" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/goto/post?id=2801131" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2801131">Mancstar said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> St13phil - I dont wanna sell my baby!! </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote>I'm suggesting you do the precise opposite: my experience was that it wasn't a harbinger of some major fault, rather that it was just &quot;one of those things&quot;. It may go against the grain, but I think it can be safely ignored as an instrumentation fault.</div>
 
<div class="bbWrapper">My C Class does exactly the same. Didn't notice it when i road tested it but its there. I've gone down the <i>&quot;I've done 4000 miles in 6 weeks and nothing has gone wrong so I'll ignore it&quot;</i> route <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f600.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":D" title="Big Grin :D" data-smilie="8"data-shortname=":D" /></div>
 
<div class="bbWrapper">Ill check ours and report back.</div>
 
<div class="bbWrapper">St13phil - Well I am hoping its 'just one of those things' and nothing more! Im sure I can learn to live with it once I have ruled out possible causes.<br /> Can I ask how long you drove with the problem and if it got any worse?</div>
 
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<div class="bbWrapper"><blockquote data-attributes="member: 133891" data-quote="Landie1" data-source="post: 2801138" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/goto/post?id=2801138" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2801138">Landie1 said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> My C Class does exactly the same. Didn't notice it when i road tested it but its there. I've gone down the <i>&quot;I've done 4000 miles in 6 weeks and nothing has gone wrong so I'll ignore it&quot;</i> route <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f600.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":D" title="Big Grin :D" data-smilie="8"data-shortname=":D" /> </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote>Kinda glad to hear that your in the same boat! It probs will take me 6 months to do 4000 miles!</div>
 
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<div class="bbWrapper"><blockquote data-attributes="member: 148902" data-quote="Mancstar" data-source="post: 2801143" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/goto/post?id=2801143" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2801143">Mancstar said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> Can I ask how long you drove with the problem and if it got any worse? </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote>Roughly 30,000 miles and 30 months - and it didn't change through that period.</div>
 
<div class="bbWrapper"><blockquote data-attributes="member: 148902" data-quote="Mancstar" data-source="post: 2801131" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/goto/post?id=2801131" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2801131">Mancstar said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> Thanks pillow for the work manual and your thoughts.<br /> St13phil - I dont wanna sell my baby!!<br /> Have been observing more today and you are correct with it being a variance of less than 30 rpm.<br /> Should an obd scanner show the 10/15 rpm normal variance as this wasn't the case when it was checked - have ordered the icarsoft scanner so gonna double check this.<br /> Im thinking as the worksheet suggests 'dirt stuck in the stepper motor' this could be the beginning of that specific problem. Cars booked in at Mercedes next week so will keep yall updated with any news. </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote>An obd scanner could potentially show one of two types of rpm. One is essentially the 'demanded' rpm that the ECU is trying to achieve. The other is the actual rpm as reported by the crank position sensor. The easy way to tell the difference is the demanded rpm will be a fixed value, e.g 600rpm and won't change. The actual rpm will update on your obd tool every second or so and you'll see it fluctuating a bit, e.g 590rpm 598rpm, 612rpm, 601rpm.</div>
 
<div class="bbWrapper"><blockquote data-attributes="member: 144009" data-quote="pillow" data-source="post: 2801216" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/goto/post?id=2801216" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2801216">pillow said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> An obd scanner could potentially show one of two types of rpm. One is essentially the 'demanded' rpm that the ECU is trying to achieve. The other is the actual rpm as reported by the crank position sensor. The easy way to tell the difference is the demanded rpm will be a fixed value, e.g 600rpm and won't change. The actual rpm will update on your obd tool every second or so and you'll see it fluctuating a bit, e.g 590rpm 598rpm, 612rpm, 601rpm. </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote><br /> The cheapo scanner I used showed fixed rpm. Heard good things about the Icarsoft scanner so cant wait to try that out. Hoping it will show rpm fluctuating slightly inline with the wobbly needle. <br /> Had the bonnet open earlier and I swear I could hear an ever so slight change in engine tone every couple of seconds, called the wife over and she thinks im trippin! Its Friday night and im looking at front grills and boot lip spoilers.</div>
 
<div class="bbWrapper"><blockquote data-attributes="member: 148902" data-quote="Mancstar" data-source="post: 2801230" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch"> <div class="bbCodeBlock-title"> <a href="/goto/post?id=2801230" class="bbCodeBlock-sourceJump" rel="nofollow" data-xf-click="attribution" data-content-selector="#post-2801230">Mancstar said:</a> </div> <div class="bbCodeBlock-content"> <div class="bbCodeBlock-expandContent js-expandContent "> The cheapo scanner I used showed fixed rpm. Heard good things about the Icarsoft scanner so cant wait to try that out. Hoping it will show rpm fluctuating slightly inline with the wobbly needle.<br /> Had the bonnet open earlier and I swear I could hear an ever so slight change in engine tone every couple of seconds, called the wife over and she thinks im trippin! Its Friday night and im looking at front grills and boot lip spoilers. </div> <div class="bbCodeBlock-expandLink js-expandLink"><a role="button" tabindex="0">Click to expand...</a></div> </div> </blockquote><br /> It's completely normal for any engine to fluctuate ever so slightly. The icarsoft tool is a decent one and will actually show you both kinds of rpm depending on which monitoring section you're looking at on it.</div>
 
<div class="bbWrapper">Update - used a better scanner to check engine rpm. Idle fluctuates between 590 - 610 rpm on scanner so needle wobble seems to be slightly over-sensitive to the rpm fluctuation.<br /> Will learn to live with it seems to be one of those things the car does.<br /> Have rinsed a full tank of premium diesel which made no difference.<br /> Thanks again to all replies, Merc drivers are the best!</div>
 
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