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Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4572
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
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Engine appears to change timing and begins to miss fire, occurs

Customer Question

engine appears to change timing and begins to miss fire, occurs if stepping on accelerator to pass or during slowing then accelerating. Check engine light has been on for a long time but the engine missing is a recent issue.
JA: The mechanics have tons of experience in that area. Do you happen to have the code?
Customer: No codes
JA: Not a problem. You can work with the Mercedes Mechanic to figure that out. Are you hoping to fix this yourself?
Customer: yes
JA: Great! What have you tried so far?
Customer: checked gas cap only no other trouble shooting
JA: Anything else I can tell the Mercedes Mechanic before I connect you two?
Customer: no
JA: I'm sending you to a secure page on JustAnswer so you can place the $5 fully refundable deposit now. While you're filling out that form, I'll tell the Mercedes Mechanic about your situation and connect you two.
Submitted: 1 year ago.
Category: Mercedes
Expert:  Lou P. master tech replied 1 year ago.
Hello, i can help with this issue, i will need to know what year and model and what engine you have please. also was a crank sensor replaced at all recently or was fuel filled up recently?
Customer: replied 1 year ago.
2000 230C Kompressor;No crank sensor replaced. Just a note, the engine cranks slow for a period of time before ignition. Almost like a low power battery, but battery is 100%
Expert:  Lou P. master tech replied 1 year ago.
ok, you have the 4 cylinder m111 engine, what scanner are you using to check for codes? if it starts to misfire there has to be a misfire code?
Customer: replied 1 year ago.
I do not have a scanner to check any codes.
I have made many fuel fill ups all with no changes so I do not think it is the fuel.
Engine will run fine at constant speeds. At stope, it will some times miss and almost stop, then returns to smooth idle.
Sometime when accelerating the engine will miss so bad I have to pull over and stop. By turning off the engine and restoring the engine runs smoothly. Whatever is causing the issue is temporarily fixed by restarting the engine.
Customer: replied 1 year ago.
Waiting for reply
Expert:  Lou P. master tech replied 1 year ago.
ok, so the easiest thing to check is for a bad coil or wire, remove the red center valve cover 'cover' that covers the plugs and wires, start the car and let it run, spray the wires and coils with some water from a spray bottle and listen for loud snapping to indicate that there is a failed coil or wire. i think the issue will be easy to find considering it happens under a load.
Expert:  Lou P. master tech replied 1 year ago.
im a slow typer.............
Expert:  Lou P. master tech replied 1 year ago.
let me know if you do or do not find anything with the coils and wires. Please take a second and click the STARS above and rate my service 4 or 5 stars if you feel I have been helpful and please request me in the future. Keep in mind then when you rate it does not end our conversation. you can still return here to me for follow up information if needed, Lou.Thanks for choosing just answer. Lou. also , if you feel i deserve one , BONUSES are GREATLY APPRECIATED !
Customer: replied 1 year ago.
Would bad wires always cause the miss fire. This appears to be intermittent. I will give the wires a test tomorrow since it is 1030pm here.How would bad wires cause the timing to appear to change and then reset or fix the problem by restarting the engine?
Expert:  Lou P. master tech replied 1 year ago.
why do you think the timing is changing? the engine module and sensors are very complex, timing in these cars are not adjustable electronically, and the only timing that can be a issue is with the timing chain but then there would be a fault code and the car would not run at all. and no , bad wires or coils dont always fail and cause a issue every time, there are a lot of instances that the ignition system can be bad but only act up when the temperature is , cold, hot ,wet, dry, freezing, so we dont know for sure until we check them, if they are ok then we pull and check the spark plugs for wear and blackness. misfiring is either due to ignition or fuel.
Expert:  Lou P. master tech replied 1 year ago.
when the engine starts to misfire the ecm will stop that cylinder from firing, that is why shutting it off and re-starting it makes it run better for the interim.
Customer: replied 1 year ago.
Thanks, ***** ***** try your suggestion in the am.
Expert:  Lou P. master tech replied 1 year ago.
ok, i am on almost all the time, so give me some time to reply when you log on, i will ALWAYS check back. Please take a second and click the STARS above and rate my service 4 or 5 stars if you feel I have been helpful and please request me in the future. Keep in mind then when you rate it does not end our conversation. you can still return here to me for follow up information if needed, Lou.Thanks for choosing just answer. Lou. also , if you feel i deserve one , BONUSES are GREATLY APPRECIATED !
Customer: replied 1 year ago.
No noticiable change i engine idea until I drive. The engine takes a lot of cranking to start.
Any other ideas?
Expert:  Lou P. master tech replied 1 year ago.
did you spray water as i instructed?
Customer: replied 1 year ago.
No as it was wet and rainy out this morning I figured the posture was enough to see if any thing changed. Will direct spraying of water make a difference? If so I will give it a go.Is there anyway to test the coils?
Expert:  Lou P. master tech replied 1 year ago.
yes direct spray my man , and water is the quickest way to test the coils, sometimes to oil can leak through the valve cover spark plug seals and soak the wires at the plugs so make sure you also remove all the coils and wires and check for oil or white arcing marks where the rubber may be broken.
Customer: replied 1 year ago.
Thanks I will give it a shot tomorrow and follow up with you.
Expert:  Lou P. master tech replied 1 year ago.
ok let me know what you do and do not find.
Customer: replied 1 year ago.
totally sprayed the colts and wires with spray bottle- no change in engine.
Expert:  Lou P. master tech replied 1 year ago.
ok, good so far, then did you also pull and check the spark plug wires and spark plugs to see if there was oil on them?if all is ok then i suggest you unplug the mass air flow sensor and then drive the car and see if it does the misfiring.
Customer: replied 1 year ago.
Area around plus and wires is like new. I will pull plugs in the am.Where is the mass air flow meter?
Expert:  Lou P. master tech replied 1 year ago.
mass air flow is the round black tube with the 5 wires coming out of it in the intake piping. https://www.google.com/search?q=2000+c230+kompressor+mass+air+flow+sensor&espv=2&biw=1366&bih=681&source=lnms&tbm=isch&sa=X&ved=0ahUKEwimpYTYoqHMAhULJx4KHehHD7oQ_AUICCgD
Customer: replied 1 year ago.
Thank you I will try it.
Expert:  Lou P. master tech replied 1 year ago.
also going back over our chat you stated that the check engine light has been on for a long time before this issue occured, what were the codes?
Customer: replied 1 year ago.
No codes as I do not have a code reader. Can I buy one some place?
Expert:  Lou P. master tech replied 1 year ago.
you can actually rent one from autozone. they will only ask for a deposit and they will allow you full refund when you return it also you can drive there and they will read the codes for free