had car 2 years, always had vibration in gear at idle. Replaced all injectors and all tune up parts and fuel filter. No change, car developed hard start condition 20000 miles later . EAH valve was leaking, replaced that, then 1 fuel pump, then OVP, then check valves. Other than other fuel pump, starting to get to expensive parts and am tired of throwing money at it. Any help would be GREATLY appreciated. Love car and is in great ccondition but starting to get to more money than really want to invest.
1990 300E hard starting
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I would start off by doing a general tune up. Replace the cap, rotor, plugs and wires. Search the forum for the correct plugs to use. You will not be able to buy them at any local parts store. As for the vibration.....it is caused by failed motor mounts. Again, search the forum for the DIY steps to replace them. Not a difficult job at all.
Good Luck,
Jayare
Good Luck,
Jayare
Thanks for your reply. Did all that 20.000 miles ago all Bosch parts. Car runs great but takes a long time to get started, 3 to 5 or more trys probably 10 to 15 seconds each. Then has to run maybe 3 to 5 mins before cleared out. If turned off and started back up within say 5 minutes starts fine. If let sit takes a while to get started even after operating temp reached.
When the car is running, how does it perform? Sluggish accel until you hit about 1800 rpm?
Jayare
Pardon me if I'm misreading here but you've said 20,000 miles twice. With normal service intervals of between five and six thousand miles wouldn't the service parts you mentioned be worn out anyway if these intervals were skipped - by now? Do you mean 2000 miles?
After reading your original reply and listening to the car run I decided to check plugs. All had carbon deposit and possibly signs of heat, number three was really bad ceramic was broken. Replaced plugs and have much smoother idle but I believe plug trouble has been caused by the problem the car is now having. I am curious however about # 3 plug.
I would have to say yes to your question about sluggish at low RPM. Seems to hesitate to rev and still hard starting. While had plugs checked compression and by my guage (which I don't trust to be entirely accurate) I have about 180 in every cylinder
I would have to say yes to your question about sluggish at low RPM. Seems to hesitate to rev and still hard starting. While had plugs checked compression and by my guage (which I don't trust to be entirely accurate) I have about 180 in every cylinder
Here are a couple of points to consider. The ignition system in these cars calls for pure copper, non-resistor plugs. The "plug" end of the spark plug wires is a resistor. So, if you are running resistor plugs + the resistor wires, you are killing the intensity of the spark. NGK BP6EFS (or BP5EFS - hotter plug) and Denso T20EP-U plugs are correct to OEM spec. The NGK's can be aquired at clubplug.com and the Denso's from Amazon both for less than $2 ea.
Secondly, you'll want to use the search feature of the forum and look up "air/fuel ratio adjustment". I suspect your car runs fairly well when cold, but begins to get sluggish as it warms to operating temperature.
If the car is running rich after it has warmed up, the performance will be sluggish until you hit 1500 - 1800 rpm. Leaning out the mixture a touch will solve this. By reviewing the suggested threads, you will get a good understanding of how others have solved this common problem.
Good Luck and keep us posted,
Jayare
I am going to do the things you have mentioned, however I dont believe you understand my real problem is getting the car started. The starter has to run 10 or more seconds 5 to 8 times to ever get car started, then engine must run 5 to 10 minutes before it will take any acceleration. Once running it runs good, see original post for all parts I have already replaced trying to fix starting problem. The one part I forgot to mention was the cold start injector. I am relatively sure it is a fuel problem.
Thank you for taking time out to help! I am at my wits end and going broke throwing money at it.
Thank you for taking time out to help! I am at my wits end and going broke throwing money at it.
I have worked on cars for 38 years (obviously not Mercedes) . I would have never believed plugs could have caused this, but did not know about resistor wires. Thanks so much for your help. Adjusted air fuel by ear until can purchase meter that reads duty cycle, but now I can drive the car . Can the idle be adjusted on this car and should it speed up when the AC is turned on? The idle will not go above 700 no matter how I adjust air fuel ( although I did not stray much past 1 turn either direction not having a meter) and it does not go up when AC is turned on. Car will almost die in gear with AC on.
Idle speed is controlled by computer. You can't adjust it. With A/C on, the computer will compensate for the additional drag. Look for vacuum leaks. Easy to use a non-lit propane torch. Place the nozzle at all the vac connections and also at each injector. Idle goes up, that is a problem area. A full turn on the A/F adjuster nut is a huge swing. You might try going back rich (clock wise) about half turn. Do all this with the motor at operating temp.
Report back and good luck,
Jayare
Report back and good luck,
Jayare
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6 Posts
I experienced a similar problem a few years ago on my 1991 300SL and solved the problem with a new ignition coil. No trouble since.
This may not sound like the correct action but the problem sure seemed to be a fuel system problem but no fuels systems parts were replaced only the coil.
If you have not replaced the coil yet you should real think about doing it.
This may not sound like the correct action but the problem sure seemed to be a fuel system problem but no fuels systems parts were replaced only the coil.
If you have not replaced the coil yet you should real think about doing it.
I am trying to set the air fuel mixture. I bought a new multimeter just for this purpose, however it will not produce a duty cycle reading . I am only getting about 1.7 volts between the #2 and #3 pins on the x11 connector. By my calculations based on things I have read , I should be reading around 7 volts to be at the proper duty cycle. My meter will not accurately read duty cycle below 3 volts. Any suggestions?
This link will help you
http://www.benzworld.org/forums/w12...77-fuel-mixture-adjustment-2.html#post2464220
There is also a meter that has a duty cycle setting available at Lowes for small money. Under $40 if I recall correctly.
Jayare
i have a 1991 300e 4matic and was having starting issues among other things. Check your ovp relay. if you have jumped your car. notorious for going bad. little red box with 2 spade fuses in mine behind battery passenger side. not sure if urs will b the same cheap fix and helps numerous things function.
http://www.benzworld.org/forums/w124-e-ce-d-td-class/1547478-92-300e-4matic-cold-start-problem.html
http://www.benzworld.org/forums/w124-e-ce-d-td-class/1547478-92-300e-4matic-cold-start-problem.html
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