Hi,We have a 1994 E420 thatwe just bought last month. Whenwe got it, it cranked just fine.Now, we have a problem getting it to start when the engine is warm. We drive it around town, stop a few places, go to crank it up and it struggles to start up again. Engine turns over but I have to try sometimes 3 times before it catches and starts and you feel a little rough idle for about 3 seconds. Once it starts though it runs beautifully and no problems at all. Idlessmooth at stop lights and hasgreat acceleration. Cold starting is fine, no problems. I had a mercedes mechanic look at it last week and he suggested tune up and the plugs were changed along with new rotors and caps. He suggested that the injectorsmight beclogged and maybe a little leakdown and suggested I run injector cleaner in it a few times with fill up. Said this happens with older cars from build up. We just don't think that is the problem because it cranked just fine hot until about a week ago.
Is there anything we need to be aware of on this car? We are trying to learn about this car so any help would be great!!!Car has 109,000 miles and otherwise drives like a dream. PLEASE HELP AS WE DON'T WANT TO BE TAKEN FOR A RIDE AT THE SHOP!

 

Sounds like you are already getting rode at the shop.You could have changed the plugs,diy job.how much did they hit you for?
Two possibilities to check first,hot start problem has the coolant level been checked and how hot is the car running?over heating engines will be harder to start.Next look at the threads on cps,a faulty cps will show the symptoms you discribe plus stalling issues at times.You stop go into a store come out the car fails to start,let it cool starts fine,repeat. cheap fix on your car you need the production date or chassis number when you order from autohausaz.com.
hope this helps
suggestion don't use the dealer
try the cps repair yourself,they are a common failure part on the benz.
it is the crank shaft position sensor.
ohlord

 

Hi, thanks for replying. Problem is getting worse!!!!!

They overcharged us greatly to the sum of 500 bucks for everything at the dealer. Wrong move on our part taking it there. The car runs at normal temps...doesn't go over the 80 mark even on hot days. Although don't know if this will make a difference, the person we got it from told us that they had just replaced a hose because it broke and the engine had overheated but no damage. It really runs great and is smooth as silk but this "hot start" problem is so annoying!!!
Just tonight, I drive it to the grocery store, stay inside for about half an hour, come out and the car turns over but won't catch. I try thisthree times and then it finally turns over and cranks. But after sitting tonight, it will start just fine in the morning. My whole family loves this Benz even more than the 300E we have.....just want to get it running back like it was!
Will look at the cps.
Thanks for the help!!!!!

 

I would also join the benz forums at mbworld.org and benzworld.org look for the forums on your year model,this is classic CPS symptoms and at 13 years it might just be failing,when they do it seems that heat cycles show up as the chief issue.Look up the threads on cps issues on those other forums.
Yes $500 for plugs is bad,when plugs only run about $2.79 each and it is a pretty easy diy job,but that is water under the bridge now,so let it go.I always tell people you paid for a lesson,pay heed and never let it happen again.Always check the forums first,for repair info ,diy articles,parts prices and deals,and if you are not the diy type find a good independent repair shop,by asking the members here and on the two mentioned above.
ohlord