I have a '94 E420 with about 241k miles. Lately (last few weeks) whenever I go to start the car it will idle with extremely low rpm, run rough, and then die. Sometimes this doesn't happen; it's hit or miss. Sometimes it starts up fine, idles nicely and I can drive it with no problem and it will be that way for days, weeks, months.
But within the last few weeks it seems that whenever I start the car it will experience the rough, eratic idle. I've searched the threads here and I have changed the spark plugs and fuel filter with no change in performance. I had the ignition coils replaced at the dealer about 2yrs ago. I've ordered a new EGR valve and oxygen sensor to see if that will fix the problem. I'm hoping it does, because the next item I would try to fix would be the fuel injectors. And at $240/ea x 8 I'm hesitant to drop $2k for a 13 yr/old, 241k mile car.
Is there anything else I should be looking at to repair or replace?
Your car has a nice diagnostic system that will usually tell what's ailing it, accessed from the 38 pin connector in the engine compartment. Don't replace your injectors, they can refurbished and tested for $14 per.
thanks for the info. this is my daily driver so if i were to remove the injectors and send them out to be cleaned i'd have to get a rental for a few days--not a problem.
is the guy who cleans the fuel injectors any good? i checked out the link you sent and juding purely from the website he seems legit. have you had your injectors cleaned by him? he do acceptable work?
yeah. it would absolutely be worth it to replace all 8 of the injectors if the injectors i need are actually $22/ea. i use autohausaz.com as well, which is where i ordered my egr valve and oxygen sensor. but the fuel injectors i need cost $236.70/ea. and i need 8 of them.
thanks for the info. this is my daily driver so if i were to remove the injectors and send them out to be cleaned i'd have to get a rental for a few days--not a problem.
is the guy who cleans the fuel injectors any good? i checked out the link you sent and juding purely from the website he seems legit. have you had your injectors cleaned by him? he do acceptable work?
I have used him for that exact engine and he is very good, very conscientious. If he can not get it to test to standards he will tell you and you will have to replace that injector only. If you work with him on scheduling and overnight the packages you should be down only 3 or 4 days. He normally provides new seals and o-rings but didn't for me because I had already purchased them before finding him. He also provides the test results that look like this:
Nice. I've decided to go with that guy to have the injectors cleaned first, and then (God forbid) replace only what needs to be reaplced. I'll email him to set up an appointment and then I guess I'll park the car in the garage this weekend, remove the injectors and hope for the best.
I've never removed fuel injectors before--is there anything in particular I should know prior to doing it? Any special tools or the like I should get before I start the project?
I've never removed fuel injectors before--is there anything in particular I should know prior to doing it? Any special tools or the like I should get before I start the project?
No special tools required but it takes a while. You must take out the entire fuel rail, the injectors come out with it or get stuck and don't come out with it. There's quite a bit of stuff - hoses and wires - to get out of the way before you can take out the fuel rail. It's largely an adminstrative job, just stay organized and you'll be fine. It's a good idea to take some pictures before you start digging into it - just in case you forget where something goes or how it is routed.
This past weekend I checked to see if the car was throwing any error codes and I got three:
5: EGR inoperative
6: Idle speed control inoperative
26: Upshift delay switch over valve-open or shorted
Now I ordered a new EGR valve so I'm not concerned about that, and I know about the transmission upshift delay error code so I'm not concerned about that either. But I am concerned about error code 6: Idle speed control inoperative. What is it? Where is it located on a M119 engine? Is it just a sensor, a mechanical part, or some line of code in the ecu?
It should be noted that since my last post I've been driving the vehicle with little to no problems to speak of. The car idles (somewhat) fine; still dips a bit when in park, at a stop light, or when coming to a quick stop. I'm still going to get the fuel injectors cleaned and flow tested next week, but I'm also going to be looking into this Idle speed control.
There is no idle speed control valve as there would be on an old CIS system. Idle speed control is now a system with multiple components. That fault code is telling you to check pin 7 for more codes. BTW code 5 / EGR is telling you to check pin 4.
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