Hey guys, I have recently bought a 2001 E320 CDI, and it has a very strange issue. There are no check engine lights or error codes or anything like that. When I first crank the vehicle, I can rev the engine to over 6k rpms but within 10 minutes of driving, it will not rev past 3k rpms at 100% throttle. This makes it really tough to pass someone or get up hills and sometimes embarrassing because it takes a few minutes to build up any speed, and I can tell people behind me are irritated. I bought an OBD2 reader and hooked it up today and I can see that when it has the issue at full throttle, the MAF sensor is about half the value it is when I first crank the car and can rev the engine to max. Does this mean that I need to replace the MAF sensor or could it still be a clogged exhaust like I have been reading elsewhere on the forums? I have taken to a local mechanic, but he just knocked some carbon build up off the throttle body I believe and didn't really help anything. I am living temporarily in Italy and it was hard to understand the mechanic and he charged me $800 and didn't really do anything to help. I do not want to go back to him or trust the mechanics here. Any help at all would be greatly appreciated! I will try to take a screenshot of the OBD2 app to explain what I am seeing.
Here are two screenshots of my OBD2 app with the MAF sensor, throttle, and RPM shown. Both are at full throttle. When I first crank the car or turn it off and back on, I can achieve full throttle and the MAF sensor shows about 85.2. Within about 10 minutes of driving, my MAF sensor at full throttle only gets to around 33 and I can only get less thank 2k rpms.
Here are two screenshots of my OBD2 app with the MAF sensor, throttle, and RPM shown. Both are at full throttle. When I first crank the car or turn it off and back on, I can achieve full throttle and the MAF sensor shows about 85.2. Within about 10 minutes of driving, my MAF sensor at full throttle only gets to around 33 and I can only get less thank 2k rpms.
try a new battery, this is not a joke.
i had trouble with my car for years, no one could fix it, put a new battery in it and it fixed 90% of it, i am happy with it now, or i was yesterday.
a friend had a 5 year old MB, some of his dash lights hadn't worked for over a year, so he said, put a new battery in it and everything worked.
good luck
The computer reads my battery voltage around 13v which I read is pretty good since the battery is located in the back seat and has over 10 feet to travel. The Mechanic says that the battery is not the issue or the car would give an error code.
Did you try "Italian tune-up" ?
I ditto that you need skilled technician with proper scanner.
Than how much are MAFs in Italy? I can buy several in US for $800
Please provide the MAF readings at various rpms. You can try to remove the MAF connector with engine off and try to start and run the car. The engine computer should run in the default mode based on throttle value and look up table. You will get a code for the MAF. If it runs better, I would try to clean the MAF first . Check the stickies on how to do it. It may help.
Also make sure that the coolant temperature indicator shows 80+ degrees C when the car is fully warmed up.
Could be a problem with the fuel pressure regulator or filler or whatever the technical word is for CDI engines.
I remember a post in w211 forum where one owner had the same exact problem, and it turns out to be the fuel pressure regulator thingy. I'll see if I can't dig it up later tonight when I get home...
Cdi red lines at 4500 rpm, I have no idea how (or why!!) you get it to 6000 or how you know it's 6000 when the tach ends at 5000.
If you somehow over rev'd it you probably triggered a limp mode though that would throw all kinds of codes.
My cdi (same year as yours) makes 170hp from about 2000rpm so no point revving it past 4000 anyway.
I posted the MAF readings, but they did not get posted. In case someone else has the issue, I found out that my engine was going into something called "Limp mode" where the engine is limited to 3k rpms and the transmission is also limited to a couple of gears. I was able to get it scanned by a Mercedes compatible scanner and the only error that came up was a CAN network failure. The mechanic wants to replace some wiring in the engine bay. I told him I would think about it. While searching, I found that I should check aftermarket electronic wiring and I saw that there was an after market radio and in the radio housing a wire was severed. After unplugging the radio believe it or not, the car drives perfectly! I can actually pass people now and the car goes up hills just fine. After a few minutes though some dash lights come on about "elec stabil prog esp abs visit workshop". Now only the engine is in limp mode and I can still go up hills and pass people but limited to 3k rpm! I am going to check with the guy today and tell him what I did and see if he will rescan the car.
Please post the error codes after the scan. It is very hard to even guess what the problem would be, especially someone did some surgery on the car wiring.
I remember many years ago, I took my car to have a new radio installed as I did not have the time to do it myself. After I picked the car and paid the workshop, I checked the radio and it was working good. It was cold outside so I turned the heater on, but the blower motor would not work. I took it back, and found out the the kid who worked on my car had no idea what he was doing and, and butchered the wiring under the dash. The shop owner personally came round and fixed the problem. I was really angry.
Was the car running perfectly before and this problem suddenly started after some change / maintenance ?
Well mrboca, I bought the car from a local Italian here, so it had the issue since I have owned it. It was raining the day I test drove, and I guess I did not try to drive it very fast to notice. I am sure he knew the issue was there when he sold it to me. He did not speak any English. I was in a pinch because it was the only automatic transmission I could find within my budget, and I was spending $1k a month on a rental car. I am only here for a year or so for work, so I did not want to spend too much on a working car. The problem has been driving me nuts for the past few months and has been a safety issue at times due to not being able to accelerate quickly. I can't believe the car does not tell the driver on the dash that it has gone into this limp mode. What a horrible design. Especially that a severed wire in the radio housing can screw up the central nervous system of the car so bad that the transmission does not work. What is worse is that in Europe they did not adopt OBDII on cars until 2001 and 2004 for diesels, so you need a proprietary software to diagnose your car I will keep this updated with the results for the next guy that comes across this thread.
Your car may have an electronic accelerator limp mode (EA limp) which really has nothing to do with a transmission issue.
You can buy an adapter (38 pin to 16 pin) to read the codes from the ECU with an OBD2 / EOBD scanner. This, at least will read the Check Engine errors, maybe more for Europe.
Make sure to record the error codes from the workshops scanner. Get a print out to post it here. Then ask him to clear the codes. After a test drive he should check the codes again. This will eliminate historical past error codes that have been there for a long while.
I have the 38 pin to 16 pin adapter and OBD2 reader, but the software only reads general information like RPMs because Europe did not adopt OBD2 on diesel engines until 2004 and needs the proprietary Mercedes star system or whatever. My scanner software does not find any error codes like the mechanic found with his system. I talked to the original mechanic I went to that charged me $800 to clean out the intake manifold and he said the "elec stabil prog esp abs visit workshop" message is because of unplugging the radio which is absurd. I do not think he really knows what he's doing. He wants me to let a "friend of his" mod the software to prevent the engine limp mode. It's crazy I have two mechanics telling me two different things.
The other major cause of system interference is an aftermarket component that has been improperly installed. To locate this problem, the technician has to disconnect each such device, one at a time, and check to see if the inference problem is eliminated.
Unplugged the aftermarket radio and I got new faults and an unbelievably better drive. Now it seems the new faults are what is keeping the engine in limp mode. I think I will take it to the mercedes benz dealer in town and see if they will pull the new fault codes for free.
This is applicable to the W210. The car going into limp mode means something is interrupting the engine electronics. The radio falls into the body CAN, which is a separate CAN bus and thus has no bearing on the engine limp mode.
These two are on a separate network, therefore the radio wiring harness being chopped up would affect the steering wheel buttons, the radio, the cluster display gauge, but not the engine/transmission.
Please note that the ABS/ASR/ETC modules feed the vehicle speed sensor information from the right front wheel sensor to the radio unit (A2). So, if this line is not terminated properly or shorted, this can cause the BAS errors. The connection s at Connector A pin 1.
So I have the limp mode resolved now by a third mechanic who I was recommended to! Unplugging the radio does clearn the CAN bus error and after that we could see the error causing the limp mode which was P1470. The mechanic checked air pressures and found a tear in a hose leading into the turbo charger. After replacing the faulty hose the car drives like a different car and no more limp mode! Still occasionally get the ABS errors with the radio unplugged, but that I can live with. Thanks all for the input!
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