- Mercedes-Benz 300E Engine idle speed is high Inspection at your home or office.
- Get the Best Priced Mercedes 300E Idle Control Valve
- 1990 300E -idles rough and stalls at stops
- 1976 to 1993 Gas Engine Shakes at Idle ( Runs Rough )
- Troubleshooting a Rough Idle on a 1989 Mercedes-Benz 300 SE
Mercedes-Benz 300E Engine idle speed is high Inspection at your home or office.James answered 7 years ago. Robert answered 7 years ago. I'm positive it is not a clogged cat. I believe it's a major Vacuum leak. Hopefully your leak is easier to find. David answered 7 years ago. I checked the brake booster a few months agoand wasnt that, i will have to get a cigar tomorrow and smoke the engine see if i can find a leak. You're talking the cold start injector? Very possible, though it could just as likely be that injectro is leaking as the sensor acting up. The injector is right there towards the front of the engine if you're wanting to pull it out and see if it's leaking or still spraying when the engine is hot. Stefan answered 7 years ago. I will check it out, I was actually referring to the cold temp sensor, if its saying its 30 below zero then it will dump fuel into the system, but the thing that gets me is that in idle its pretty much normalonly acts up in gear. MercedesMonkey answered 4 years ago. Sitting on the side of the road in my SEL waiting for AAA, I've had almost everything replaced to fix this problem, literally 10k into this 4k car And no one mentioned a vacuum leak Could be the Bosch EHA valve. It can be worn out and become temperature sensitive to functioning, working well when engine is cold, but irratic when warm. The cool gas going into it complicates the picture because once you stop the car the gas warms up in the area and makes starting difficult until cool gas reaches it again, but it may not be cool enough anymore with a hot engine under it. New, these are very expensive little critters. Guru6S3CF answered 2 weeks ago. No, I found a brick of coke stuffed in one of the exhaust pipes. I bought the car in 86, so sign of the times I guess.
Get the Best Priced Mercedes 300E Idle Control Valve
There is also a smell of unburned fuel around, and popping in the exhaust sometimes, also indicative of unburned fuel. So I can either drive it like I have nine lives, or I can fix the problem. When my tech pulls the fuse for the fuel injection computer a. Here I am reporting on my work so far. He advises first ruling out typical ignition-related problems, by replacing the:. Spark plugs, though, I can handle. I like to keep it to the classic recipe: Bosch brand, with copper core. As explained to me by my tech, this engine uses an integral resistor in the high-voltage circuit, and the matching spark plugs are becoming rare. I like to do an engine compression test whenever I change the spark plugs. So, yesterday, my tech and I did just that. Inspection of the individual spark plugs showed some of them being heavily carbon-fouled while others were fine. That rules out central components like the distributor rotor, the central coil and its central high-tension wire. I like to put anti-seize compound on the threads, carefully avoiding getting any on the tips of the spark plugs. With new spark plugs, the problem was still there … but I could rule out the spark plugs as the cause. The next task would take maybe an hour, I figured, but in fact it took me four-and-a-half hours. I removed the distributor cap from the bad car, removed one from a good car, and put it on the bad car. The Allen-head key at the bottom of the distributor cap was a pain to access. With the distributor cap off the bad car, I used sandpaper on the edge of the distributor rotor to clean it up. I used grit but grit would have been better. Then, after another 90 minutes or so, I had the distributor cap off, and it could be put onto the bad car. Yet another 90 minutes later, I was done. On two of my cars, the bottom part of this sleeve was brittle or gone, so I need to order some new ones. With all of these parts replaced, the problem was still there … but I could now rule out the spark plugs, spark plug wires, distributor cap, distributor rotor, and also the engine, the central coil and its central high-tension wire. For an internal-combustion gasoline engine to run well, it needs good — compression — ignition — fuel. So now I can rule out the first two, and focus on the fuel system, and because the problem exists whether or not the computer is active, it means I can rule out the computer and everything that might cause it to misbehave. Since the problem is specific to only some of the cylinders, and under full power the car runs fine, I can rule out the fuel pump and the fuel pressure regulator, too. I do have a morbid fascination with hooking up a fuel pressure gauge whose fittings I had custom-made for this engine. My tech has advised me to not go rip one off one of my good cars, because the year-old gasket between the fuel distributor and whatever is below it will be damaged in the process, and using it thereafter means an open fuel leak, and the risk of an engine compartment fire. I gather that ethanol in the fuel is part of the reason why these parts need a rebuild. My tech played me a sound clip of a similar engine, before and after such a rebuild. The difference is stark. So, yes, I plan to buy a rebuild kit. However, the fuel injectors could be a problem too. Could they be dumping too much fuel? I suppose so. For example if an injector is leaking that might cause a too-rich condition. When installing the new seal, lightly coat the with engine oil. The gasoline fuel injectors come in two sizes, the later ones being smaller as used on the later engines, the engines and the M engines. The earlier gasoline fuel injectors are the same size as the diesel injectors. I gather poor fuel injector behavior is typical, after three decades of neglect.
1990 300E -idles rough and stalls at stops
More often that not a customer just wants to know what part to buy to fix the problem. If your older gas engine, starts hard, idles poorly, or accelerates with hesitation the problem may or may not be solved with replacing a part or parts. The problem needs to be approached first with a thorough understand of how to troubleshoot the cause or causes BEFORE you throw parts at the problem. For instance you don't want to order a new fuel pump just because your engine is hard starting. My merc is a manual, petrol W E from and has KM, in very good condition no rust, almost full history etc I really enjoy driving it around and wouldn't trade it for any recent model. However something has been bothering me ever since I acquired it. I'm very attached to this car and have already brought it to a Mercedes repair shop and they haven't been able to identify the problem, all they could do is stress that the car has no problem when driven no power loss, no jolts, no abnormally high fuel consumption or anything of the sort. They have tested and ruled out the following: - Spark plugs - Fuel pressure - Intake manifold sealing - Air mass sensor I know from the history that the fuel pump was changed not long ago before I brought the car, but the Mercedes guys found nothing wrong with it. And here's also something that may or may not be relevant: the bouncy idle happens only when the car is fully stopped, ie as long as the car is advancing even slowly in neutral gear, the rpm is perfectly stable, but as soon as the car stops, it starts bouncing like in the video Have you already seen this situation? Is there anything I can do about it? Thanks a lot, Lucas P. Hi Lucas, Your problem is not uncommon especially as these cars age. Sometimes it is not so easy to find the real culprit. Should not be so on your engine. I would start by doing a compression test on the engine. If your compression is not equal that will cause the rough idle. Once you know your compression is good. Spark next: you said you replaced the spark plugs but nothing about the wires or the distributor cap. I have seen a lot of problems with the caps due to age and wires should be changed every 80, miles. Has you engine been put on a diagnostic scope for check for breakdown of ignition spark delivery. Fuel next: once you have determined your compression and spark are ok I would think about your fuel delivery system. Start with the idle speed controller. Make certain there are no cracks in the intake and exit rubber hoses. If you have a to C. See my video below for rough startup and idle troubleshooting. If all the above pass ok, then it may be time to think about your fuel injectors. I have a number of videos on Youtube talking about the problem of poor spraying injectors. I have a tester kit that will allow you to remove test and clean your fuel injectors. The injector seals could also be leaking. This is common because of the age not mileage of those critical seals. If one or more of these seals are leaking air can be sucked in and the engine will idle unevenly. See related products below:.
1976 to 1993 Gas Engine Shakes at Idle ( Runs Rough )
There have been 3 problems with my car CE, latemiles, automatic transmission for over a year now:. The car shakes about once per second awkwardly noticable by vibrations through the seat without any noticeable change in rpm. A bridging wire in place of the fuel pump relay or the overvoltage protection relay brings no change! It happened only 5 or 6 times in over a year now and only at or close to idle speed — once it happened rolling towards a red traffic light at very low speed in overrun mode. First it immediately starts, runs for less then 1 second and stops again. Then when you start it the second time it stays on. When the car has not been used for a 1 week or longer it starts perfectly within less then a second and stays on. Fuel pump relay. Only genuine Benz relays are okay, in my opinion. Seen brand German aftermarket parts that failed within weeks. What brand plugs and wires are you using? No offense, but even some of the German aftermarket ignition components are junk. Seen it too many times. Most CIS cars are on their seconds set. Air leaks and lousy injector spray patterns are a curse. Not saying this is the cause here; only that CIS can be that finicky. First I want to apologise, if my reaction on comments is a little delayed. Next I want to thank you for your comments, which sound very experienced. I did not use a smoke machine. I took off the air filter housing, let the engine run in idle and - equipped with a vaporizer filled with brake cleaner fluid — I thoroughly checked every corner of the hole intake system. Small hoses which are connected to it which use vacuum like the lock of the backrest of the passenger seat, I took off and used my finger to plug the hole. It certainly took me half an hour to do the false air test. The use of a smoke machine is probably more proper for a false air test. A month ago I connected a small 12 volt lamp to the wire which supplies the fuel pump with voltage. I placed it on the center console with a switch. But so far it never happened again yet. As for the rough idle the fuel pump relay can be ruled out, because there is no change if I pull it off and use a bridging wire instead, so that the fuel pump runs as long as ignition is switched on. But as I said, after a longer shutdown time the engine starts immediately within a second — and stays on! The plugs and wires I installed 2. I attached pictures of the current plugs, cap and rotor. That is half of the regular price at the local Bosch or Mercedes dealer. The seller accepted that I connect them one by one to a test pipe which I connected to the fuel distributor injector aiming into a big plastic bottle.