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first off, id like to say hi to everyone here as i am new to this forum and to mercedes as well. i recently bought at 1989 300te w/ 155,000 on the clock, which i payed $5K for. most things seem to work but there are a few bugs that are on the list to get sorted out. this is my first ever mercedes... untill now ive only owned mazda sports cars... so the wagon was quite a stretch for me. it is a boat compared to my RX-7, and took me a week just to feel comfortable parking it. anyway, its a relaxing car to drive and i finally have to ability to use my car for daily life (although i still have the 7 for a weekend car :D ). i love the car very much already.

anyway, ever since ive had it i have had a few problems with it. the transmission is clunky when it shifts gears, reverse takes 3 seconds of waiting to "engage" , and if i try to downshift on the highway from 4th -> 3rd gear it makes a loud "boom" sound and violent clunk. needless to say i only did it twice as i didnt want to destroy my tranny. obviously somehting is wrong, but if i drive it with some care it runs just fine. thats the first problem (which i might or might not do anything about untill it actually kicks the bucket and i throw a rebuilt unit in or get a used one)... but please, any recomendations on how to proceed would be much appreciated.

the other major thing (my most imidiate concern) is starting. if the car is cold, or has sat for more than 20min i have to either crank the car twice for it to start, OR sometimes if i leave it cranking for a long time (~6sec) it will start up. once it has started it runs fine... slightly lumpy idle but nothing that i would consider out of the ordinary. my first thought is that maybe i have bad compression in one or more cylinders??? does this seem plausable? i havent had the compression checked yet. other than that, i would be at a loss to try and diagnose why it takes 2 cranks to start. if you guys have any ideas, or can point me in the right direction as to what to check i would be very gratefull.

lastly, today i pulled the air cleaner assembly to clean some stuff up under the hood. i noticed that i had a few cracked rubber "L" vacuum line connectors. i replaced them with silicone line and zip-tied them (i had some left over from doing the 70+ vacuum lines in the rx7 which is notorious for vacuum leakes from the stock rubber lines). anyway, i noticed that there is a sensor on top of the engine (on the intake side) with 2 vacuum lines going to it. first of all, what is that sensor and what does it do? secondly, the nipples were cracked off. i epoxied them back on, and added silicon line to the nipple ends and reattached everything. i didnt notice any differences in how the car ran so i figured its either still leaking or whatever it is, is not very significant. (does it matter which of the 2 lines i attach to either nipple??)

one very last thing before i go... does anyone know if there is a pdf file for a 300te workshop manual floating around anywhere?? if so i would really appreciate it if someone could shoot me the link. thanks once again for reading my long post, and hopefully you guys can help. greetings to everyone here, heath
 

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transmission sounds to be getting tired..that Clunk can be from bad diff mounts..my TE was doing the same thing..new diff mounts, no more clunk. PITA to change though.

When was the transmission serviced last? Fluid and filter should be changed every 20ish K.

Next time you start the car, put you foot to the floor. If this helps you have bad injectors (to be expected at this mileage). Does it only give a hard start when it's cold? When it starts, if you turn it back off and back on again does it fire right up?

It sounds like you are talking about a thermo vacuum valve. Get me the part # and I'll tell you what it does.

Hope that helps!

Jonathan
 

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jhodg5ck - 5/6/2005 12:18 AM

transmission sounds to be getting tired..that Clunk can be from bad diff mounts..my TE was doing the same thing..new diff mounts, no more clunk. PITA to change though.

When was the transmission serviced last? Fluid and filter should be changed every 20ish K.

Next time you start the car, put you foot to the floor. If this helps you have bad injectors (to be expected at this mileage). Does it only give a hard start when it's cold? When it starts, if you turn it back off and back on again does it fire right up?

It sounds like you are talking about a thermo vacuum valve. Get me the part # and I'll tell you what it does.

Hope that helps!

Jonathan
car in question:


here is a picture of the sensor with the broken nipples. (the epoxy did not hold sadly):


tomorow ill try starting it with hte throttle open... and report back. -heath
 

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Thats your idle and warm start problem right there. Replace the sensor.
Also check your tranny fluid level, if you didnt change the fluid when you got it consider changing it now.
I would have to say the W124 is even more notorious fo vacuum leaks[:)]
 

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Discussion Starter #5
Yal - 5/6/2005 9:11 AM

Thats your idle and warm start problem right there. Replace the sensor.
Also check your tranny fluid level, if you didnt change the fluid when you got it consider changing it now.
I would have to say the W124 is even more notorious fo vacuum leaks[:)]
THANKS! [:D] ill replace it and report back.
also, when i bought the car the previous owner claimed to have changed the oil a week before. ill recheck the fluid level/color.
 

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ok so i discovered that if i press the gas pedal a few times before i go to start the car up and then proceed to start it normally, that the car starts as it should. is that an indication of clogged injectors? what would cause these strange symptoms?? thanks
 

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[8D]
You may have a partially clogged fuel filter or a tired fuel pump or a small leak in a fuel line. All of those conditions will appear to go away if you...

1. Turn the key on but don't engage the starter.
2. Wait 10 to 20 seconds.
3. Engage the starter and it starts right up.

That procedure allows the fuel pump to pressurize the system, unless it really has a bunch of holes and the fuel filter is collapsed, which is unlikely since the car does run.

Good luck,
Dave
 

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Discussion Starter #8
imon_2nd - 5/14/2005 11:48 PM

[8D]
You may have a partially clogged fuel filter or a tired fuel pump or a small leak in a fuel line. All of those conditions will appear to go away if you...

1. Turn the key on but don't engage the starter.
2. Wait 10 to 20 seconds.
3. Engage the starter and it starts right up.

That procedure allows the fuel pump to pressurize the system, unless it really has a bunch of holes and the fuel filter is collapsed, which is unlikely since the car does run.

Good luck,
Dave
BUT, why would the symptoms disappear if i just open and close the throttle a few times before i even put the key in the ignition?? all the throttle does is move the butterflies correct? all fuel stuff should be separate right?
 

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Don't open and close the throttle a few times before hand..all you are doing is allowing a tiny bit of fresh air into the plenum. What I would like you to try is As you start the car, put the pedal to the floor and hold it there. If the car fires up w/ ease in that situation you are most likely experiencing an overly rich situation created by leaky injectors. Stepping on the gas causes excess air to come in, helping correct the overly rich mixture.

Jonathan
 

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I have a recently purchased 91" 300E that's is doing the exact same thing. From what a friend of mine thinks, it's the cold start sensor.

Note however that the hoses and my nipples (on the car) look good.

It's also been getting hot when sitting and like others here on the board it shift slow until it warms up. I just put in a thicker (20-50) oil today so I'll see how that does.

Looking forward to seeing the responses.

Thanks!
Marb
 
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