300e No rev when in gear but only in park and N
04-18-2015, 12:50 AM
#1
Newbie
Thread Starter
Join Date: Apr 2015
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Mercedes 300e
300e No rev when in gear but only in park and N
Hi, forgot my accountname and so once again new. Anyhow, bought me a 1991 300e and could drive it an awesome 20miles. From then on it sits in my garage.
Aside of some problems like it does not rev in park over 3500rpm or when I tried to drive it to my house for those 20miles it would not go over the same amount of 3500 rpm, the major one seems to be that whenever I put it in gear, it wont rev at all anymore.
And please recall when I am in park or neutral it does, so the cable is fine. I cleaned everything that was possible to clean and it idles now just fine, fuel flow is good as well, but after letting two mechanics check it out without getting a decent answer I want to ask here if someone has ANY idea or if I should just part it out.
(one mechanic said its the battery, which I changed afterwards and nothing changed, but the old battery was really not strong enough. And the other said its the transmission, yet if it would be the transmission it should rev at least)
Thanks in advance for any answer.
(My guess it is the torque converter, yet I am not a mechanic and I want to be at least halfway certain before I start taking things apart since I do not know if a defect torque converter would cause just that. On this forum I found an halfway equivalent topic and there was stated it is a vacuum leak, but would the effect be that drastically since really absolutely nothing happens when in gear, it just dies then after a 30 second or a minute? Or it is just the ghost in the machine who does not like me... :-) ) Again any answer will be appreciated. Thanks.
Aside of some problems like it does not rev in park over 3500rpm or when I tried to drive it to my house for those 20miles it would not go over the same amount of 3500 rpm, the major one seems to be that whenever I put it in gear, it wont rev at all anymore.
And please recall when I am in park or neutral it does, so the cable is fine. I cleaned everything that was possible to clean and it idles now just fine, fuel flow is good as well, but after letting two mechanics check it out without getting a decent answer I want to ask here if someone has ANY idea or if I should just part it out.
(one mechanic said its the battery, which I changed afterwards and nothing changed, but the old battery was really not strong enough. And the other said its the transmission, yet if it would be the transmission it should rev at least)
Thanks in advance for any answer.
(My guess it is the torque converter, yet I am not a mechanic and I want to be at least halfway certain before I start taking things apart since I do not know if a defect torque converter would cause just that. On this forum I found an halfway equivalent topic and there was stated it is a vacuum leak, but would the effect be that drastically since really absolutely nothing happens when in gear, it just dies then after a 30 second or a minute? Or it is just the ghost in the machine who does not like me... :-) ) Again any answer will be appreciated. Thanks.
Last edited by Julian0922; 04-18-2015 at 01:03 AM. Reason: addition
04-19-2015, 07:21 AM
#2
Junior Member
Join Date: Feb 2015
Posts: 19
Likes: 0
Received 0 Likes
on
0 Posts
300e
I don't see how the torque converter being bad would make it die when you put it in gear?
The first thing I would do would be to run it for a few minutes then turn her off and pull each spark plug. See if any of them are wet with gas, or coated in oil?
Another to dry would be when its dark outside, fire it up and let it idle with the hood up. Jump out and look under the hood for any sparking. Especially along the length of the spark plug wires. Also listen for the sound of sucking air anywhere.
Even if everything looks good I'd still do a complete tune up. Check the air filter as well. Also pop the cap off of the overflow bottle and look for and oil in the coolant, then pull the dipstick make sure the oil isn't light brown and clowdy (kinda like chocolate milk.)
The first thing I would do would be to run it for a few minutes then turn her off and pull each spark plug. See if any of them are wet with gas, or coated in oil?
Another to dry would be when its dark outside, fire it up and let it idle with the hood up. Jump out and look under the hood for any sparking. Especially along the length of the spark plug wires. Also listen for the sound of sucking air anywhere.
Even if everything looks good I'd still do a complete tune up. Check the air filter as well. Also pop the cap off of the overflow bottle and look for and oil in the coolant, then pull the dipstick make sure the oil isn't light brown and clowdy (kinda like chocolate milk.)
04-19-2015, 01:35 PM
#3
Newbie
Thread Starter
Join Date: Apr 2015
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Mercedes 300e
Thank you for your response.
The spark plug change and test I have done already (was the first I have done) and as well the rest of a complete tune up, including air filter, oil change and check, cleaned out the gas tank, checked relays and so on. (No oil in coolant overflow btw)
Yet what you are indirectly referring to is that it should or could be a vacuum leak and so I will look into that now and try to figure out how to test it. Would make somehow sense although I am not a mechanic and dont understand how a possible vacuum leak can cause the car not to take any movement in rpm when put into gear even if you floor it.
So again, thanks for your reply.
BTW, A neighbor told me that it could be a plugged exhaust, yet also that I have checked and nothing. Funny, somehow, is simply to id the problem to be able to finally work on it. I am stubborn and want to drive it at least a few more miles no matter what. :-)
The spark plug change and test I have done already (was the first I have done) and as well the rest of a complete tune up, including air filter, oil change and check, cleaned out the gas tank, checked relays and so on. (No oil in coolant overflow btw)
Yet what you are indirectly referring to is that it should or could be a vacuum leak and so I will look into that now and try to figure out how to test it. Would make somehow sense although I am not a mechanic and dont understand how a possible vacuum leak can cause the car not to take any movement in rpm when put into gear even if you floor it.
So again, thanks for your reply.
BTW, A neighbor told me that it could be a plugged exhaust, yet also that I have checked and nothing. Funny, somehow, is simply to id the problem to be able to finally work on it. I am stubborn and want to drive it at least a few more miles no matter what. :-)
Last edited by Julian0922; 04-19-2015 at 01:38 PM. Reason: correction
04-21-2015, 06:26 AM
#4
Junior Member
Join Date: Feb 2015
Posts: 19
Likes: 0
Received 0 Likes
on
0 Posts
300e
No problem. I wish one of the "real" mechanics around here would jump in. I know a lot about cars in general but in my experience there are so many things that are exclusive to Mercedes-Benz that there may be an obvious fix I'm missing?
Your friend is right it could be a clogged exhaust. I had an old Camaro where I'd burnt out the catalytic converter and it did something similar to what you describe. Although in that car the cause of the problem was that I had rounded my cam doing too many long burnouts (I also blew my muffler clean off at one point). lol I doubt this motor has enough torque to round a cam. You would probably be safe crawling under it and following the exhaust pipe to the back of the car. Look for anywhere that looks like it has been squished from bottoming out, or if the muffler is dented in or something?
I'd guess the problem is either a pretty big vacuum leak, fuel pressure related, or less likely some fault with the ignition system electrical. I believe you'd get a check engine light with a fuel pressure or ignition electrical fault? So assuming you don't have any warning lights that leaves vacuum or exhaust.
If you search the forum you can find a few threads on how to run the trouble codes with nothing more than a multi meter. Provided you don't find a vacuum leak or damage to the exhaust that would be my next step. I don't see any possible way this could be the torque converter so possibly look for another mechanic to diagnose it if you can't figure how to run the trouble codes or if they don't reveal anything amiss?
Your friend is right it could be a clogged exhaust. I had an old Camaro where I'd burnt out the catalytic converter and it did something similar to what you describe. Although in that car the cause of the problem was that I had rounded my cam doing too many long burnouts (I also blew my muffler clean off at one point). lol I doubt this motor has enough torque to round a cam. You would probably be safe crawling under it and following the exhaust pipe to the back of the car. Look for anywhere that looks like it has been squished from bottoming out, or if the muffler is dented in or something?
I'd guess the problem is either a pretty big vacuum leak, fuel pressure related, or less likely some fault with the ignition system electrical. I believe you'd get a check engine light with a fuel pressure or ignition electrical fault? So assuming you don't have any warning lights that leaves vacuum or exhaust.
If you search the forum you can find a few threads on how to run the trouble codes with nothing more than a multi meter. Provided you don't find a vacuum leak or damage to the exhaust that would be my next step. I don't see any possible way this could be the torque converter so possibly look for another mechanic to diagnose it if you can't figure how to run the trouble codes or if they don't reveal anything amiss?
