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- 90 300E (sold) - 93 400SEL - 2001 Land Rover Discovery II - 1998 Jaguar XJ6 (sold) -
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Discussion Starter #1 (Edited)
Hey Guys, I just bought a '93 400 SEL with 140K. It has a few problems -- was running really rough until I replaced the caps, and distributor rotors.... but still acts like it's not running 100% - (slow acceleration, slower than my old '90 300E) It also has a problem idling when you first start it up, (wants to die with your foot off the gas) but then not after you drive it for a bit.

... and a less problematic issue is that i'm having a problem with the reverse antennas and the trunk (closing) on it's own. Checked fuses. They're all fine. Trunk handle (that pops out) is blocked by a dent in the truck, so perhaps that's part of this issue....

I've read a few of the posts in this forum, and it seems like everything is connected to the vacuum pump under the rear seat. My door locks work fine, but the reverse antennas simply won't come up when in reverse... so it seems like the pump should be OK. Any suggestions? Lines from pump? :confused: Pulled liner out in the truck around the pumps which make the antenna go up on either side, and they are both connected (light red vacuum lines) but I found one (dark red) vacuum line on the drivers side of the trunk next to those which is disconnected. Don't know what that one is to- it has a clear plastic fitting on the end.

Thanks in advance. I'll keep an eye on this thread.
 

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94 s420 250kmiles
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827 Posts
there are two air pumps in the car, the one under the rear seat controls the door locks/gas door lock, lumbar support, rear headrest release, reverse guide rods, and pop out trunk handle.
the pump in the trunk on the left side of the gas tank controls the doors and trunk auto close.
 

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- 90 300E (sold) - 93 400SEL - 2001 Land Rover Discovery II - 1998 Jaguar XJ6 (sold) -
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Discussion Starter #3
there are two air pumps in the car, the one under the rear seat controls the door locks/gas door lock, lumbar support, rear headrest release, reverse guide rods, and pop out trunk handle.
the pump in the trunk on the left side of the gas tank controls the doors and trunk auto close.
Thanks! So where is the pump in the truck exactly? The driver's side left, in front of that Bose power amp? I have nothing installed right there now currently....
 

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1992 600SEL and 1990 ford taurus GL
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the close assist pump actually has all dark red lines, and is behind the bose amp crammed between the fuel tank, and the suspension. the one dark red line that you found that is connect to nothing is an outlet line from the close assist pump. it shouldn't be hooked up to anything.

the light red/ orange lines (and other colors, but mainly orange) are connected to the pse pump(located on passenger side under back seat), which controls EVERYTHING. it controls the door locks, the lumbar supports, the reverse antennas, and the trunk handle, etc.

but if the reverse antenna are not coming up then that means you might have a leak in the lines going to them. you said that the handle doesn't pop out because of a dent? if the car had an accident of some kind, then the same thing could have happened to your antenna as the handle, something could be jamming them. if you pull back your trunk liner in the corners next to the tail light, you should be able to find the white grenade looking components that house the reverse antennae when their not up. if you take the line off, you should be able to blow into it, and have the antennae come up.

as far as your trunk not self closing.... does the self close work on the doors? if it does, then first try pulling out famous fuse number 9 and leave it out for about thirty seconds then put it back in. then check to see if the trunk will self close. if it still doesn't then try flipping the leaver i circled in red in the picture and see what happens. i actually just got my trunk to self close yesterday by doing this after restoring the rest of my closing assist. but if there is a dent to stop the handle from coming out, then it might have messed up the close assist system as well. it would help if you posted a pic of your dent.

if the closing assist does not work at all, then you need to look for an issue more directly related to the pump. i would need more info to be able to direct you further.

as far as idling rough, im not entirely to knowledgeable on that. have you checked the spark plugs to see what condition their in? they might just need replacing. it could also be one of the dreaded wiring harnesses, either the upper or lower one, although their might only be one with yours, im not to sure with the 400s.
 

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- 90 300E (sold) - 93 400SEL - 2001 Land Rover Discovery II - 1998 Jaguar XJ6 (sold) -
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Discussion Starter #5
Wow, thanks for the awesome reply Bomb10177. Good to know that line on the drivers side doesn't goto anything. I was wondering about that.

I don't think the self closing feature is working on the doors, either. I flipped that lever (red one) yesterday and messed with the no.9 fuse.

The trunk seemed to self close (once) then wouldn't do it again after that fuse change :confused: I'll try popping the fuse out for a minute, then back and and see what happens next. The fuse is still OK (not blown) .

I'll post a pic of where its dented around the handle... I think I can push it in so that handle comes out like it's supposed to though. Not a big deal -- I am wondering too if this dent around the handle is causing a fault with the rest of the system (doors, trunk, reverse antennas) ...

I am also going to pop the rear seat out and take a look at that pump. Something tells me it's not connected right or something.

And another thing I just noticed -- my stupid windshield wiper fuse has popped twice now. I hope I don't have wiring harness issues :crybaby2:
 

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1992 600SEL and 1990 ford taurus GL
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welcome :) i'm more than happy to convey my knowledge onto another.

as far as the closing assist goes, what happens when you don't close a door all the way? does the pump run at all? or does the door close or move at all?it appears that your trunk is just timing out, but if it's self closing, then that's a good sign. you just have to adjust your shut off pressure. ill include a link on how to do that. what your doing when you take the fuse out is resetting the pump so that it forgets that it timed out whichever door or the trunk so it will try and self close it again.

the dent in your trunk, unless it's extremely massive, shouldn't cause issues with anything besides the trunk handle, and possibly the self close on the trunk, but if it will self close once, then that's an indicator that everything is ok. but other than those two, even if the trunk lid was completely gone, it wouldn't affect the self closing on the doors, or the antennae.

looking at your pse pump would be a good thing to check, although i don't have too much experience with it, i know that it controls soooo much that there are about a million and one hoes coming from it. Generally the reverse antennae are pretty reliable from what i understand.

and i don't think that you have a bad wiring harness, on the 400s its actually pretty safe from the bad wiring harness, although it can happen. you probably just have a short going somewhere on the wiring for the windshield wiper which causes the fuse to blow. does it blow the fuse even if you don't use the windshield wipers, or only if you use them?

here's that link to the close assist pump article that should help you. i know at first it was all very confusing to me, but slowly over time it will become a lot more easy.
Getting to know your Closing Assist Pump: Function, Tips, and Fixes by Brett Allison | V12 Uber Alles

and here's a video that shows one taken apart which gives a better visual


 

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Discussion Starter #8 (Edited)
Thanks guys. Another thing --- I guess I just wasn't proficient enough with this model, because the automatic door closing feature (is working) on all of the doors. But, apparently my windshield wiper system won't work. It looks like one of the wipers for the headlights is getting stuck as well, which might be the culprit. It blew a fuse last time, I installed a new one (which didn't blow this time) and the system won't kick in. Fuse blew even though I didn't use the system. No sound from the wiper motor at all when I hit the switch , not sure about the relay. I'm going to check relay contacts today I think.

Any ideas on that note?

I'm going to look at that pump probably today or tomorrow and follow bomb's advice on the matter. The truck self closing obviously might not be working because of the dent -- so I went to the junk yard and bought another lid. I'm probably going to have it re-sprayed first before I install it though. I also replaced the wire set, and low and behold the engine has those Bosch +4's, which I hear aren't so great on these cars. She runs a bit better now, but still laggy.... like the gas pedal is disconnected from the engine or something, lol. Idle is fine, it just doesn't seem to accelerate like it's supposed to. I wonder if (one) of the two fuel pumps has gone... perhaps I'll replace both of those soon too ; but I can hear (what I think is both) running when i turn the key.
 

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Discussion Starter #9
You should entertain replacing every component in the crankcase ventilation hose system.

http://www.benzworld.org/forums/w140-s-class/1660406-rough-idle-issue-fixed.html

Brett
Thanks Brett --- i'm not really having a problem with idle though, it's more like the car feels like it's disconnected from the gas pedal or something -- doesn't accelerate the way that I think it should. When I floor it, it's like no difference from the pedal half way to the floor.My 300E was faster, and this is a v8! :eek:
 

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sorry for the late reply, i just started school :cool: but if you keep having the fuse blow immediately on the wipers with out even using them, then that generally means you have a short to ground (a positive wire touching a ground), some where on the circuit before the actual wiper motor. i believe that the wiper motor has a switch to ground to make it work, but ill have to double check on a wiring schematic. but long story short, you'll have to find out where the wiring is shorting out.

as far as the self closing goes, it's good to hear that all of the doors self close correctly. :thumbsup: i actually just had this discussion with Brett on the trunk, so ill make sure to include that link, plus another he gave me which was really helpful. if the dent possibly harmed one of the airlines going to the trunk, then that could cause it to self close once or twice, then stop, because it cannot reach the shut off pressure. as far as replacing the entire trunk lid, are you replacing the trunk lid itself, or all the components that go with it? because the hoses going to the close assist are really probably what the issue is, not the actual mechanism that closes the trunk it self. and if you replace the lid, you will have to disconnect and reconnect both the hoses. and i don't know if the older lids are compatible with the newer ones. they still work the same, but just like the actual close assist pump, the newer and older ones are not so compatible.
 
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