[W126 Coupe] 1982 380SEC various issues

[Dick Spellman]

Tad Heckaman wrote:

> Replys below...

>

> On 12/9/06, *Dick Spellman* <spell.yy at verizon.net 

> <mailto:spell.yy at verizon.net>> wrote:

>

>     Tad Heckaman wrote:

>>     I just purchased a 1982 380SEC, and it runs great. There are a

>>     few little issues that I'd like to get fix.

>>

>>     The first thing is the locks. I know they are vacuum based, but

>>     other than that I dont know much. Basically what happens is that

>>     when I lock the drivers door, either with the key or the lock

>>     itself, I hear the pump run, and all they all lock, but then the

>>     passenger/trunk/fuel unlock, and then they all lock. It never

>>     actually stops doing that (it did it for about 10 time before I

>>     decided enough was enough and pulled the drivers side lock back

>>     up to stop the endless lock/unlock cycle). Now this car did have

>>     a dead battery for a while, so perhaps some sensor needs to be

>>     reset? I am not sure.*   You'll need to read up on the simple

>>     3-wire vacuum pump on your 82 SEC in the MB manual.  Pull the

>>     fuse for now from the engine compartment fuse box so you do not

>>     burn out that expensive pump in the trunk spare tire well.  Pick

>>     up a Mighty Vac ($30) and start with the vac line at the pump and

>>     work your way forward from trunk lid to gas cap to passenger door

>>     to driver's door to see if there is a slow leak or a break in the

>>     vac line.  I've seen many breaks at the point where the line

>>     passes through the door hing rubber seal.  Don't pump pressure

>>     above 10 inches on the Mighy Vac when testing*

>

>

> Purchased a mighty vac today, I will test the vacuum in the next few 

> days. I didnt pull the fuse, I unplugged the pump in the back. Is that 

> bad or should I go ahead and pull the fuse as well?   *So long as the 

> pump is not powered you are all set.**

> *

>

>>     The car idles low, and lags roughly for a second before the car

>>     accelerates. While idling, it also surges, almost like its idling

>>     so low than it revs itself to keep it from stalling. The previous

>>     owner said that the injectors were dirty from sitting for so long

>>     (probably sat for a year or 2, then he drove it everyday to work

>>     for a few months and then parked it again). He took it to our

>>     local MB dealership and also to a regular car shop and they said

>>     that it just needs to be run, with some injector cleaner in it.

>>     They recommended that if its 'working' then dont touch the

>>     injection system. Is that all that it really needs, or should I

>>     take it in myself and have it checked? Is there anything I can

>>     check myself?  *Well, you can start with 1 can of BG-44K  ($30 or

>>     less at MB dealer) and see if the performance improves.  If not,

>>     take it back the the MB dealership for a proepr run through or

>>     you will have to become somewhat expert in short order to do all

>>     that is required to diagnose and fix the engine and it's systems

>>     yourself.*

>

>

> I have already put a standard bottle of injector cleaner (Tekron brand 

> I think). This morning its not doing the lag when revving the engine, 

> so it already seems to be improving. The engine will start doing the 

> surging after about 2-3 min of running from a cold-start, but it 

> doesn't seem as bad. Whats the idle rpm supposed to be? Perhaps its 

> too low?  *Park or Neutral and coolant temp <42 C 750 rpm minimium; 

> >42 C 500 rpm minimum for 116 81/82 380 US.*

>

>

>>     A gas gauge does not work, where should I look first to fix that

>>     (makes me worry that I will run out of gas at some point)

>>     The radio/antenna does not work (I really want to replace the

>>     radio with something more modern, and if I want to upgrade in the

>>     future, having a working antenna would be nice)

>>     The sunroof sometimes works (prev owner stated that alot of the

>>     electrical problems are just caused by poor contacts on the

>>     switches, and opening the dash and cleaning up the contacts on

>>     the switches would help) (hah) *Start by ordering up a complete

>>     fuse replacement kit ($10) and replace every fuse in the fuse

>>     box.  See what is then fixed and report back.  I would not dive

>>     into much of anything until the fuses are replaced.*

>

> Just replaced all the fuses, nearly ran autozone out of those types of 

> fuses. Should I find a fuse replacement kit and do it with those, or 

> did I effectively do the same thing by buying standard fuses? *Copper 

> tipped fuses replaced every 10 years of the correct value and you 

> should be all set.  Clean any fuse holders that were pitted or burnt 

> with a qtip and sandpaper.*

>  Fuel gauge doesnt seem to be working yet either. Where is that sensor 

> located? I suspect the car sat without fuel in the tank for a period 

> of time, and perhaps the sensor rusted or froze up.  *The sender is in 

> the fuel tank behind the rear bucket seat driver's side.  Probably 

> need a new sender and seal if as you say the car was let to sit with 

> anything less than a full tank of fuel.*

>

>>     Odometer does not work, title already states that its 'not

>>     actual', but can I get that fixed?  *Fuses first and yes the

>>     speedo can be repaired if needed.*

>

>>     Since I have never had a MB before, this will be a great way for

>>     me to get familiar with how these cars are put together. I just

>>     replaced a few lights and the sealed beams (cant wait for euro

>>     lights later on, what a PAIN to replace those sealed beams), so

>>     now I can get it registered and on the road.  *I'd suggest you

>>     have someone confirm that the timing chain on the 380 motor has

>>     been converted to a dual chain before spending any $ on the SEC. 

>>     You need to get a copy of the MB Cd-Rom for service on your SEC

>>     ($20-40 as a guess). *

>

>

> I emailed the local MB dealership, where it was supposedly taken 

> regularly for all its maintenance. Would the dealership automatically 

> upgrade it to dual chain if they replaced the timing chain?  *I'd sure 

> hope so!* * The engine is junk if it's not dual chain.  And then try 

> and obtain the mileage on the dual row chain, tensioners and guide 

> rails since it was last done.  See what the dealership says.*

>

>>     Thanks for any replies!

>>     -- 

>>     Tad Heckaman

>>     *Comments highlighted.  Good luck.  Dick*

>>     ------------------------------------------------------------------------

>>

>>     The MB Coupes Website!

>>     W126 SEC Mailing List

>>     Postings remain property of MB Coupes, L.L.C.

>

>     The MB Coupes Website!

>     W126 SEC Mailing List

>     Postings remain property of MB Coupes, L.L.C.

>

> Replys are inline, thanks for the replys!

>

>

> -- 

> Tad Heckaman

> ------------------------------------------------------------------------

>

> The MB Coupes Website!

> W126 SEC Mailing List

> Postings remain property of MB Coupes, L.L.C.

You mention odometer not working.  Does everything else on the 
instrument cluster work except fuel guage?  Clock, tach, speedo all okay???

-\Dick
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