a US model 1984 240 should be a B23F engine, with LH-II electronic fuel injection. If you got your hands on a European or other world market car somehow, it could have an A series engine (B21A, B23A) with dual SU side-draft carburetors, but that's highly unlikely.

with LH injection, there is a 'fuel rail' (slender metal pipe) across the top of the intake manifold, with 4 injectors that stick into the manifold throats right at the head, each injector has a rectangular electrical connection on top. the fuel line goes into a skinnier tube that comes off that fuel rail and feeds the back end of it, and on the front end of it is the fuel pressure regulator, which has a skinny rubber vacuum hose, and the fuel tank return line comes off the bottom of the regulator.

here's someone's picture of a 1984 LH-II B23F engine.
http://www.vandsautodismantlers.com/...601_engine.jpg

earlier US model 240's had "K-Jetronic" continuous injection, this was quite different... the 4 injectors had no electrical connection, instead they each had a thin metal pipe that bends around and disappears under the intake manifold where they are all connected to a mechanical 'fuel distributor'.

 

so are you saying that one of these relays could be stuck

 

yeah, basically. on the 84, the two relays are the same kind, both quite generic 4-pin bosch style relays, quite common and cheap, any import-type car parts store probably has a compatible relay on the shelf (bring one in for matching, make sure the pins are in the same place, 30,85,86,87). on later years, they combined these into a single dual-relay which costs quite a bit more :-/

if you pull those relays, and there's STILL a 0.8amp draw on this 30A fused circuit, I'm gonna suspect bad wiring or that someone has tapped something into that circuit.

 

great thanks.. i can tell you when i hook up the battery i did here something click or made a one time clicking sound

 

each of these 2 relays, the coil is between pins 86 and 85, and the switch is between 30 and 87. the 'main' relay, the coil is powered by that red wire from the 30A fuse, and is energized when pin 85 is grounded by the ECU. this pin 85 is the yellow-red wire (except, another drawing shows it as orange?) and goes to pin 21 on the ECU (which is probably under the passenger side footwell, on the right fender side just forward of the front door).

so, if that 'main' relay turns out to be the source of your drain, I do believe I'd unplug the ECU and see if that relay switches off. if it doesn't, then I'd unplug both the relay and ECU, and check relay pin 85 to see if its shorted to chassis ground (with an ohm meter, with the battery ground is disconnected), or to any other pin on the ECU connector except pin 21. these relays should be behind the glovebox, so its a short run from the relay to the ECU...

 

ok thanks .. but these pin numbers your giving me are they numbered somewhere

 

the relay pin numbers should be on the relay (the socket might just say 1,2,3,4 rather than 30,85,86,87), and the ECU pin numbers should be on the ECU connector, at least they were on my 87 and any other I've looked at. its possible on the ECU connector, just the pins at each end are numbered, so you have to count the ones in the middle... and sometimes, its 1,2,3,4,... up one side, and then the rest down the other, or its possible they are evens and odds on the two sides, you kinda gotta figure that out when you look at it. I had to use a very bright small flashlight and a magnifying glass to see the numbers on mine (but my eyes are starting to fade with age).

 

ok great Pierce thanks for everything ..i will check the relays first and keep you posted .. you have been a huge help brother ...mine are fading as well at 53 y/o .. have a good evening

 

well i pulled both relays and tested them both good and got 0.00 with them disconnected.. so i plugged one in one of the connectors and still 0.00 tried the same relay in the other connector and got 0.82 again.. wish i can tell you what connector it is that is giving me that reading but cant read anything on the connector but it has brown , red, orange etc.. the one with the relay off is the one that shows the draw... dont know why the yellow wire is connected the blue/red wire to the other red wire

http://i131.photobucket.com/albums/p...psac931b7b.jpg

http://i131.photobucket.com/albums/p...ps35ffc1b8.jpg

 

 

i cut the yellow wire that was bridging the two and the engine stalled

 

ok, interesting. verrry interesting...

lets see, the blue-red-wire has key switched power via fuse 13 and goes to pin 30 (relay coil +) on the fuel pump relay. the other end of the red-blue wire connects to the ECU [om 18 (to provide it with juice when the ignition is on, so that it can turn the relays on) and from ECU pin 18 it goes to that main relay pin 86..

jumping it to the red wire is probably powering the ECU all the time, so the ECU in turn is enabling the /other/ ('main') relay (the one with the yellow-red wire on pin 85)... so the car runs, but the ECU is never shut off, so its always draining power.

so, what needs to happen is... leave that yellow jumper cut as you did, and instead, connect a new wire to fuse 13 to replace the blue-red wire... on the right side of the fuse panel as you're facing it, there are three spade lugs... the one closest to the fuse should have a blue-red wire on it. unplug this[***], and plug a new wire (should use a standard spade lug) in that you run under/across the dash over to the relays, and connect to the blue red wire. my guess is, the original blue-red wire is broken somewhere under the dash. don't cut the blue wire, just tap it like that jumper did, as both ends of the blue-red wire need to be on that ignition switched power so both the ECU and 'pump' relay see it.




[***] of course, if that wire either isn't plugged in, or the connection looks funky, before running a new wire, try cleaning it up, I use a pink pencil eraser on electrical connections to 'polish' them, and plug it back in to that same lug on the fuse block, and see if that fixes things. also, use a volt meter, and make sure that lug has 12V when the ignition is on, relative to chassis ground.

[****] OH YEAH. ...30 year old car with crappy 'ceramic' fuses... get out on ebay or whatever, and find a kit of 'mercedes w123 fuses' (or W124... those two generations of the Mercedes Benz 300D/300E made in the mid 80s,90s) that are copper/brass and from Germany. the ones that we can buy in our crappy auto parts stores in the little "Buss" or "Littlefuse" hang cards are garbage tin fuses. replace ALL your fuses with these copper/brass ones, cleaning the fuse block contacts as you go. example: Mercedes Fuse Kit W123 W126 240D 300D 300CD 300TD 300SD 560SEC 380SEL 300SDL | eBay

 

btw, do your instrument panel lights work? fuse 13 also powers them via another blue-red wire. and yet another blue-red wire from 13 powers the electric cooling fan on the radiator, but that only comes on if the engine is very hot, so to test it, on the left end of the radiator, near the top, there's a thermoswitch, you can short its contacts together, this should turn that fan on, if the ignition is on.

fuse 13 also powers the seatbelt reminder circuit, and the turn signals, and yup, these use blue-red wires too, eeek.

so... my point is, this is a little more complicated, there's at least 3-4 circuits off fuse 13 using blue-red wires. someone did some pretty ugly hacking to get this car running due to wiring issues.

there's no clue where these wires are spliced, whether they call come directly from the fuse panel, or whether there is a junction somewhere under the dash. so triple-meh. how to know WHICH blue-red wire was the fuel injection switched power?? now I'm thinking, do NOT disconnect any blue-red wires at the fuse panel, instead, splice your new wire that you're running over to those relays onto an existing blue-red at the fuse panel...

 

ok will do some research ..the dash lights work plus i have a clutch fan thank god .. is the blue/red wire a hot turn on ignition wire 12v

 

ok that yellow wire i cut in half ......the connector posted in the picture with the white relay pluged into it has that yellow wire spliced to the blue/red wire to give it 12 volts and that is why they had it jumped to the other relay connector"s red 12v continuous wire killing the battery.. what im going to do is re-splice where the yellow to blue/red was and run it to the fuse panel to power on only when key is turned on ... does that sound ok and how many amp fuse should i use or do i even need a fuse.. so what i come up with is that blue/red wire is dead somewhere along the harness when key is on..what was draining the battery was the power from the red wire spliced to the red/blue wire from what i get

 

use fuse 13 (8A), thats where it is supposed to come from.

fuse 13 should have 1 or more blue-red wires coming off of it. they should be +12 when the ignition is on, and cold when its off, and if you remove the fuse they should be cold even with the ignition on. I know there's 3 spades on the right side of the fuse block, but I'm not sure which are the 'in' vs 'out' side of that (iits possible all three are 'out', and the 'ins' are on the other side where you can't see them, I'm going from memory as my daughter's 240 is never home anymore). the drawings show the connections going to spade closest to fuse on the right side of the fuse block.

 

Thats great so you agree like i do ... im glad you understood what i wrote...lol
i should have this finished up this weekend and will keep you posted..thanks so much for sticking with me on this

Brett

 

funny you say this cause this car came with a big variety (bunches of them) like the link you sent me lol you need some lol..

 

all done works like a champ thanks again pierce

 

hey, my car is having the same problem, the battery keeps dying, when i connect my test light between the neg battery post and cable, the light turns on then off right away, do I need to recharge my battery before doing this test?