Hi all, have been reading for a while but this is my first post so please bear with me.
Today, I stopped off at a service station. After fueling (I've checked the receipt - it is the right fuel), I got about 30 seconds down the motorway when it just died. Total loss of engine power.
All the lights come on as they should, it cranks fine, it just never fires up.
I'm suspecting something fuel related as when I loosened a fuel pipe, nothing appeared to be getting through on cranking the engine but haven't as yet been able to test the pump(s) to see if they work.
However, when i went to inspect the pumps I found something I don't quite understand. From one of the terminal posts on the pump, someone has run a wire all the way back to the battery bay, following the brake pipes and often wrapped around them. However, this doesn't appear to be connected to anything.
In the same area, there is an identical connector also unconnected, which appears to be spliced from one of the wires feeding what I believe is the OVP relay.
Does any of this make any sense to anyone, or explain why I suddenly have no power?
I've attached a photo to try and explain this better.
Having read a little further around my little problem, people seem to think that the fuel-pump relay is a likely potential culprit (and as good a place as any to start fiddling bearing in mind the weird wiring thing that's put me off testing the pump so far).
Assuming that I have the right relay (0035452405 - I've googled it and it's a fuel-pump relay), can anyone tell me how I can go about testing this? In particular, how can I open it up if I want to check the connections and any joints inside? It seems completely sealed apart from the gel-like substance that surround all the terminal posts.
Sorry for all the questions, I'm finding my way with this. Any input from knowlegable people would be greatly appreciated!
It sounds like a previous owner may have installed a set of jumper wires to get around a power-to-the-fuel-pumps problem. He/she probably connected those loose wires directly to the battery terminals to start the engine when the pumps wouldn't run. Weird. Maybe he/she looked at the price of a fuel pump relay...
As for opening up relay, don't. You would be amazed at all the crap in there. It is *far* from a normal relay with only a coil and contacts. That box is packed with resistors, capacitors, little circuit boards, and even some integrated circuits. That's becasue the "fuel pump relay" does a lot, lot more than power the fuel pumps.
If you can figure out what's going on in there you're on your way to a career in electrical engineering.
Augapfel - thanks so much for that! It was exactly that. Once I connected the jumper wires to the battery, all was right with the world. Disconnect them and the engine stops immediately.
I'm guessing the PO had problems with the relay, did this as a temporary fix until he could get a replacement and now that replacement relay has gone the way of the first.
So, off to find another relay. Thanks again -your advice saved me potentially hours of head-banging frustration.
If the relay isn't working then the pumps won't run when you turn the key to the "run" position (not the crank position). My pumps run for a couple seconds and you can hear them. My relay was a bit flakey but I took it out banged it around on all 6 sides and put it back in and the car has been working fine for months! Something is loose and rattling inside. Oh well, a new relay is about $180 here in Canada from NAPA.
I'm diggin up an old thread of mine for some advice about an unusual problem - all suggestions welcome!
I managed to get my 260 up and running again with a new (scrap) fuel pump relay. Good news.
However, within 4 weeks, this relay had packed up too and so I decided, in the meantime, do dismantle the old relay and have a look.
Basically, I found that part of the PCB had burnt through, meaning no power to the pumps. So I soldered a piece of wire across the burnt out section, crossed my fingers, and...have been running it perfectly lke that ever since.
I've just cracked open the 2nd relay unit and found that it had burnt through in the exact same place, so I'll be repeating my soldering trick so I have a back-up.
My questions is: was i just unlucky to have this happen or have I uncovered a deeper electrical problem with my 260 that could be causing the burning out?
Incidentally, I'd recommend it to anyone who has lost the use of their fuel-pump relay - it can be opened and yes it's a complicated-looking object, but the actual repair was 2 minutes long and monkey-simple.
Yeah, it is a bit strange. I'd have thought a fuse would have protected it somewhere along the line, but it doesn't look that way. In any case, i'm pleased to have it running so nicely, even if I do start to imagine electrical burning smells in my nightmares!
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