Originally Posted by ssoliman

Dude that sucks.

if you get nothing at all with the starter it could be a ground issue.

do you have a Bentley manual? All the wiring diagrams are in it as well as the ground locations. Might help.

do you have volts on the positive side of the starter?

Originally Posted by ssoliman

good to hear! what is the volt reading on the battery? Is it new?

4 pumps, crap. can you hear the pump prime when you turn the key to 2nd position, just before start position?

with the pump I hear that they should not run without gas, can burn. does the tank have enough gas in it? Also does the electrical plug only plug in one way? or could it be reversed?

Originally Posted by RedSky455

It's kind of hard to follow the original problem statement of this thread, gauges quit, fuel pump crapped out, started chasing down gremlins, splicing connectors, new 42-pin etc something something...car sat for a while then more fuel pump problems, starter was a non-starter, at some point swapped in a new alternator then:



Is there any way you can kind of...un-do all of this? Like just carefully put everything back to stock and start over? Get a new battery, leave in the new alternator but carefully reverse everything else you've just tried?

Here's what's making my stomach and head ache reading through this: the reality is these cars hate hate HATE low battery voltage, which quite often begins with a dead or dying battery and/or alternator that won't keep it charged. Just as bad, they also hate sitting for a long while - even as low as two or three weeks - without being started up and driven or at least put on a battery tender. There are parasitic current draws just sitting there, so a battery can't last indefinitely if the car isn't started and driven from time to time. Welcome to the wonderful world of BMW electronics.

With this in mind, you may not have had a short, an open, or anything like that. I once had a similar issue - intermittently the tach and its lights and digital display would die, then come back to life then die again. Turned out it wasn't a gremlin, short, moisture or pinched wire. It was a s**t battery from my local brick and mortar parts place. These days we're lucky to get a couple years from a battery. Most aren't warrantied longer than 36 months.

Whatever is the problem, we're pulling for you to find it and get back on the road soon. Anything we can do to try and help we will.

In case it helps, here is the BMW Newtis link for online chassis service manual and wiring diagrams, sometimes it's easier to go through it on screen than leafing through Uncle Bentley.

Good luck and keep us posted!

Originally Posted by RedSky455

Okay, that's a pretty significant detail. Hence why the car interior is torn apart; get it now. At this point we don't know what's operating and what isn't due to old age, sitting, corrosion, the rats etc. Cleaning out the infestation and seeing where they have been and what they've chewed makes sense as a first step (after you get the rats excluded from that garage if possible).

Hopefully you can find it all and sort it out which will take time. If it's really bad, maybe source a whole loom from a junk yard car, assuming you can find one that hasn't likewise been eaten up by rats. That might prove even more challenging.

As for a battery, I'm obviously not an expert and others will weigh in, but I've "seen some Bimmer guys on YouTube" (Nathan's BMW Shop for example) who've sworn by Walmart. Just simple, ordinary flooded lead acid (not AGM) battery. No battery is cheap anymore, like they used to be, unfortunately. My last one was free under warranty, so I didn't research it much further. Probably should.