Bought a mess of an E38 for $600s

[daytonatrbo]

This should be a fun(frustrating) project.

its a 2001 740iL with 128K miles, a trashed interior, and no key.

The car had a no-crank issue and the previous owner was told that the transponder chip in the key had failed. He then promptly lost said dead key.

I bought the car for $600 figuring I could spend a little money on a new (wallet) key and just see what happens.

I don't have a key for it yet, but I did take the ignition switch off and I can turn on the car.



**here's my first problem:

When I hook up my OBD/USB cable to the car, there's no response... the light on the cable doesn't even come on. On my e46 it comes on whether the car is on or not. Is it fair to assume that some portion of the DME is not receiving power? I've checked all of the fuses that seem to be related and haven't found anything bad yet.

The previous owner replaced the fusible link block that sits down by the passenger footwell. Ive checked all of the connections there, and there is power going into and out of all connections.



I can already tell this car is going to be a mess of electrical problems. Things like the Nav computer and (seemingly) DME are totally unresponsive.


All insight appreciated. Ive spent the last few weeks researching the e38 extensively. I do know that my 2001 model should allow me access to all modules through the OBD port, so I have not gone out and bought the 20 pin plug.




EDIT: I'VE ADDED SOME PHOTOS ON PAGE 5

[purplecty]

Part out?

[andsteve]

Saw your post on r/BMW, you never said it was this​ bad.

[Mayorchuck]

Did you check the fuse carrier in the ebox? Has 5 30A fuses that protect the DME. Looks like this:

[Binjammin]

sounds like maybe an ews issue? only skimmed the post but no key plus rotated ignition switch?

any history of the car?

[board57796]

JK good luck with the car! Wish I could be more help but electrics are not my forte with these cars.

Enjoy it!

[daytonatrbo]

Did you check the fuse carrier in the ebox? Has 5 30A fuses that protect the DME. Looks like this:

With the ignition off, 3 of those fuses show power, the remainder don't. I will investigate further when I have daylight.




As for pics, all of the pics I have are in the dark and aren't worth much. The car needs a deep clean to even look passable.

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Saw your post on r/BMW, you never said it was this​ bad.

I'm still discovering the extent of the issues. It was difficult to determine much looking at the car 150 miles from home with no keys. I took a gamble.

[roys740]

it may not be as bad as you think. for 600.00 that was a steal. if you part it out you will easily make your money back. I would tally up everything you need to do and then take a step back and re-evaluate. if you decide to get rid of it, I will gladly come and get it. I will tow it back to Illinois and give you 600.00 or a little more for your trouble.

[jaron]

If you are interested I have an ECU and EWS out of a 2001 740i WITH an ignition key cylinder. you can swap the ignition cylinder and ecu/ews and atleast have a working key.

[daytonatrbo]

If you are interested I have an ECU and EWS out of a 2001 740i WITH an ignition key cylinder. you can swap the ignition cylinder and ecu/ews and atleast have a working key.

I appreciate the offer. I just got a quote for a wallet key for $68. I think I'm going to start there.

Something tells me I'm going to have to perform surgery on at least one or 2 of the main modules. This car suffered from a plugged sunroof drain and I'm betting the GM is soaked.

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it may not be as bad as you think. for 600.00 that was a steal. if you part it out you will easily make your money back.

That was basically my thought process.

[danno14]

Check the ignition switch assembly. An issue there can cause many of the electrical gremlins you mention. Just swapped a new one into my buddies car and $68 later- all is well.

[Zedbimmer]

Multimeter is your friend, it lets you know where the power is, where its going, and where it has to be, your mission is to follow the power and discover its break.

[daytonatrbo]

Check the ignition switch assembly. An issue there can cause many of the electrical gremlins you mention. Just swapped a new one into my buddies car and $68 later- all is well.

I removed the ignition switch. I haven't ohm'd it out, but it looks brand new. The contacts are clean and I don't expect it to be an issue.

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Multimeter is your friend, it lets you know where the power is, where its going, and where it has to be, your mission is to follow the power and discover its break.

I agree 100%. I won't be able to dig in as deep as I need to until the weekend. And I misplaced my multimeter. Might be time to buy a better one. So far I've been following the power with a test light. I probably ought to pick one up that is electronics-safe.

[Zedbimmer]

if there is a voltage drop your test light will still light up, but your equipment will not.

[daytonatrbo]

No progress tonight. Had to work late and ended up doing the rear springs on my e46 by streetlight.

[jaron]

LOL I have a GM3 if you're interested too haha

[spetsnaz55]

16 pin obd2 port does not allow access to all modules.

i have a launch Diagun scanner and it only opens up tranny and dme modules through 16 pin, everything else required the 20 pin underhood

nav computer is most likely fried from someone jump starting the car from the battery in the trunk

easy to test by just temporarily swapping with someone that has a working one and seeing if that will light up your nac screen

[blackknight530i]

Does the car have an aftermarket radio? My co-worker has a 97 740il that I sold him in which the previous owner when installing the head unit, disconnected the wires going to the OBD2 port. Can you try to pick up one of the $8 OBD2 to 20 pin round connectors and try it that way? My co-worker needed to get his car inspected and I lent him my adapter cable to take to the inspection station and it worked great. This will also give you access to all the modules in the car, rather than just the DME and EGS.

[xboss]

16 pin obd2 port does not allow access to all modules.

i have a launch Diagun scanner and it only opens up tranny and dme modules through 16 pin, everything else required the 20 pin underhood

nav computer is most likely fried from someone jump starting the car from the battery in the trunk

easy to test by just temporarily swapping with someone that has a working one and seeing if that will light up your nac screen

The OBD cap mod makes the 16 pin work

[spetsnaz55]

hmm any more info? links?? thanks

[blackknight530i]

http://forums.bimmerforums.com/forum...5-OBD-Port-Mod

[daytonatrbo]

16 pin obd2 port does not allow access to all modules.

i have a launch Diagun scanner and it only opens up tranny and dme modules through 16 pin, everything else required the 20 pin underhood

nav computer is most likely fried from someone jump starting the car from the battery in the trunk

easy to test by just temporarily swapping with someone that has a working one and seeing if that will light up your nac screen

Being a 2001 model e38 all modules *should* be accessible through the interior plug, just like they are on my 2003 e46. I read elsewhere that the interior port is left dead for an undetermined amount of time after connecting the battery. This is to prevent someone from fooling an inspection station by cycling the battery to clear the MIL. I ordered the 20 pin adapter just to be sure.


I did did a little digging around in the car just now and found another very corroded power distribution block. There were even some 18-20AWG wires broken loose from it. I'll be finding the bently manual to try to sort out where they broke off of. I'll try to post up some photos.

This guy:


Looks like a few pinched wires too.

I also plan on re-doing the previous owners repairs with proper solder and shrink tube and some better fittings.


Still ill can't find my multimeter. Last I saw it was a few months ago when I was working on my MacBook.

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Does the car have an aftermarket radio?.

All stock.

[E38740iMD]

Did you check the fuse carrier in the ebox? Has 5 30A fuses that protect the DME. Looks like this:

you check these fuses yet? if three show power the 4th one has a blown fuse.
did

[daytonatrbo]

you check these fuses yet? if three show power the 4th one has a blown fuse.
did

Theres 2 hot wires feeding that block of fuses. Only one of them was on with the ignition off. I didn't get a chance to check with the ignition on.

If they are all supposed to be on with the ignition off, it's not those fuses that's the problem, but one of the circuits feeding them.

[E38740iMD]

Theres 2 hot wires feeding that block of fuses. Only one of them was on with the ignition off. I didn't get a chance to check with the ignition on.

If they are all supposed to be on with the ignition off, it's not those fuses that's the problem, but one of the circuits feeding them.

They should all be hot I'm not sure to about if ignition is off. Just check. Promise you'll thank me later. I ran into a similiar issue before