Melted ECU?

[Skychismo]

I've been having intermittent drivability issues with a cheap '84 325e I picked up. It's fuel injection related, so I pulled the DME. Inside it appeared there was dried Coke on the board. This isn't normal, correct? What DME can I replace it with?

[george graves]

I've been having intermittent drivability issues with a cheap '84 325e I picked up. It's fuel injection related, so I pulled the DME. Inside it appeared there was dried Coke on the board. This isn't normal, correct? What DME can I replace it with?
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I can't tell what it is from that pic. Could be conformal coating.

[Navarone]

The boards are coated to weather and vibration proof them. I haven't seen inside the DME, but my cruise control board was dipped and looked very even, not like that which does look a lot like coke spilled on it. I would guess that's not the problem.

[Skychismo]

The boards are coated to weather and vibration proof them. I haven't seen inside the DME, but my cruise control board was dipped and looked very even, not like that which does look a lot like coke spilled on it. I would guess that's not the problem.

I was thinking it was capacitor guts. There is a portion of the board that is visibly burnt. I've never seen a PCB with thick brown stuff unevenly dripped over it.

[DesertBMW]

I've been having intermittent drivability issues with a cheap '84 325e I picked up.

Those computers never go bad, it is common to see varnish on the board. Old M20 engines will act inconsistent,

[Skychismo]

Those computers never go bad, it is common to see varnish on the board. Old M20 engines will act inconsistent,

The DME's never go bad? It's one of the most common issues with these cars. They have no sort of surge protection. They go bad all the time. The DME's on the E90s are even prone to failure. There are write ups all over the inter webs about bad DME's on the early 325e.

[Navarone]

Melted ECU?

I was thinking it was capacitor guts. There is a portion of the board that is visibly burnt. I've never seen a PCB with thick brown stuff unevenly dripped over it.

What does the other side of the board look like? That seems like a lot of electrolyte so it must have huge caps on it to be their guts. Is it sticky like oil or hard like resin? I work on electronics and it's usually large caps and inductors or small transformers that are glued down, usually cleaner than that, but I've seen some sloppy jobs.

Here is the cruise control board I just took out of my 85 318i. Donno why it doesn't work, no visible faults. Those caps look too small to dump that much electrolyte.

[Skychismo]

What does the other side of the board look like? That seems like a lot of electrolyte so it must have huge caps on it to be their guts. Is it sticky like oil or hard like resin? I work on electronics and it's usually large caps and inductors or small transformers that are glued down, usually cleaner than that, but I've seen some sloppy jobs.

Here is the cruise control board I just took out of my 85 318i. Donno why it doesn't work, no visible faults. Those caps look too small to dump that much electrolyte.

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[ATTACH]90369[/ATTACH]

I'll get a pick of the other side tomorrow. The stuff is hard like resin. Also, the DME was hot to the touch even though the cars been sitting. It felt like it was out in the sun. Even if it's glue I'm wondering if the board heated up and melted it hence the drip pattern. The stuff was oozing out of the case.

[Navarone]

Hrm, wow. Does it drain the battery? Digging through potted circuit boards to fix em is annoying, probably easier to just throw a new one at it.

[Skychismo]

Hrm, wow. Does it drain the battery? Digging through potted circuit boards to fix em is annoying, probably easier to just throw a new one at it.

The battery seems to be holding a charge. Here is a pic of the middle of the two boards. I also have a close up pic of some discoloration on the board. I do t know a lot about circuit boards, so I don't know what is normal. There does seem to be missing solder around a lot of the joints. My plan was to put a new DME in rather than fix this one.

[Navarone]

This is the parts side of the board, so the solder isn't missing, it's all on the other side. I'm not sure of the discoloration you're seeing, is it just the darkening near the silver can op amps and "S200" printed on the board? Or the cream colored puddled stuff? Pretty normal for an old board to be discolored or crusty, but look around heat sources for bad solder joints or puffed up capacitors. I don't see any visible faults, like a blown component, so it'll be too much work to trace down an intermittent fault unless you have a schematic and a scope. Most of the heat in that case is coming from the large resistors and the transistors (probably 5volt regulators) mounted to the case, and that's pretty normal to get warm, but not scalding hot.

[Skychismo]

This is the parts side of the board, so the solder isn't missing, it's all on the other side. I'm not sure of the discoloration you're seeing, is it just the darkening near the silver can op amps and "S200" printed on the board? Or the cream colored puddled stuff? Pretty normal for an old board to be discolored or crusty, but look around heat sources for bad solder joints or puffed up capacitors. I don't see any visible faults, like a blown component, so it'll be too much work to trace down an intermittent fault unless you have a schematic and a scope. Most of the heat in that case is coming from the large resistors and the transistors (probably 5volt regulators) mounted to the case, and that's pretty normal to get warm, but not scalding hot.

Thanks for the input. Sorry, I meant I can see missing solder from the back of the board, not from that photo.