Oil on the 52-pin dme connector

[bryancornish]

Hey guys,

First off sorry for a (probably) way too long story haha.

The car in question is a '99 520i with a ms42 dme

So 2,5 weeks ago i bought my first bimmer. And last week i already had a problem that got me scratching my head.

I drove to work and as soon as i went through the gates at work my car went into limp mode i saw the eml light up together with my asc light. So i went ahead and called roadside assistance maybe they knew an temporary solution to at least get home that evening. They came and they read an A9 code: engine-throttle output-stage shutoff after diag. Error.

He thought it was the throttlebody but i was going to be able to come home. And i was, at a maximum of 100kph, but i came home. So i wanted to check out a few connections and to be sure i disconnected the battery and started checking. Found nothing. Next morning i realised i made a mistake by closing the boot with my battery disconnected. Lol. Rookie i know. So i went and called roadside assistance again and they unlocked the car for me. the guy was really nice and said he knew quite a few things of of older bmw's so he wanted to read the code(s) too.
This time it gave the a9 code and 2 p codes
P1580 and p0505

This made it point only more to the throttlebody and i went to a bmw specialist for a diagnose on inpa/dis. He told me to replace the throttlebody too. So over the weekend i bought an used one with warranty of 6 months and put it in the car. I went back to the specialist on tuesday to try and clear the codes and go through the learning-in proces of a 'new' throttlebody.

Well this backfired and he said i still cant get the codes out but you also have an malfunction on your maf and a relay that has to do with your thermostat is also malfunctioning. And that i should check for corrosion on my dme. (He couldn't check it himself as he was shorthanded in the shop due to vacations and what not, but he diagnosed it in between other work and for free!)

So i went and opened the box around the dme and unplugged it and what do you know... oil on connector 3 the 52-pin one.
Im not really sure what to do now i tried cleaning out the port on the dme, this worked with contact cleaner. but i cannot get the oil out of the little pinconnectors on the plug side. I already opened up the plug and took the wires out of the sockets and tried to clean it but still no luck. Maybe a suggestion for a solvent?

I am planning on replacing the wiringloom for the engine in my vacation but thats still 6 weeks away from now. I there something else i can do? Or any tips?
Also the mechanic said my fail-safe (eml+asc) should go off as soon as i fix the issues, is this true?

Oh and i already checked my disa this stil has vacuum with the 'finger test' but doesnt close at idle as if there is no power coming from the plug. Also no movement as i unplug it.
I cleaned my icv and it is moving freely. No rough idle maybe the first 10 seconds on a cold start and after a rev it seems it searches to find the idle point. But quickly stabilizes.

I am sincerely sorry if i did ask all this in the wrong place or if i should have put this in another thread as i couldnt find a similar problem.

Many, many thanks in advance!

[pleiades]

Can't help much with the oil on the dme plug connector but are you sure it's oil and not coolant? I know this is probably irrelevant because your car is not one with the V8, but the 540i models do have one scenario where coolant wicks up the harness from the thermostat into the DME connector.....

Also, about the trunk (boot) .... You can manually open it with your key turned all the way (90 degrees) to the left. Battery power not necessary (at least this is true of e39s that were shipped to the US market ....)

And welcome to the forum, you are in the right place ...

[geargrinder]

Quick google comes up with also stories of M62 VANOS solenoid connectors wicking oil to the DME connector. I'd never heard of it before so its freaky rare, but there's a similar VANOS connector on the M52 I think, so maybe have a look at that? If its pushing through oil all the way to the DME then you should be able to see it wet and drippy at the 'source end' for sure...

As well as any other oil-touching DME sensors... although it'd be more likely to be something high up on the motor and not down low, I wouldn't expect an oil level sensor to be able to push the oil up all the way to the e-box.

[bryancornish]

Well i've been trying to find out what the 52-pin connector is for and it seems that it is controlling all the valves and sensors for air coming into the engine. For example; maf, throttlebody movement, disa, icv etc. etc. So i think i narrowed my problems down to my dme being fried or the connector being so clogged up it isn't sending/receiving signals. But i also have to do something about the root of the problem being the oil... is there a solenoid or sensor that is near oil that is reading/controlling something in the air intake system? Also what is best to use to remove oil residue but isn't inducing corrosion?


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[bryancornish]

Btw thanks for the helpfull tips already! I really appreciate it!


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[JET79]

I had this happen to me. I have a m62tu though. Check all your connections to all the sensors from the engine harness. I had oil pushed to all my coil connectors maf connector and even down to my O2 sensor connectors. Found when I unplugged my passenger side Vanos solenoid oil dripped out of it. Replaced the solenoids and scored a clean engine harness from the junk yard and all my strange check engine lights went away.

[geargrinder]

is there a solenoid or sensor that is near oil

Alstublieft... ^^^^ This is the first question you need to answer... and not try to get too smart about...

that is reading/controlling something in the air intake system?

Because if that oil is gooping stuff up at the DME, it easily could be screwing up things that are not related to the wire that is doing the leaking. Fix the oil situation first, then see what's happening. Its probably the oil leak causing a problem with something else on the connector or in the DME.

Also what is best to use to remove oil residue but isn't inducing corrosion?

Hard to tell you exactly what to get in the Lands of Nether, but generally some kind of solvent based no-residue electrical cleaner, at least first.

There are more or less 2 general kinds of 'contact cleaner' you'll find on the shelf -
1. kinds with pure high-flash solvent to wash stuff up... and
2. kinds with solvent but also some lubricant / oils to treat contacts and/or potentiometers

If you want to get really specific, there's often several kinds of the latter... like 2.a - 'contact' type lubricants for pin connections and switches, and 2.b - 'pot & fader' lubricants for things with potentiomter tracks and wipers. The distinction isn't that big a deal tho unless you're working on some kind of vintage pro audio gear or something.

In your case I'd open up the DME, then use the first kind without lubricants to wash everything down, then I'd put the DME case back together and hit the contact pins and the connector side both with some thing that has some 'contact treatment'.

Again no idea whats available but here in USA I'd use something like this:



Followed by something like this:

[bryancornish]

Hey guys, ive been looking for an oil leak near any sensor or solenoid and couldn't find any.. maybe an previous owner had a leak and fixed it?? I've also read stories about doing a sloppy job at a headgasket job can result on dripping oil on the wiring loom. Anyway i now know my disa and my second sourced throttle body arent working. So i need a way to know if these are broken or my wiring loom/dme is broken or damaged. Any suggestions?


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