[pred]

OK,
So due to some issues I let my 1999 528IT 5 speed sit for about a month,
Its been a great wagon which I typically used for my weekly 600 mile highway drive across the state.
Ive had a ACS light on for about a year due to the module, But all else has been fine and working well,
So today I jump in it,
The EML light is on, The temp gauge reads full hot and the AC compressor won't turn on, All else words as it should,
While sitting in the car the EML light flashed off and the temp needle returned to center and then EML light back on the temp needle went right back to full hot,
The wagon has about 180K miles,
The cooling system has been replaced and it is not running hot,
The only thing which happened in recent history is that the Exp tank blew on a bad factory seam and filled the engine compartment with nice hot antifreeze steam, I replaced the tank and did 1200 miles on it worry free since then.
So now this goofy stuff is going on and I need to start to run the car again in two days, 300 miles across the state and back again in a few more days,
Is there anything I can clean of check?
No CEL light on at this time,
Just the dang EML light,
AC is filled with R34 and has never leaked, At this time there is pressure in the system buy my Gauges are at work so I don't know exactly how much or if the two things are related somehow,
Any and all suggestions will be checked as swiftly as my job will allow,
Thank you,
Peter B

 

[pred]

Update
Took wagon out for a drive,
Its drives 100% normal EXCEPT these items
Oil service light stays on,
EML light on
TACH not working
MPG swinging needle not working
AC not working
Voltage not running 12.5v
At idle 13.8v
Temp needle reading full hot when running perfect temp.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Any ideas?

 

[johnstern]

I think the first thing to do is check/test your battery/alternator system. Our cars do strange things when the electrical system produces less than 12 volts. If you have a digital volt meter you need to check the battery voltage with the car off and with the car running and reports back. You can also unlock your OBC (on board computer) and do the same test with test #9.

If you don't know how to unlock the OBC, do a search.

BTW-an EML light always indicates a throttle body (or its associated parts) problem. You'll need a Scan tool that reads proprietary BMW systems to read the codes.

 

[sixpot_simon]

That voltage at idle is about right. What is the voltage with the engine off?

My guess is that the problem is in the dash, or a connection to it.

 

[AH673000]

Bad ground for the dash or a weak/ dead cell in your battery. Start with the battery .

 

[pred]

Battery good,
It was new about 1 year ago and I can let car sit for 3 to 4 weeks and she always starts tight up,
If you come to car after sitting, Voltage is 12.4 or real close to that,
I was thinking of the issues Ive had with the car and I remembered that one weekend trip is would miss and skip pretty bad on the way out, It had me really worried,
But the next morning it rad 100% as it always has, That was after it sat for a couple weeks and there was a lot of rain,,,,
The floors don't ever get wet after a rain, But I am now moving it into a garage when not in use,
You're saying ground for dash,,,,
DO I need to pull the cluster to get to the dash grounds or are they located in a more spacious space?
Whats next step?

 

[TheAngryBear]

Some obvious questions but then some thoughts:

Update
Took wagon out for a drive,
Its drives 100% normal EXCEPT these items
Oil service light stays on, When was the last time the service interval was reset?
EML light on
TACH not working this and...
MPG swinging needle not working this point to abs. Have you checked your wheel speed sensors? Are you getting signal and same speed when you are moving and watching this via scanner?
AC not working
Voltage not running 12.5v
At idle 13.8v
Temp needle reading full hot when running perfect temp.Did you rebleed your cooling system? Any leaks?
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Any ideas?

Battery good,
It was new about 1 year ago and I can let car sit for 3 to 4 weeks and she always starts tight up,
If you come to car after sitting, Voltage is 12.4 or real close to that,
I was thinking of the issues Ive had with the car and I remembered that one weekend trip is would miss and skip pretty bad on the way out, It had me really worried,
But the next morning it rad 100% as it always has, That was after it sat for a couple weeks and there was a lot of rain,,,,
The floors don't ever get wet after a rain, But I am now moving it into a garage when not in use,
You're saying ground for dash,,,,
DO I need to pull the cluster to get to the dash grounds or are they located in a more spacious space?
Whats next step?

did you check for evidence of water around the brake booster?
Most importantly, have you read the codes? Maybe I missed it but I don't see that you connected to your scanner to read for misfires, codes, etc.

Edit: forgot the fuel trims need to be read too