Low Idle and now stalling....98 528i

[blodi]

My 98 528i started having idle issues the other day after I came out to start it and the battery was dead. I charged the battery and was able to start it, but it was idling really low 3-400rpm. This morning I came out and the battery was dead again. I was able to jump it and drive it and pick up a new battery for it. I replaced the battery, but the idle is still really low and rough.
I took out the ICV and cleaned it, it didn't look too bad. I put it all back together and it was no different, still low idle. I took it for about a 1 mile drive and now it won't even hold an idle as I was coming back, it runs fine if I keep my foot on the gas, but won't hold an idle itself.
Any thoughts? I disconnected the battery to see if maybe that will reset the ecu....maybe the ICV is just shot?
It just seems strange that its been fine before the battery went dead.
Any help is appreciated.

[Ken....]

[blodi]

Just came on....
Got "Idle speed not plausable" and "Air Mass Sensor"

I replaced the MAF back in the spring. It was idling rough and shifting really rough. Maybe that's it? I tried putting the original MAF back in just now and there was no diff. It was an aftermarket MAF I bought, so maybe it already went bad?

[Blodi]

Just tried to start with maf disconnected. Still won't idle and reved a little rougher. Also the car will not start unless i am giving it gas.

[JimLev]

"Drive It Like You Stole It, A Sickness for Quickness"
The Bottle Rocket "King of Spray" 2 Stage Nitrous Oxide
Dare to be different and stand out among the crowd of me-to-cars!
No guts, no glory! Tire smoke, not traction control!
Zionsville all aluminum radiator to replace the 3 leak prone Nissens Radiators!

NOS Progressive 2 Stage Controller with port injection
Snow's Performance Methanol/Water Injection
Dinan downloads, VAC Under Drive Pulleys
Dinan Carbon Fiber CAI
Dinan Front Strut Bar
Electric Cooling Fan w/PWM controller
NGK Iridium Plugs
DDE Enhanced Angel Eyes, Smoked Lenses
Koni FSD's/H&R Springs, BAV Brass Caliper Bushings
Eisenmann Race Exhaust (from H8-Rain's car)
///M5 3.15 LSD
///M5 Sway Bars, Front & Rear
Energy Suspension Polyurethane Sway Bar Bushings
///M5 Gauge Cluster Rings ///M5 Lip Spoiler
///M5 Mirrors and Switches
Leather Z weighted shift knob (thanks H8-Rain)
Rogue “Octane” Short Shift kit w/WSR
Rogue Tranny Mounts
StopTech Brake Lines Front & Rear
Axxis Deluxe Plus pads Front & Rear
Staggered M Parallel 66, Xenons
Modified CDV, UGDO
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Redline in Diff and Tranny
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G-Tech/Competition Pro Data Logger
Auto Enginuity OBD-II Scan Tool
25% Tint, X-Pel, LoJack
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[Blodi]

Looking for leaks.....nothing.

[JimLev]

"Drive It Like You Stole It, A Sickness for Quickness"
The Bottle Rocket "King of Spray" 2 Stage Nitrous Oxide
Dare to be different and stand out among the crowd of me-to-cars!
No guts, no glory! Tire smoke, not traction control!
Zionsville all aluminum radiator to replace the 3 leak prone Nissens Radiators!

NOS Progressive 2 Stage Controller with port injection
Snow's Performance Methanol/Water Injection
Dinan downloads, VAC Under Drive Pulleys
Dinan Carbon Fiber CAI
Dinan Front Strut Bar
Electric Cooling Fan w/PWM controller
NGK Iridium Plugs
DDE Enhanced Angel Eyes, Smoked Lenses
Koni FSD's/H&R Springs, BAV Brass Caliper Bushings
Eisenmann Race Exhaust (from H8-Rain's car)
///M5 3.15 LSD
///M5 Sway Bars, Front & Rear
Energy Suspension Polyurethane Sway Bar Bushings
///M5 Gauge Cluster Rings ///M5 Lip Spoiler
///M5 Mirrors and Switches
Leather Z weighted shift knob (thanks H8-Rain)
Rogue “Octane” Short Shift kit w/WSR
Rogue Tranny Mounts
StopTech Brake Lines Front & Rear
Axxis Deluxe Plus pads Front & Rear
Staggered M Parallel 66, Xenons
Modified CDV, UGDO
Euro Storage Tray (thanks Zombywolf)
Redline in Diff and Tranny
Passport 8500 X50, Escort ZR3 Laser Jammer
G-Tech/Competition Pro Data Logger
Auto Enginuity OBD-II Scan Tool
25% Tint, X-Pel, LoJack
PIAA Driving Lights
BMW CCA Member Boston Chapter

[Ed CT]

Did you do these things when you disonnected the battery to reset the ECU:

1. open trunk and wait :16 minutes until car goes into sleep mode (trunk light will go out)
2. disconnect the neg terminal cable, then the positive terminal cable
3. touch the disconnected CABLES together while turning the ignition on for 15 seconds (this will disipate any residual power in the systems
4 reconnect the pos cable to the battery, then the neg cable

Might be worth a shot. A low battery can cause all sorts of funny electrical gliches.
Ed CT
1998 528i (aka, best car I ever owned!)
5-Speed
Aspen Silver
Aubergine Leather
Zeckhausen CDV
Nokia CK-7
D-Con Cache on Fuel Pump Cover

[Blodi]

My new MAF is supposed to get here tomorrow, so hopefully that does the trick. I appreciate the suggestion though,

[E39_Silver]

something that happened overnight. You have a new battery (consider unrelated), I would take a look at your intake manifold gaskets, since you say you have fairly new MAF and start from there back to the intake gaskets and all vacuum lines. From personal experience I was unable to find these leaks with the old "spray TB cleaner and see if RPM go up/high". And also can you hear the ICV "humm" when you open the ignition switch?

[Craig in Canada]

I haven't had a MAF go bad on my M52, but from everything I've read if the problem is the MAF then disconnecting it will fix the symptoms. From what you've described, it doesn't. Perhaps you'll get lucky - please let us know.

[Eurodavid]

hoses will cause the idle to do exactly what you, Blodi, are describing. You need to get in there and, as Jim says, remove them to check them thoroughly (it's not hard to get at the ICV and it's hoses). As far as the continual dead battery, the two issues may not be related.

Eurodavid

[Ken....]

I had an aftermarket MAF go bad on me after a few months.

Also check the air intake boot.

Ken....

[Ed CT]

If the new MAF doesn't do it, and you don't find any leaks, it could be the camshaft position sensor. A bad one will cause rough idle and stalling. BUT, read the CEL code first to get pointed to the system that has the fault.
Ed CT
1998 528i (aka, best car I ever owned!)
5-Speed
Aspen Silver
Aubergine Leather
Zeckhausen CDV
Nokia CK-7
D-Con Cache on Fuel Pump Cover

[Craig in Canada]

Blodi: M52 or M52TU engine (what's your date code in 1998)?

On my M52, when my camshaft sensor went at first the only thing I noticed was the CEL. After that, and with it disconnected, the only thing happening was that VANOS wasn't active. In this state it was gutless, but if you were just driving sedately around town you might not even notice the difference.

I'm not sure how the double VANOS M52TU might react differently. I think it's a much more serious issue with double VANOS engines when these sensors don't operate correctly since both cams are adustable.

[blodi]

It was the MAF. Put the new one in and it took it about 10 sec or so for the ECU to readjust, but just took it out on a test drive and its running good as ever. Thanks for all the suggestions and help guys!
To answer a question its the single vanos M52.
I guess the moral here is, don't buy cheap MAF's!

[Craig in Canada]