[ccericks]

I'm new to this forum but I've found such great advice here in the past that I needed to post some questions. I have a 2002 325i and about 2 weeks ago, upon start up, there was a very rough, cough, idle and sluggish acceleration. Felt like a vacuum leak or coil misfire. I looked under the hood and did find a bunch of holes and cracks in the lower intake boot, especially around the smaller diameter tube that goes into the engine. Replaced this lower boot and was hoping that would completely fix the problem. It fixed about 80% of the problem, but my check engine light remains. Codes read P0313 - misfire, P1619 - cooling system (thermostat), and P0102 - MAF, vacuum leak.
The symptoms that remain are a slightly rough idle. It is consistent and steady, very rhythmical. It doesn't sputter and die like I've read on some other posts. The acceleration is still sluggish, but not nearly as much as before, and only seems to be sluggish up to about 3000 RPM, after 3000 RPM it feels like it pulls better.
I should also mention that the car uses oil, so that I have to add at least 4-5 quarts between 3000-4000 mile oil changes
I've watched videos and read multiple posts. Where should I go next? I would like some direction rather than just pulling things out and guessing. DISA valve, CCV, ICV, thermostat, MAF????
Thank you for reading.

 

[Fast Bob]

OK, let`s take a realistic look here. Your car is 13 years old now, which means it probably needs pretty much everything by now....to wit:

ICV cleaned
DISA valve rebuilt
VCG
VANOS seals
CVV and all attendant hoses (don`t forget the oil dipstick tube)
New Plugs
(Probably) New 02 sensors (should be replaced after 120K miles)

and, of course, a cooling system rebuild (this is the MOST important thing)

 

[ccericks]

Thank you very much for the help and information Fast Bob. Yes, the car has some years and some miles on it, appox 161,000. I will start this weekend with cleaning and checking the ICV and DISA valve since they are close together. The CCV, from what I've read is a pretty big job, I'll have to have a little more time for that. I'll have to watch some youtube videos and read some more forums on the O2 sensors as I haven't done that before. If no luck, I think I'll go into the coil packs and spark plugs. What exactly is involved with a cooling system rebuild?

 

[Fast Bob]

Thank you very much for the help and information Fast Bob. Yes, the car has some years and some miles on it, appox 161,000. I will start this weekend with cleaning and checking the ICV and DISA valve since they are close together. The CCV, from what I've read is a pretty big job, I'll have to have a little more time for that. I'll have to watch some youtube videos and read some more forums on the O2 sensors as I haven't done that before. If no luck, I think I'll go into the coil packs and spark plugs. What exactly is involved with a cooling system rebuild?

Here`s a decent deal on a good, basic cooling system rebuild kit:
http://www.oembimmerparts.com/BMW-Cooling-System-Refresh-Kit-p/e46coolrefrkit.htm

G.A.S. makes a DISA rebuild kit (around $85, I think) that will make the DISA better than a new factory unit.

The CVV is difficult due to it`s location, but not impossible. Cleaning (or replacing) the dipstick tube is important.

As long as your current coils are working, you will gain nothing by replacing them.

 

[ccericks]

Other than the code that my car threw for the MAP cooling, what are the symptoms associated with a thermostat or cooling system problems? Would that cause my rough idle and sluggish acceleration? More importantly, would replacing those things fix my issues?

 

[Fast Bob]

Other than the code that my car threw for the MAP cooling, what are the symptoms associated with a thermostat or cooling system problems? Would that cause my rough idle and sluggish acceleration? More importantly, would replacing those things fix my issues?

On BMWs, the cooling system is it`s weak point....the old "Weakest Link In The Chain" concept. One thing you can be 100% sure of, is that the system WILL fail, often catastrophically, taking the engine with it. These engines do NOT tolerate overheating, not even one episode. So, with that in mind, it`s always best to be pro-active, and head trouble off at the pass....while a full system rebuild ain`t exactly cheap, it`s a drop in the bucket compared to cleaning up the aftermath of an overheated engine.

 

[marcozandrini]

Op, Google "BMW E46 OBC hidden functions." It will show you how to read various data that the ecu is seeing. Test #7 is the coolant temp reading. It should be between 95*C and 100*C once the engine is fully warmed up. If it's in the high 80's the thermostat is kaput. That's probably why you've got a thermostat related code. Also, have the intake smoke tested. As noted, these cars are getting old, and rubber & plastic parts are nearing the end of their useful life.

 

[Rob43]

OP, what Bob has already stated in post #2 is accurate, here's another way the cooling system ties into your current issue. Hopefully the owner before you didn't cook your motor with a bad cooling system leaving you with a bad cylinder or two, because I doubt you performed a Compression Test on the motor when you bought it. Other new parts that I'd look into would be: 1) Fuel Filter 2) Fuel Pump, & 3) 2 Cans of BG 44K Fuel Injector Cleaner (Dealer Grade).



Good luck,
Rob43