RPM bouncing between 400-1k on cold start..ISSUES?

[72dan]

I have run many tanks of gas through the car with the problem. A buddy who races dirt bikes said California has been putting in more ethanol and that may be it. I tried blending super unleaded with 100 octane unleaded. I think I picked up a few horsepower but didn't fix the idle problem. The race gas here is over $9 a gallon, ouch. Don't know if it threw any codes.

I used to build race engines over 20 years ago. My normal routine with something like this is change the spark plugs, clean the throttle bodies. Had a similar issue with my first Toyota Tundra, an independent said I needed a throttle position sensor, I cleaned everything out, new spark plugs and it was perfect.

The problem with dealership mechanics is flat rate, they get paid x hours for a job so there is incentive to rush it. If I have them clean the throttle bodies they will spray carb cleaner in with the motor running. That washes down the cylinder walls with the crap which isn't good for the engine.

If I want it done right I think I have to do it myself.

[Arben72]

It's the gas. Even if your using 93-91 it's still the gas quality. I had the same problem from 93 from bp.

[Dkhan23]

Are you sure it's not the Winter Blend gasoline which I think California uses?

[thekurgan]

Do it yourself, if techron hasn't helped.

[Magnetic Fusion]

Originally Posted by e92zero

Hi, I have just started to notice this on my car also. I have about 24k miles on my car. Happened 2 x the last couple of months when it's really cold and I left the car outside for the whole day. If I start driving off right away (like 10-15 seconds after start up), at the first stop sign that I get to, the idle would jump between 500-800. Never feel like it wants to stall and will go away if I just let it do that for maybe 10 seconds. If I let the engine warm up for 30 seconds or so before driving off, this won't happen. Sean05/Richpuer, does your car need any fix or it runs perfectly fine as time go on. Thanks in advance.

I just moved from sunny Arizona to freezing ass cold NY and starting noticing this same problem...like the car has to warm up or something. This is my 6th BMW and I always like to clean the ICV but I usually will do this when I need to take the intake off...which is a hassle! I let it run for about a minute and it goes away and I have a smooth idle. I'm throwing no codes but I know it never used to do this in Arizona. I used to travel for work and within 1 year of owning the car I had only driven it three times for about a week at a time. Now I driving it everyday and its getting annoying. Is there anything I can do to clean this without removing it? I like my cars to run smooth and I've never had a BMW break down on me in 10 years of owning one. The inline 6 is one thing but this V8 is another....its a very tight squeeze in the engine bay! A quick fix it needed please

[Magnetic Fusion]

Originally Posted by Dkhan23

Are you sure it's not the Winter Blend gasoline which I think California uses?

The M3 engines are calibrated to run 87 octane because idiots don't like to read the "Premium Unleaded Fuel Only", and they would complain their car ran like shit. So with the E9XX cars BMW calibrated for use with 87 to solve the "idiot" problem but still use the "Premium Unleaded Fuel Only" sticker. If you can afford a M3 you can afford to pay an extra $0.30 cents a gallon! So, yes...the gas shouldn't be a big deal. BMW recommends Shell because they use nitrogen that will keep your valves clean. Of course, no Shell where I live

[e92zero]

Originally Posted by Magnetic Fusion

I just moved from sunny Arizona to freezing ass cold NY and starting noticing this same problem...like the car has to warm up or something. This is my 6th BMW and I always like to clean the ICV but I usually will do this when I need to take the intake off...which is a hassle! I let it run for about a minute and it goes away and I have a smooth idle. I'm throwing no codes but I know it never used to do this in Arizona. I used to travel for work and within 1 year of owning the car I had only driven it three times for about a week at a time. Now I driving it everyday and its getting annoying. Is there anything I can do to clean this without removing it? I like my cars to run smooth and I've never had a BMW break down on me in 10 years of owning one. The inline 6 is one thing but this V8 is another....its a very tight squeeze in the engine bay! A quick fix it needed please

I think we are talking about a different issue. Mine is as the OP stated, it only happens when driving off right after it starts and the engine jumps around a bit . My idle don't really jump around if I am not moving. I just let it run for like 20 seconds on start up before driving off and I don't experience the jumpy/jerky engine response. You might have a different issue with the ICV which seems to be a common thing on this engine. Hope you find the issue.

[Sandye90m3]

Anybody know the cost to replace the ICV without warranty?

[e92zero]

Originally Posted by Sandye90m3

Anybody know the cost to replace the ICV without warranty?

I think Mike has it done and listed the bmw work order here:

http://www.m3post.com/forums/showthr...+control+vavle

[Magnetic Fusion]

Originally Posted by e92zero

I think we are talking about a different issue. Mine is as the OP stated, it only happens when driving off right after it starts and the engine jumps around a bit . My idle don't really jump around if I am not moving. I just let it run for like 20 seconds on start up before driving off and I don't experience the jumpy/jerky engine response. You might have a different issue with the ICV which seems to be a common thing on this engine. Hope you find the issue.

No. We are talking about the same issue. When I drive off the car kinda studders a bit when its getting going for about 20 seconds, then goes away. My idle doesn't jump around at idle either. I was just stating that I try to let the car warm up for a few secs before I take off because I hate when it studders. Like its starving for gas for 20 seconds. Trying to find out if theres a cleaner or system flush I can do to the intake or gas system to fix this.

[thekurgan]

Originally Posted by Magnetic Fusion

No. We are talking about the same issue. When I drive off the car kinda studders a bit when its getting going for about 20 seconds, then goes away. My idle doesn't jump around at idle either. I was just stating that I try to let the car warm up for a few secs before I take off because I hate when it studders. Like its starving for gas for 20 seconds. Trying to find out if theres a cleaner or system flush I can do to the intake or gas system to fix this.

Have you tried a couple of tanks with Techron concentrate plus? Maybe two tanks back-to-back? Cheap enough to give it a try, in the event it's not the ICV causing your issue.

[Magnetic Fusion]

Originally Posted by thekurgan

Have you tried a couple of tanks with Techron concentrate plus? Maybe two tanks back-to-back? Cheap enough to give it a try, in the event it's not the ICV causing your issue.

No but I will on my days off. Now that I have a recommendation. The car has 88,000 miles Im sure its time for some fuel system cleaner

[RogEphedra]

Sorry to bump an old thread.

If anybody is researching this problem and has the following observations:

• fluctuating idle problem (down to 400 RPM, up to 1100 RPM, back down to 400 RPM, up to 1100 RPM, etc etc continuously)
• you notice or can re-create the problem after filling up with gas and then sitting idle for a few minutes
• also have the problem under other circumstances
• the problem isn’t related to cold starts

Then it is extremely likely your “fuel tank vent valve” aka “fuel tank breather valve” needs replacing. Replacing that fixed the fluctuating idle problem for me and others. See this thread called "E92 M3 Erratic Idle After Fill-Up":

http://www.m3post.com/forums/showthread.php?t=953477

[gpitts]

Originally Posted by RogEphedra

Sorry to bump an old thread.

If anybody is researching this problem and has the following observations:

• fluctuating idle problem (down to 400 RPM, up to 1100 RPM, back down to 400 RPM, up to 1100 RPM, etc etc continuously)
• you notice or can re-create the problem after filling up with gas and then sitting idle for a few minutes
• also have the problem under other circumstances
• the problem isn’t related to cold starts

Then it is extremely likely your “fuel tank vent valve” aka “fuel tank breather valve” needs replacing. Replacing that fixed the fluctuating idle problem for me and others. See this thread called "E92 M3 Erratic Idle After Fill-Up":

http://www.m3post.com/forums/showthread.php?t=953477

The other important thing was that my issue (the thread you posted) only occurred immediately after a fill-up. If the OP is experiencing this issue at other times, it is probably unrelated to the issue I posted about.

[RogEphedra]

The other important thing was that my issue (the thread you posted) only occurred immediately after a fill-up. If the OP is experiencing this issue at other times, it is probably unrelated to the issue I posted about.

Hey gpitts. I had the issue at other fuel levels, in addition to after filling up. Though it was easiest to re-create after filling up and sitting idle. I may be going out on a limb, but I'll say that if the idle issue is happening as we have experienced and described, then I'm sure it's the breather valve (or breather valve + carbon canister), regardless of how much fuel in the tank. I could be wrong though. But I haven't read where anybody experiencing this exact idle issue replaced the breather valve and it didn't solve the problem.

[MiamiE93Vert]

Is there a DIY guide on this yet?

[rzm3]

I have the same symptom. Changed idle control valve, didn't work. Updated to latest software, didn't work. No codes. Still trying to figure out the cause...

The "bouncing" occurs as the engine transitions from the catalyst heating phase to normal map. After that, runs completely normal.

[rzm3]

Originally Posted by RogEphedra

Sorry to bump an old thread.

If anybody is researching this problem and has the following observations:

• fluctuating idle problem (down to 400 RPM, up to 1100 RPM, back down to 400 RPM, up to 1100 RPM, etc etc continuously)
• you notice or can re-create the problem after filling up with gas and then sitting idle for a few minutes
• also have the problem under other circumstances
• the problem isn’t related to cold starts

Then it is extremely likely your “fuel tank vent valve” aka “fuel tank breather valve” needs replacing. Replacing that fixed the fluctuating idle problem for me and others. See this thread called "E92 M3 Erratic Idle After Fill-Up":

http://www.m3post.com/forums/showthread.php?t=953477

Doesn't occur after fill up for me. Although I did buy a new tank breather valve just for the sake of trying...

[Andersson]

I had the same problem with pending rpm, not only during cold start. I checked for codes and found out that I had a bad acceleratorpedal. I changed the whole module and the car has been running fine since I changed it. Knock on wood!
Hope this can be helpful!

//Andersson

[rzm3]

To re-revive an old thread... the fluctuating rpm can be replicated if you blip the throttle 55+ seconds into a cold start (car parked overnight). Still no clue of why it happens... No code whatsoever.

[e46e92love]

Guys, I had same issue. Changed spark plugs---GONE.

We all forget just how magical a part the spark plugs play, it's the reason along with the intake it's the one part no one goes aftermarket. This engine is INCREDIBLY smart at protecting itself and running outside perfect scenarios. Just another reminder of how incredibly special this engine is.

Cheers,
e46e92