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Discussion Starter #1
idle issue:
I'm assuming it's normal, but I noticed that when the car is cold, the idle seems to fluctuate from 500-1k in a steady rhythm.
Is that normal or do I need to change a sensor? Is this something that should not occur after an inspection II?
My mazdaspeed6 would normally start at about 1k (maybe a bit over) and then drop down as it warmed up.

1st gear performance:
It has been two weeks since I got a new clutch installed by an indie. (German Motor Specialists in Sunnyvale, CA).
I figure it is safe enough now to see what my new car can do, so I did a few launches.

I noticed that if I upshift based on my ears, I'm usually shifting up around 20mph.
When I was doing some shifting research on the board, I found the article about whether to shift based on torque or hp.
In that article, someone mentioned hitting ~40mph on 1st gear before shifting up, so I tried it.
It seems I'm closer between 30-35 when I am approaching redline, so I'm wondering if there is an issue I should be looking into.

From what I feel, it seems the beast loses that "feeling of pull" earlier than in 1st than it does in the 2nd, 3rd, and 4th.
It seems to be between 4-5krpm when I steal a glance.

Now that I think about it, I'm not sure if I have sport mode on or off when I first noticed it, but I know that I had DSC enabled still to minimize tire spin (I'm not prepared to shell out new tires just yet).

recent work:
inspection II just done.
new clutch and flywheel.
I just replaced the breather valve (E8 Peake code fix) and made sure that any lines under the plenum were still connected (more on that repair story later... since the pictures are missing a part).

Caveat:
Most of my experience about the "pull" comes from riding a sportbike. The only sports car I've had to compare it was my old mazdaspeed6, but I don't remember paying attention to the redline for that car.

and for those that mangaged to read this far without getting mad at this post:
Anyone know a place to get a dyno run around the Sunnyvale area? I'm hoping it is cheap enough that I can get a reading on what this car is doing now.
I'm hoping to compare it with other dyno charts, since I don't know what a new car should feel like under spirited driving.

Thanks.
 

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im not sure what question you are asking lol
idle is fine to fluctuate a little bit, not too much though
you notice 1st feels to lose the pull feeling earlier because thats just the way the torque curve is. Its the same through the gears but because you notice the power so substantially in 1st, you notice the slight dip around 5252 rpm as opposed to other gears where you may not "feel" it

no idea for dynos, gonna need to go to the regional forum for that
 

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Discussion Starter #3
Thank you.
You answered the question about 1st gear performance that I didn't actually ask.
 

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If your idle is fluctuating, it could possibly be a vacuum leak. Since you've been under the plenum to replace the canister (I've done that, too) you might have dislodged a vacuum line somewhere.
 

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Vacuum leak likely

Idle on cold start (or any other time) should be steady. With a 500 RPM fluctuation, something is definitely amiss.
I suspect that the vacuum line going to the port on the #7 throttle body has disintegrated. This is the vacuum
reference signal going to the fuel pressure regulator, providing full pressure (5 bar, approximately 70 PSI) during
wide open throttle. Without it, a significant power loss will occur.

While you are in there with the plenum removed, I would suggest you remove the idle air control valve and clean
the rotary spool valve. In addition, check the 90 degree elbow that connects to the lower port of the rubber tee
that is clamped onto the aft port of the idle air control valve, since it's prone to cracking around the inside radius.

Regards,
Alan
 

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Discussion Starter #6 (Edited)
Idle on cold start (or any other time) should be steady. With a 500 RPM fluctuation, something is definitely amiss.
I suspect that the vacuum line going to the port on the #7 throttle body has disintegrated. This is the vacuum
reference signal going to the fuel pressure regulator, providing full pressure (5 bar, approximately 70 PSI) during
wide open throttle. Without it, a significant power loss will occur.

While you are in there with the plenum removed, I would suggest you remove the idle air control valve and clean
the rotary spool valve. In addition, check the 90 degree elbow that connects to the lower port of the rubber tee
that is clamped onto the aft port of the idle air control valve, since it's prone to cracking around the inside radius.

Regards,
Alan
Are you talking about #1 for the idle air control valve?
RealOEM.com BMW E39 M5 Idle regul.valve/fuel tank vent valve

When I was trying to remove the fuel tank breather valve (#14) from #19, I kept twisting and pulling.
Could it be the #18 hose that I messed up?
If the SES light hasn't come on again, is it safe to assume the lines to the breather valve aren't an issue?

I'm using the diagrams from here as the basis of identifying parts, along with pictures from the DIY threads.

I did dislodge a vacuum line connected to the area where the #7 throttle body is, but I made sure it was connected back.
A visual inspection didn't show any cracks in the hose and it felt pretty flexible still.
Is this a dealer part or should I be able to pick it up from any car parts store?

Thanks.
 

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The rpms are available in the secret menu...IIRC mine varies by maybe 10-15 +/- at idle very smooth...sumthin's amiss...
 

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I've had the idle hunt on my car upon stone cold start, backing out of the garage...then put the clutch in, but not after about a minute of running.
 

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How many miles have the MAF's and the CPS's done? I've issues with MAF's when they're on their way out, cold idle is always fluctuating even stalling and it looses power at 4 to 5k rpm, which after a bit more time would lead to an engine light and limp home mode.

Also had CPS's fail and cause idle to be rough and even stall on start up.
 

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Are you talking about #1 for the idle air control valve?
RealOEM.com BMW E39 M5 Idle regul.valve/fuel tank vent valve

When I was trying to remove the fuel tank breather valve (#14) from #19, I kept twisting and pulling.
Could it be the #18 hose that I messed up?
If the SES light hasn't come on again, is it safe to assume the lines to the breather valve aren't an issue?

I'm using the diagrams from here as the basis of identifying parts, along with pictures from the DIY threads.

I did dislodge a vacuum line connected to the area where the #7 throttle body is, but I made sure it was connected back.
A visual inspection didn't show any cracks in the hose and it felt pretty flexible still.
Is this a dealer part or should I be able to pick it up from any car parts store?

Thanks.
Here's the DIY I did when I replaced that vacuum line:

http://www.m5board.com/vbulletin/e3...or-throttle-body-vacuum-line-replacement.html

Part number is in there.
 

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Discussion Starter #11
Here's the DIY I did when I replaced that vacuum line:

http://www.m5board.com/vbulletin/e3...or-throttle-body-vacuum-line-replacement.html

Part number is in there.
Thanks, I hope the dealer has it in stock and that I can give it a shot this weekend.
Did this solve your issue? Someone asked in your thread but you didn't respond.
While the plenum is off, I'd like to take a closer look at stuff around it, just in case something else looks iffy.

I'm waiting for my 5point bit so I can take the MAF's out and clean them.

So a clearer description of the issue.
It would idle around 500rpm, bounce almost up to 1k, drop slowly, then bounce up again after half a second.

The car hasn't stalled on me by itself and the idle isn't rough. Just noticeable, especially from a cold start at a stop light.
It's as if I am somehow bumping the accelerator just a tad.

After it is warmed up, it doesn't seem to happen enough where I notice it, but I'll be paying attention later at lunch, when I go for a long enough drive.

I'm assuming that I cannot check the vacuum line while the plenum is off, but maybe I am wrong.
Removing that is such a hassle. Mechanics and dealers must love any job that requires removing it, since it is an automatic 30 minutes of labor.

Best I can think off is sucking on the vacuum line to see if there are any leaks, followed by a :beerglass:.

-- D
 

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Thanks, I hope the dealer has it in stock and that I can give it a shot this weekend.
Did this solve your issue? Someone asked in your thread but you didn't respond.
Nope. Didn't resolve it, but my thinking is I still have a small vacuum leak somewhere. I am planning on pulling the plenum again (it's easy after the third or fourth time) and looking around some more.

I'll also try to recondition the plenum cover gasket in case that's a weak point and attempt to clean the idle control valve, as I didn't do this before.

My issue is odd because once the car has been idling for about 45 seconds, everything smooths right out. I think that's because the vacuum gets reestablished and the leak is small enough that it doesn't overwhelm the running motor. Or, I could be crazy. I won't really know until I get in there and do the work.
 

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i also suspect mafs,


jumping idle is a known side effect from mafs going bad..the fact the car holds back a little at 4-5000rpm is because it doesnt get enough air/fuel at that point..it just chokes.

have you tryed the maf test on the cluster allready too see what numbers it still gives?
i would do that first and see what comes up there..


iff they give you a 130L reading, i would shift my suspicion too the pre cat o2' sensors.
 

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Discussion Starter #14 (Edited)
i also suspect mafs,

jumping idle is a known side effect from mafs going bad..the fact the car holds back a little at 4-5000rpm is because it doesnt get enough air/fuel at that point..it just chokes.

have you tryed the maf test on the cluster allready too see what numbers it still gives?
i would do that first and see what comes up there..

iff they give you a 130L reading, i would shift my suspicion too the pre cat o2' sensors.
I'm not sure if I'm doing it right, since I tend to lay off the WOT as even on the freeway, I approach "ticket speed".
Can I do this test on neutral or do I need to have a load on the car?

Are there any fault codes that will point to a specific problem?
My Peake reader finally arrived.
Here is a video of the tach. The bump isn't very pronounced as the car is already warm, but you can see some movement. It is more noticeable by ear.
My brother took this, so the radio is still on.
http://www.ktb.net/~enigma/pics/idle.mp4

-- D
 

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you have too run the car , second or 3th gear full wot. the car needs too have enough air coming in too get a good reading trough the instrument cluster..130-140 L/H is ok, less then that is getting bad mafs.
iff your scared too get a ticket, go out at night on a quit road, do a normal run and look iff there are cops around, and then go for it on the way back :D :wroom:




here's a tread with everything you need to know on mafs
http://www.m5board.com/vbulletin/e3...788-how-test-mafs-yourself-how-mafs-work.html
 

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Discussion Starter #17
Yep, read it several time and hoping to get the OBD-II setup soon.
I may try the volt meter test as well.

My hesitation for the method A test is I feel the officer will not find my "I am debugging a performance issue with my car" line as a valid excuse when I am tagged for going over 80, haha.

The link to the MAF cleaning isn't working anymore. Is there another place to get it?
 

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The link to the MAF cleaning isn't working anymore. Is there another place to get it?

maf cleaning trick is just, take them out and clean them with crc maf cleaner spray..let them dry out and put them back in..nothing special

cleaning mafs is a temporary solution,
 

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Added info

Are you talking about #1 for the idle air control valve?
RealOEM.com BMW E39 M5 Idle regul.valve/fuel tank vent valve

When I was trying to remove the fuel tank breather valve (#14) from #19, I kept twisting and pulling.
Could it be the #18 hose that I messed up?
If the SES light hasn't come on again, is it safe to assume the lines to the breather valve aren't an issue?

I'm using the diagrams from here as the basis of identifying parts, along with pictures from the DIY threads.

I did dislodge a vacuum line connected to the area where the #7 throttle body is, but I made sure it was connected back.
A visual inspection didn't show any cracks in the hose and it felt pretty flexible still.
Is this a dealer part or should I be able to pick it up from any car parts store?

Thanks.
Yes, #1 is the idle air control valve. After you remove it, you will notice the rotary spool valve should move freely as you
rotate the valve assembly. Using throttle body or carb. cleaner, flush the rotary valve until it and the surfaces around it
are thoroughly clean.

Your reference to hose #18 (supply line to carbon canister) is not likely to be damaged, but the connector fitting (#19)
that attaches to it has an internal 0-ring which seals the connection around the port on the fuel vapor purge valve which
you replaced. However, if either the hose or connector were leaking, you will get an SES light and fault code for failure to
hold system pressure when the programmed pressurization test is performed. I don't understand why you separated the hose
(#18) from the connector (#19), since that connector must be removed from the valve anyway. Are you actually referring
to hose #16, which connects to the lower port (seems more likely)? This hose connects to the 90 degree elbow (#17),
which I was referring to earlier. This elbow may be cracked, creating a vacuum leak, which was the case with mine. Also,
check the rubber tee that the 90 degree elbow connects to, for tears/cracks.

Another area you might check, is the vacuum supply to the brake booster. At the back side of the #4 and #8 throttle
bodies, you will see hose connections that feed a common manifold pipe, then another section of hose with a vacuum
check valve going to the booster. While the plenum is off, start the engine and then pinch-off each of the hoses, isolating
each of the sections, as well as the booster.

The section of vacuum hose (and 90 deg elbow) from the supply port on #7 throttle body can be easily replaced using
standard supplies from any decent auto parts store. Preferably, use thick-walled silicone hose. It will be far more durable
over the long term.

Regards,
Alan
 

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Discussion Starter #20
Yes, #1 is the idle air control valve. After you remove it, you will notice the rotary spool valve should move freely as you
rotate the valve assembly. Using throttle body or carb. cleaner, flush the rotary valve until it and the surfaces around it
are thoroughly clean.

Your reference to hose #18 (supply line to carbon canister) is not likely to be damaged, but the connector fitting (#19)
that attaches to it has an internal 0-ring which seals the connection around the port on the fuel vapor purge valve which
you replaced. However, if either the hose or connector were leaking, you will get an SES light and fault code for failure to
hold system pressure when the programmed pressurization test is performed. I don't understand why you separated the hose
(#18) from the connector (#19), since that connector must be removed from the valve anyway. Are you actually referring
to hose #16, which connects to the lower port (seems more likely)? This hose connects to the 90 degree elbow (#17),
which I was referring to earlier. This elbow may be cracked, creating a vacuum leak, which was the case with mine. Also,
check the rubber tee that the 90 degree elbow connects to, for tears/cracks.

Another area you might check, is the vacuum supply to the brake booster. At the back side of the #4 and #8 throttle
bodies, you will see hose connections that feed a common manifold pipe, then another section of hose with a vacuum
check valve going to the booster. While the plenum is off, start the engine and then pinch-off each of the hoses, isolating
each of the sections, as well as the booster.

The section of vacuum hose (and 90 deg elbow) from the supply port on #7 throttle body can be easily replaced using
standard supplies from any decent auto parts store. Preferably, use thick-walled silicone hose. It will be far more durable
over the long term.

Regards,
Alan
Alright, I will also check those hoses as well.

When I was trying to remove connector #19, I ended up breaking it (I have ham hands, so it was really hard for me to hold two screwdrivers to pry it out), so I had to replace it. Hose #18 was connected with what I can only describe as a crimped hose clamp. I ended up using tin snips to cut the clamp and replaced it with a regular screwbased hose-clamp.

You wouldn't happen to know the diameter of those hoses would you?
Thanks.
 
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