Cold Start Gremlin!

[ac427]

I think I did, but I haven't driven long enough to said fully resolved as currently the interior is gutted for refreshing and cleaning

I smoke tested it, turn out the intake elbow is causing a very very tiny leak (high positive LTFT +14%, but not great enough to trigger CEL). I thought I clamped it at the right location, but no... I ended up rotating the clamp and wiggle the elbow a little and tighten it. It seems to bring the LTFT down a bit which is a good sign. However, prior to re-tightening the intake eblow. I replaced pre-cat O2 sensors, fuel pumps (Hella) and injectors that fixed the CEL or P030x misfire at start up, even cold start, so far. I threw alot of money to catch up the maintenance as it was neglected by the previous owner.

Here's my journal of my E46 m3, I tackled all hectic oil leak and CEL one by one since I bought the car 3 years ago.
https://www.e46fanatics.com/threads/my-02-m3-steel-grey-oem-build-journal-finally-back-to-the-road-after-1-5-year-of-diy-fix.1300910/page-2?post_id=19241887&nested_view=1&sortby=oldest#pos t-19241887

Thanks for the reply. I wish mine was just a water temp sensor as in the the posts above. I just checked INPA after leaving the car on the drive without starting it for 2 days. The both the coolant (brass one) and radiator return (Plastic one) were the same value. I watched the temperature rise on the the block mounted sensor the outlet lt stayed the same.

Like you i swapped or replaced quite a few parts:

Coil Packs
Spark Plugs
Injectors - Made a load of diffrence to performance but the start up idle was still rough.
Pre cat O2 sensors

I even swapped the ECU to no avail.

I checked the fuel tank split by looking at dash test. 007330 which means most of the fuel is in the RH tank.

If i stab at the throttle whilst in neutral, the acceleration response form the engine is good. As it returns to idle, there seems to be a very slight bit of hunting to acheive idle. Perhaps the ICV is the issue or at least contributing to it.

[sapote]

Thanks for the reply. I wish mine was just a water temp sensor as in the the posts above. I just checked INPA after leaving the car on the drive without starting it for 2 days. The both the coolant (brass one) and radiator return (Plastic one) were the same value. I watched the temperature rise on the the block mounted sensor the outlet lt stayed the same.

The outlet temp won't change until coolant is hot enough to open the Tstat and more delay time for the radiator to heat up.

[y2k_o__o]

Thanks for the reply. I wish mine was just a water temp sensor as in the the posts above. I just checked INPA after leaving the car on the drive without starting it for 2 days. The both the coolant (brass one) and radiator return (Plastic one) were the same value. I watched the temperature rise on the the block mounted sensor the outlet lt stayed the same.

Like you i swapped or replaced quite a few parts:

Coil Packs
Spark Plugs
Injectors - Made a load of diffrence to performance but the start up idle was still rough.
Pre cat O2 sensors

I even swapped the ECU to no avail.

I checked the fuel tank split by looking at dash test. 007330 which means most of the fuel is in the RH tank.

If i stab at the throttle whilst in neutral, the acceleration response form the engine is good. As it returns to idle, there seems to be a very slight bit of hunting to acheive idle. Perhaps the ICV is the issue or at least contributing to it.

are your LTFT value from both banks normal when the car is warmed up?

[ac427]

are your LTFT value from both banks normal when the car is warmed up?

The engine temp was around 54°C. I can warm the engine up more and get some Analog readings when it is hotter. I thought at this temp it would be in closed loop mode, so any sensor issue would show up. Do you think a higher temperature is required?

[ac427]

are your LTFT value from both banks normal when the car is warmed up?

I replaced the oil/coolant sensor (the brass screw in one) becuase i had one and i also had a slight leak from the heater matrix return hose.


Is your car still fixed or have you had some cold start issues?

I'm not sure how i would seal my CSL airbox inlet.

How did you go about using the smoke tester?

[Cubieman]

After reading through the first few posts in regards to cold start I wonder if having a cold start "delete" isn't the best idea.

I have my SAP removed and cold start deleted, I always figured that the cold start raised revs only to warm up the cats, but it would seem there is more to it than that.

Also, I don't know what all is "deleted" when you check the box for cold start delete on the binary modification tool program.

[ac427]

After reading through the first few posts in regards to cold start I wonder if having a cold start "delete" isn't the best idea.

I have my SAP removed and cold start deleted, I always figured that the cold start raised revs only to warm up the cats, but it would seem there is more to it than that.

Also, I don't know what all is "deleted" when you check the box for cold start delete on the binary modification tool program.

I understand your point but i want to know what is actually wrong rather than mask the issue.

My SAP has been deleted for years but i have not removed the actual hardware.

[y2k_o__o]

I replaced the oil/coolant sensor (the brass screw in one) becuase i had one and i also had a slight leak from the heater matrix return hose.


Is your car still fixed or have you had some cold start issues?

I'm not sure how i would seal my CSL airbox inlet.

How did you go about using the smoke tester?

My cold start problem is gone after fuel pump and cleaning injectors, but my LTFT after the car is warmed up is very high / lean. (+15 to +20%)

smoke test didn't show any leakage, this is really puzzling

I didn't have time to replace all the 3 lines connecting to the airbox, but very likely they are having tiny holes or broken hose since they have 190k km on them.

[ac427]

My cold start problem is gone after fuel pump and cleaning injectors, but my LTFT after the car is warmed up is very high / lean. (+15 to +20%)

smoke test didn't show any leakage, this is really puzzling

I didn't have time to replace all the 3 lines connecting to the airbox, but very likely they are having tiny holes or broken hose since they have 190k km on them.

Thanks. Which 3 lines are you thinking of?

I know of the following pipes:

• Air shut off valve from the top of the airbox.
• OIl separator pipe from the top of the engine.
• ICV feed from the bottom of the airbox.
• Crankcase vent pipe to the bottom of the airbox.

Did you mean the brake servo/booster lines and air shutoff valve setup?

Are you measuring your LTFT through INPA ?

[y2k_o__o]

Thanks. Which 3 lines are you thinking of?

I know of the following pipes:

• Air shut off valve from the top of the airbox.
• OIl separator pipe from the top of the engine.
• ICV feed from the bottom of the airbox.
• Crankcase vent pipe to the bottom of the airbox.

Did you mean the brake servo/booster lines and air shutoff valve setup?

Are you measuring your LTFT through INPA ?

These are the 3 airbox hoses I am replacing with Genuine BMW parts. Along with airbox hoses replacement, I am replacing the SAP line too since it's not hat expensive as well as the fuel pressure regulator line since they always fell off from the air rail.
From what I've read from forum, many people are having problems with airbox-to-dipstick hose ( the very far left in the picture, PN# 11617831930) since they are the flimsiest.
Since I am taking all the old hoses out, I will be replacing all the o-ring at the NORMA connector and replace all the plastic tubes with fuel hoses as spare parts. (which I already have doen for oil catch can / PCV hoses). The culprit are the thin-wall material tubes will crack under thermal cycles. The connectos are fine.
and I don't want to pay $400+ USD in the future again for these cheap plastic parts that won't last



At this point, I am taking my time to gather the technical drawing from NORMA / internet so I know which correct viton o-ring size I am replacing

[ac427]

These are the 3 airbox hoses I am replacing with Genuine BMW parts. Along with airbox hoses replacement, I am replacing the SAP line too since it's not hat expensive as well as the fuel pressure regulator line since they always fell off from the air rail.
From what I've read from forum, many people are having problems with airbox-to-dipstick hose ( the very far left in the picture, PN# 11617831930) since they are the flimsiest.
Since I am taking all the old hoses out, I will be replacing all the o-ring at the NORMA connector and replace all the plastic tubes with fuel hoses as spare parts. (which I already have doen for oil catch can / PCV hoses). The culprit are the thin-wall material tubes will crack under thermal cycles. The connectos are fine.
and I don't want to pay $400+ USD in the future again for these cheap plastic parts that won't last



At this point, I am taking my time to gather the technical drawing from NORMA / internet so I know which correct viton o-ring size I am replacing

Thanks for all the info. I've seen the diagrams that show the a connection to the dipstick tube but i am pretty sure i don't have that on mine. Perhaps it is not on the Euro cars.

I do have a shorter plastic pipe that fits into the bottom of the CSL airbox. It looks a lot like the leftmost pipe in you picture but it is much shorter.

The NORMA elbow connector for the bottom of the airbox is the same as the ICV to additional air line connector. There are reasonable cheap still from BMW.


When you say you are replacing the vacuum line to the fuel pressure regulator. Are you going to run a new line the length of the car or just replace the rubber elbow at the back of the airbox?

Here is a link to a pic of the standard dipstick. I cannot see where the pipe would plug in: https://www.ecstuning.com/b-genuine-...e/11437832140/

[ethan]

Crankcase vent pipe to the bottom of the airbox.

I rebuilt that hose with aftermarket material for my build, and I set the orientation of the check valve to allow flow from the airbox down to the crankcase. I think you're suggesting that's backwards, but it's my understanding that this line is actually an oil drain which returns oil falling out of suspension from the CCV output back down from the airbox to the crankcase. Would appreciate it y2k_o__o if you could check the direction of your factory hose's check valve before installation so I can make sure I have it right. Thanks!

[ac427]

I rebuilt that hose with aftermarket material for my build, and I set the orientation of the check valve to allow flow from the airbox down to the crankcase. I think you're suggesting that's backwards, but it's my understanding that this line is actually an oil drain which returns oil falling out of suspension from the CCV output back down from the airbox to the crankcase. Would appreciate it y2k_o__o if you could check the direction of your factory hose's check valve before installation so I can make sure I have it right. Thanks!

You might be right but i am wondering about a line feeding into the dipstick tube which I am sure i don't have.

It was a while ago but I have tried the CSL dipstick and then gone back to a standard dipstick.

[y2k_o__o]

Thanks for all the info. I've seen the diagrams that show the a connection to the dipstick tube but i am pretty sure i don't have that on mine. Perhaps it is not on the Euro cars.
I do have a shorter plastic pipe that fits into the bottom of the CSL airbox. It looks a lot like the leftmost pipe in you picture but it is much shorter.
The NORMA elbow connector for the bottom of the airbox is the same as the ICV to additional air line connector. There are reasonable cheap still from BMW.
When you say you are replacing the vacuum line to the fuel pressure regulator. Are you going to run a new line the length of the car or just replace the rubber elbow at the back of the airbox?
Here is a link to a pic of the standard dipstick. I cannot see where the pipe would plug in: https://www.ecstuning.com/b-genuine-...e/11437832140/

I have a 2002 M3 manual, according to RealOEM, the airbox-to-dipstick hose #3 is only up to 09/2004 for manual vehicle.
For the crankcase ventilation pipe, in early model like mine, it's just a piece of tube with two Norma elbow like below picture #2. The later model after 2004 has a more complex design

https://www.realoem.com/bmw/enUS/showparts?id=BL93-USA-11-2001-E46-BMW-M3&diagId=11_2996

Regarding the vacuum line to FPR, yes I will be replacing with brand new silicone hose. The existing BMW design has a barb and a small U-shape tube that always fell off and ended up dangled or lost.

[ethan]

You might be right but i am wondering about a line feeding into the dipstick tube which I am i don't have.
It was a while ago but I have tried the CSL and then gone back to a standard dipstick.

Neither my stock M3 nor my CSL airbox one with CSL dipstick has a line connecting to the dipstick, but my 330xi had one stock. The M54 PCV system which, unlike the S54's cyclone separator, is external to the engine and lives underneath the intake manifold, has a cyclone separator which drains oil back to the pan by way of the dipstick.

Seems like the M3 dipstick part number (11437832140) doesn't have that plug, but the M54 one (11437531260) does. Looks like the euro M3s use the same tube as the US ones. Dunno.

Edit: I wonder if the picture shows that connection, but it actually connects to the oil pan directly because they're effectively doing the same thing and they figured it wasn't worth revving the document.