Cold Start Problems

[BMWHeer]

ghead Can some clever soul help me. BMW cannot solve this so this is major respect if you get this right. It tries to cut out until it gets warm, I have changed the Idle control valve and the Air flow meter. The car has a K&N induction kit if that helps the diagnosis. Please help me the wife is going nuts when she drives.

[Furious]

hmmm , maybe you are getting excess condensation on the MAF sensor wire and when its cold its causing problems with it. I honestlly dont know, try puttting the stock airbox on and see if that doenst help. secondly check a pontetial problem with the fuel line, maybe your fuel filter is past due for changing.

[jllphan]

I know this sounds almost sarcastic, but when's the last time you changed the sparkplugs? If there is enough carbon build up on the diode, it would take a while for them to heat up, and keep the car idling smoothly.

The ICV wouldn't have been the problem unless you were having idle problems all the time, not just when the engine is cold.

Beyond that, it may be a vacuum leak. Once your car is warm, rev the engine up (4 or 5K) and then let offf. Does the engine almost die? IF so, would look into the vacuum lines

[93 325i]

I put my money on O2 sensor. Was just reading that a bad O2 sensor can cause irregular idle on warm up and even irregular idle once warmed up. Assuming you have OBDI its a relatively cheap fix and easy to install yourself.

[pcy]

Originally posted by 93 325i@Jan 14 2005, 09:11 AM
I put my money on O2 sensor. Was just reading that a bad O2 sensor can cause irregular idle on warm up and even irregular idle once warmed up. Assuming you have OBDI its a relatively cheap fix and easy to install yourself.

[snapback]271319[/snapback]

Please correct me if I am wrong...
I thought that until the engine goes to closed loop mode (i.e., until the engine is warmed up), the O2 sensor information is ignoed by the computer.
So, the original poster's car problem is that irregular idle during warm-up shouldn't have anything to do with O2 sensor.

My guess (just a guess) would be intake manifold gasket is leaking.
So, what could be happening is that when the engine is cold, the gasket
is fully shrunk and lets the air in (this extra air is NOT measured by the MAF sensor) since this air is not measured by MAF, computer doesn't know anything about this extra air and is not proportionately mixing the fuel. Hence, the irratic idle.

Now, once the engine warms up, the gasket expands and fills-up the leakage; thus, idle improves.

[BMWHeer]

Originally posted by Furious@Jan 14 2005, 02:10 AM
hmmm , maybe you are getting excess condensation on the MAF sensor wire and when its cold its causing problems with it. I honestlly dont know, try puttting the stock airbox on and see if that doenst help. secondly check a pontetial problem with the fuel line, maybe your fuel filter is past due for changing.

[snapback]271044[/snapback]

Thanks for the help, I have tried another standard air box with MAF but it does not resolve the problem. The fuel filter was changed last year. Please keep the mails coming any help is greatly appreciated.

[BMWHeer]

Originally posted by jllphan@Jan 14 2005, 02:31 AM
I know this sounds almost sarcastic, but when's the last time you changed the sparkplugs? If there is enough carbon build up on the diode, it would take a while for them to heat up, and keep the car idling smoothly.

The ICV wouldn't have been the problem unless you were having idle problems all the time, not just when the engine is cold.

Beyond that, it may be a vacuum leak. Once your car is warm, rev the engine up (4 or 5K) and then let offf. Does the engine almost die? IF so, would look into the vacuum lines

[snapback]271052[/snapback]

Thanks mate, I have changed the sparks last year, if I rev the car when it's cold it will die, it's ok when it's warm. Please keep the mails coming any help is greatly appreciated.

[BMWHeer]

Originally posted by 93 325i@Jan 14 2005, 03:11 PM
I put my money on O2 sensor. Was just reading that a bad O2 sensor can cause irregular idle on warm up and even irregular idle once warmed up. Assuming you have OBDI its a relatively cheap fix and easy to install yourself.

[snapback]271319[/snapback]

Sorry mate, The Lambda probe is 3 years old and the exhaust emissions are bang on. Please keep the mails coming any help is greatly appreciated.

[BMWHeer]

Originally posted by pcy+Jan 14 2005, 10:50 PM--><div class='quotetop'>QUOTE(pcy @ Jan 14 2005, 10:50 PM)</div><div class='quotemain'><!--QuoteBegin-93 325i@Jan 14 2005, 09:11 AM
I put my money on O2 sensor. Was just reading that a bad O2 sensor can cause irregular idle on warm up and even irregular idle once warmed up. Assuming you have OBDI its a relatively cheap fix and easy to install yourself.

[snapback]271319[/snapback]

Please correct me if I am wrong...
I thought that until the engine goes to closed loop mode (i.e., until the engine is warmed up), the O2 sensor information is ignoed by the computer.
So, the original poster's car problem is that irregular idle during warm-up shouldn't have anything to do with O2 sensor.

My guess (just a guess) would be intake manifold gasket is leaking.
So, what could be happening is that when the engine is cold, the gasket
is fully shrunk and lets the air in (this extra air is NOT measured by the MAF sensor) since this air is not measured by MAF, computer doesn't know anything about this extra air and is not proportionately mixing the fuel. Hence, the irratic idle.

Now, once the engine warms up, the gasket expands and fills-up the leakage; thus, idle improves.

[snapback]271696[/snapback]

[/b][/quote]
Thanks for this information, this seems to be very logical, I will conduct a test to see whether this resolves the situation. I shall be in touch and let you know how I get on. Does anyone know if the size of the cables on the lambda probe could cause this problem as I have been told that mine were longer than required.
Please keep the mails coming any help is greatly appreciated.

[Cruzin 323is]

i dunno.. but i think it could be a fuel pump or the o2 sensor!

[Rooz]

am curious about this thread as I seem to have a smaller version of this problem, reason is relating to the first thing that Furious said

"maybe you are getting excess condensation on the MAF sensor wire and when its cold its causing problems with it"

[93 325i]

Originally posted by pcy+Jan 14 2005, 04:50 PM--><div class='quotetop'>QUOTE(pcy @ Jan 14 2005, 04:50 PM)</div><div class='quotemain'><!--QuoteBegin-93 325i@Jan 14 2005, 09:11 AM
I put my money on O2 sensor. Was just reading that a bad O2 sensor can cause irregular idle on warm up and even irregular idle once warmed up. Assuming you have OBDI its a relatively cheap fix and easy to install yourself.

[snapback]271319[/snapback]

Please correct me if I am wrong...
I thought that until the engine goes to closed loop mode (i.e., until the engine is warmed up), the O2 sensor information is ignoed by the computer.
So, the original poster's car problem is that irregular idle during warm-up shouldn't have anything to do with O2 sensor.

[snapback]271696[/snapback]

[/b][/quote]

This is straight off of pelican parts:
There are a few signs that your oxygen sensor may be failing. In general, it is difficult to diagnose problems with the sensor, unless all of the other components in the fuel injection system have been checked and determined to be operating correctly. Some of the symptoms of a failed oxygen sensor system are:

Irregular idle during warm-up
Irregular idle with warm engine
Engine will not accelerate and backfires
Poor engine performance
Fuel consumption is high
Driving performance is weak
CO concentration at idle is too high or too low
Check Engine light is illuminated

BUt pertaining to his problem if they are newer and emissions are in check it obvioulsy isn't the problem..