I have a 1998 BMW 318i with approximately 170,000 kms on it.

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I have a 1998 BMW 318i with approximately 170,000 kms on it. I changed the plugs and wires last summer. The water pump is new and so are all of the belts. I am running 5W30 Castrol Synthetic in it. Just though I would get that out of the way. My problem is this, the engine light is on, but not flashing. The idle is lumpy, but engine doesn't stall. I am running in -24 to -35 C temperatures. When the engine gets up to full operating temperature, temperature gauge with needle at 12 o'clock, the idle becomes stabil. No loss of coolant noted and accleration is good. This all started about 3 weeks ago, but only yesterday did the engine light come on and stay on. The engine light came on before, but went out after driving about 20kms.

Optional Information:
1998 BMW 318i M44

Already Tried:
I put gas line de-icer the fuel tank, no change. I tightened up the intake ducting, no change.

Customer (name blocked for privacy)

Status: Closed Value: $40

Hi XXXXXXXXXXXX,

Your first step should definitely be to get the check engine light code scanned. I know you're not in the USA, so I'm not sure where you can go in your country to get the code scanned besides the dealership. An independent BMW specialist with the proper equipment should be able to scan the code.

There are quite a few things that can contribute to poor idle. The obvious problems are a bad idle control valve, or a vacuum leak. It could be coincidence that it just started with the onset of very cold temperatures, or it could be related.

Before you start looking for a tough-to-find vacuum leak or replacing any parts, can you get the code scanned? We can go from there...

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I am living in Northern Alberta and my scan tool is in Nova Scotia. I am 5 houirs driving from a BMW dealership and the local bandits where I live charge $140 to $175 an hour for services rendered. I am going to try to get a scanner on Jan 2 as soon as I can get a hold of the Mac or Snap-On dealer.

You are right about the parts end. It could be one thing or a combination of things. I am a licensed Truck and Coach mechanic and a licensed Machinist, but I never assume on anything, especially when I am familiar with diesels and not gasoline engines. I figured on what you surmised with O2 sensors thrown into the mix.

I will get back to you in a couple of days. It is New Year's Eve. Raise a glass!

Just FYI, BMW recommends O2 sensors every 100,000 miles, so if you're at that point and still have the originals installed, it certainly wouldn't hurt to replace them.

Let me know what you find out after the 2nd, and happy New Year to you too!

If you found my answer helpful, please don't forget to Accept. I can continue to provide assistance even after you have Accepted. Your positive feedback is greatly appreciated!

I figure I will replace the O2's regardless. I was looking for them yesterday, but didn't want to throw parst at this. I am going to order off of E-Bay from a source of mine, Bosch only, as soon as I get a reply back.

I read your bio. I know it is easy to be BSer online, but I travelled around to round out my trades and desires in them in Canada and the US. If you like old things, then eventually you will like new things. I moved to Northern Alberta to get into the tarsands, for the money. Why so? I want to build a house that incorporates a few things that I learned over the years: ICF building construction, blacksmithing and stained glass. You are obviously mechanically minded. Try things that are mechanically unrelated and you will always be fresh.

I got a code reader and the following codes showed:

P0300

P0301

P0302

P0304

P1174

The last one being the most important. What does it mean in terms of a part that is bad, or not, or a wiring issue.

I got a code reader and the following codes showed:

P0300

P0301

P0302

P0304

P1174

The last one being the most important. What does it mean in terms of a part that is bad, or not, or a wiring issue. Also, the spark plugs and wires are new. The most annoying thing about this is the rough idle settles out after the car warms up. Before anyof this happened I renewed the rubber intake duct hoses from the MAF back this summer. They were cracked from. There wasn't any problem with the idle then, it was just a preventative measure.

I'm sorry for the delayed response, for some reason it was showing that your last response was on January 1st. This site can be really weird sometimes.

I agree that the last code is the most important, the first four are likely the result of it. My chart says it's "Fuel Trim Adaptation Malfunction." The problem with OBD codes vs. BMW's codes is that they don't give much information. I'm thinking it means adaptation limits have been reached. In other words, it's running so lean or rich that it can no longer compensate.

The first thing I'd check for is intake manifold leaks because they're very common on this particular engine. With the engine running and cold (while it's still running rough), spray a can of brake cleaner around all of the gasket surfaces for every section of the intake manifold. There are several potential places for air leaks, so be generous with the stuff. Does the idle smooth out when you spray it?

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Kellie:

I didn't know what had happened to you in regards to not responding and contacted another tech with justanswer and he answered. He said the same thing you stated. I checked things over again and found the CCV hose had opend up underneath on the valve end. The idle immediately evened out once covered.

Like I mentioned, being in -35C weather it was near impossible to diagnose. I put a temporary patch on the split till a new part comes in.

Troy,

I apologize for the delay, but I'm glad to hear that you got your problem resolved. Thanks for updating me.

If you found my answer helpful, please don't forget to Accept. I can continue to provide assistance even after you have Accepted. Your positive feedback is greatly appreciated!

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I have a 1998 BMW 318i with approximately 170,000 kms on it.

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