Hello, I live in Minneapolis and started having very-cold start issues with my 318ti this past winter. The issue gets progressively worse the colder it gets.... At about 0F, the car will crank like crazy, give a few intermittent "pops" then fire up. The first 20-30 seconds after it starts, it will run very roughly. Indicated RPM is fairly constant, but it feels and sounds rough. It'll smooth out after that 20-30 seconds and run cleanly just sitting at idle. From 0F to -5F, the car will still crank strongly, but the ignition "pops" are further between. I get, "crank like crazy", pop, "crank like crazy", pop pop, "crank like crazy", pop pop pop. The iginiton pops get closer and closer together before it finally starts. After it starts, it'll do the same 20-30 seconds as above beofre it cleans up. From -10F to -20F, I can lay on the starter for 30 seconds and get random pops before it'll fire. The car will barely start and run. Same 20-30 second thing as above before it runs cleanly. The car has 181,000 miles and has never had an issue with cold starts over the past 5 Minnesota winter's I've owned it. It would fire instantly at -20F. I'm religous on maintenance, and everything is fresh (less than 2 years, 20,000 miles) including battery (new last winter), plugs, ALL fluids, belts, filters, etc. I cleaned the MAF and ICV, as well as did the electrical tests in the Bentley on the coil, maf and ICV. I ruled out water in the fuel lines and a slow ICV valve (put in deep freeze and quickly installed, which is a 30 second job on the M44 engine.) TheICV also freely moved right out of the deep freeze. Any ideas? I thought maybe a temp sensor of some sort, but the idle cleans up so quickly that there's no way fluids would warm up much at -20F at idle power in just 30 seconds. Thanks! The tough part is troubleshooting this thing as once it's warmed-up (over 30 seconds), it'll start again perfectly. There's only limited nights where it's -5F and colder in the morning here, but it's the worse time to not have you car start
All I can do is throw out a guess but my first thought would be plugs. It almost sounds like wrong plugs or wrong gap. Did you have these same plugs in last winter or was this their first winter? Plugs are one of the only things in the equation that would actually heat up in 20 - 30 seconds (at least heat up enough to have any significant effect on operation). Like I said, it's strictly a guess so take it for what it's worth! If you can't get any additional input here, you may want to check out www.318ti.org, it's dedicated to the 'Compact'.
Thanks for the replys! I'm a poster on 318ti.org, but haven't posted this question there yet. I just looked at my records and I did replace the spark plugs in July 2008 (12,000 miles ago), so this could be an issue. I used the stock NGK BKR 6 EK plugs. The fuel filter was replaced in Sept 2007 (24,000 miles ago) with a Mahle filter. I certainly could proactively replace both the plugs and fuel filter since they are cheap. I did post over on bimmerforums and someone suggested a leaking intake manifold gasket. I did replace that gasket before the winter of 2007/2008, so it already started fine through one winter. The theory was that the cylinder head -to- lower intake manifold mating surface might heat up quickly and seal a small leak. I'm pretty sure it's not the gas, which I was my first thought, since I let the car thaw in a heated garage during a warm stretch of days. I dumped a bunch of "Heet" type/ gas dryer products and the issue came back with another cold stretch. My only other guess cold be a bad fuel pump? Maybe that motor gets strained when it's really cold and can't spin fast enough?
Maf????? This may or may not be your problem, but I had a problem with my 540i where it ran rough on cool mornings then would run fine the rest of the day. I had cleaned the MAF, but it did not seem to help. Fortunately (or unfortunately) I was having the same prolbems to some extent with my daughter's 2001 VW Jetta and my wife's 2000 Mustnag GT. The VW and the 540i did start popping 'Lean Codes', but the Mustang did not. Out of frustration I replaced the VW's MAF and that cleared up many years of driving around with the EML on. Next I replaced the MAF on the 540i and that cleared up the rough running on start up and EML. Both were done over a year ago with no further problems. The Mustang was sold before I changed the MAF, but not after it had been in the shop for the problem three times. I suspect it was the MAF also, but can't confirm. I purchased the MAFs on ebay at less than $80.00 a piece. As a side note (less anyone thinks I like VWs) one of the happiest days of my life was when the new owner took it home a few months ago.
