Crank no Start at 15 below zero

[RL740IL]

2001 740il build date 7/2001 Miles 145k
Trying to come up with a plan of attack in this extreme below zero forecast=-15 to -25 for the next week.
Replaced battery on Saturday to avoid winter issues(five years on the old one). Replaced in the parts store parking lot at -9 below.
Drove home fine about an hour.
Saturday pm 9 below started fine-ran up to temp, 20 minutes or so.
Sunday am 10 below zero, started fine-ran up to temp, 20 minutes or so.
Tuesday am 17 below, crank no start, cranking at a fine speed with this new battery!
1/4 tank of fuel.

What I have done so far- nothing lol are you kidding it is freaking 10 below- high temp for the day.
I did notice no tach movement while cranking. Is this normal - this car has always started instantly.
Never had an engine code show on this car. Just lots of LCM issues- currently on number 4 (all used units)
As background to avoid some common suggestions that I see researching - no water leaks ever found on this car when dealing with LCM issues.
I rechecked in November while doing the latest LCM, pulled passenger seat- looked like new! LCM units have always been dry (dust only).
Alternator is a new Bosh unit 10k ago.
Ignition switch is new OEM 10k ago.
Hoping for faulty fuse or fuel pump relay, can I swap with another relay to test?
If my thinking is correct that the tach should show some movement while cranking, I am probably looking at a crank position sensor.
I do have a Laptop with PS Soft running that I have only had to use to code LCMs.
I would like to plot this out like a F1 pit stop.(LOL)
1.Run to car open trunk replace fuse 57, swap relay- test start, if it starts leave running and run back into house.
If it don't start - run back into house.
2. Open hood replace fuse 11, test start, yes / no run back into house.
3. If forum users advise Order crank position sensor or possibly fuel pump, stay in house until part shows up.
4. install crank position sensor/ fuel pump if it ever warms up!

Any and all suggestions welcome, you all saved me a bunch time and money during my five years with this monster!
Thanks

[clarkitect]

Wait until it warms up tomorrow and see if it'll start. Then fill the tank with ethanol free before the weekend when it's going to get even colder. I think starting and shutting down every couple days isn't a good idea either, drive it around to warm it up.

[RL740IL]

Thanks good advise. I understand that ethanol can be issue in certain situations as it can absorb moisture from the atmosphere and at 1/4 tank its possible. Ill dump some dry gas in tomorrow as well. But i think it will have to start for any chance to move through the fuel system. Not my normal routine, I usually do 100 miles or more per day every day in this 7. We will have to get together sometime and compare rides as we are not that far apart.

[bluptgm3]

I understand that ethanol can be issue in certain situations as it can absorb moisture from the atmosphere and at 1/4 tank its possible. Ill dump some dry gas in tomorrow as well.

Isn’t gas dry simply ethanol?

I think starting and idling for short periods of time in extreme cold isn’t helping your new battery. You should go for a longer drive with varying engine speed, not just idle speed.


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[haynes740]

Starting Fluid? It is -12*


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[clarkitect]

Thanks good advise. I understand that ethanol can be issue in certain situations as it can absorb moisture from the atmosphere and at 1/4 tank its possible. Ill dump some dry gas in tomorrow as well. But i think it will have to start for any chance to move through the fuel system. Not my normal routine, I usually do 100 miles or more per day every day in this 7. We will have to get together sometime and compare rides as we are not that far apart.

I would skip adding the dry gas. I **think** what you need is the car to thaw out. Thinking some ice in the fuel line or somewhere preventing fuel from getting to the engine. Back when my family ran a service station we would sometimes have to bring cars into the shop to let them warm overnight and thaw out to get them to start. Then we'd add dry gas and fill the tank and they'd be good to go. We'd add a pint to say a 15 gallon tank so the concentration was about 0.8%. If you filled with typical pump gas you have 10%, so don't bother adding more.

Hopefully if it gets into the 20's today and your car gets a little sun things might thaw and it'll start. Fill it with ethanol free to get the concentration of ethanol and water down to better levels.

Isn’t gas dry simply ethanol?

I think starting and idling for short periods of time in extreme cold isn’t helping your new battery. You should go for a longer drive with varying engine speed, not just idle speed.

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Yeah dry gas is ethanol, but there are also some isopropyl dry gas products. I agree with the starting and idling point.

And shooting a little starting fluid in the intake as you crank like haynes suggested it would help determine whether or not you're getting spark, no fuel.

[RL740IL]

I would skip adding the dry gas. I **think** what you need is the car to thaw out. Thinking some ice in the fuel line or somewhere preventing fuel from getting to the engine. Back when my family ran a service station we would sometimes have to bring cars into the shop to let them warm overnight and thaw out to get them to start. Then we'd add dry gas and fill the tank and they'd be good to go. We'd add a pint to say a 15 gallon tank so the concentration was about 0.8%. If you filled with typical pump gas you have 10%, so don't bother adding more.

Hopefully if it gets into the 20's today and your car gets a little sun things might thaw and it'll start. Fill it with ethanol free to get the concentration of ethanol and water down to better levels.



Yeah dry gas is ethanol, but there are also some isopropyl dry gas products. I agree with the starting and idling point.

And shooting a little starting fluid in the intake as you crank like haynes suggested it would help determine whether or not you're getting spark, no fuel.

Starting fluid will be difficult working by myself but it does auto crank for about 15 to 20 seconds so I'll give it a try. Just enough to check for spark.
As for isopropyl vs ethanol both are hydroscopic but water stays in solution in isopropyl. Not so with ethanol in fact with time a little pressure you get 3 layers ethanol, gas, and water. Thanks for all the advise!

[RL740IL]

Well the temp was up to +20 tried starting, cranks and sputters feels like its got spark! checked fuses, Swapped fuel pump relay with rear defroster relay same result. Not practical to try starter fluid by myself.
May be stuck driving the girl mobile until the weather breaks. Snow tomorrow then back below zero for the weekend.

[clarkitect]

This weather stinks on ice!

[RL740IL]

Did I see you picked up an IL? You going to keep it or flip?

[SpeedyE38]

Love your post.

I walked out on Tuesday morning, -9 and went to start the car. While the car turned over a bit slower, it started right up and purred like a beast. Now, the pixels on all the displays were taking some time to come on. I drove it for about 40" to the office''s underground, heated garage. It was nirvana watching ice chunks fall off the car in puddles of muck. It was also nice being able to open the other three doors finally (I tried to get some pine needles off my car and used an outdoor car wash to remove snow, debris...you know what happens to water under 32 degrees...)

[clarkitect]

Did I see you picked up an IL? You going to keep it or flip?

Yeah picked it up as a project to hopefully flip and not lose my shirt. It's very nice, nicer than my sport. Weather and Christmas screwing with my game though. Need to put some heat in my garage and maybe hit it hard this weekend.

Where you at upstate?

Love your post.

I walked out on Tuesday morning, -9 and went to start the car. While the car turned over a bit slower, it started right up and purred like a beast. Now, the pixels on all the displays were taking some time to come on. I drove it for about 40" to the office''s underground, heated garage. It was nirvana watching ice chunks fall off the car in puddles of muck. It was also nice being able to open the other three doors finally (I tried to get some pine needles off my car and used an outdoor car wash to remove snow, debris...you know what happens to water under 32 degrees...)

Heated parking is a real treat!

[RL740IL]

I'm in Crown Point.
One of my work sites is in Saranac Lake often the coldest location in the country on any given day. My latest trip there it was 28 below.

[kouks]

I used to live in Rome...I moved to So Cal.

[racer2086]

I remember that stuff when I was in CT! Enjoying Tampa now!

Do you have fuel pressure? The fuel pump may have given out in the cold.

[RL740IL]

I remember that stuff when I was in CT! Enjoying Tampa now!
Do you have fuel pressure? The fuel pump may have given out in the cold.

Its just been to cold to work outside, I have only checked fuses, Swapped fuel pump relay with rear defroster relay same result.
Weather is getting better by the end of the week and I will check the pump. I'm sure the the original as I got the car with 80k on it.
Enjoy the sun!

[RL740IL]

Finally got above freezing. Tested all fuses, relays. All good. Pulled MaF and gave a shot of starting fluid, fired right up. Ran for about 15 seconds on each shot of fluid. Fuel pump ordered.

[xboss]

Nobody uses block heaters anymore?

[RL740IL]

Nobody uses block heaters anymore?

The only car I ever had a block heater in was 74 Mercedes 240d. Did not help much after about 15 below. I used to let it run all night when temps were 20 to 30 below. Used about 2 gallons of fuel. I have had this BMW for almost 5 years and it has always started. Even started at -37 last winter.

[RL740IL]

Issue resolved. Hit 40 degrees today so I installed the new fuel pump, primed the system by manually closing the pump relay for about 30 seconds. Started instantly.
Thanks to all for the input. By the way looks to have been the original pump. So failed at 145k, not bad considering the age as well.

[clarkitect]

Excellent! Glad you’re back on the road!

[racer2086]

Nice! That is some incredible cold you get up there. Wow.

[XAlt]

The only car I ever had a block heater in was 74 Mercedes 240d. Did not help much after about 15 below. I used to let it run all night when temps were 20 to 30 below. Used about 2 gallons of fuel. I have had this BMW for almost 5 years and it has always started. Even started at -37 last winter.

Oh god.

My friend challenged me to drive his 69? 200D with the gorilla knob on an actual highway, and I immediately took the nearest exit.... A 1987 Range Rover is a spaceship compared to that thing.

[RL740IL]

Oh god.

My friend challenged me to drive his 69? 200D with the gorilla knob on an actual highway, and I immediately took the nearest exit.... A 1987 Range Rover is a spaceship compared to that thing.

LOL. The old 240d (1974) had a little more horsepower than the 200d, but still was the slowest thing I ever owned. It was built like a tank and they reach some of the highest miles ever. Many with 5 million documented miles. I seen one at the MB museum with 5 million miles! I gave up when the blower failed, the amount of work to fix was crazy. They built the car around the blower motor.

[clarkitect]

Ha, I just replaced the blower fan in my 740iL this weekend. Was no picnic but not as bad as some cars. I replaced one in our W126 280SE (1985 euro version) and I think it took about an hour. So easy.