Stalled 1979 BMW 528i

start
bmw
528

#1

Today during Portland’s heat wave, my car, a 1979 BMW 528i with 120,000 miles, stalled at a stoplight. This is the first time this has happened since I bought the car 3.25 years ago. When I purchased the car, in May of 2006, the tags on the license plates were dated 1995, suggesting the car had been not been driven for at least 11 years. The gas tank had rusted interiorly from sitting for so many years, which I replaced immediately. I have changed the spark plugs twice and I regularly change the oil and fluids. Eva has been a very reliable car that is super fun to drive. I noticed Wednesday and again today (Friday) that the car was running hot. The needle that indicates the engine temperature, which usually sits at just a tick under the halfway mark, was nearing the red zone. When I noticed it on Wednesday, I immediately parked the car and walked the rest of the way to my destination. When I came back, over two hours later, Eva started right up. Today however, I stopped at my destination and when I went to leave again 5 minutes later, Eva did not start right away. She started the second time I turned it over. While at a stoplight 5 blocks later, she chugged a little, like she wasn’t getting enough gas, but the light turned green and I went through the intersection, albeit, slowly. At the next stop light 3 blocks later, she died just as the light turned green. It was if I’d run out of gas. She would not restart. The kind woman next to me in traffic blocked the intersection with her truck and recruited the driver behind me to push my car across the intersection. I sat with the car on the side of the road waiting for the engine to cool. Thirty minutes later, I turned it over and she started, no problem. What happened? and how can I avoid this happening again? I kinda think it was the heat, and this too shall pass, but when I have seen cars overheating in the movies and on TV, there is smoke coming out of the engine; this did not happen. Eva just sputtered a bit and died. It may be important to note that, especially in the somewhat cold, extremely damp winters here in Portland, on an initial start, there seems to be a problem with the gas. She always starts right up, but when I drive for the first 8-10 blocks, the gas pedal can be floored an I am only going 10-15mph. It feels like dampness in the gas or something. After those first few blocks: no problem. And it only happens on a cold start in the 8-month-long damp season. I would be so very grateful if you could diagnose my Eva. I love her and don’t want to sell her, but I need a reliable car. Thank you very much, Lea


#2

You are placing too much blame on the weather,be it hot, cold wet ,dry your car should run. It sounds like two problems overheating and a no start be it from no fuel or no spark. It is time to stop driving your car until the overheating issue is resolved as these cars can easily crack a cylinder head when overheated.


#3

Other than agreeing with oldschool’s comments I can only throw one thing out there considering how little detail is known about the symptoms.

You state the gas tank was rusted and had to be replaced. What about the fuel pump and filter? These could have been killed by a rusty tank.
Not only that, the Bosch pumps used on European cars take a real beating anyway even under ideal conditions and it’s possible (quite) that the pump is failing.

Tear apart any aged Bosch pump and you will find that the commutator (part of the pump armature) is worn pretty badly. Badly worn commutators mean weak or erratic in operation fuel pumps which translate to poor performance and/or stalling.


#4

I agree that a car should run in any and weather conditions. I only mention the weather to help diagnose what may be the root cause. When the car died at the stoplight this afternoon, it was definitely getting a spark when I tried to restart it; it felt more like a gas problem to me. The overheating only happens when driving in stop and go traffic, on the freeway unencumbered it has no overheating issues.


#5

I am pretty sure the fuel pump was replaced when I replaced the gas tank in June of 2006, although I couldn’t find my receipt for that, so I can’t be sure. The fuel filter was replaced in the fall of 2006. How often should filters be replaced? And if the pump was replaced would it be time to replace it again? The cold start slow 8-10 block routine has been happening for quite a while, I’d say 2 years. It is not a major problem, performance-wise, I am just curious what is wrong. I just chalk it up to the car being 30 years old and in need of some TLC. Thanks for your help.


#6

Let me check with some experts and I will get back,at least I will give you a better idea. Are you backing off the overheat issue?


#7

Fuel filters should be replaced about every 15k miles in my opinion, and even more often if fue contamination is suspected.

In theory the pump should not need to be replaced IF it was replaced along with the tank at the same time but even that is not etched in stone.
If the tank was rusted out then rust in the fuel lines themselves is also a possibility. Rust in the lines will wind up in the filter, can even clog up the screens in fuel injectors, and rust can even make its way back to tank via the fuel return line.

A cold engine requires more fuel to run than a warm engine so a disruption in the fuel volume (faulty pump, clogged filter, faulty fuel press. regulator, etc.) could be responsible for something like this.
Without car in hand it’s hard to say but my feeling is that a fuel pressure check should be performed.

A few questions though. When the car is only moving at 15 MPH is the engine revving up high or is it just sluggish and not wanting to rev?
Automatic transmission?


#8

Yes, it is an automatic transmission.
When the car is doing the 15 mph-for-8-blocks-on-a-cold-start thing, it is sluggish, the engine is not revving. It is as if I am not giving it much gas, even though I may have it floored. I usually don’t floor it, instead just give it the gas it needs to go the speed it wants to go. After about 8 blocks it responds ideally to the gas pedal. Just to clarify, this isn’t happening now in the summer, it only happens when it is cold and rainy. Weird, right?
I will get the fuel filter replaced. That seems easy enough and it is probably time to do it, given your 15K rule. Is it possible to just check the fuel pump without having to replace it? How much is a fuel pressure check? How is it performed? My mechanic operates out of his home garage. It is a small operation, but he’s pretty good.
Thanks.


#9

I think the engine was really hot, but I am confused why that would cause the car to stall. It felt more like I ran out of gas, but somehow I just knew that if I let it rest a little bit it would start again, which it did. In general, the car runs a little hot in stop and go traffic and traffic jams, but usually the needle doesn’t get much further than a little bit passed the halfway point, and it has never died before.
Thanks!


#10

I am thinking of that little door sticking in those early air flow meters,but just not sure.

Would be nice if I had laid a wrench on one in the last 20 years.


#11

My expert said there are know problems with the actual throttle bodys,the outside lever moves but nothing inside does. He did second my thought about a mass airflow meter (physicaly damaged inside) as being a likely cause.


#12

A fuel pressure and fuel volume test could be performed and neither one is difficult to do at all. No idea on cost but it should not be much.

The general sluggishness throws me off a bit though. Lack of fuel pressure/volume usually means an engine that bucks and jerks, hesitates, surges, etc.
Cold and rainy weather should not affect the pump at all but usually does affect the secondary ignition system (plugs wires, coil, distributor, etc.) Moisture can condense on the plug wires, coil, and inside the distributor cap and cause a car to run poorly but this also means an engine that will usually buck and jerk, etc.

This would be easy to check. On a cold rainy day before the engine has been started simply pop the cap loose and inspect the inside of the cap. If it appears to be damp on the inside then that’s the problem. Dry the cap out, reinstall, spray the cap/wires down with WD-40, and see what happens.

The reason for this condensation is that heat attracts moisture. Shut a hot engine off in humid and/or cool conditions and moisture may be pulled into the distributor cap.
Think of a window in a house sweating on a cold damp day. Same thing.
Sometimes the moisture can clear out by itself pretty quickly and sometimes not.

Oldschool has a good point about the flap in the air meter also. They’ve been known to stick or even get blown out with one decent backfire.


#13

thanks, guys. I have an appointment with my mechanic tomorrow morning. I’ll let you know how it turns out. Thanks again for your help. Lea


#14

My mechanic changed the fuel filter and checked the fuel pressure. The pressure seemed to be fine and the filter was definitely in need of a replacement. At first he suggested cleaning the fuel injectors, but after talking a bit more he said I “vapor locked” and thought the best thing to do would be to change the fuel pump. I drove today without a problem, but it has also not been nearly as hot outside and I was able to get from point A to point B unhindered by stop and go traffic. Thanks again for your help, hopefully this is all the work it needs.