High pitched whine morphs – bimmerfest – bmw forums electricity magnetism and electromagnetic theory pdf


A friend came by and we noticed the battery (a few years old) was taking a long time to charge fully, so I took it to autozone, and they declared it dead. Bought a new one (AGM, I think it was classified as). Car started and drove. But the whine still persisted.

My next step was that several posters mentioned changing the fuel pump relay worked miracles with starting issues for a low cost. So I had stepped into the jungle of unclear documentation, and could not find one clear source of the exact location of the fuel pump relay. Even the manual I purchased had a blank column for 2000 up E39 and said it was behind the glove compartment. Though many show it behind the trunk panel. While some have 3 relays others 4…

I bought the new relay for around 30 at autozone and had a heck of a time taking the glove compartment apart and then getting to the relay access points, but I did finally find the green fuel pump relay ( I think, in picture) and replaced it. Turned on the engine, and tack tack tack….. So I took it out and put the old one back, then tack,.. whirr whirr… Puling hair out at this point.

So now, my friend listens all around, for the high pitched whine, and we remove the back seat. He says it sounds like its coming from the catalyctic converter (leak?), but not sure. Add to that, the car keeps having trboule starting, click click rrr rrr rr. Restart… rrr rr. So, he thinks it is the fuel injector. But argues it’s not really a DYI job as the car needs to be lifted, and gas can go flying everywhere (happened to him).

Now at this point, I"m tired of throwing money at it, 1k here another 1k there adds up, and shop says it’s well let’s try this.. that.. No computer errors show up. And even though BMW code reader showed 13.7 volts with car running, atutozone and my hone charger, show pretty much dead. Any thoughts on throwing in the towel? I don’t know how you guys can afford to keep ‘trying’ different things.

Thank you. I can say that when we lifted the back seat, we agreed that the sound was definitely not from the passenger side, but more towards the driver side of the back seat, and not right at the fuel filter access covers(? I think there were two round covers, one on each) beneath the chair, but a little more ‘around’ the driver area. Using a screwdriver all around the engine only produced faint idling noises; the howling whine seems to be coming more from the back for sure, and ‘near’ the driver side. But very hard to isolate without lifting or going under car. It is prominent intermittently, but can be during acceleration, idling, or even freeway driving, just not always present. The howling all started right after putting liquid moly in the gas tank.

I’ll try to see if I could post a video. Can I post video clips here? Haven’t run down battery to dead state, I just bought today. I figured the alternator might drive it that high for the CPU measurements, but find it a bit unreliable as a battery test code. I would think they would have one for a non alternator state…. or at least one saying the capacity is done for. I’ll look into the AGM charging, I know my sears charger has several types of charges, I always try to keep it below high rates (fast charge, etc…) and stay close to long trickle type chargers.

No. Just learning about shrader valves and procedure, plan to go to autozone and either borrow or buy pressure gauge. I noticed the book says always release pressure by opening gas tank first and in another place it says close all fuel lines before opening valve to test. I take it that means, open gas tank, release pressure, close, and proceed? It’s those little minutia that throw me off some times (only obvious after you’ve seen or done it once or twice). Another e.g. Had a really hard time finding the fuel pump relay behind the glove box, and very few links show precisely how to release some of the attachments that are way up there, without breaking things. Bentley book was very vague and misleading.

It only returned the DME and EGC windows. I tried to open to try to short pins, but a screw stripped. So I can either break it, try to dremel, or proceed later, but I don’t think the pressure is shown in those (DME/EGC) diagnostics. ALso, I could not find an exact pinout diagram, so when people say to short, I’m not certain where the pin out count starts, or could just check the continuity on outside. Some people say it comes shorted on theirs. Does anyone know if I can use the same hardware from PASoft and just install INPA software? Or does it require its own hardware module.

My original thought was the whine all started after putting liquid moly in for the first time on 7/8 tanks. I’m not sure if that was the cause, but the sound was RIGHT after. And I’m trying to burn it off. Unfortunately, my cluster board is also fubar, I can barely read the milaege… it has that (well known) problem that requires replacing entire cluster, which I haven’t gotten around to yet. Another money drop. I’ll drive it down though, and try to observe sound correlations.

Right. I agree, hate to blame it. Spurious correlation is quite likely, with so many problems and activities (shop also just supposedly fixed problem, etc), that it’s hard to nail down one or true source. At some point I can only take note of specific activites at time of failures.