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1994 K75S High-pitched chirping noise when hot?

Sudden slight change of plans!

Out of curiosity I decided to track down the original source of my FPR substitution to locate the recommended brands and part numbers.

Long story short:

Two different sources confirmed that either a Napa/Echlin 21709A

or a Standard PR134 would work fine in any early K (brick).

With further curiosity and diligent searching I also learned that the Standard PR134 is OEM equipment on many different cars ranging from late 1970s Porsche
911s to VW Vanagon and Super Beetles as well as JEEP, AMC, Chrysler, Audi and Jaguar models in the late 1970s to mid 1980s.

Bingo!

I decided to take the plunge and try a brand new PR134. The lowest SHIPPED price was $51.08 on Amazon.com (with FREE Super-Saver Shipping) and the next best was RockAuto at $53.03. One on ebay was $64.83 with free shipping and there were a couple of places that had them as low as $47 but with shipping they were back up to $55 or thereabouts.

So one is on its way to me via Amazon and I've no doubt it will be here in a few days even though they claim their Super Saver shipping is 5-8 days. Even when I ordered things in Hawaii that way they arrived so fast I'd have to duck...

Thanks again, Don for encouraging me to try a substitution out. I'm still going to buy a used one if I can get it for dirt cheap (and it looks like I will) so at least I'll have a backup on hand from now on. I think the new Standard will be just fine as it has been used in so many different fuel injection systems over the years.

If it's good enough for Porsche, VW and Audi I reckon it'll be just fine in my beloved Berlina.:dance

I'll give a full report once it's installed and running, too.

PS: Forgot to mention that the Standard is absolutely identical in appearance and dimensions to the OEM BMW FPR, even has the M12x1.5 mounting thread on the top.

Also, I just realized that a new OEM would cost me at least $162 with the 7% tax we pay in ABQ if purchased at the dealers so I am buying the Standard actually at less than 1/3rd the cost! Makes for a darn good argument to try one out assuming it'll work just as well, doesn't it?
 
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Installation in progress

Got all the parts required (including a new airbox lower half as one of the original spring clip mounting points had broken) and am currently installing the Standard PR134 fuel pressure regulator.

Will update again in the next day or two once it's all back together. Since I'm also reinstalling all four of my auxilliary lights that I removed just prior to some fork work it may be a little while, though. I also fabricated some new mounts for my Hella FF50s which will go onto the forward engine-to-frame mounting bolts (less weight on the fragile and somewhat rickety K75S fairing this way) and will need to reconnect and reroute some of the wiring thusly before completion.
 
Pictures of Replacement Part

Hello Zagando,

You should post a picture of the replacement FPR. I am sure many, including myself, would profit from your thorough experience and newly acquired knowledge on replacement parts. If the FPR is $162 in the US, I am scared to even ask how much it would sell for in Canada.

Get us some pics if you can, they are easy to post. I followed the advice of some members of this Forum and got a free Photobucket account into which I upload the pics from my computer and then "tag" them as required for various threads.

Ghyber
 
OK, Ghislain; Here's a photo of the aftermarket FPR as requested.

Last night when I posted my reply I forgot to mention that my new FPR was already installed and well hidden behind the airbox---so here's a stock photo that I got off the internet when I was searching around. Although the brand of this one is Delphi it is absolutely identical right down to the silver color and style of fittings as my Standard PR134:

DelphiFPR_zps30dd07fc.jpg


I'm still working on my new auxillary lights brackets and the associated rewiring but will post a report once the bike is back up and running, of course.

If it works as fine as I expect I imagine many brick riders up in Canada would be interested as you point out. Since the PR134 is made in Mexico and is a stock replacement for many imported cars you should be able to obtain them in Canadaat any auto parts chain store at prices somewhat close to the $51 I paid.
 
Woeful surprise + water pump question now

Well, I got the brand-new FPR installed and guess what; the bike is still screeching like mad once it's warmed up and the fan starts to come on!

I can't tell you how disheartened I am now, after spending so much time, energy and dollars that I couldn't really afford to spend in the first place---to no avail still.:banghead:banghead:banghead:banghead:violin

The noise seems to be coming out of the front of the engine as far as I can tell and I would say it's the fan bearings going out except for the fact that the screeching occurs sometimes before/after/during I can hear the fan going. If it was happening only when the fan is on then I'd have the answer but sadly that is not the case.

So my question now is, could it be the water/oil pump bearing going out? Has anyone had a bearing in that go out and if so, did it sound like a stuck pig? Was it intermittent over a period of months? (this actually started happening late last year in Hawaii when I was down in warm/hot sea level places---but never up in the cool rain forest where we lived at 4000 feet):dunno

As always, any ideas or help is vastly appreciated.
 
So what was the result of the fuel pressure test that led you to replace the regulator?

I thought you said the noise was coming from the pump? You should easily be able to tell if the noise is coming from inside the tank. Open the cap and listen with your ear to the opening.

There are several bearings that could make a screeching noise, but not in the tank. Oil/water pump, alternator, transmission,and some in the intermediate housing.




:dance:dance:dance
 
Lee; I decided to replace the FPR after two different BMW mechanics told me it sounded like the FPR, not the fuel pump (one actually heard it squealing as I rode it into his shop and he was trained at BMW in Germany).

Ted; Guess I may have to break down and get one of those stethoscopes. I have not gotten one yet as the noise is so loud it is actually hard to pinpoint the source. I think the stethoscope might deafen me but I'll take a chance now.

Lostboy; No, still have the same pump. I'll try the open gas cap/listen test first chance I get (might have to round up my spare key first so I don't have to turn the engine off to open the tank).

Thanks for all the quick responses on this! I'll post what I find/figure out when...
 
The stethiscope works because it isolates all the ambient noise except for the exact spot you poke the probe. You could probably wear it over earplugs if the noise is too loud :)

Do you have a smart phone? I'd love to see/hear a video clip (host/post free on YouTube or Vimeo) of this noise!

One warning on Harbor Freight, it is sort of like a toy store for big boys. My last trip I set out to get just a lever grease gun for the side/center stand and with the coupons (sign up online for them, they are awesome) I walked out with a $5 set of punches for doing brake pads, a $4 snap ring pliers with exchangeable sized heads, a $10 torque wrench (that is apparently surprisingly good), a $3 set of picks, $5 set of ball end metric Allen wrenches, $4 organizer for various sizes of crush washers, $4 magnetic pickup wand, $3 magnetic cup bolt holder, etc. etc. etc. If you walk in with a shopping cart, you're doomed ;)
 
Uh, unlock the cap before you start it.:dunno

I already thought of that, Lee but the trouble is the noise doesn't show up until I've really warmed up the bike (as in lots of stop and go traffic or on a hot day)---so I don't feel comfortable with an open tank while riding around town. I just filled her to the brim with Chevron regular (her favorite brew), too.

I do have a spare which I will fetch as soon as I get going this morning. I'm heading up to Harbor Freight which is just the right distance for getting the screech to happen as I pull back into the driveway...

Stay tuned.




:dance:dance:dance

.
 
Harbor Freight stethoscope, etc.

The stethiscope works because it isolates all the ambient noise except for the exact spot you poke the probe. You could probably wear it over earplugs if the noise is too loud :)

Do you have a smart phone? I'd love to see/hear a video clip (host/post free on YouTube or Vimeo) of this noise!

One warning on Harbor Freight, it is sort of like a toy store for big boys. My last trip I set out to get just a lever grease gun for the side/center stand and with the coupons (sign up online for them, they are awesome) I walked out with a $5 set of punches for doing brake pads, a $4 snap ring pliers with exchangeable sized heads, a $10 torque wrench (that is apparently surprisingly good), a $3 set of picks, $5 set of ball end metric Allen wrenches, $4 organizer for various sizes of crush washers, $4 magnetic pickup wand, $3 magnetic cup bolt holder, etc. etc. etc. If you walk in with a shopping cart, you're doomed ;)

Good morning Ted; I'm heading to HF in a little bit to get the stethoscope and will endeavor to use it without losing my hearing---the over earplugs is a good idea, at least for starters.

I suppose I could stick it in the gas tank and listen to the fuel pump even though the tank is full (I'll make sure the 'scope is clean). Then I can try the new FPR just to be double sure. I'll check the water/oil pump next and then around the alternator (I wonder if monkey nuts make such a high-pitched screeching sound? Kind of doubt it but I've never heard the sound that they make when they start to go).

No, I'm sorry but I don't have a smart phone but I might be able to make a cassette recording that could possibly be uploaded---we'll see what I can learn with the stethoscope and go from there.

Your comments about Harbor Freight are classic. Should be made into a sticky!

After the first time I went there this summer I told my wife, "It's like Trader Joe's for mechanical stuff!"

I, too, came home with a bunch of stuff that I couldn't pass up.

Worth mentioning is their 5lb. capacity vibratory tumbler that was on sale for $55 (vs. $100 reg.). I've used it to de-rust all the non-stainless steel bolts on my bikes and assorted rusty bits and tools that had suffered "rain damage" from living in Hawaii too long. Makes the steel and galvanized bits look like new but doesn't wear down the threads. Only takes an hour or two in a couple pounds of hard plastic tumbling media that they also sell in huge jars.

Well, I'll post a report here as soon as I have further developments. Thanks again for your help.
 
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Video possibility

PS: Just remebered that we have an older point-and-shoot digital camera that can take video; I'll add that to my to do list and see if I can post it on YouTube (unless I find something obvious with the stethoscope beforehand).
 
I think you will be able to identify the sound on the outside of the tank, you should be able to hear the resonation if it is the pump inside. Literally just keep poking the end around until you isolate the source of the sound. It is sort of like trying to find an air leak, just go slow and methodically.
 
I'm back from Harbor Freight and it was a beautiful ride both ways. I took the windscreen off when I was taking the tupperware apart to do some rewiring for my auxiliary lights and decided not to put it back on until the weather turns really cold.

If it weren't for this noisy problem I'm encountering I would say that my bike is absolutely running the best it ever has. I had the valves adjusted a couple of weeks ago at the dealer's and I also had them put in new plugs for good measure.

It's so smooth that I wanted to keep on riding around Albuquerque, zooming down the wide boulevards in the cool fall afternoon but I needed to get back and attend to another minor problem first (fixing one of my bag's latches that broke off when I pulled too hard).

I got out of HF for under $15 but it was not easy there are so many temptations that await you!

I got the $4 stethoscope, a $6 pair of large 3X power magnifying glasses that clip on to your regular glasses (for close up electronic repair that I do sometimes) and a $3 box of 3/16th" rivets that I plan to use for the latch.

Im going outside to start on the latch and then I'll take my wife to work on the bike a little later. That should warm it up enough so I can induce the noise long enough to start probing the tank and engine casing for the source of such a racket.

Good to know I won't need to actually probe inside the tank, Ted, too---I'll try the lower right outside of the tank first screech that comes on parked at idle.
 
Rivets and SCREECHING DIAGNOSIS AT LONG LAST!

The smaller rivets inside the cases are 1/8th as that's what I used several months ago to replace a couple; they matched perfectly. But the large latches sure looked bigger so that's why I went with 3/16ths. My latch is now back on the bag securely and it's working fine again. Yes, I did have to drill out the old rivets first which was a bit tricky but I think I'm good to go now.

Maybe the OEM size is 4.0mm which may be right in between 1/8th and 3/16ths?

On the screeching front I reached a diagnosis about 5 minutes ago. After finishing the latch job I put my gloves and helmet on and set out for an around town ride to get the engine well-hot, mon (as they say in Jamaica).

Not so sure if I should jump for joy as it's still going to be a major task for me to fix but it's nothing to do with the fuel system after all!

After riding around for twenty minutes the noise came back as I came to a stoplight near my home.

With the bike running, I pulled over on my street, took off my helmet and quickly got out the stethoscope. (Works great, Ted! Thanks for the suggestion)

Fuel pump? No.

Alternator? No.

Engine block? No.

Oil/water pump? No, thank dog!

New FPR? No, so the old one is probably still fine. Now I have two good spares besides the new one I just installed!

The culprit? The swan song of the radiator fan bearings is the noise I've been hearing all this time!

I'm surprised I didn't suspect the fan a lot more than I did because it would always happen when conditions were hot enough for the fan to engage.
While I could have sworn that there were times the noise wouldn't be there when the fan was on and vice-versa; I didn't take into account that it would be hard to hear the regular fan noise at speed. Only the chirping would get through and was especially prominent at stoplights or slow traffic.

So now I will look into replacing the fan which seems like both an expensive and daunting task. I don't suppose there is a way to save it instead of replacing it, is there?

I'll check MaxBMW first to get the major price jolt, then Beemer Boneyard and Drake's website up in Seattle for used ones that might be available at lower cost.

That's the news for today. With the cooler weather on its way I suppose I can still ride the bike as is for a while longer, at least. I should have known that the big clue I was overlooking was the fact that the noise only popped up when it was hot outside or on the bike. And the fan was on when it was happening a lot.

Thanks for all the support and interest along the way, guys. I'm sorry it took so long to figure it out.

I'll be standing by for any further advice on how I should go about repairing or replacing the fan.
 
Jeff - your best bet - visit a Harbor Freight and purchase a mechanic's stethoscope. That should let you localize it.

"Under the tank" is a wide expanse of territory to guess where the noise is coming from. It could be anything from a bearing going bad somewhere, to the a plugged fuel filter (the fuel pump has a blow-off valve that chirps when it's pushing against too high a resistance.)

Try to narrow it down a bit and get back to us with your findings.

http://forums.bmwmoa.org/showpost.php?p=801468&postcount=2

Hmmm... this was the very first answer to your original posting..

Think about how much time/$$$ could have been saved.. :dance
 
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