Leak from fuel tank connector (1985 k100)

[CCalms]

Hey there! My fuel sender unit is dripping gasoline. On my bike (85 k100), this is located under the front left side of the tank, and it appears that the fuel sender unit threads out (with a gigantic wrench that I don't have). I did some investigation of the BMW parts diagrams and found that the fuel sender unit has an O-ring that helps to seal the gas tank. I'm sure mine is dried and old like the rest of the rubber on the bike, so I bought a replacement.

Before taking my gas tank off, I wanted to see if you motobrickers could lend me some advice. How do I unscrew this fuel sender unit? Do I really just need to find a >35mm wrench that fits? Also, will I have to unhook the wires from the fuel pump in order to replace the O-ring?

Thanks!

[Scott_]

Actually, there will be 4 mounting bolts that hold the plate in place.

[Inge K.]

Actually, there will be 4 mounting bolts that hold the plate in place.

Not on a -83 to early -85.....the float sensor with four screws was used from 05/85 and on.

[Scott_]

Actually, there will be 4 mounting bolts that hold the plate in place.

Not on a -83 to early -85.....the float sensor with four screws was used from 05/85 and on.

That's an interesting one there Inge, guess I learned something today.......

[Inge K.]

Did remember wrong, the change was 04/85.
Also notice the different tank mounting than the later models........

To OP you must remove the wires from the pump....it's ring terminals with different dia....difficult to mix.
Be gentle With 30 years old brittle plastic.......

[Vespa no more]

I have just been through this.

Early K100s have the fuel sender at the front left hand side. I have been told that, due to faulty readings and lights coming on, from 1985 the sender was moved to the back (ie 4 bolts).

Big but gentle adjustable wrench freed mine. Standard threaded item. No issue of brittle plastic.

But this was just the start of it for me.

After 3 weeks waiting, two different shops supplied me with the o-ring from an 85 (approx 50mm OD) at $10 ea. Cheap!
You can buy online a box of mixed sized metric o-rings ... 419 for $16 made from NITRILE BUTADIENE rubber (petrol / gasoline and oil proof... apparently Vitron is a similar product) in a red box... which is what the second shop had "out the back". Mechanic had reportedly tested them in petrol / gasoline

This is the link I used. Probably out of China no doubt (given the "Professional quality" on the label)
http://www.ebay.com.au/itm/180934755336?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

While you are in there, a car fuel filter might be a lot cheaper than OEM BMW filters ($10 v $58).
I also replaced the rubber fuel hose in the tank with EFI submersible hose (NB must be submersible - which means both the inner and outer of the hose is resistant) (2metres for $50, 250psi, 8mm ID) from a performance auto shop in QLD rather than BMW hose. . I will do the outer hoses when I work it out.

Hope this helps.

[billday]

Here's a list of alternate fuel filters:

http://www.motobrick.com/index.php/topic,2057.0.html

Beemer Boneyard has reasonable prices on fuel system items (and much else) that you know will fit:

http://www.beemerboneyard.com/airfuelfilters.html

[Vespa no more]

Thanks for that.

Meanwhile down here in Australia we don't get a lot of the US filters (23 million ... 0.00075% of them own a BMW - in a good year!)

CCalms: check the size of the o-ring they have sent you. It might be the wrong one. I was told that it was not available in Australia from the BMW warehouse (NSW and Qld). Hence the search for a suitable replacement. I think yours needs to be 27mm OD / 23mm ID (approx ... NOT 50mm OD) and the original has a squared cross-section (o-rings are of course circular). I am yet to test the o-ring because I will not put the tank back on until I have replaced hoses and injector o-rings. I looks like it will work (seems thick enough).

Does anyone have a list of the alternative parts (including air filters: I know the Ryco 418 has been recommended (I am yet to fit mine)) for BMW in Australia?

Should I start a new posting on this topic?

regards

Guy Francis

[blakey]

Guy, there have been tests conducted on a dyno using the stock air filter and "the other type" and there is no real discernable difference between the two. The original air filter is good for 40,000km's or thereabouts (depending on your local environmental conditions) and it doesn't need reoiling either.

There are some Aussies using injectors from the local Falcons and even some Hyundais. Fuel pumps from Falcons too (with a bit of creative engineering, they fit well).
On eBay you'll find injector "rebuild" kits with o rings, pintle caps and the mini filter that fits in the top of the injector. Cheap.

I hope that helps.

[Vespa no more]

Thanks for the reply

I saw the "Ford Falcon" reference somewhere. Was there a specific model of falcon?
For $9.50 you get 6 injectors covered. Great Value!

think I will get down to the local wreckers and liberate a few - if only to practice on.

GF

[blakey]

Injectors form the Ford Falcon 5 litre V8's, not the 6 cylinder.

Also Hyundai X3 SOHC injectors apparently "work ok".

Please post any information on your findings.

Thanks.

[Vespa no more]

Australian BMW Fuel Injector Alternatives: Ford Falcon V8 Injectors

Replacements / Repair Kits available from $10 (for one) $13 for 8, $23 for Bosch – if they fit the existing OEM BMW injectors.
Set of 8 injectors (may have to go halves with someone else)

Cheapest on Ebay (9.12.15)

$186 for 8 “Compatible with Bosch”

http://www.ebay.com.au/itm/Fuel-Injectors-Ford-Fairlane-NL-NF-NC-NA-Falcon-EB-ED-EF-EL-XH-LTD-DL-DF-V8-5-0L-/291584999865?hash=item43e3d201b9:g:PR4AAOSw9mFWFx-h

$200 for 8 – Genuine Bosch

http://www.ebay.com.au/itm/8pcs-NEW-AU-FALCON-FAIRLANE-LTD-V8-5-0L-GENUINE-BOSCH-FUEL-INJECTORS-0280155917-/172015613088?hash=item280cedf4a0:g:jiIWhere AAOSw14xWNxXX

Makes you wonder what the BMW OEM injectors cost?

$174 AUS per injector (from USA) Price as a reference – does not fit my 1984 K100Rt
http://www.ebay.com.au/itm/Fuel-Injector-BMW-K1-100-1100-1200-13-64-1-461-523-Bosch-OEM-/371503180882?hash=item567f50ac52:g:YWMAAOSwQoFWPOiE

Best option may be to go to the wreckers and fill your pockets with injectors off a V8 Ford, then get the repair kits online.

I can't see why we need to be precious here - it is only a bloody injector - an electronically controlled solenoid in a plastic tube with an o-ring each end and a little filter on the top. Sometimes we get priced into silence without questioning the science behind it. Imagine what the production costs are - lucky to clear $5 each.

If I find out anything or have successes will let everyone know.

Regards

Guy

[Martin]

Vespa do you know whether the Ford injectors are single hole or four hole. Apparently the four hole are supposed to be better.I have also read that BMW 318i E30 injectors fit ,
but again don't know the number of holes.
Regards Martin.

[Laitch]

I can't see why we need to be precious here - it is only a bloody injector

Are all injector apertures the same diameter, I wonder? Anyway, in MB.com's alternative injector list, certain Ford Six injectors are recommend. That would contradict a previous post in this thread.
http://www.motobrick.com/index.php/topic,5021.0.html

You're in a labyrinth, Vespa. Experimentation with parts recommended by the most verifiable source may be the only way out, unless you volunteer for an OEM flogging , of course.

[Vespa no more]

Might have to change this thread to "injectors"

I'll call it a draw for now... have retired from the garage having tried to pull all the injectors out. Got 3 but not the #1 injector (nearest the front).

I haven't been able to find an example of someone "doing the injectors" on a K100 (it's got to be somewhere!). So I've taken a few photos and worked out the sequence and will post it for other newbies.

With regards to getting beat up on the forum re: injectors... I'll admit my ignorance here and now. But I am keen to find better cheaper options where possible and where proven to work.

Now to find a way of getting that injector. There is a tool out there waiting for me...

Guy

[Laitch]

I think with a little modification and some more personnel to stabilize the bike, this method may be just the thing, Guy.

[enb54]

I had to remove all injectors on my daughter's Pontiac Montana van, sure glad I didn't have to resort to the lever and fulcrum on that 530D...

[Vespa no more]

Injectors now removed!

As stated above, number 1 cylinder injector refused my persuasions and I had to do some homework.

Local BMW mechanic recommended a hot air gun (definately not flame - eg blow torch or oxy-acetylene). Upon trying this I had mixed success. Area heats up readily (including the metal body of the injector and if you are not careful, the plastic top of the injector and the wiring harness that supplies power to the injectors). Perhaps try and contain the application of heat by reducing the diameter of the air vent on the heat gun. Anyway all very hot. And still the little bastard refused.

So it was out the the multi grips. Grabbed onto the metal body of the injector and muscled it out. The cap on the bottom and the lower o-ring came off. Will be easily fixed back into position. Inlets behind / below injectors partially closed with build up - easily removed with small vacuum hose.

Apart from #4, all the others came out using a two handed wide rotating action - not straight out and not wiggling back and forth. Maybe some heat proof grease around the lower o-rings on re-installation might be useful.

Next task is to clean injectors (there are plenty of youtube suggestions) and reinstall.

Enquiries at BMW shop (looking at their spare parts exploded diagram on computer) did not show any petrol / gasoline filter in the top of the injector. Just two o-rings to be replaced. Can someone explain what the pintule cap is and its role.

Have taken pics of this and will up load when I have time. There are sure to be others wanting a detailed description with pics.

On another note, the centre stand broke and needed time and attention. Will upload this little saga as well. Apparently the early ones are prone to breaking. All fixed now. Provided a good opportunity to finally get the free oxy-acetylene working after 5 years or more.

Next task is to make / find a bracket for the headlight and indicators. I want to ride the bike without fairing for a while so that I can see and attend to any "teething" problems.

I expect many of our American friends have their bikes off the road for winter (snow). Here in Australia, it's hot and the flies are as insistent as they ever were.

Happy riding

Guy

[Laitch]

Thanks for this followup explanatory post, Guy.

[rbm]

Enquiries at BMW shop (looking at their spare parts exploded diagram on computer) did not show any petrol / gasoline filter in the top of the injector. Just two o-rings to be replaced. Can someone explain what the pintle cap is and its role.

The pintle cap is an important pre-filter screen.  It's fine metal mesh is the last line of defense against small particles that could jam the injector nozzle.  It's very important to replace it at the same time as the O-rings because an old one might be clogged causing reduced fuel flow.  Replacement kits available through ebay usually come with this pintle.

[Inge K.]

Can someone explain what the pintle cap is and its role.

The pintle cap is an important pre-filter screen.

The pintle cap is around the nozzle opening at the lower end of the injector and secures the lower o-ring.

But the mentioned the small filter basket at the injector inlet is a good idea to change if they looks dirty.

[Vespa no more]

I'm all for changing this now that the injectors (NB: K100RT 1984) are out but BMW told me there aren't any.

Perhaps they are an integrated item. This would be very un-BMW.

Will pursue this and let you know what I find.

With all this injector talk, I will get all the information (provided by everyone so far) into one detailed post and couple it with my pics and experiences into a new post. We are deviating off script (ref the heading "Fuel leak") and it probably wont be found easily.

Just need to find the lead to connect camera to laptop.

Guy

[jakgieger]

Yes, apparently the thread is hijacked... :hehehe.  I bought/installed a set of these injectors and am happy with them so far.  http://www.ebay.com/itm/1984-85-BMW-318i-E30-M10-Fuel-Injectors-Best-Direct-Bosch-Upgrade-4-Hole-Spray-/191748253555?hash=item2ca5162773:g:Cr8AAOxycmBS6PL9.  The cost was similar to a professional cleaning.  I come back to efficiency, the more complete the combustion=greater  power/efficiency.

[blakey]

Guy, this http://www.ebay.com.au/itm/FUEL-INJECTOR-SERVICE-KIT-SUIT-HOLDEN-COMMODORE-VN-II-V6-3-8L-90-91-INJECTORS-/191647450482?hash=item2c9f140572:g:TAwAAOSwPcVVuY8t is what I use when refurbishing the injectors (you don't/can't rebuild them).

The little filter at the top of the injector can be removed by screwing in a screw (duh) and pulling it out. It may take a bit of force, but you'll do it. Make sure the screw only cuts into the filter and not the injector body...in other words, do not use a big screw.

[The Mighty Gryphon]

In other words we're screwed if we screw up the injector by screwing around with too big of a screw?