Fuel Pump Melody

[Billsmith]

Tonight the allure of the golden hour seduced my ‘73 Tii, Sahara, to pull over for a quick portrait.  Mind you, I had little control over this.  Having savored the moment, I hopped back behind the driver’s seat for the transcendent glide back to the home base, about 10 minutes away.  Alas, I turned the key, she rolled over, misfired a time or two and left me to decide whether I should stop before I ran down the battery.  After waiting about 15 minutes, she finally cranked.  Initially, I was parked on the uphill side of a slight knoll.   On the successful restart attempt, I had pushed the car to the downhill side of the slight knoll.  I ran out of gas about a week ago.  Prior to that incident, the fuel pump offered a slight melodious whine when the ignition switch was activated.  I think that since that time, the whine may have gotten more pronounced.  The increased volume of the fuel pump melody be what they call the power of suggestion or just all in my mind so to speak.  Here are a few queries I have for the FAQ/BMW brain trust:

 

1.  Why would a car start easily when cold but after sitting for 10-30 minutes be somewhat difficult to start?

2.  Is a whining fuel pump normal or might I have damaged it when I ran out of gas?

3.  Should parking the car with the nose pointing downhill have any affect on a quick start when warm?

4.  Should I go ahead and replace the fuel pump before it fails?

 

This is just for fun.  As always, any responses will be appreciated.  Having owned a base model ‘72 about 10 years ago, I should have known, each one sort of has it’s own personality.

 

 

[Son of Marty]

The first check for any Tii with suspected fuel problems is fuel pressure needs to be 28psi +/- 1 psi then check delivery amount, if you have pump problems one of these checks should show it, if all that passes the my next stop would be the start injection maybe no starting squirt when warm or maybe injector over fueled for a warm engine.

Edited March 7, 2021 by Son of Marty

[Conserv]

Bill,

 

Have you replaced or cleaned the screen on the fuel pickup in the fuel tank? After that screen, there’s a small filter screen before the gas enters the fuel pump, the larger primary filter adjacent to the radiator, and yet another small filter screen in the banjo fitting on the top front of the Kugelfischer pump.

 

Your pump could well be at the end of its life. But clogged or dirty screens/filters can make a good pump work poorly!

 

Regards,

 

Steve

 

 

 

[dlacey]

1) mixture and/or ignition timing

2) some noise is normal, if it ran dry for more than 10-15 minutes then it might be damaged.

3) no, tii will start in zero gravity

4) if the pump runs I would leave it alone. Maybe purchase a spare pump as insurance (when you have a spare part, the original will not fail).

 

the tii system squirts a bit of extra gas at every start, if you click the starter multiple times it will squirt gas at each flick and flood the engine. Starting discipline for a tii is to turn the key and hold it in start till it fires & runs..it may turn over for 10 or 20 seconds before it gets its act together.

 

Warm starting is worse when ignition is out of tune... What ignition do you have? 

 

 

 

 

 

 

 

[Billsmith]

Thanks to all for the great insight.  My ignition is what was original to the car.  Distributor/points.  My to do list is to have an electronic ignition installed.  When my mechanic comes up for air and can actually take a look at the car, I will print out your ideas to jump start his troubleshooting efforts.  Again, thanks for all the support you guys offer and your patience in providing it to a guy who is just along for the ride (very limited mechanical knowledge or ability).