BMW doesn't start after standing still long time.

[Tim Schoon]

Hi All. Thanks very much for all the input. We have done a couple of tests to understand behaviour of starting the car. It starts immediately every day and or every other day. It will also start after 2 weeks not being used. It is not an issue to use some break fluid spray if it has stood idle longer, so we will stick to that. One of the other options we could think off is the opposite: too much fuel and we are ' drowning' it, but that seems unlikely so far. Thanks again for all comments and input and will close this post. Niels and Tim

 

[Bravo]

I replaced my standard pump with an electric pump, problem solved

 

[deQuincey]

obviously you can decide to close a problem at this stage, but is a false closure, problem is still there, and it will pop up again and again,

brake fluid spray is not the solution
change mechanical pump with an electrical pump is not the solution (not for all the problems, like it is not a solution for all the problems to replace the engine with a new one)
mechanical pump is indeed reliable, but how is the setup ? what exactly have you renewed in the car ? and do you know how to start the car ? those are relevant questions

ok, your car your decissions, wish you good luck

 

[Boobouna]

obviously you can decide to close a problem at this stage, but is a false closure, problem is still there, and it will pop up again and again,

brake fluid spray is not the solution
change mechanical pump with an electrical pump is not the solution (not for all the problems, like it is not a solution for all the problems to replace the engine with a new one)
mechanical pump is indeed reliable, but how is the setup ? what exactly have you renewed in the car ? and do you know how to start the car ? those are relevant questions

ok, your car your decissions, wish you good luck

Hi deQuincey,
What is the correct way to start the car? I have heard mixed responses on this. If you read the e9 owners manual it says to press the throttle briefly once and then turn the key. I have heard others say floor the throttle once and then turn the key. I have heard briefly press the throttle once and turn, if doesn’t start then floor throttle once and then.
There are so many different responses. I like to go my the owners manual but let’s say the car has been sitting for 6 weeks and we use the owners manual method and briefly press throttle once and turn key. If it doesn’t start then what? I had this issue recently, so it didn’t start first turn, so I cranked it long another 4 times and didn’t start.
What is the correct method assuming your car is set up perfectly?


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[deQuincey]

Hi deQuincey,
What is the correct way to start the car? I have heard mixed responses on this. If you read the e9 owners manual it says to press the throttle briefly once and then turn the key. I have heard others say floor the throttle once and then turn the key. I have heard briefly press the throttle once and turn, if doesn’t start then floor throttle once and then.
There are so many different responses. I like to go my the owners manual but let’s say the car has been sitting for 6 weeks and we use the owners manual method and briefly press throttle once and turn key. If it doesn’t start then what? I had this issue recently, so it didn’t start first turn, so I cranked it long another 4 times and didn’t start.
What is the correct method assuming your car is set up perfectly?


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thank you for your question,
let me answer as a CS owner, i can not say a word about other versions
you said wisely that the car should be perfectly setup first, the setup itself is relevant,

clean fuel tank, clean hoses, anti return valve, clear cristal or plastic filter (to see the fuel) (much better if it is a decanter old style filter with a cristal reservoir that will assure 100ml fuel close to mech pump), fuel pump, carbs

i recall i never had the car sitting longer than 6 weeks so your question meets timely my own experience

a brief press in the throttle will close the primary buterflies with a nice "clack" sound, you can even do it with hood open to listen
then flooring the throttle will produce the injection of the fuel that is in the small pumps inside the carbs (this will help provided your carbs are in perfect condition and the mentioned fuel has not evaporated)
then crank the starter
done !
anything else is lack of maintenance
...IMHO,...AFAIK,...and so on

does this help ?

regards

 

[Boobouna]

thank you for your question,
let me answer as a CS owner, i can not say a word about other versions
you said wisely that the car should be perfectly setup first, the setup itself is relevant,

clean fuel tank, clean hoses, anti return valve, clear cristal or plastic filter (to see the fuel) (much better if it is a decanter old style filter with a cristal reservoir that will assure 100ml fuel close to mech pump), fuel pump, carbs

i recall i never had the car sitting longer than 6 weeks so your question meets timely my own experience

a brief press in the throttle will close the primary buterflies with a nice "clack" sound, you can even do it with hood open to listen
then flooring the throttle will produce the injection of the fuel that is in the small pumps inside the carbs (this will help provided your carbs are in perfect condition and the mentioned fuel has not evaporated)
then crank the starter
done !
anything else is lack of maintenance
...IMHO,...AFAIK,...and so on

does this help ?

regards

Thanks for the response. My only concern is that the process you describe is not what the manual recommends. If the car was perfect I would expect the description in the manual to be the correct process.

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[deQuincey]

Thanks for the response. My only concern is that the process you describe is not what the manual recommends. If the car was perfect I would expect the description in the manual to be the correct process.

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yes, valid for the next day cold start
but we were mentioning 6 weeks after last start

 

[Stevehose]

In the case of stock zeniths I would press the pedal once to the floor to set the chokes/cold start linkage then pump the pedal 3-4 times to get some gas in there (but if floats are dry this will not work) then crank. If no start then crank the engine till the fuel pump provides fuel an repeat above. This is where a check valve should shorten the time to replenish fuel to the bowls.

 

[deQuincey]

In the case of stock zeniths I would press the pedal once to the floor to set the chokes/cold start linkage then pump the pedal 3-4 times to get some gas in there (but if floats are dry this will not work) then crank. If no start then crank the engine till the fuel pump provides fuel an repeat above. This is where a check valve should shorten the time to replenish fuel to the bowls.

i would kindly disagree, with full respect, steve as:
1- to set the chokes you would only need a slight touch of the pedal, flooring will do the same effect but will add the injection of the internal pumps (if they are still full), nothing against, but just to separate effects

2- to my understanding of the internal pumps of the zeniths pumping the pedal more than 1 time will not produce any other effect but placebo, you are not filling the internal pumps with the internal reservoirs (at that speed of pumping pedal)

to me if the starting is after less than one week, i would only do the choke engagement, so 1 slight touch + 2 crank (@Boobouna , just what the manual says)
if it is more than one week, then 1 slight touch + 2 floor the pedal once + 3 crank

agree that if there is not fuel in the reservoirs you will need to feed them again, and here priming the mech fuel pump might be the issue, so an antireturn valve is a must (if fuel pump has not fuel inside it will take much more time to feed the whole line)

could you agree with this ? did i miss anything ?

regards

 

[Boobouna]

i would kindly disagree, with full respect, steve as:
1- to set the chokes you would only need a slight touch of the pedal, flooring will do the same effect but will add the injection of the internal pumps (if they are still full), nothing against, but just to separate effects

2- to my understanding of the internal pumps of the zeniths pumping the pedal more than 1 time will not produce any other effect but placebo, you are not filling the internal pumps with the internal reservoirs (at that speed of pumping pedal)

to me if the starting is after less than one week, i would only do the choke engagement, so 1 slight touch + 2 crank (@Boobouna , just what the manual says)
if it is more than one week, then 1 slight touch + 2 floor the pedal once + 3 crank

agree that if there is not fuel in the reservoirs you will need to feed them again, and here priming the mech fuel pump might be the issue, so an antireturn valve is a must (if fuel pump has not fuel inside it will take much more time to feed the whole line)

could you agree with this ? did i miss anything ?

regards

So the anti-return valve is not standard equipment from factory? You need to install one yourself?


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[Stevehose]

I don't have my zeniths on any more but I thought I remember seeing more than one squirt of fuel from the accel pump jets with the engine not running? Perhaps an experiment! You're correct on the chokes as long as the linkage is operating as it should, maybe I'm thinking the downdraft Webers need the pedal pushed to the floor to set the fast idle circuit.

2- to my understanding of the internal pumps of the zeniths pumping the pedal more than 1 time will not produce any other effect but placebo, you are not filling the internal pumps with the internal reservoirs (at that speed of pumping pedal)

 

[Bmachine]

So the anti-return valve is not standard equipment from factory? You need to install one yourself?

Until someone more qualified expands, yes I believe that is correct.

 

[deQuincey]

So the anti-return valve is not standard equipment from factory? You need to install one yourself?


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not standard, but advisable,
as the e9 was not born as a classic car bmw engineers did not equipped it with such a valve, i assume is because it was inteded to be a daily driver ;-)
new times, new rules, new needs, new solutions