Tip of the day....

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6423

  Z3 roadster 3.0i
Location: Johannesburg

Tip of the day....

Post by Southernboy » Tue 26 Mar, 2019 08:15

I recently did an EWS swap and during the process I had contact with various people, one of which was a BMW mechanic at a dealership.
When I was leaving, he came out to see my Z3. I put the key in the ignition, and cranked the motor which took more than the usual one and a half turns to fire up. He commented on the fact that it didn't take immediately and said that if / when that happens, I shouldn't continue cranking. He told me to switch the ignition on and off 3 times form off to position 2 (when all the lights come on in the instrument cluster). He said by doing this one is actually re-starting the fuel pump in the tank which pumps fuel up into the fuel rail creating pressure there.
He said that sometimes fuel pressure drops in the fuel rail and by doing the switch on / off / on thing this will create the correct pressure for an "instant" start and will prevent excessive cranking.

I asked him why pressure would drop in the rail and he told me that this is most often due to very small leaks past the rubber O rings which seal the injectors into the manifold and head.
Anyhow, I have subsequently ordered a new set of O rings and will do a replacement, and while the injectors are out, I will have them professionally cleaned by a fella that has an ultrasonic "injector bath".

But the tip is valid. I have been using it and the car fires up instantly.
"Normal is overrated"
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TheStorm
Joined: Tue 12 Feb, 2019 13:24
Posts: 22

  Z3 roadster 1.8

Re: Tip of the day....

Post by TheStorm » Tue 26 Mar, 2019 08:41

IMHO partially correct.

Especially when the car has not been started for a long time - several fuel pump pre-ignition start helps a lot. And I am doing this with all my cars that I dont drive daily.

BUT

If the injector o-ring is leaking .. this means that the fuel goes in the cylinder head and washing the piston .. which is NOT good and also if excessive can cause massive detonation when you try to start the car.
The actual reason for pressure drop is the pressure regulator on the rail. Yes .. these things are .. practically the one that came from the factory. Rarely we change them .. they just work... So first you can try changing the Orings on the regulator, then the actual regulator.
In some cases the pressure valve is located in the fuel filter, which again - is good to be changed from time to time :)

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Southernboy
Joined: Thu 07 Oct, 2010 13:39
Posts: 6423

  Z3 roadster 3.0i
Location: Johannesburg

Re: Tip of the day....

Post by Southernboy » Tue 26 Mar, 2019 08:56

Cool ! ... Love it when the brains trust chips in with good advice.. I'll certainly have a look at those areas - Thank you !
"Normal is overrated"
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Gazza
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Joined: Tue 04 Oct, 2005 21:58
Posts: 9401

  M roadster S54
Location: Romford Essex

Re: Tip of the day....

Post by Gazza » Tue 26 Mar, 2019 13:11

I have a similar problem with my Z1 M20B25

It’s like it is flooded with fuel and eventually starts like a long stroke engine.
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

Z3 S54 M roadster Image, BMW Z1, BMW M3 CSL, Z4M Coupe
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