Re: E30] 325is Hard Start, Fuel Pumps, and SI Batteries. [a little shorter] BA

["Brett Anderson" <bretta@xxxxxxxxxxx>]

>Date: Thu, 10 Dec 1998 18:43:22 -0500
>From: Jason Cammisa <jcammisa@domain.elided>
>Subject: [E30] 325is Hard Start, Fuel Pumps, and SI Batteries.
[LONGISH]

> We took it to a local mechanic, who is rather insistent that it's a
leaky
>injector.  I disagree-- I've never heard of a leaky injector on any
German
>car

Then you have not done much work on German cars have you ?
Leaking injectors are problably one of the most common hard start
causes, and a very simple one to check.
Buy yourself a fuel pressure gauge, an essential tool in diagnosing a
fuel injected vehicle, and place it in-line with the fuel feed hose.
Run the car, shut it down and check the pressure reading.  Clamp off
both the return and feed lines and let the car sit. Fuel pressure should
not change, not in an hour or a week.

>So, I am still
>here looking for another explanation.  That is the absolute last
resort;
>replacing the injectors.
> I do subscribe to the idea that the car is losing fuel pressure after
>shut-off; that would cause Vapor Lock, which would cause hard starting
>until the car is completely cooled.  Has anyone had any experience with
>leaky injectors?

See above

> What about the fuel pressure accumulator by the tank?

What fuel pressure accumulator ?

>And how about a crazy coolant temperature sensor? Any tests for that?

My second choice for troubleshooting.  Disconnecting it sends the system
full rich, should stall a running engine.  Jumping the pins in the
connector runs it lean, set the vehicle up to the point that you know it
is going to start hard, but before cranking, disconnect the blue coolant
temp sensor and jump the pins of the connector together.

> I am open to any suggestions.. I would love to hear the collective
advice
>of 3000 people!

I doubt that you really would like that.

>something occured to me.  When Eric turns the key to "ON", his fuel
pumps
>don't kick on for a second or so like they do on many Bosch FI systems.

The fuel pump should run for a second (literally) and then not start
again until engine rpm goes to about 450

> Isthis normal?  Should the pumps only click on once the engine is
turning over?
> And my last question (I promise), is related to the SI Batteries that
are
>mentioned on the FAQs... what the hell? Batteries? Where? And what does
SI
>stand for?

SI = Service Interval.  The SI board controls the service lights, and
has an effect on the tach, fuel and temp gauges and some of the idiot
lights.  There are two batteries on the board to maintain SI light
memory when the car battery is diagnosed.

>Jason
>jcammisa@domain.elided


Brett Anderson
BMW and ASE master technician
http://frontpage.bestweb.net/~bretta

Please include all correspondence when replying
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