BMW: Hard to start E34 535i revisited

> I have trying to find the cause why the car is hard to start. 
... 

Could it be leaky fuel injector(s)?

Comments from anyone with actual leaky injector experience?

I'm just going to get my injectors checked due to largely same kind of symptoms
with M40B18. Needless to say, the fuel pressure regulator will be checked as
well.

> Could it be leaky fuel injector(s)?

Fuel hoses tend to crack inside at the ends and that will cause lower
fuel pressure than would otherwise be the case after the car has sat
overnight. Chopping 1/2" off helps in my experience. My 635 started a
good bit quicker once I'd done this.

--
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In article <bj095s$vgh$pp.htv.fi>,
JNo <an> wrote: 
 

If they were leaking and making the mixture too rich, I'd guess it would
start better cold than hot. If they were leaking such that the fuel
pressure started out low, the pump should soon sort this - but you might
check by running it (them) before attempting to start.

--
*Gargling is a good way to see if your throat leaks.

Dave Plowman co.uk London SW 12
RIP Acorn

Thanks for the inputs from all!

I have suspected for some time leaky injectors/malfunctioning residual
pressure but
there are two things which speaks against this:

::1:: If I turn the key to position II the fuel relay and pump will go on
and start
building up pressure for, I think, 10 seconds (IIRC). But when I try this,
no
improvements can be noticed and it will still crank for a long time.
::2:: The symptom where the car is very easily started when not driven (or
started)
for more than 2-3 days does not fit into the equation. If the car is hard to
start after
3-4 hours of rest it should also be hard to start after 2-3 days, if there
are any
issues with the pressure.

The funny thing is that I have seen lately is how the grade of the problem
varies with the time after the engine was running last time. I have tried to
see a pattern, and the table below is a very approximately description
of how easily the engine starts. The time to the left is how long time
it has passed the last time the engine was running.

0-5 min => Starts directly
5min - 30min => A few cranks and then starts
30min - 48 hours => Cranks and cranks and cranks, and then starts...
48 hours - ? => Starts almost immediately

/Henrik

"Dave Plowman" <co.uk> wrote in message
news:co.uk... 

Henrik,

I had the same symptoms with my 735 which I believe has the same engine as
yours. After checking lots of things... we finally found that the main
computer had a bad capacitor which was not allowing a signal to get through
and allow the engine to fire up.

As I cranked the car the capacitor would build up a charge and then it would
start. 5 to 7 seconds was the usual with some a bit longer and some
(depending on the amount of time the car had been left to sit) almost
immediate. The car also seemed to stumble a bit upon start up. Your
explanation of the symptoms brings back bad memories...

I am not sure of the exact capacitor that was changed as I had a local shop
do the fix and they made various attempts before finally pinning it down. I
can find out more information if you feel this might be the problem, but it
sounds pretty similar to me.

Good luck,

Bob


"Henrik Johannisson" <com> wrote in message
news:kBN4b.22177$telia.net... 

In article <Twf5b.133119$K44.93277@edtnps84>,
Bob Balbirnie <net> wrote: 

You're extremely lucky to have a shop which diagnose ECU faults down to
component level.

--
*It doesn't take a genius to spot a goat in a flock of sheep *

Dave Plowman co.uk London SW 12
RIP Acorn

"Dave Plowman" <co.uk> wrote in message
news:co.uk... 

You are sure right there Dave! The way it worked out the shop traced the
fault to the ECU and then we took the board to a local computer shop and had
them check it out before we decided to buy a new one as the price was too
much for my scottish heritage to bear prior to checking alternatives...
As luck would have it the shop did a quick fix and it worked...

but... overall we spent about 3 months tracking the problem down.

Cheers, Bob

Does 535i have the same cold start injector as M20 engine? I know these can
clap out and give starting problems and also the thermo-time switch.
Also check the vacuum hoses for leaks and breakages.
If you want to get really adventurous you can open the engine management
computer and look for dry joints, which are common on BMW circuit boards of
this era.

Steve

"Henrik Johannisson" <com> wrote in message
news:kBN4b.22177$telia.net...