85 240 DL won't start first try, but second time every time

[disallow]

Hi there,

I have posted quite a bit over the past couple
weeks about my buddy's 85 240DL Sedan that I just
rebuilt for him. Trying to get a feel for how the
car should be acting....

I started by running all the old gas out of it
from sitting for the last 9 months. That is
done now, and fresh gas is in the tank. It runs
much better.

Before the old gas was gone, it was impossible to
time the engine properly. Now we have tried again,
I think we may be 1 tooth off, as the distributor
is all the way advanced, and it still seems a
little off. Any comments about this would be
appreciated.

Now I've noticed that the car does not like to
start on the first crank. I get in, turn the key
to the ON position for a few seconds, then
crank it over for about 5 seconds. It turns and
turns, but does not catch. Second try, usually
it starts within the first 2 turns over (1-2
seconds or so).

Any ideas? All ignition components have been
replaced with the rebuild. We patched up the
ignition wiring harness, so there are no problems
there. There is a new ECU wire harness.

I do smell some unburned fuel.

Any ideas are appreciated.

Thanks
t

 

[disallow]

oh ya, and the main relay was replaced during
the tune up as well.

t

 

[Michael Pardee]

Hi there,

I have posted quite a bit over the past couple
weeks about my buddy's 85 240DL Sedan that I just
rebuilt for him. Trying to get a feel for how the
car should be acting....

I started by running all the old gas out of it
from sitting for the last 9 months. That is
done now, and fresh gas is in the tank. It runs
much better.

Before the old gas was gone, it was impossible to
time the engine properly. Now we have tried again,
I think we may be 1 tooth off, as the distributor
is all the way advanced, and it still seems a
little off. Any comments about this would be
appreciated.

Now I've noticed that the car does not like to
start on the first crank. I get in, turn the key
to the ON position for a few seconds, then
crank it over for about 5 seconds. It turns and
turns, but does not catch. Second try, usually
it starts within the first 2 turns over (1-2
seconds or so).

Any ideas? All ignition components have been
replaced with the rebuild. We patched up the
ignition wiring harness, so there are no problems
there. There is a new ECU wire harness.

I do smell some unburned fuel.

Any ideas are appreciated.

Thanks
t

This is usually a symptom (and shadetree diagnostic) of pressure in the fuel
rail bleeding off. The first attempt gets the fuel pump running to rebuild
the pressure but the ECU has already gone off searching for the correct
setting to make it fire. The second attempt starts fresh with pressure in
the rails and it fires right up. Even a half second of cranking the first
time will trigger the pump to run long enough to make it fire the second
time.

The most common cause is leakage in the fuel pump output check valve, but
other leaks (like injectors dripping) can do it. With the history of funky
gas, it could be either. If you haven't run injector cleaner through it yet,
this would be a good time to do that. Let it consume a tank of treated fuel
and see if it still misbehaves.

Mike