The results (WAS: Differential Pressure Regulator Checking)

[Huw Powell]

> Went home, hooked it back in and started the car again. Yanked the injector
> out, plugged the intake manifold hole with my finger and watched what
> happened. This time I got a pretty nice cone shape out of the spray and the
> spray increased as I revved... The engine ran pretty nice (on 4 cylinders).
> Then all of the sudden flow stopped and the engine died...

...

> I cannot check the harness going to the DPR for 2 reasons. #1 I do not have
> a tool to measure duty cycle, and Schucks wants $80 for one. #2 I cannot get
> the engine to run long enough to reach operating temp anyway, so even if I
> had the tool to measure duty cycle of the harness I cant get the engine hot
> enough to where I could.

There is no duty cycle measurement for the DPR, you measure the current
flowing through it.

For this you can make a harness out of a couple of old connectors, or
just jury-rig some wires.  You will need a meter with a very low DC
current range (30 or 300 mA usually).

Although you'd only be measuring the current at the cold start phase
(how long do you have to wait before the car will run for 1 minute
again?), that will still tell you *something*.  Or tell me/us
something...

It would be very interesting to figure out *what* it is that
precipitates the car dying.  I think you are digging way further into
the "CIS" end of things, when it might be simpler and stupider.

If the fuel pump relay has a bad internal connection, that would kill
the pump, end of story.

If something ignition related creates a problem, more subtle than losing
spark, the fpr will turn off - it only runs when there is an rpm signal
from the coil.  If you can wathc the tach while the engine dies that
might tell you - does it fall dead or drop slightly slower as the engine
slows?  (This is easier to determine going down the road in gear, which
keeps the engine turning, of course)

Have you tried this start and run thing with the fuel pump jumpered?

--
Huw Powell

http://www.humanspeakers.com/

http://www.humanthoughts.org/