Good Morning. I'm working on an 87 Escort that has an intermittent
starting problem. When it doesn't start, I notice the fuel pump keeps
running for close to a minute when turning the KOEO. When it's not
throwing a hissy fit, the pump runs for it's approx. 5 second cycle
with KOEO and is fine. I thought there is a timer in the computer that
controls the fuel pump relay, but am not sure. I asked two mechanic
buddies of mine. One says yea there's a timer. The other said the fuel
pump shuts itself of after reaching the proper pressure. There might
be some out there, but I haven't seen any cars that "fuel pressure"
shuts the pump off. Before I hook up my breakout box and start getting
to involved, anyone no for sure? Thanx, Greg
HLS@nospam.nix - 28 Jun 2005 15:18 GMT
> Good Morning. I'm working on an 87 Escort that has an intermittent
> starting problem. When it doesn't start, I notice the fuel pump keeps
[quoted text clipped - 7 lines]
> shuts the pump off. Before I hook up my breakout box and start getting
> to involved, anyone no for sure? Thanx, Greg
Dont know about Fords, but was of the opinion that some of the GM variants
came on when the ignition switch was turned on, and shut off when pressure
preset was reached.
GM also had some that activated only when oil pressure exceeded a preset
value, sometimes 3 psi. This was apparently intended to assure prelube
before
engine started.
Would like to know what you find out about the Ford.
HLS@nospam.nix - 28 Jun 2005 15:32 GMT
> Dont know about Fords, but was of the opinion that some of the GM variants
> came on when the ignition switch was turned on, and shut off when pressure
> preset was reached.
This may have been a misconception of mine, based on an 84 Fiero I owned.
The literature I have found on later products says the pump activated via a
relay
for 2 seconds. I do not know conclusively that there was ever a pressure
shutoff
used. Hope someone else can clarify this.
Shep - 28 Jun 2005 17:44 GMT
I would replace the relay, seen this happen before with Ford relays.
> Good Morning. I'm working on an 87 Escort that has an intermittent
> starting problem. When it doesn't start, I notice the fuel pump keeps
[quoted text clipped - 7 lines]
> shuts the pump off. Before I hook up my breakout box and start getting
> to involved, anyone no for sure? Thanx, Greg
Thomas Tornblom - 28 Jun 2005 19:34 GMT
> Good Morning. I'm working on an 87 Escort that has an intermittent
> starting problem. When it doesn't start, I notice the fuel pump keeps
[quoted text clipped - 7 lines]
> shuts the pump off. Before I hook up my breakout box and start getting
> to involved, anyone no for sure? Thanx, Greg
I assume the Escort uses the EEC-IV ecu.
It has a LOM (Limited Output Mode) that is automatically entered if
there is a problem with the processor part. In this mode the fuel pump
runs continuously, the injectors runs a fixed duty cycle and the
ignition is run at a fixed advance, controlled by the TFI module, if
it has one.
If the processor works, then the pump is shut off after two seconds in
KOEO.
In LOM you will not be able to pull codes, as the processor is out
picking daisies, or something similarly useful, instead of controlling
your engine ;-)
So to comment on your mechanics, yes, there is a timer, but it is a
software timer that will not work of the processor doesn't work, and
no, there is no switch that shuts the pump down based on pressure, at
least not with these old systems with a return line.
I have converted a 351 Cleveland to EFI using parts from a Mustang,
with an EEC-IV, and I'm using an add on board that allows me to tune
the EEC, and one dead giveaway of processor problems is when the
fuel pump runs continuosly.
Cheers,
Thomas