88 Bronco II Intermittent Low Pressure Fuel Pump
My daughter's 88 Bronco 2 has been idling a bit
rough and sometimes low. It wouldn't start the
other night while she was shopping. Had it towed
home after driving to the mall and checking the
usual suspects. I stopped checking stuff when I
didn't hear the in tank fuel pump prime.
I took another look the next day. Listened again
for the whirl of the FP and heard only a click back
there. Engine turned over, but wouldn't crank (just
a sputter). I also found that the ground cable from
the battery had been damaged when one of her
belts broke a month or so ago. It is getting spark.
So, I haven't dug into the distributor yet. I checked
the test port on the fuel rail and no fuel when I turn
it over.
I was convinced that it was the FP. So, as I got
started working on it today, I sprayed some
starting fluid in the throttle body. It started and ran
until the SF burned off.
Now, I failed to follow the scientific method here
and injected 4 variables before I tried to start it
again. 1. I pushed the button on the inertia switch.
It didn't click or feel 'tripped'. (Not sure what it
should feel like if it's been tripped). 2. I moved the
ground wire around a bit when reconnecting the
breather hose onto the throttle body. 3. I moved
the vehicle a bit (short somewhere). 4. I removed
the fuel pressure regulator vacuum line.
Immediately after that, I had my son turn the key
and I heard the whirl of the FP. I removed the
vacuum line from the fuel pressure regulator and
had my son turn it over to check for fuel out of th
FPR. It started right up and ran great. It would bog
down a bit as I started to put the vac line back on
and stabilized as I would remove it again. Revved
the engine a bit and put the VAC line on all of the
way and it seemed to adjust itself to run fine.
Of course, I'm glad it's running. But, I'm worried
about sending her back to school with the
likelyhood that it will leave her stranded again. I
am going to give it a mini-tune up tomorrow (plugs,
oil-fuel-air filters, pressure regulator, ground cable).
All that just to ask: What might make the FP
operate intermittently? Could it have been the
inertia switch, wiggling the ground cable, releasing
pressure on the regulator?
I'm looking forward reading some responses.
