My 1994 Explorer Sport would not start even though plenty of cranking power
to the starter. Simply would not fire a single cylinder. Towed to the shop,
they replaced the AC relay and it now works fine. Does this make sense? I
had experienced the no-start problem two or three times before and managed
to get things to work by backing the key all the way, three times, thinking
it would reset the computer. What does the AC relay have to do with the
firing the spark plugs?
On Wed, 03 Aug 2005 17:34:36 GMT, "Wayne Lundberg"
Makes no sense to me. Are you sure it was the AC relay they replaced
and not the fuel pump relay? I think they both sit next to each
other. It's also possible the yanked the AC relay and put a new one
in and then it started and they said "ah, that's it" when all that
happened was they jarred the old fuel pump relay when the replaced the
AC relay and that made it work again (for a while). If my memory is
correct, the relays are interchangeable (ac and fuel pump) so if it
does flake out again you could try swapping them.
The relay they took out has a label "A/C relay" or something to that effect,
so I am assuming that's what they changed. But thank you, thank you, thank
you for the suggestion to swap out the relays if the problem persists. Are
they the ones on the fuse box under the dash?
On Thu, 04 Aug 2005 16:40:37 GMT, "Wayne Lundberg"
No, I believe they are in the engine compartment along the passenger
side fender. There is a fuse block there (it has a cap you have to
take off to see the fuses and they are large fuses, not the little
ones like the inside fuse block). The top of that fuse block, with the
fuses in it, detaches from the bottom and comes up revealing the
relays. This is from memory so it may be a little different but that
should put you in the ballpark.
Thanks again Ashton, I checked the fuse box, it's where you said it would
be. And looks like there is a new relay in the a/c slot and not the fuel
pump. Which means I should get a new relay and have it handy for the fuel
Once the engine starts, is there a mechanical device that pumps the fuel or
is it always on electric. Meaning that it could fail any time I'm driving on
the freeway? Or is the electric just for starting?
The fuel pump on your Explorer, just like on most other fuel-injected
vehicles is located inside the fuel tank and operated by an electric motor.
Once the motor fails (or has no power), the engine stops. Actually, it's a
good thing. A shock-activated cutout switch disconnects power to the pump
and prevents a fire if you ever get in an accident.
Weird! On three occasions I cranked to start the engine and nothing
happened. On the first two I backed the key three times thinking I was
resetting the computer and it started right away. On the third, I had to
have the SUV towed to the mechanic. Who replaced the a/c relay and all is
well. But I'm not so sure.
What I'm reading from Happy Traveler and Ashton is that the fuel pump relay
may be the cause of this. But I have not had a single stall while running,
and I have over 144,000 miles on the vehicle!
So... I am assuming the relay and fuel pump motor are OK, but the reason I
could not get it started is due to some other, as yet unidentified, and
potentially 'lurking' problem???? In the computer? Signal to fire
sparkplugs? Because on cranking (on those three times it failed to start) I
did not get a single explosion. Dead, as a doornail can be dead.
Any ideas what I should look for, or do the next time this happens while at
a way stop in the middle of the Nevada desert?
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