1988 Mercury Grand Marquis - just drove it across countries and it worked
and drove like a charm!
My original problem started when I went out one morning to start the car and
it was dead. Got a new battery, since it was a used car and I had no idea
what shape the original was in. Still couldn't get it to crank over at all
(just clicking). If I trickle charged it enough to get it going and jiggled
the wires near the relay boxes (with the ignition key out), I got a clicking
noise down near the starter. As if one of the relays was trying to make
contact even though the car was turned off. That is why I switched out the
EEC and Fuel Pump relay. I think this may have been the original problem
that drained both batteries. Could be there was a short in a relay that
kept it running when the engine was turned off.
In any event, I returned the new battery and got another. Came home,
connected up battery, new cables, and relays properly. It still will not
start. It cranks over and all accessories now light up completely, but no
starting. I have never heard the fuel pump run on my car, so it is hard to
figure out if it is running or not. I checked every fuse in the fuse box,
none blown. I know that there are fusible links that have something to do
with the fuel system, but I have no idea where they are. I am not sure if
there are circuit breakers involved either.
Suggestions and ideas would be greatly appreciated. I am going to the
library to see if I can scrounge up a manual. I am on a VERY limited
income, that is why I am driving an older car and trying to get it working
myself. I am in this area, away from my mechanical friends, because my Mom
is sick. I cannot afford a tow or a $62 hour mechanic. Thanks and take
Try the crash switch in the trunk that turns the fuel pump off in an
accident. It is near where the fender and trunk lid hinges meet. If you
have a manual, it will show you where. Usually, there is a white button on
it you press (down or in). It hides behind the trunk upholstry but on some
cars there is a cutout to reach thru.
Your car uses the TFI ignition module (I think it is still on the side of
the distributor on those cars) and failure there will also cause a
crank-but-no-start problem. The best checks I can think of is to see if you
have spark and fuel. I use an old spark plug in the end of a plug wire and
a jumper cable clamped around the body of the plug with the other end of the
cable connected to ground. I can usually lay the plug somewhere so I can
see it when I crank the engine. To check fuel, first be sure no ignition
source is nearby, then find one of the release valves on the fuel lines up
front - it will look like a tire valve near the end of the fuel rail on the
top of the engine. (Don't get the one on the A/C). Bump the center pin
with something pointy after you have had the key of a few seconds. Fuel
should squirt out.
You need to determine if you are missing fuel or spark to get it going
again. Those are nice cars and usually go forever - with a little bit of
I am asking your to be patient with me and help me through this, if you
possibly can. I went to the library today for wiring schematics, if I need
Pushed the button, multiple times, just in case. No change.
It is there, is there a way for me to test it?
I could not do the tests that you told me to do because I do not have a
jumper available to me here and I could not find the relief valve you were
I did, however, do a standard test. I cranked the car multiple times
(cranks over, but no starting) and pulled a spark plug. The smell and feel
of oil was definitely on the plug, but there was not even an inkling of a
fuel odor. I would assume there would be if the fuel is getting to the
I took some digital pics of my engine compartment, if you could tell me
where this relief valve is, I would greatly appreciate it. Just tell me
which pic and in what general location. Thanks for any help you can give
me. By the way, I love this big boat of a car. When my husband was alive,
he used to joke with me about my affinity to 'boats'. The pics:
I saw only one thing in the fender pic that might be one of the relief
valves, but it is just behind that distributor cap cover. Not a good place.
Take Care, Sharon
The TFI module is a real pain to remove - it is the gray plastic box with a
mess of wires coming from it that is attached to the lower part of the
distributor. You can see it in the lower middle of the "center" photo. The
module has special screws that hold it onto the distributor and then has 5
or so prongs that plug in to a component inside the distributor. It's
probably not a job for a novice. If you do decide to remove it - AutoZone
and similar shops can test them.
Looking at the "fender" picture, the chrome tube with fittings dropping down
just behind the distributor is the fuel line. The fitting is probably on
the end of it and right behind the distributor is as likely a place as any.
I don't actually see the valve in the photo but it's on the chrome lines.
There might be two of them, one for each side of the engine. They will be
near the front.
Mr. Moats is right, check for spark and fuel pressure. I am trying to help
you do that without a pressure gauge or spark tester. I'm not sure if you
will smell fuel with your test or not. I seem to remember trying that trick
with the same result as you but it turned out the fuel supply was fine. You
*might* smell gasoline at the tailpipe after cranking, but I doubt it.
Try this, get a can of starting spray, flip open the air cleaner, and shoot
a 3-4 second blast into the air tube to the engine. Close the cover, then
try starting it. If it runs a bit, you have a fuel problem. No pop, cough,
or sputter, assume no spark.
The local parts place will have tools like a spark tester and fuel pressure
gauge. I don't have a clue about the cost. You really need a manual - the
wiring diagram usually doesn't show you where stuff is or how to do things.
The Chilton or Haynes from a parts store or Wally World would be better than
nothing, I suppose. If you can look at them first, get the one with the
most pictures. Check Ebay for a real shop manual, too.
My parents have an '88 GM, I have tinkered on it a bit for them but it's 200
miles away. I drive a Crown Vic but it's enough newer that it's lots
different so I can't use it's book or look under the hood. I'm doing this
from a foggy memory.
Just a couple of thoughts. Have someone stand near the back of the car a
listen for the fuel pump to energize when you turn the key to the on
position (do not crank the engine). It should buzz for just a second. If no
buzz, then a fuel pump in the tank may be the issue. Second, the TFI module
is a bad design on those and earlier 5.0 cars. Vibration and heat cause them
to fail at any given time without warning. I changed out a bunch on my '85
5.0 cougar during the 250K miles I drove it.
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com ).
Paul, did this and it cranked right over. I am now trying to double check
the wiring schematics for the relays. I have four mounted on my fender and
I went by the AutoZone cross reference numbers to tell which one is the EEC
and which one is the Fuel Pump. I have asked 'Spark' to send them to me
because I could only find wiring diagrams for a 1986 in my library. The
wires to the relays (colors, type) do not match. So, I will try to dig up
diagrams before I go any further. If the ones I have are the same
functioning, it could be a number of things including solenoid, starter
relay, fusible link, TFI, or fuel pump, fuel filter. I changed the fuel
filter just prior to leaving NY, so that was less than 3000 miles ago. Car
drove fine in between. I doubt that would cause all of this.
The fact that when this first started, I could move the relay wires around
and get a clicking noise at the starter WITHOUT the ignition key in and that
the battery was drained, tells me that it has to be electrical more than
mechanical. And that (I pray) it is in the engine somewhere, not the fuel
pump in the tank. I can get a simple multimeter here at 'Wally World' for
less than $10, if you think that would help.
Any help from anyone who might have a schematic or further suggestions would
be appreciated. I am going to check wiring to the relays out first.
Someone has let me borrow their car, which has helped out a great deal. I
will also get a TFI installed I think, since it looks like the original, as
mentioned. Even if it is not that, it may be a 'problem waiting to happen'.
Thanks to everyone that has given suggestions.
Take Care, Sharon
Re: TFI, I'm not sure about fixing what isn't broken... The fact that it
fired with the starting spray tells you that the spark system is OK.
Something is preventing fuel from getting where it needs to be. Faulty
wires or connectors are a good start.
Look closely at all of the wires in the harnesses near the relays. Since
you were able to make noises wiggling them, there may be broken, frayed, or
corroded connections down there. On my '84, a few of the engine harness
wires actually lost their insulation. I assume it was due to faulty
plastic, the stuff would crumble right off. I've never seen it on any other
cars, tho. As the car got older, I also found some splices that had
corroded bad enough to stop current flow. From what I remember, that was
addressed by '88. tho.
I'd almost bet the actual problem is near the wiggle - click area.
wrote in message
This is just a shot in the dark, but on my 88 F-450 Super Duty truck, I had no
fuel delivery at start up,. similiar to your problem. On my negative battery
terminal, there was a smaller black ground wire hooked up in addition to the
main heavy negative cable. When I wiggled the small black wire, the fuel pump
came on and the truck started. The smaller black wire was probably for the fuel
pump ground. In any event, check to see if you have a smaller black wire
attached to your negative terminal and see if it makes a good connection.
Checked all wiring today near the relays, but everything is looking good.
You said, "check where the wiggle was". Oddly enough, there were some bare
wires on one of the other relays that I taped up with electrical tape in the
very beginning. When I did that the clicking noise stopped. What is even
odder is that it did not click near the relays (where I was wiggling the
wires). The clicking noise was at the starter area, down below the engine.
I thought that was very odd when it happened. Like some wire up near the
relays was actually shorting something near the starter. But the oddest
part of it was that the key wasn't even in the ignition. I sometimes wish
we could go back to complete fuse systems instead of fusible links and
self-resetting circuit breakers, etc.. I prefer changing a simple inline
Still not running. Checked out relays, all is okay. I can't believe the
fuel pump would go abruptly, with no warning. I have had electric pumps go
before and usually you get a little sputtering beforehand. This car ran
like a top right up until it died.
Take Care, Sharon
You can easily check the relay at the inertia switch. Put a test lamp on it and
have some one cycle the key to run. If the test light lights the relay is
closing and you can then assume you have a bad pump.
wrote in message
I don't mean to sound dumb Thomas, but where is the inertia switch. Is that
the switch in the trunk that cuts out in case of an accident? Thanks for
helping. It is interesting to note that two years ago you were answering
questions on this same problem. I saw it in the newsgroup archives today
and I was thinking about how great it is that you are still here trying to
help people. Thanks again. Sharon
You are making your way thru the process of elimination - I'm sure you will
find the problem. By the way, one of the first things I figured out when I
got here was to listen to Thomas, he's usually right on the money.
Keep us posted.
I got a multi meter and checked out the power going to the inertia switch
first. The meter checked out fine at the car battery, so I know it wasn't a
bad battery sold with the meter. I could not get the meter probe into the
small opening for the wire, so I actually had to puncture the wire
insulation. I put the meter hot wire in the orange wire at the inertia
switch. This is the incoming power from the relay switch. I grounded to
the car fender, buried it past paint to get a good ground. Had someone
crank the engine over. No reading what so ever. Tried it several times.
That meant that power was not coming from the relay to the pump.
So, I figured my next step was to check out the relay power. Went to the
relay and started to THOROUGHLY test the wires. I found one area of the red
wire (part of the closed loop of the relay) that had a small amount of
insulation cracked off. When I touched it with my fingernail, it literally
fell apart. I stripped off all the bad insulation (wire was still good and
not corroded) and wrapped the heck out of it with electrical tape. Tried to
start it, no dice.
So, my next question to you is this. If that sparked or arced, could it
have ruined the brand new relay? It is not part of the loop that goes to
the inertia switch and pump. According to the wiring schematics, this is
supposed to be an 'always hot' connection. Does that mean I can check for
juice without someone cranking the engine? What would you suggest as my
Thanks for all your help. Take Care, Sharon
Just tried one last step. The Yellow wire, coming into the fuel relay is
supposed to be part of an 'always on' connection. It supposedly bypasses
the 'start' process (according to the schematic), so I turned the key to the
on position, put the positive lead of the multimeter into the yellow wire
(that is what feeds it the juice for the operation of the fuel pump relay)
and of course grounded it prior. I got a zilch reading. I tried this
several times. Then went to the battery with the tester and it tested out
fine. Went to the starter relay and it tested out fine. So, somewhere
between there and that relay is something bad, I believe. Can someone
correct me if I am way off base.
Thanks and take care, Sharon
Well, if you have the schematic, its just a process of elimination.
Power goes from point a to point b. Somewhere between point a and
point b your losing it. Start with where you have it and work to where you
don't. I assume you checked all the fuses in your fuse box.
This could also be a fusible link under the hood. Sometimes, a connector will
get corroded and cause a bad contact.
Sometimes a wire harness will get worn through by brushing
against something hot or something sharp.
If you have the schematics, start with where the constant on power
originates, then work your way forward until you find where it quits.
Keep narrowing it down like that. Make sure you have a good ground
connection as you are testing the relay and connections. To do this,
find something you know is good and hot for the one lead while the
other is located where you want your ground connection. If you are
under the hood (where my light truck's relays are) then you can just
use the battery itself for ground. Try all the wires. See what
voltages you can find in various situatoins. The schematics, if
accurate, will tell you which wires should be hot at which times.
You may have seen my posting about a similar type problem with my
BroncoII. Last night my dad and I checked the voltage at the inertia
switch. With the key off, there should be no power on the
"downstream" part of the relay (pump is off). When the key is turned
to the on position the reading spikes to 12V then drops again to 0V.
This is because the pump only runs for a short while before the engine
is started. When the engine is started, the meter should read 12V
A relay is just a switch that is electrically controlled instead of
manually controlled. I think one method of operation for relays is
for the relay to be closed only when the control side is powered. In
that scenario then you won't read a voltage on any of the wires unless
the engine is running. Nonetheless, if you have an assistant turn the
key back and forth you should see power temporarily as I described
If you don't see that then work your way to the source -- follow the
wires (or the schematic, if that helps) to the device (EEC module? I
don't know.) that controls the relay. Perhaps the problem isn't the
relay itself but is further "upstream" of it. You can check the
wiring by unplugging both ends of the wire and measuring resistance
(aka impedance, could be marked with an Omega on your multimeter)
between the connectors. You should see approximately no resistance.
Another test is to simply make a short between the battery and the
inertia switch side of the relay. Doing that should cause the pump to
run. If that works (and the engine starts like that) then you have
positively identified the relay, or its wiring, as the source of the
problem. I don't know that much about the theory of operation, so I'd
be careful about pressure and such if you do short out the relay. I
think it'd be safe to short if for a couple seconds, simulating the
pressurization just before starting that the engine normally does. I
would also think it's safe to have someone try cranking the engine and
at the same time short out the relay, simulating the pump running
continuously during normal vehicle operation. However, it wouldn't be
a bad idea to get someone else's opinion on that!
I hope this helps :-).
Be sure of this: The wicked will not go unpunished,
but those who are righteous will go free.
The yellow wire is hot at all times, it is the same circuit ( just a branch )
for the EEC power relay. I would advise you to use a test lamp that has a ground
clip. Use the alternator body as ground. The reason you get a good reading at
the battery with your meter is you are probing really good contacts. I.E. the
battery posts. If you still have no power at the relay there is a open on that
circuit. The starting point is at the starter relay.
You need to take a step back and go about this with a little more logic. A relay
has two circuits. Primary and secondary. Remove the relay. In the relay socket
you now see four terminals. Two will be 12 volts the other two will be ground
and fuel pump circuit. Put the key in the run position and check to see if you
have 12 volts at two of those terminals. Relays are very durable and just do not
fail that often. A test lamp is better for these tests. Even tough you tried to
get below the paint to get a ground, it's possible you never made it. You should
look for a fastener that is attached to the body, like the screws that hold the
switch to the car.
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