1997 Mercury Marquis No Spark, no Fuel no PCM communication

ABELL

MEMBER
1997 MERCURY MARQUIS
V8
2WD
AUTOMATIC
126,000 MILES

I have a 1997 Mercury Grand Marquis that I am working on and I cannot get it to start. The car ran fine until one day when I came out and I did not hear the fuel pump pumping. The things I have tried so far are:

-new fuel pump
-pulled all fuses and maxi fuses
-new fuel pump relay
-checked for Voltage at Throttle Position Sensor (none)
-traced as many wires as I can think of for voltage and resistance
- connected a brand new Scan Tool only to see it's not detecting being connected to car (plugged the scan tool into another car and it worked fine)
-swapped PCM with a used one (still no fuel or communication to scan tool)
-tried starting fluid in intake
- pulled one spark plug wire from plug and connected spark tester and got no spark
- checked #16 pin in data link connector for voltage and #5 for ground (seems okay)
- I am pretty sure I heard the PCM relay clicking when I turned the key to the ON position.

I am about out of ideas. Anyone have any suggestions?

3 Replies

BMRFIXIT

MECHANIC
19,053 POSTS

Turn key on do you have check engine light on
if not PCM have no power
check for an open wire and or fuse 1st
use a test light check fuse #7 its 25A under dash it should be live with key on

let me know

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Saturday, June 6th, 2009 AT 5:33 AM

ABELL

MEMBER
5 POSTS

The check engine light was not on. I pulled the fuse and there was power. I checked for power from there to the diode in relay center, from the diode to the relay, and to the y/br wire on the other side of the relay. All had power. At one point, the check engine light was flickering when I had reinstalled the #7 fuse, but it has not done it again.

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Saturday, June 6th, 2009 AT 2:09 PM

BMRFIXIT

MECHANIC
19,053 POSTS

Do wiggle the wiring harness and have a helper watch the light for you
trying to pin point the area where the light flicker
check the wiring and fuse terminals

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-3

Saturday, June 6th, 2009 AT 6:30 PM