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1995 Crown Vic No Start


bigj-dog
03-09-2010, 04:44 PM
Hey, had a guy drop off his 95 Crown Vic, non-interceptor with a 4.6L. According to him, one day it just didn't start. Told me it needed a fuel pump. Before removing it it checked the power to it, the gauge has power and ground, but the pump only has ground, the power (red with black or blue tracer) is dead. So, I ran a jump wire back there and the pump turned on, sounded normal, fuel pressure gauge sat at 40. Tried to start it with the pump hot wired, no start. Upon further testing, no spark. All the dash lights come on, gauges work, turns over fine, but no spark and no power to the fuel pump. I checked the emergency shut off switch and it doesn't appear to be popped. Even if it was, wouldn't it only cut off the power to the pump? Any ideas? All fuses are good and I can't find anything else that doesn't work.

way2old
03-09-2010, 07:01 PM
Check under the right front bumper area under the battery where the wiring loops down. These have been known to get water in the loom and allow the wires to corrode and break. Might not be, but worth a look.

bigj-dog
03-10-2010, 01:56 AM
Update:
Through some research based on some nice wiring diagrams, I guessed that the computer most likely wasn't turning on, so I checked the wires to the PCM power relay, assuming i'd find them all fine and a new computer would be in order. Not the case. The power supply to the PCM relay (yellow with black tracer) is dead, and should be constant 12V. I back probed and put power to that wire and turned it over and it ran. Tomorrow I'm going to try and track down the bad spot in the wire. Probably in the loom eluded to above.

bigj-dog
03-10-2010, 11:31 PM
Good call on the area of the bad wires. I continuity tested the yellow with black wire at the fuse box near the battery to the wire bunch loom running just in front of the radiator and behind the grill near the center of the car, no connection. So the bad spot was most likely in that bendy area just in front of the right front tire. I just clipped it, and ran a new wire from the fuse box around the battery and through the radiator core support and hooked it back up just below the hood latch. Fired right up. Can't find anything else that doesn't work just yet, but i'm guessing there are already more wires broken in the bundle. I'll deal with them when they cause trouble. The car's on its last leg anyway. Thanks for the tip way2old, I appreciate it.

way2old
03-11-2010, 07:04 PM
That is why we come to these forums. Thanks for the post telling us what the repair was. Good luck and keep that tip handy. The PCM, fuel pump, ignition and other power wires run through there.

myford89
07-12-2010, 07:03 PM
Where would I find these wires on a 1989 model? I have had my car in 2 shops for 1 week each and now they are saying I need a new PCM. According to this posting, it may just be a wire. Car is hard to start and will run for hours in park, but will stall out when I drive down the road just a few miles (3 miles or less).

Mike K.

bigj-dog
07-12-2010, 07:18 PM
Your Crown Vic is a different breed than the one I was working on. I'd first find out when it stalls if it's because of a lack of spark or fuel. Then go from there. How does it run while driving? Does it run great, then all of the sudden die? Or does it miss and feel gutless?

myford89
07-12-2010, 07:58 PM
Mechanic had in shop running in park for 3-4 hrs and no problem. When I drove it down the road 2-3 miles it ran ok then died out (stalled) and was hard to start up again. It would just crank over & over & not start. I was told to turn ignition switch to off position, then in on position until count of 3 or 4, then back to off position , then start car. This helped to start it a bit easier & faster, but after going down road just a little bit, it stalled out again going about 30-40 mph.

First shop did not know what was wrong (Firestone), second shop has had it all last week and finally told me today they think it is the ECM, engine control module. I'm not sure to believe them at this point. I don't want to spend $200 on a ECM that is non refundable to find out later it may be something less expensive. I have replaced rotor & dist cap.

bigj-dog
07-12-2010, 08:53 PM
The first thing I'd do is mount a fuel pressure gauge in the fuel system up by the plenum, and observe it as you drive. My guess is that your fuel pump is going bad, and doesn't supply enough pressure to keep the engine running when the load on the engine is increased and more fuel in consumed. Essentially, the car is running out of gas when you drive it. When you cycled the key on and off and on, the pump ran for a few seconds each time, thus (ideally, anyway) the fuel pump was able to replace the fuel the engine used while you were driving and increase the fuel pressure back up to where it's supposed to be and the car would start easier. That's where I'd start anyway, if it was my problem.

myford89
07-12-2010, 09:48 PM
Thanks, will check it out.

way2old
07-13-2010, 05:45 PM
Good advice bigj-dog.

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