1996 crown vic fuel/spark issues | Ford Explorer Forums

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1996 crown vic fuel/spark issues

osteologation

Well-Known Member
Joined
April 7, 2008
Messages
140
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0
City, State
Caro, MI
Year, Model & Trim Level
1994 Sport
I Have a friend who's Vic shut off on him. Basic troubleshooting showed no fuel pressure. So made sure to check for power at pump, there was, but bit did not turn on. So new fuel pump. Now it has pressure if you bypass relay. Still wouldn't start. Used a timing light to verify no spark. We checked timing light on his other car to make sure it worked. Then checked ll relays and fuses for 12v, all had power. Then decided to check crank position sensor, failed to generate any reading on multimeter while cranking. So it's bad right? What is really troubling to me is both of them failing at the same time. But that old pump would not turn on with current directly applied to it. And the ckp test said to use a multimeter in AC mode directly on sensor while cranking, all zero's. So really the question is: is this unheard of? Ckp is only $11 at rockauto but jeeZ.
 



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BrooklynBay said:
Do you see a check engine light when you turn on the electrical system? The computer controls the fuel pump relay as well as the spark timing.

The relay kicks on initially when you hit the key, like it supposed but since it's not starting the relay won't stay on. I'm fairly familiar with troubleshooting fuel problems, seems like everything ford I've owned has needed fuel pump. It's the no spark thing that interested me. I will state that a lot of the initial troubleshooting was done over the phone with my friend doing the actual work. By the time I got there a week later he had the fuel pump changed. 200k miles on a car he just bought but beautiful condition, owned by a snow bird. Fuel pump replacement may be good insurance if it needed it or not. I worry that he may not have checked everything correctly, and it may have been the crank sensor the whole time. But I was more curious I anyone had run into 2 not exactly related problems at once like this
 






BrooklynBay said:
Do you see a check engine light when you turn on the electrical system? The computer controls the fuel pump relay as well as the spark timing.

Also he did state there was intermittent cel While trying to start but idk if it's still the case. The ckp test has you unplug the sensor and see if it's generating an AC current, which it is not.
 






Don't confuse the fuel pump relay with the computer relay. The computer relay controls the computer in addition to the fuel pump circuit to activate the fuel pump relay. It's a domino effect. The fuel pump relay needs to have the computer relay work.
 






BrooklynBay said:
Don't confuse the fuel pump relay with the computer relay. The computer relay controls the computer in addition to the fuel pump circuit to activate the fuel pump relay. It's a domino effect. The fuel pump relay needs to have the computer relay work.

They are not being confused. The fuse, diode, and relay check out. The pcm "should" be getting power, time was limited but I am going to borrow a code reader to make sure PCM is fine.

Anyways the crank sensor testing has nothing to do with PCM seeing as you unplug it to test it. And it tested bad. But... We shall see.
 






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