98 Crown Vic LX Fuel Pump

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  #1  
Old 05-03-18, 06:58 PM
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98 Crown Vic LX Fuel Pump

37k miles stored in garage last 4 years.

Last week it dies after running 30 minutes, won't start till next morning.... 70° garage and it has NEVER died while running although it was cold back then.

Today: ran 30 minutes then died, volt meter on the relay wire to the pump showed 12V which stayed for a second or two then zero AFTER it died. Pump is getting voltage?

After it died I hooked up fuel pressure tester and it showed 0 pressure yet the voltage still showed 12V to the pump from the relay. I get the 12V prime then 12V cranking.


I have never had an electric fuel pump fail but I've always heard when they do it just won't start – never heard of one just stopping while running.

Any thoughts here?

Thanks

 
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  #2  
Old 05-03-18, 07:45 PM
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next time have a second person bang on the tank with a mallet. yes they do fail that way. i personaly had a 92 crown vic. when my pump was going out. i just added a subwoofer in the trunk. when ever it failed to run i would hit the bass hard. worked for a few years. untill the pump pulled so much amps it started blowing fuses.
 
  #3  
Old 05-03-18, 08:13 PM
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Ahhhhh yes...... Ford fuel pumps.

They can fail to start or just crap out. I've seen both. I've also seen problems at the connector at the tank which is where you need to check for power.
 
  #4  
Old 05-05-18, 04:50 AM
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Check For Spark ?

Fuel pressure steady at 32#, ran for 42 minutes then the pressure dropped to 0 - engine died - power to pump shut off. So I'd like to check for spark.


After reading my Haynes Online manual all night I guess I have the Integrated Electronic Ignition System (COP) where it says to check for spark:


18 Connect a incandescent test light across the coil harness connector, disable the fuel pump, then crank the engine. If the test light blinks while the engine is cranking the PCM is most likely not the problem.


I have a 12V tester, does this mean I just pull the wires off one coil (all plugs have a separate coil) and check there? Not positive but I think there are two wires to each coil.


My brother thought I was nuts when I couldn't find the spark plugs.


In this picture I think the yellow things are the injectors and those round black things are the coils with the plugs below.


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If I can run it today till it dies and I do find spark then it has to be the pump, I think.

Thanks
 
  #5  
Old 05-05-18, 08:56 AM
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If the fuel pressure dropped to zero and then the engine stalled.... that would be a pump issue.

It is normal for the 12v power to be shut off to the pump when the engine stalls.
 
  #6  
Old 05-07-18, 03:25 AM
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If the fuel pressure dropped to zero and then the engine stalled.... that would be a pump issue.

Yeah, you guys are right. I had it in my head a relay or something was getting hot until yesterday. Backed it out of the garage, went back a few hours later and it wouldn't start. Nothing can heat up running it for one minute.

These complex new cars are way over my head, even though it's 20 years old. I'm glad my weekly driver is my trusty 89 K1500. At least I can find the damn spark plugs on that.

Thanks guys, it's goin' to the shop.
 
  #7  
Old 05-07-18, 03:29 AM
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Depending on access, replacing an electric fuel pump isn't a big deal although some tanks require the tank be dropped to get access
 
  #8  
Old 05-10-18, 08:44 AM
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Depending on access, replacing an electric fuel pump isn't a big deal although some tanks require the tank be dropped to get access

Yeah... this car has the vertical tank hidden up between the trunk and rear end, apparently so you can fit 20 cases of beer in the trunk.


I'd maybe do it if this was a couple decades ago, no patience now and even less ambition.
 
  #9  
Old 05-10-18, 10:07 AM
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I know what you mean, when we were young money was hard to come by and we'd feel bad if we had to pay someone to do something we could do our self. No that we are older and have a few extra bucks it's harder to talk yourself into doing some of the harder or dirtier jobs.
 
  #10  
Old 05-18-18, 07:55 AM
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I'm Wrong Again

I've also seen problems at the connector at the tank which is where you need to check for power.

Right you are however you pretty much have to drop the tank for that so I'll do next best and check in the trunk right before the tank. There I'll have the pink/black from the relay and the large black ground.

Found this very early this morning:

When the ignition switch is on, full battery voltage is supplied to the control module and to the pump, either through the control module or through a separate fuel pump circuit.

The control module operates the fuel pump by controlling the motor’s ground circuit on a pulse width modulated duty cycle.



Here's a comment on a Ford Explorer:

..."finding operating voltage" on the fuel relay. Of course, that is always true CAUSE the PCM isn't switching in a voltage to operate the relay, it switches in a GROUND.


In other words, me putting my volt meter at the relay was more or less useless if the pump is controlled by the PCM on the ground wire.



If I'm correct, I will go in the trunk with my volt meter on the hot and ground to the pump and if it drops voltage before it dies it's the PCM and if voltage drops after it dies it's the pump. Worth my time??


Reason I'm so crazy, and I am, if I can determine it's the pump I'll have it towed to my nephew's shop in Duluth where he can change that and my 20 year old tires.

If it's the PCM it has to be towed to a dealer. $$$$

Please tell me I'm on the right track.


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  #11  
Old 05-18-18, 07:45 PM
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Well, did my test on the hot and ground in the trunk.

+ steady 12 volts for 35 minutes

+ at 35 minutes the voltage dropped to 9-10 volts then the engine died

+ tried to restart, prime and crank stayed at 9-10 volts, wouldn't start.


Could it be the pump itself is overheating and drawing the voltage down?

I haven't a clue.
 
  #12  
Old 05-18-18, 07:54 PM
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why dont you have 14 volts while running?
 
  #13  
Old 05-18-18, 08:22 PM
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That's a good question, didn't think of that.

I still have everything hooked up so I'll check that again tomorrow with my other glasses. It did definitely drop a couple volts though just before it died.
 
  #14  
Old 06-19-18, 06:45 AM
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If the fuel pressure dropped to zero and then the engine stalled.... that would be a pump issue.

Right you were. It eventually died and never started again. Had a new pump put it plus a fuel pressure sensor and runs like new.

Four new Cooper Tour tires must be gold belted radials. No idea why a smaller car like this takes such wide tires but they do ride nice. $$$$

Thanks all
 
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