I Removed vac line from Fuel Press Reg, my car will finally idle and drive better?

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  #1  
Old 06-05-02, 10:23 AM
rozebek
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Talking I Finally found out what is wrong with the Mercury

1989 Mercury Grand Marquis 302 5.0

If my car runs better with the vaccume line disconnected from the Fuel Pressure Regulator, Does that mean that my fuel pressure regulator is defective? With the vac line attached my car will not idle and it shudders while driving, usually right after the shift into 2nd. My car will idle now and drive without shuddering only a slight loss of power throughout speed range. Please give me some Ideas.
 

Last edited by rozebek; 06-06-02 at 03:49 PM.
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  #2  
Old 06-05-02, 10:24 AM
Joe_F
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Any fuel or liquid in the line? If so, the regulator's wiped.

What's the fuel pressure look like on a gauge? Rent one from Autozone and find out.
 
  #3  
Old 06-05-02, 10:30 AM
rozebek
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I checked the fuel pressure with the vaccum line removed and it was at 40 psi. When I reconnect it the psi drops to about 32 as the engine dies. I didn't see any fuel in the vaccume line.
 
  #4  
Old 06-05-02, 10:59 AM
Joe_F
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What does the spec in the service manual say it is?
 
  #5  
Old 06-05-02, 11:49 AM
rozebek
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joe

manual says:

Fuel system pressure (at idle)
Vacuum hose attached---------------30 to 45 psi
Vacuum hose detached--------------40 to 50 psi

It falls within spec's but why would my engine run better with the vacuum hose detached and the psi higher?
 
  #6  
Old 06-05-02, 12:07 PM
Joe_F
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Check your vacuum lines throughly. You may have a vacuum leak causing the concern.
 
  #7  
Old 06-05-02, 03:05 PM
rozebek
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joe

I have checked all of my vacuum lines and all of them seem ok. The problem with my car shuddering while accelerating started a year ago, from almost non existent shuddering to shuddering and then dying. The car would not start for 20-30 minutes. In the beginning it would only happen after driving the car for an hour or so, then it got to be all the time and it wouldnt always die.
It is not something that just broke, it just took it a year to get to the point of not getting me down the road even a couple of blocks without dying. If I use both feet to drive then it will go but it will die not far down the road. With that vaccum hose unattached from the Fuel Pressure Regulator my car has none of the above symptoms only lack of power.
 
  #8  
Old 06-05-02, 03:16 PM
tstokka
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it runs better with a vaccum leak you created by pulling off the line to the regulator. I would look for something restricting the air coming into the motor. like air cleaner, or intake gunked up.
 
  #9  
Old 06-06-02, 03:40 PM
rozebek
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Talking It took me a year and $200

I threw out the idea of the fuel pump regulator being bad, every test I ran came out ok. So I took the unused regulator back and got a digital voltmeter. I started probing around several sensors and then as I tried to take the connector off of the TFI Module, the distributor moved. The screw on the distributor hold down was about 4 turns from being tight. It was the distributor the whole time. I started having problems about a year ago with the car shuddering and then stalling after driving it for about an hour. I had to wait about 15-30 minutes before the car would start at all. Mostly the car would start shudering and jerking right after the car shifted into each gear and going around curves like the ones getting onto the highway. Not to mention, it wouldn't idle. If you ever have any weird problems with your car just remember me for one second and give your distributor a little nudge and see if it moves. Thanks for everyone who helped me with this problem. Sometimes accidents happen and this time it made my car work after a year. It sure runs great with all of the new gifts I have given it this year. I love my Mercury again!
 
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