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Raoul Duke
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Discussion Starter #1
I searched like a madman and could not replicate my problem with an existing thread, so I had to start a new one.

The facts:
1996 Cougar XR-7. 121k miles. 4.6. Stock engine and fuel system.
Brand new battery with brand new terminals, alternator tested good.
When running, system puts out healthy 13+ volts and will run absolutely perfect, even with a full load (headlights, stereo, HVAC, etc).

At seemingly random times, the car will crank and not start. When this happens, there is zero pressure at the rail and the pump won't even prime. Voltage at the inertia switch is usually around 5.7 volts when it won't start.

I took apart the CCRM and inspected the solder joints with the wiggle test (look fine). Battery ground seems to have very good conductivity to engine and frame.

One thing I have noticed is that the volt gauge is reading low with key-on engine-off; somewhere around 8 volts, which is odd because the battery is brand new and healthy. When I can actually get the car to start, the volt gauge jumps up to where it should be and the car runs like a Swiss watch. The no-start condition is unpredictable and seemingly random, which keeps me from driving the car at all.

Will low voltage prevent the fuel pump from running at all? If so, why is the pump randomly getting ~6 volts when the battery, terminals, ground and CCRM all appear to be functional?

Thanks.
 

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CC - The battery terminals may be good, but how are the other ends of both cables?

And how are the cables? How old are they?

May be a bad ground or even "green rot" internally. I'd replace both cables.

RwP
 

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Raoul Duke
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Discussion Starter #3
I haven't checked the other ends of the cables, but I plan to lift the car up this weekend and take a look. They are factory original from 1995.

With that said, I didn't notice any internal corrosion when I stripped them back to install the new terminals. I will check the ground at the engine mount and the hot at the starter this weekend.

Thanks for the reply!
 

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I searched like a madman and could not replicate my problem with an existing thread, so I had to start a new one.

The facts:
1996 Cougar XR-7. 121k miles. 4.6. Stock engine and fuel system.
Brand new battery with brand new terminals, alternator tested good.
When running, system puts out healthy 13+ volts and will run absolutely perfect, even with a full load (headlights, stereo, HVAC, etc).

At seemingly random times, the car will crank and not start. When this happens, there is zero pressure at the rail and the pump won't even prime. Voltage at the inertia switch is usually around 5.7 volts when it won't start.

I took apart the CCRM and inspected the solder joints with the wiggle test (look fine). Battery ground seems to have very good conductivity to engine and frame.

One thing I have noticed is that the volt gauge is reading low with key-on engine-off; somewhere around 8 volts, which is odd because the battery is brand new and healthy. When I can actually get the car to start, the volt gauge jumps up to where it should be and the car runs like a Swiss watch. The no-start condition is unpredictable and seemingly random, which keeps me from driving the car at all.

Will low voltage prevent the fuel pump from running at all? If so, why is the pump randomly getting ~6 volts when the battery, terminals, ground and CCRM all appear to be functional?

Thanks.
there is a plug right below the engine circuit breaker box, it's the wire attached with the ground wire of your car that runs from the battery to the engine block... that is the ignition wire, check the plug for corrosion and get under the car /check starter connections. ALSO; a bad alternator connection can fry the fuel pump and cause all kinds of wierd things with these cars. my voltage gauge danced around alot and it eventually killed the pump and the battery. i replaced the alt connections (stopped dancing battery gauge), fuel pump, the battery and i'm waiting on a brand new duralast alt (just to be safe).

check the circuit breakers also.





http://www.justanswer.com/uploads/VirtualWrench/2008-12-18_185125_fuses.pdf

check this link out... not sure if its the same for a 96
 

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Raoul Duke
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1,747 Posts
Discussion Starter #5
Alternator connections are good and solid. I actually got it running tonight and had 14.3 volts at the battery. Circuit breakers all appear to be functional.

I checked the connections under the circuit breaker box; after cleaning and tightening them, there seems to be no change in the issue. I had no idea those terminals were hidden under there, so I'm glad you mentioned it.

After running the engine for 10 minutes and reaching operating temperature, I shut it down and keyed it back into the 'run' position, and the pump did not prime. Very sporadic and random, so I'm beginning to worry about the fuel pump.


Thanks again for the replies so far.
 

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Raoul Duke
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1,747 Posts
Discussion Starter #6
Replaced the ground cables and it had no effect.

Out of desperation, I whacked the tank with a rubber mallet and it started right up and ran great. False positive with a bad CCRM, or bad pump that is intermittently going out?
 

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Replaced the ground cables and it had no effect.

Out of desperation, I whacked the tank with a rubber mallet and it started right up and ran great. False positive with a bad CCRM, or bad pump that is intermittently going out?
I'm 100% sure that's a bad fuel pump. I had the same issue with the truck of mine and it would start right back up.

You should be able to get the OEM part for pretty cheap --->http://www.bluespringsfordparts.com

I wouldn't get a generic one from autozone, I had to replace mine FOUR times because the harness was bad on EVERY part until I went OEM.
 

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In the past I have had bad relays give some of the conditions that you describe. Ignition relay or maybe starter relay. Its been awhile so I don't remember exactly. Cleaning the blade contacts made it work for awhile but I ended up replacing them to solve the problem. They're cheap so I would check before doing a fuel pump install.
 
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