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87 F250 7.5L won't run over 50 mph.

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  #16  
Old 09-07-2011, 02:33 PM
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Checked on the battery when off. 12.82 When running it is 14.42 so I think it is ok. Even with reving the engine it stayed around 14.42. Took off the distributor cap and found that under 3 of the wires they were corroded and a forth one is cracked around the housing. Will replace this this afternoon and drive it again.

We were out driving today and it was fine. Turns out the previous owner took out the fuel filter and didn't put one in. I bought a new one and installed it and it worked great until we went over some bumpy road and then it did the same thing as before. I am thinking fuel pump and distributor working together to cause problems?
 
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Old 09-07-2011, 04:07 PM
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Just replaced the distributor cap and rotor. Problem not yet resolved. It was idling with a quiet tapping noise but after about 5 minutes the tapping stopped and it idled smoothly from there. If I step on the gas to rev it there is a hesitation before going up.
 
  #18  
Old 09-07-2011, 04:15 PM
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Originally Posted by jlbreak
Just replaced the distributor cap and rotor. Problem not yet resolved. It was idling with a quiet tapping noise but after about 5 minutes the tapping stopped and it idled smoothly from there. If I step on the gas to rev it there is a hesitation before going up.
You said your wires were pooched too.
 
  #19  
Old 09-07-2011, 04:34 PM
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I don't think that the wires are bad because it idles smoothly and drives until high speeds are reached.
 
  #20  
Old 09-07-2011, 07:03 PM
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Originally Posted by jlbreak
I don't think that the wires are bad because it idles smoothly and drives until high speeds are reached.
That doesn't mean anything. At idle, your ignition system is hardly working and the firing voltages (the amount of voltage that the coil needs to generate in order to fire each plug) are low.

When you are at higher engine speeds, the load is greater on the motor and the firing voltages increase. If you have any leaks in your secondary ignition system (coil center terminal to distributor, rotor and distributor cap, plug wires, plug insulator ceramics), the voltage will take the path of least resistance once it gets high enough, causing misfiring.

Since your engine is completely dying, I would look at the coil and the wire from the coil to the distributor especially, since it seems to be affecting all of the cylinders. If you were only misfiring on a few cylinders, the engine wouldn't completely die.

I'm not saying that your problem is this, but it's certainly something to look at. Based upon what you have said thus far, I would strongly recommend at the very least a new set of QUALITY plug wires. Driving all the way to Alaska is not something to consider lightly, and just forget about it if you don't have a reliable rig. I drove cross-country in an old vehicle once, and I kid you not, every day I was down for several hours in one shop or another getting something fixed. And I thank God that there are still towns and cities in flyover country that have car parts and repair places!
 
  #21  
Old 09-07-2011, 08:04 PM
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Its pretty rare for plug wires to shut an engine down, I'd check fuel pressure like Paul suggested. Your local Autozone may have a "loaner" puel pressure gauge... tape it to the windshield and go for a ride. I think you either have an intermittent no spark (possible module) or, more likely, fuel starvation problem.

Edit: A fuel pump volume test might reveal your problem.
 
  #22  
Old 09-08-2011, 02:02 PM
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I am fairly certain that I can put it back together...

It was recommended to tear apart and clean. Working on that right now.
 
  #23  
Old 09-08-2011, 04:24 PM
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Originally Posted by jlbreak
Checked on the battery when off. 12.82 When running it is 14.42 so I think it is ok. Even with reving the engine it stayed around 14.42.
Good
Took off the distributor cap and found that under 3 of the wires they were corroded and a forth one is cracked around the housing. Will replace this this afternoon and drive it again.
BAD

I am thinking fuel pump and distributor working together to cause problems?
Fuel pump pumps fuel and distributor directs spark. They must both work flawlessly but do not share functions.
 
  #24  
Old 09-08-2011, 05:16 PM
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Originally Posted by jlbreak



I am fairly certain that I can put it back together...

It was recommended to tear apart and clean. Working on that right now.
Thank's for the chuckle! I do wish you the best of luck though.

I rebuilt a 4- barrel Rothschild once...nevermore...nevermore...Close though! Took it to a Carb shop for the final tweeking.

No one mentioned "rebuild kit"?

One suggestion. Don't keep walking away from it & coming back to it later. Git er done!
 
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