1993 Ford F-150 After truck gets to running temp it looses p

Tiny
GOODOLBOY72
  • MEMBER
  • 1993 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 82,000 MILES
I have had this problem before and took it to a hack and it ran better for about 6 months, then it started again. I do not have the money to spend on someone who cant fix the problem correctly. See when I start my truck which has a 5.0 302 engine, it seems to run smooth. I rev it up in stages from 1000 rpm to 1500 to 2000 and so on and it runs smooth. I put it in gear holding the brake and putting it under a load while doing the same thing as before and it seems ok. Then it hits running temp. On a ford it is in the middle of the gauge, although I imagine its about 180 or so. Once it hits that it turns into a shaking knocking mess. I cant even get the rpms above idle and it struggles for what sounds like fuel, except for the 15 minutes it took to warm up it did not exibit any of these problems. If I try and give it the throttle it gets worse and seems like the thing shakes so bad the engine is going to rip off the mounts, plus it sounds as if it is deiseling or knocking really bad. I have put fresh fuel in it, I had tried to use a fuel additive in the past and nothing works. Both pumps run as I said until it gets to running temp. I cant drive it because I do not have a current licence on it and I also do not like chugging down the street. I do not have any code readers and cant afford them. I should not even be working on this thing but I have a back injury and need to go to the dorctor and cant afford the $120 trips. Is it something simple that I can fix in my own garage, a oxygen sensor, fuel pump, relay of some kind, Or should I save my money and take it to a shop that wont screw me over. I even checked the emergency fuel shut off and it was not activated so I am stuck. I was a trained tech, in a college course but that was back in 1990 and most of the cars we worked on were not loaded with all this computer crap. So My knowledge only goes as far as do things I know will not mess up the computer, basic diagnosic. I really need help. I have a place to take it but if I can do it with out spending the money I do not have That would be great. It also sounds like when it is warmed up that it is sucking in alot of air rather than fuel. Don't know if that would help but thats it. Can you help. Thanks so much. Tim
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Wednesday, July 22nd, 2009 AT 3:10 PM

7 Replies

Tiny
BUDDYCRAIGG
  • EXPERT
That sure sounds like the coil or ignition module is breaking down after it gets hot.
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Wednesday, July 22nd, 2009 AT 7:56 PM
Tiny
GOODOLBOY72
  • MEMBER
So if it is the coil or the ignigtion module is there a way to test for it. I am pretty sure I have delt with the ingnition module before. It is located on the drivers side engie compartment about 5 inches long one wire harness near the fire wall right. How do I test these? I sure am not messing with the coil while its running, I like to have control over my central nervous system. Thanks for the start now just if you can give me a little more to go on I would appreciate it. Other wise my dad is going to try and fix it and the last car he worked on was a 1979 caddie. Thanks for the help so far, now I need a little more. I already am going to buy a new battery, should I have the coil tested then. Thanks, Tim
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Thursday, July 23rd, 2009 AT 1:16 PM
Tiny
BUDDYCRAIGG
  • EXPERT
Thanks for the laugh.

You will need a special tool to remove it.
Or you can grind down the sides of a socket to be skinny enough to fit in the holes to get the little itty bitty screws out.

Sadly there are two things that are going to interfere with KNOWING that it is the coil or the module, or if it's really the problem at all.
The truck is still running, not well but badly.
If it was flat dead, then you could verify that you do not have spark, but (if I am correct) you just have a weak spark.

Next. It has to be hot for it to start to mess up.
And you cant duplicate that.

Some auto part stores have a machine that can test modules.
While I have seen them still pass a bad module, if the test comes back bad, then you know it's bad.
If it comes back good, well, maybe that's because it's not 180 degrees when it's being tested.

To help be comfortable that it is indeed an ignition problem, get a can of starting fluid and try spraying some in the air cleaner while it's messing up, and see if you can get the engine to rev up higher. But i'm not expecting it to.

I know your next question is going to be which one is the problem.
I will say 60/40 that the module is bad.

Feel free to come back an cuss at me if I am wrong.
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Thursday, July 23rd, 2009 AT 6:51 PM
Tiny
BUDDYCRAIGG
  • EXPERT
PS, here's a picture of that special tool.

Probably 5 10 bucks at the parts store.
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Thursday, July 23rd, 2009 AT 6:53 PM
Tiny
GOODOLBOY72
  • MEMBER
I appreciate the extra time you put into the question I had. I actually think I had to replace one of those on a previous car I had, now I could be wrong but I think a 88 ford escort had a very simular ignition module, and If it was not that one then that mean I have take the one out of my truck before. In any instance I do recall it being a pain in the butt to get out. They probally make them need specialty tols so that your forced to take them in to get repaired and then they charge you 500 bucks because the have the tool and you didn't. Like I said I know I have taken one out before so if I have to grind down a socket I will. I have cut a car in half, welded on jackstands, rerouted all the fuel and electrical lines, and made it a training car for people who did not know how to drive a stick, and this was when I was in highschool, also why I was accepted as a student at a college or trade school class that I recieved my certified mechanics certificate from, but that was in the 90's Now its computers and crap. I miss the old 350's by chevy or my favorite the 455 olds, when you could just take them apart clean them, bore them, do what ever, and then your biggest decision is do I want to save gas an put a two barrel carb, or kick butt and go for 4 barrel. Now its all chips, relays and computers.
By the way you mentioned the coil, on my truck right next to the coil there is a cylinder about as big as your pinky with one wire coming out going into the loom hooking into the coil somehow. It could be a resistor, or regulator of somekind, I just know it is not mentioned in any book I have read by chilton, is it a sensor and could it be fried after all it looks like it is an original piece, and is sitting above the maniforld where it gets hot, wouldn't that be a pisser if it was such a little thing like that. If you know what that is can you let me know so I can rule it out or maybe its time to replace it. See my truck has 82000 miles on it, but I bought it in 94 and it already had 29000 so in15 years I have only put 50000 on it and I really baby it thats what is frustrating me so bad. One more thing what would be the resultif someone may have duped soda into your gas tank at one time or another. Not saying it happened its just last time it ran right I stopped for gas and there was soda all over the side of the truck near the gas hatch, Ex Girlfriends. That is why I flushed it with a fuel additive before. Just thought I would throw that in incase it could have a impact on the performance, it just does not explain why it only happens when it at operating temp.
Thanks again, and glad I could make you laugh. TIM
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Thursday, July 23rd, 2009 AT 11:14 PM
Tiny
BUDDYCRAIGG
  • EXPERT
The ENTER key is friendly,
don't be afraid to use it.

The skinny cylinder thing next to the coil is probably a capacitor, to help cut down on noise in the radio and keep the tach (if you have one) a nice smooth needle movement.

They can also go bad and cause problems.
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Thursday, July 23rd, 2009 AT 11:34 PM
Tiny
GOODOLBOY72
  • MEMBER
Thanks, I appreciate it.
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Thursday, July 23rd, 2009 AT 11:39 PM

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