Ignition

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  #1  
Old 01-28-03, 06:10 PM
jmac55
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Ignition

I just bought a 1985 Ford F-150 with a 4.9L engine. The engine will not start in weather (or engine) with the temperature below 60. I have been told by the previous owner, a very good friend, that If I use a hair dryer & blow hot air on the distributor for a few minutes, it will start & run great. As long as the engine is warm, it will start & run fine. I have replaced the distributor, module (attached) & stator/pick-up. This vehicle does not have vacuum advance. I checked coil with OHM meter, its O/K. I checked the spark from coil wire into distributor & found out that the only time that there is a spark is when you "bump" the starter. When you turn the ignition key (or remote jumper) as if you want to start the engine, the only time you get any spark is the first instant the motor is cranking & then no more spark. What to do? What does the hair dryer have to do with it? I don't know but I don't think my friend would lie to me about it after I asked him repeatedly. I haven't tried the dryer yet but I will tomorrow. Regardless, I only have one spark per key turn.
 
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  #2  
Old 01-28-03, 06:56 PM
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next time it will not start see if you have spark all the time if you unplug the spout connector located by the distributer that you unplug to set base timing, if it now has spark likely an ecm problem, if it doesnt sounds like a pickup assembly problem.
 
  #3  
Old 01-28-03, 08:13 PM
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Wonder if you have an ignition switch problem? Now the deal with the hair dryer might indicate a problem with the connector that attaches to the TFI Module. Have someone try to start the truck while you gently wiggle the connector and see what happens.
 
  #4  
Old 01-29-03, 05:29 AM
jmac55
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Thanks for the replies guys. I'll try them all. I received some e-mails too. Just wanted to restate that the new items installed (distributor, stator/pickup, module) were fresh from the parts store & installed & same results as parts replaced. Can't be a moisture problem & nothing close-by but ignition components. It seems my immediate problem is to get a spark to the distributor while the starter is turning the engine. 1 spark per key turn (or remote button) at the very first contact & no more spark for the entire time the starter is engaged. I'm going out to try the dryer now. I have to satisfy my own mind. I'll post the results.
 
  #5  
Old 01-29-03, 09:44 AM
Joe_F
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You may have gotten a defective ignition component at the parts store. The spark should be fat, blue, and consistent.
 
  #6  
Old 01-29-03, 01:45 PM
jmac55
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Well, I tried the dryer. In a period of about 15 minutes of trying to start the engine, it "hit" maybe 3 different times. There is no difference in the symptoms between the old components & the new components. As described in the above posts & replys, when I do get the one spark, it is blue & true. But I just get it once. I bought a new coil to install. I spoke with someone that said a cold faulty coil may work properly when warm. If I keep replacing sooner or later I'll find the problem. I did jiggle the wires on the module plug as it was being cranked, no difference.

So, still, my problem is: Only 1 spark (a good one, the instant the key is turned) per key turn & then, unless warm, no more spark.
 
  #7  
Old 01-29-03, 04:07 PM
Joe_F
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How's your timing and timing chain/gear condition?
 
  #8  
Old 01-29-03, 04:12 PM
jmac55
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Timing has been set by an A.S.E.
I'm assuming chain/gear are fine as the truck runs great once you get it to run.
 
  #9  
Old 01-29-03, 08:54 PM
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Join Date: Sep 2002
Location: Colorado
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Try running through these diagnostics and see what you come up with. also check the connector on the computer to make sure its in good shape and fitted tight. check for bad connections at the coil also.
http://www.cybrrpartspro.com/Chilton...576CH02_8.HTML
 

Last edited by Stevo2; 01-29-03 at 09:29 PM.
  #10  
Old 01-30-03, 03:31 AM
Joe_F
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Check all computer grounds, as equipped. I believe that era F150 is carbureted with a 1 barrel Carter (yuck!)
 
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