I am at my witts end with my truck. Ii just spent 500 dollars, and am still having the same problem.
my truck runs great it is an 87 f150 with the 300 six. Except hear is my problem if i run it for a while and go shut it down to run into to a store for say twenty minites it won't start. I just paid 500 dollars because my garage said it had a fuel delivery problem. Great so he replaced the relays and pumps. Picked it up it ran great for one day. Today it happened again and i called the guy who worked on it. After looking it over we discover it has no spark. So we go inside to get a tester and come out the stupid thing fires right up.. Guy tells me he can not diagnose the problem because it is running now. So basicly sorry i screwed you on the other work that did not need to be done, but see ya later Help please i am at my witts end and can not figure this out why is this problem so intermitent it does not happen every time. Thanks in advance

 

Try a new TFI module. If that works, try to get your money back for the other work, or get a credit for it.

 

RE: Won't run!

Hi, do you have any spark? That's a good place to start, that is asuming the engine turns over. If there is no spark but it turns over check the following and not necessarily in this order.
1. Bad coil -- be careful this can give you a nasty jolt if you grab the coil lead.
2. TFI Module on the side of the distributor. The wiring harness plugs in to it on the distributor. This will have to be removed to test it. there are 4 recessed screws on the module that have to be removed and there is a special thin walled socket sold in all auto stores for $5 that gets in there. If you remove it remove the screws and tip the bottom of the module away from the distributor slightly and pull STRAIGHT DOWN . The module has three brass male spade connectors on it that point straight up and connect into the connector in the distributor. Some auto parts stores I believe can check this module for you.
3. Distributor cap and rotor and distributor to coil wiring.

4.------ HERE IS one not many people know about. The EEC Relay ( Electronic Engine Control Relay) this supplies power to the computer. If the contacts on this relay are bad the engine will turn but will not start.:-( It is on the drivers side inner fender pannel near the wire harness connectors it is a metal relay about one inch square and 7/8 inch thick. If you find it give it a couple of raps with a screw driver and see if it does anything. You can test it with a volt meter to see if there is any output to the computer, should be battery voltage. The one on my 90 was full of water and still worked some times the other times the engine would die or not start. My 93 Ford car had he same problem wouldn't start intermitently.


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