Drew McGlohon

i have a 93 f150 4.9 IL6 i just bought recently. i bought it knowing it had problems and here's what i know. the guy i bought it from told me he had replaced the fuel pumps (2 tanks) here and there when they had went out. he said the truck would shut off on him after a while and wouldn't crank back up until after sitting there a while. he drove it until it went out again and then bought a new truck. he was insistent on it being fuel pump problems. i bought it a few days ago and have been driving it around a lil bit when the problems started with me. at first, it wouldn't start one night randomly. it would turn over, just not start. then the next morning it started right up. i had the same problem yesterday and i pulled the plug coming from the ignition coil to see if i could get any spark. i stuck a screwdriver in it and held it next to the distributor cap where that plug goes. no spark at first but after messing around with it for a minute i finally got some spark. i then proceeded to plug it back up and the truck started up, with a lil roughness at first. i drove it around for a while, turning it off and then starting it again, with no problems. this morning i went to start up the truck and nothing. the power comes on with the key in on position, but when i go to crank it, nothing. before it would at least turn over. i am really confused on whats going on but I'm pretty sure its an electrical problem. i first fought about replacing the coil but if it doesn't turn over, isnt that a starter problem? why would it turn off randomly while driving and randomly not start? i dont have an electrical tester to test the ohms on the coil to tell if its bad. and i dont really have any money to take it somewhere to get raped by some outrageous price for a simple fix. please help me with
ANY knowledge u might have about this situation.

RLXXI

Replace the ignition switch before you do anything else. Not the mechanical tumbler where you put your key, the electrical one further down on the column, I can't tell you how many of them I replaced during a recall Ford had when I worked at the dealer for some of the very same symptoms. Hundreds if not thousands. Easy to check it, the plastic part will have separated from the pot metal part and you can squeeze it and make the two parts move separate from each other like a clam shell.

Drew McGlohon

thanks for the response, any images of what the ignition switch looks like? plus i have some more info: i can get it to start by bypassing the ignition control module. and now its starting but it backfires for a few seconds and cuts off again. thanks for your help!

RLXXI

Apparently your truck had the new model ignition switch and did not exhibit the problems of the older pot metal/plastic that would separate and cause issues, this is what your looks like and as I said it was the new year revision that began in 1992-04.



The symptoms you describe could very well be the fuel pump from here on out you will need some test equipment, fuel pressure gauge, DVOM, test light.

RLXXI

P.S. If he used after market fuel pumps the chances of them being bad are increased 1000 fold. Never had any luck with any pump other than what the dealer sells.

Drew McGlohon

ok, i have an update. i have replaced the ignition switch, ignition control module, and distributor. i have it timed well enough to start but im still having issues with spark. when i turn the key to the 'on' position, the coil gets spark one time to charge it up. i know this from simply taking the plug off the coil and watch it ark to the block. now when i try to crank it up, i get no spark at all, even with holding a screwdriver to the coil closer to the block. anybody know about the computers on these trucks? i hear that if u take the jumper piece (close to the ignition control module) off and see spark, your ecu could be bad. any ideas? im close to jumping off a cliff!!!

red5standingby

Did you ever get an answer to your problem? I have exactly the same symptoms as you have. I've ben chasing a no spark issue for a while now. Just like you I have replaced the distributor, the ICM, the ignition switch ( lower one not the keyed switch) I removed the computer and gave it a good look but didn't see anything obvious. no leaking capacitors or burns or discoloration. I'm at my wits end.