I have a 1988 f-150 with a 351 eng and it is having ignition problems ! First the starter started to stick on every once and a while. So i replaced the starter solenoid worked for a little while now it wants to turn over as soon as you try hooking up the battery and wont quit unless you disconnect the battery! Just put another ignition switch in and tried to connect the battery and as soon as i hooked the battery it tried turning over again ? HELP IAM LOST Thanks Greg

 

On the column is a rod connected to a plastic sliding switch. This is your actual ignition switch turned by the key cylinder. Make sure it slides up and down as you turn the key. I suspect it may be stuck and the linkage to the key cylinder broken. If all is good I would examine the solenoid wiring. Disconnect the ground wire and trace the power back to the solenoid. Make sure it switches on and off. Check for power in the loop from the solenoid to the key switch. Somewhere something isn't turning off. Remember its a simple relay. 12v high amp goes into the starter solenoid. 12v low amp goes out to the key switch. The key closes the circuit sending 12v low amp back to the solenoid which activates the solenoid and sends 12v high amp through to the starter. Something is stuck on or bypassed.

 

Ok i got it to start and then drove for less than 24 hrs and it died while driving it and now when you turn the key all i get is the starter solenoid sounding like its engages but nothing else. now have check engine light on pulled the codes and got an egr code and throttle position sensor code could either of these be the issue ? HELP !!!! thanks Greg

 

Is the switch cycling like it should now? If its working right, check the charging and starting system. Usually a click and now crank indicates bad battery, bad battery/starter wire or connections bad starter or bad solenoid. Visually check everything than check the battery voltage. A load test is best but you can get a good idea by turning on your lights and checking voltage with a DMM. Then check starter draw by measuring battery volts while cranking. If you can start it take it to AutoZone for a charging system test. Check your alternator output. Should have @14.7 at idle. Once thats cleared, clear out your codes drive it and recheck.