I 'd appreciate any assistance I can get on this one. I have a 1989 F150 302 automatic, tilt wheel and air conditioning.
Up to about two months ago the truck ran fine. At that point it started coughing and stalling while driving. It then started to stall out and die. After a few minutes it would start back up.
It eventually reached a point where it would not start at all.
When this problem began I changed the fuel filter and added fuel injection cleaner to the gas. As problem worsened I replaced the fuel pump. When it died completely I went to AZ to get new plugs, distributor cap, etc. The wizened elder at AZ listened to my description of the problem. He told me I needed a new ignition module. I replaced this to no avail.
To date I have replaced the ignition coil and condensor, the ignition module,the rotor, the cap, the distributor, the starter relay and the fuel pump and fuel filter.
At this time I am not getting fire from the distributor.The starter turns over but the truck won't start. The coil is outputting 12 volts with the key on. This drops to around 5 or 6v when we try to start the truck. The truck was bought used. The O2 sensor and catalytic converter were removed by a previous owner.
The computer generates code 21,24 and 11 when I perform the keyon engine off test. Code 11 means the computer checks out.
Any suggestions as to my next step? Could the computer be bad?

 

Try this..it wont hurt..and needs to be done from time to time anyway. At the negative terminal of the battery cable is a pigtail with 2 small ground wires coming off of it,disconnect the connector so you can clean inside. If it looks too bad, just rework the connector by cutting it off and adding in fresh pieces of wire and terminals to complete the circuit. Over time, the battery acid migrates into these ground wires and they go straight to the computer so you cab imagine how important it is to maintain a good curcuit here. I also wanted to know if the check engine light comes on when you turn the key to the run position ? If not , also check for open fuseible links at the starter solenoid.
Phil

 

Thanks for a quick response! I'll check the negative teminal first chance I get. Yes, the check engine light does come on when the key is put in the on position.

I'll get back to you once I 've checked the negative terminal.

Thanks again

 

Do you have power to the fuel pump, I was having the same problem with my 88 f350 351w and the darn ground wire going to the fuel pump had been broken inside the cluster of wires. Maybe this will help

 

I checked the pigtail at the negative battery terminal. Contacts looked good. I have continuity from both pins in the plug to the battery terminal.
I 'll have to check the fuel pump voltage in the morning. I was not aware that the spark from the distributer was affected by the fuel pump.

 

Just an update. The problem turned out to be the computer. I replaced it and The truck is running as well as can be expected for it's age and condition.