1988 Ford F150 - 302 V8 Fuel Injection-AC-PS-Auto Trans

Been helped here many times on this vehicle ie IAC, TPS, 6 port Fuel Exchanger, etc... all successful. Trouble free since 2013... Hoping my luck holds out once again.

Now... Friday, (11/11/16), encountered what felt like a rapid ignition breakup, a very fast jerking type breakup. Using the count method... 1001, 1002, 1003, etc, The engine jerking sensation took place approximately 3 or 4 timer per second. The engine did continue to run however and got me home.

Friday (11/11/16), At home, later, I attempted to start engine via holding the key in the START position = No response! In my attempt to start the engine, it's possible that I flooded it as approximately 5 minutes later the engine would make a effort to start (fire a couple times) when I would release the key to the RUN position but would not continue to run.

Saturday (11/12/16), The engine started normally in the morning and sounded normal. Did not drive the vehicle but simply raced the engine somewhat to see if it would breakup = no breakup encountered. Not sure if it started in the START position.

Saturday (11/12/16), Afternoon, did not use vehicle but did start it again in the driveway. The engine started and sounded normal. Again not sure if it started in the START position.

Sunday (11/13/16), A 3 mile drive to have Sunday breakfast = engine started and ran normally to the restaurant. Once again, not sure if it started in the START position. Driving home, I encountered the rapid breakup as described initially. After parking in my driveway and shutting the engine down, then a few minutes later turning the key to the START position, the engine would not start... BUT... releasing the key to the RUN position resulted in the engine starting.

Same day (11/13/16, Sunday, 07:30pm), Test run before sending this message = Engine will not start in START position... BUT... does start when the key is released to the RUN position. Racing the engine somewhat (no tachometer) results in a breakup of sorts but didn't seem as pronounced as when on the highway.

 

I would pull all of the spark plugs and check them carefully. Compare them to each other and see if one or more is noticeably different.

Also check the electrical connectors to the fuel injectors. A loose, dirty or damaged connector can cause an injector not to inject fuel when it should.

Have you done ANY work on the engine lately?

 

just a wild guess here. Does the 88 still have the ignition module mounted on the front of the distributor? If so, they are prone to failure due to the heat coming out of the radiator.

 

Both good suggestions. Could also be the ignition switch on the column. Not the key tumbler, the one underneath with all the wires. Presumably you checked everything under the hood for loose connections.

 

joe51..... All spark plugs look the same (good). All connections look okay, no corrosion or looseness.

 

Roadie..... I'm not sure where that module is located. How could I tell?

 

1995XLT..... The only ignition switch I'm aware of is the key switch just below the steering wheel. Is there another one further down.... between the dash and the floor? Any hints as to what it might look like and where?

 

There is a rod going down the steering column from the key switch to the actual ignition switch.

 

In the second picture you can see the rod going down to the white ignition switch. The key moves the rod, the rod moves the ignition switch internal slider which makes contact for electrical stuff to happen.

 

I appreciate the two pictures, thank you.

I took the truck out today running as it was... a gamble I know but I needed to get some topsoil and other heavy big stuff. Coming home, the brake pedal went to the floor ... broken brake line front right wheel. Always something. I'll get back to you ASAP. Thanks again. (Joe)

 

(Brake problem repaired.)

Present Bottom Line Problem:

Engine cranks over at START position BUT will not start (fire). Engine will start if when cranking in START position for a few revolutions, then letting the key drop to the RUN position.

Engine seems to idle normally BUT breaks up as throttle is applied... a quick instantaneous ignition type breakup, happening approximately 3 or 4 times per second.

Attn 1995XLT: I removed the fuse panel cover to get a better view of the switch on the steering column as per the picture you sent. I can't get my hand in there to even feel it let alone check it out. Sort of at a loss what to do at this point.

 

Your problem is probably not the ignition module but if it is where I was asking, it is mounted on the side of the distributor in the front where it gets heated by the air coming through the radiator.

 

Thank you "Roadie", I appreciate the information and will be looking at that area as soon as the weather warms up a little.

 

I think they may have deliberately made it a little difficult to get at to make it harder for people to steal your truck.
You would have to lie on your back and look up. Using the picture you should be able to feel your way around to undo the 2 nuts and pull the switch.
Your switch is almost 30 years old, it wouldn't be a surprise if it failed.
From your description, ignition switch would be my first best guess. Could be something else of course, but it sounds like a faulty ignition switch.

 

It does make one wonder.