1988 F-150 - Intermittent Ignition
 

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.

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.

Hi Joe, welcome back!
From what I believe you are describing, it does remind me of an ignition switch problem , that may be caused by the linkage from the key switch section down to the ign switch mounted on the lower steering column. There is a rod with a rack that has teeth on it and as the key is rotated the rack is moved down and activates the switch section.The electrical part may have come loose and it would be a good idea to check that first. Makes me wonder if that might have played a part in the window motor saga.
If you decide to check it out , let us know you find, thanks.

Hi Hanky, glad to see that you're still here,

I blew a brake line on the right front and had to transfer repair priorities momentarily.

Now, back to my ignition problem.... Someone told me that the key tumbler was simply a turning device that moved a rod to engage/disengage the actual switch/circuit located lower on the steering column. Your explanation coincides with what I was told previously.

I've found via pictures what the switch looks like and the general area where it is located. I removed the fuse panel cover for better viewing BUT found that the switch is impossible to see and I can't get my hand anywhere near it. Apparently it's mounted on the top portion of the column with so much in the way.

I feel for sure, going by your explanation, that this is where the problem lays... but I'm sort of brought to a halt by the lack of working space there. Sure hope I don't have to remove the steering column.

Me being a marine mechanic from 1960 to 1991, I've encountered my share of bad and intermittently bad ignition switches and understand what you've told me here. I feel I need to replace this switch before going any further if any additional problem exists.

Thanks for your help my friend... I do appreciate it.

OH, the window motor saga... I replaced all the door lock solenoids and window motors on this 88 F150 and also my late wife's 89 Crown Victoria (pretty much worn out). They've worked fine ever since.

Hi Joe,
the steering column does need to be lowered to get to the switch assy.
I believe there are 4 nuts that need to be removed to allow the column to drop down enough to replace the switch. A younger guy probably would be able to support the steering wheel on his knees while doing this, but guys that are a little out of practice could wind up speaking a foreign language before they get this done. If you can rig up something to support the column while you lower it a few inches to get to the switch that would help make the job easier. You don't have to remove the battery negative cable to do this, but it would help eliminate some stress while doing the job. Once you get the switch and start the job it may not be as bad as it looks.

Yes Hanky, there is what I would call a heavy duty rectangular metal support under the steering column retained by four studs/nuts. I'm assuming by what you've said above that I wouldn't need to remove any retainers at the lower end of the column. I did have to replace the P/S gearbox some years back and drawing from memory right now (9:35 PM) it seems to me that the lower end of the steering column was a universal flex setup of sorts. I'll check that out before I start on it.

I will, first of all, disconnect the negative battery cable to be on the safe side.

I can make a customized adjustable length cradle out of wood to hold the column... it doesn't look too heavy but I wouldn't want to be holding it up for any great length of time.

I'm waiting now for a cold front to move out... 48 or 50 degrees is still pretty cold to us down here in central west Florida (Tampa area).

You are greatly appreciated Hanky, thank you.

Tuesday 11/29/16... Drove the truck in a semi jerking/vibrating state a 5 mile distance running a errand. Engine died/cut out completely, AAA tow truck carried it home.

Using a spark tester with a 7/16" air gap to test coil... spark was red, very thin, intermittent, weak. Bottom line = coil failed.

Installed new coil = Engine starts in START position. Actually starts better than it ever did, even when new.

I suspect that previously engine would not start in START position as the failing coil couldn't function properly with the starter drawing voltage away from it.

The DC voltage being applied to the coil is a full 12v in the RUN position. Resistance is the same and normal with both coils (new/old)... Suspect the old coil is arcing out to the yoke.

The spark still looks red to me but it is hot and constant, however since the truck now starts promptly in the START position, I'll hold off on replacing the ignition switch UNLESS it acts up once more, at which time I'll have to put it in the shop as I can't get into the necessary position needed to replace it... leastwise I don't think I can.

I don't understand why the spark from the new coil isn't a strong blue.

Thank you once again Hanky for your time and advice... whatever happens, I'll be sure to get back to you.

Thanks for the update , Joe!
Funny thing, the same spark can look great on a darker than normal day and yet look weak on a bright sunlit day, could this apply here?

That "Bright Sunlit Day" could be what tricked me Hanky..... I had the hood up, the spark tester in the engine compartment, and the bright central Florida sunshine beaming in there.

I'm going to remember what you had to say here, and if this young truck drops into this same type engine failure again (or any type for that matter), I'll be yelling for you.

So far it's been starting and running normal so far... got my fingers crossed.

Ya know,
If we didn't have some of these challenges , we might have to settle down to just watching the grass grow. These little problems are what keep us going and without them ,,,,,,,,,,,well glad everything is going well !