Cees Klumper
Active Member
- Joined
- Nov 4, 2019
- Messages
- 189
- Reaction score
- 134
- Points
- 43
- Location
- De Luz, CA (near Camp Pendleton)
- Vehicle Year
- 1990
- Make / Model
- Bronco II XLT
- Transmission
- Automatic
Well I spoke too soon. As I wrote right above, on Dec 24, I picked up the truck from the shop who said they fixed the stalling by addressing a vacuum leak and fitting the new distributor, I took it for several test drives over the past few days and, when in over 5 trips totaling some 50 miles it never stalled or even faltered, I took the plunge today and drove it from LA to our new home in Fallbrook, some 120 highway miles. All was going 100% perfect until, after about 60 miles, the engine stalled again! Doing 65 mph in the middle of 5 lanes of heavy traffic, in the rain. I managed to coast off to the nearest exit, while putting it in neutral and starting it back up - it did start right back up but as I was taking the exit, stalled again. The exact same problem decided to rear its ugly head out of the blue, after more than 100 miles of trouble-free cruising where, just before the shop took it in, it would not drive for more than a mile and it stalled out 5 times on the 3 mile drive to the shop.
Oh boy, what can this be?!
I had no tools with me but I was carrying some kitchen stuff including a roll of tin foil. I figured what the heck and proceeded (in the rain, in a strip mall parking space) to wrap the TFI module and spout connector wires in some tin foil. Since the code I was getting could indicate some interference with the ignition signal from the TFI back to the ECU, e.g. if too close to spark plug wires. Started it up and went a couple hundred feet and it stalled again.
My last resort, before calling AAA, was to once again turn my attention to the inertia switch (inside the warm and dry cabin, that was nice). As I posted before in this thread, I had disconnected the plug and jumpered it, to try and rule out the inertia switch as a possible cause of my troubles early on, however that did not seem to make any difference back then. Then, when I went to plug the connector back into the switch, I noticed my jumper had backed out of one of the two connections, thus no longer providing the circuit that normally the inertia switch does. That was very strange and someone commented that it was indeed strange.
I decided to jumper the connector again, taking the inertia switch out of the picture.
But before I made the new jumper with the one piece of electric wire I happened to have in the truck, I decided to just unplug the connector and see if it would start. It started right up! Without the inertia switch connected, and without a jumper - just like before. Weird, still.
So I made a new jumper, inserted it into the connector and started off once more, this time avoiding the highway and sticking to local roads to continue my journey. I fully expected it would just stall out again within a mile, as I had not let the engine cool off (it all seems heat-related) but to my surprise the engine didn't stall or misfire even once, during none of the remaining 58 miles.
So, to recap: 6 or so trips totaling about 120 miles and not even a hint of the problem, then all of sudden after an hour and a half of highway trucking, the engine just stops cold several times. The only things I was able to do today was"insulate" some wires under the hood (but that did not seem to have fixed anything as it stalled out almost immediately) and then re-jumper the inertia switch connector, thereby taking the switch out of the equation.
But even without the jumper the engine was starting and running?
Yet it was no longer stalling now that I had a secure jumper in the connector. Here's my theory - I think it may be a combination of:
- a bad inertia switch (I can see many of these are sold all the time, they do go bad), AND
- one of the wires to the inertia switch is grounding out somewhere, usually closing the circuit that is normally provided by the switch (or a jumper)
- I did not notice the switch was bad since the wire was grounding out anyway, so with or without the switch, OR a jumper, the truck would just run - most of the time
- explaining why earlier, and today, I was able to start the engine without the switch connected and without a jumper in the connector. Normally that should not be possible
- HOWEVER, sometimes, when the engine gets good and hot, or it shakes a bit, or whatever, that ground that the defective wire 'normally' gets, is interrupted. If the bad inertia switch is connected, the ECU gets the message that the inertia switch has been 'tripped' and shuts off power to the fuel pump, killing the engine
- now because I today inserted a solid jumper, whether the wire grounds out or not, the signal to the ECU is "all is good" and no more stalling
Well that is the only logical explanation I could come up with for what happened today (and earlier in this saga).
Time will tell. Ordering a new inertia switch and going on more test drives, not too far from home this time ...
Oh boy, what can this be?!
I had no tools with me but I was carrying some kitchen stuff including a roll of tin foil. I figured what the heck and proceeded (in the rain, in a strip mall parking space) to wrap the TFI module and spout connector wires in some tin foil. Since the code I was getting could indicate some interference with the ignition signal from the TFI back to the ECU, e.g. if too close to spark plug wires. Started it up and went a couple hundred feet and it stalled again.
My last resort, before calling AAA, was to once again turn my attention to the inertia switch (inside the warm and dry cabin, that was nice). As I posted before in this thread, I had disconnected the plug and jumpered it, to try and rule out the inertia switch as a possible cause of my troubles early on, however that did not seem to make any difference back then. Then, when I went to plug the connector back into the switch, I noticed my jumper had backed out of one of the two connections, thus no longer providing the circuit that normally the inertia switch does. That was very strange and someone commented that it was indeed strange.
I decided to jumper the connector again, taking the inertia switch out of the picture.
But before I made the new jumper with the one piece of electric wire I happened to have in the truck, I decided to just unplug the connector and see if it would start. It started right up! Without the inertia switch connected, and without a jumper - just like before. Weird, still.
So I made a new jumper, inserted it into the connector and started off once more, this time avoiding the highway and sticking to local roads to continue my journey. I fully expected it would just stall out again within a mile, as I had not let the engine cool off (it all seems heat-related) but to my surprise the engine didn't stall or misfire even once, during none of the remaining 58 miles.
So, to recap: 6 or so trips totaling about 120 miles and not even a hint of the problem, then all of sudden after an hour and a half of highway trucking, the engine just stops cold several times. The only things I was able to do today was"insulate" some wires under the hood (but that did not seem to have fixed anything as it stalled out almost immediately) and then re-jumper the inertia switch connector, thereby taking the switch out of the equation.
But even without the jumper the engine was starting and running?
Yet it was no longer stalling now that I had a secure jumper in the connector. Here's my theory - I think it may be a combination of:
- a bad inertia switch (I can see many of these are sold all the time, they do go bad), AND
- one of the wires to the inertia switch is grounding out somewhere, usually closing the circuit that is normally provided by the switch (or a jumper)
- I did not notice the switch was bad since the wire was grounding out anyway, so with or without the switch, OR a jumper, the truck would just run - most of the time
- explaining why earlier, and today, I was able to start the engine without the switch connected and without a jumper in the connector. Normally that should not be possible
- HOWEVER, sometimes, when the engine gets good and hot, or it shakes a bit, or whatever, that ground that the defective wire 'normally' gets, is interrupted. If the bad inertia switch is connected, the ECU gets the message that the inertia switch has been 'tripped' and shuts off power to the fuel pump, killing the engine
- now because I today inserted a solid jumper, whether the wire grounds out or not, the signal to the ECU is "all is good" and no more stalling
Well that is the only logical explanation I could come up with for what happened today (and earlier in this saga).
Time will tell. Ordering a new inertia switch and going on more test drives, not too far from home this time ...