For the past few days, my pickup (77 F150 4x4 3spd 400) has randomly died while in a variety of conditions. It has done it driving through town, at idle in a parking lot, on the freeway, and stopped at a light. basically it shuts off all of a sudden as opposed to lugging and sputtering. It takes a few tries to start it back up (5-6), while normally she fires right up in the morning and through out the day. Last night I replaced the Ign. coil and inspected all relevant wires. When I got the pickup, it had a new control module (maybe called an ingition module?) on the front seat, I replaced the old one with that and kept the old one with me. Anyway, today it died driving through town (20 mph) after driving fine for 45 minutes the night before after replacing the coil. I got her to start and continued my way to work (30 minutes, freeway). She drove great, but cut out again opnce I pulled into my parking spot. She did not want start, so I quickly replaced the new control module with the old one and she fired right up. was/is the module my issue? is something making the module act up? I have searched the forum and found a lot on the topic, but I guess I need special advice, thanks!

 

Sounds like it. What you are describing is the typical "death throes of the duraspark module". You might want to get another one and keep it in the truck just in case, get a real Motorcraft one, not a knockoff. The Motorcraft ones are much more reliable.

 

Heat is the killer of these modules. As n91hm stated, get a new, high quality unit. When you mount it place a small spacer between the module and the inner fender, helps air circulate around the module.

 

Thanks, I'll look into getting a motorcraft module and ensure there is plenty of space for it to stay cool. I hope this fixes any issues, if not I'll pick your brains some more (I appreciate the help, thanks)

 

It seems a lot of people assume someone has a Module with no space behind it when mounted.

I like to ask instead.

Did the other IM have a 1/4" of space behind it ?

There are many variables with these ignition systems .

Like corrosion on terminals/connections.
Make sure ALL connections are clean and secure especially right at the distributor.

The Ignition system needs a MINIMUM of 8.2 volts to run the engine.
Very rarely do coils go bad unless they have been hooked up to 12 volts instead of the OEM resistance wire.
Excessive Heat Kills Coils.
They are also very easy to test.

 

Thanks Mil1ion, I will re-check all of the wires heading into the distributer, and both of the modules are from NAPA and seem to have a built in space behing them. Three bolts secure it at the corners/middle, and the middle is raised away from the wheel well area. Would bad/lose/corroded wires cause this intermittant (sp?) stall? Some more information, The truck had some serious wiring issues when I got it with people bypassing this and that and splicing here and etc, do you think that there may still be some of that going on that I haven't identified yet that may be causing my problem? thanks

Dan

 

When it comes to wiring anything is possible.

I had a wire that is part of the distributor harness fraying and 2 strands of it were occasionally touching a metal part causing intermittent ignition problems.

Vibration was the biggest culprit.

Once I started investigating ...It took me about 5 minutes find the problem.

It was just that " Quick Visual Inspection" that happened so many times leading up to the "Precise Inspection" solved nothing.

 

I havn't totally Isolated my problem, but with the help of Mil1ion "Dennis"; I beleive I've narrow my similiar problem down to the wires on my coil connector. The red wire was very fragile hanging on / half way torned and pulled apart real easy the other night when I was checking my coil. Mil1ion recommendation of checking the small ignition wires; will elimate numerous potential faults. I also recommend having your module check; prior to purchasing one.
Additionally; I mention the coil connector for 75 & later models, (don't know the exact years installed after 74). I couldn't find one parts supplier to sell one, and had to revert to salavage yard hunting. And there is a very limited supply around my parts and the risk of working correctly. Tommorrow I'll update if the coil connector on my recent post was the culprit on my 78 model.
Just though I would mention this..

Mitch

 

Thanks customcab. My positive wire on the plastic cap that connects to the coil is also exposed/weak. I think that the previous owner opened up to test/bypass something leaving the copper exposed. I guess that could be my culprit?

 

I've learned from Mil1ion, aka Dennis; those little wire's are a common cause and need to be checked. I started a post similiar to yours, where my 78 would die after a short distance. Sometimes start right back up on first try, then several try's. I first though the electric module was bad. I pulled it and had it tested at the zone. I also though maybe my fuel filter; so for preventative maintenance I change it ($1.99). But it wasn't any change in it. Sitting idle my truck ran just fine; but I guess the road bumps, vibration's while driving is where I would stall. My red wire was very weak and slightly torn.
So many area's to trouble shoot...



Mitch

 

I just wanted to provide a quick update, as I like to be able to see what resolved issues when I am searching the forum. For its been three days now and the pickup has been great. I'll keep an eye on it, but it appears that the ign module change has fixed my problem. I will take the other module in and have it tested just to see what it says.
thanks to all.

 

Thanks to all for your help thus far. I need some help diagnosing a fuel issue that is popping up. I have the main seat tank and an Auxiliary tank in my 77 150. Five times in the last week the truck has begun to sputter ( three times at freeway speeds, another two in town) and act as though I am running out of gas. I quickly switch to the Aux tank and resume as if nothing happened. A minute or so later I will switch back to the main tank and run fine until the next episode (a day or so later).
The gauge is bad for both tanks, the main tank doesn't read at all and the Aux tank shows between 3/4 and 1/2. I do think that the switch is working appropriatly however, and actually switching tanks when I want it to. The qauge issue doesn't need to addressed, I just wanted to give you all pertnaint information to my problem. I know there is already plenty of posts to read about gauges.
The truck sat for six years until about a month ago. I used two cans of that SEA FOAM in each tank and filled them up with premium. I driven over 500 miles so I have probably flushed the system of all the old gas. I replaced the fuel filter under the driver side door and a bunch of cracked fuel hoses. There is no fuel filter leading into the carberator, should I add one?
Sorry for the long post, thanks

PS I will be away from the computer until monday that is why I tried to give you as much info as possible, I won't be able to answer questions.
Thanks for you time, I appreciate it.

Dan

 

Fuel filter under the drivers side door? That sounds like someone added in inline filter. The fuel line to the carb has a short neoprene hose leading to the screw in filter. Every 1967/79 truck had one originally.

Never seen an undercab inline fuel filter till the electric fuel pumps came out in the 1980's.

Each gas tank sending unit has a float and FILTER. The filter slips over the neck of the pickup tube and is a mesh design made of plastic.

The floats are two pieces of copper soldered together, solder breaks down, gas leaks in, float settles.

D1AZ-9A011-A .. Filter Screen
C0AZ-9202-B .. Float
C0AF-9276-A .. Gas Tank Sender Gasket

 

There isn't a fuel filter in the OEM system until the carb on a mechanical fule pump system.

I installed a generic Fuel filter just before the pump and there should be a filter right at the carb fuel inlet and it works fine.
If there isn't an carb fuel fliter put one in.

fuel system.

 

What do you guys think is causing the random sputtering while on the main tank that goes away after switching to the Aux? crap in the tank that covers the pickup tube?