Hi All,
1980 F150 5.0 c6 2150 2wd ran like a dream for last two years. I would tell myself that 'this is why I dumped so much money in this thing. It should run like this." Well, my worst fear of a stall at at a red light happened and it started back up and no further troubles. My last firing module swap took care of that about 6 years ago. So I went and got a new one. Would not start. Acted like the coil was bad. I just assumed no spark. Took it back by putting in old one to start it up. While there I bought a new coil and 24k gold plated battery lugs because there was some hesitation like needed battery maintenance. Got home put on new battery terminals, new coil, and 2nd new firing module. No start. Put old module back on and it started up. I took 2nd module back and he tested it and said it was fine. I didn't pull existing one off there because I was told they either work, or don't. I stopped at a light and it died. It idled louder/rougher right before then. Started right back up but while giving it gas it acted like it was flooding out. I had to look when traffic had a break in it and threw it in gear and stomped on it. I barely made it home. Acted like the choke was on trying to die. I ran a couple lights and limped it home. By the time i got home it was purring again. I'm still getting that high pitched whine sound after shutoff ever since the temps went up. Thought new radiator fixed that-nope. Lifted the hood, module feels extremely hot-too hot to leave my hand on it. Is this normal? Is the module a sometimes thing that starts failing when warming or warming due to failing, etc.? While at oreilley's I picked up a new stator for the distrib. Could this be a possible culprit? Lastly, could this be a fuel issue.? The 1980 fuel tanks have yet to be dropped-ever. I would drop this old module and take it in to test but they said if it got me there, it's fine. The harness is replaced but with a used one. Can't find one under $100 on line. Maybe will have to fork it up.

 

Check the horseshoe coil connector. A weak connection at the coil can cause all kinds of strange ignition problems. Been there.

Also, if the EGR is sticking open, that will cause stalling and bad idle. It's like a big vacuum leak when they stick open (or won't close all the way.

 

Egr and horseshoe connector. Will definitely check those. Thanks for responding. Does any FTE forum legends out there know whether that module is normally hot after engine warms up? Too hot to leave your hand on it. The fact that it's built with a heat sink tells me heat is a factor. Will the heat make it operate differently/eratic? Thanks for any time taken to reply to this. I'm also starting to wonder more about that temperature controlled vac switch.

 

They do get hot and heat is their enemy.

But reading through your post, it sounds like you are not exactly sure what is wrong with the truck, whether it's ignition or a fuel problem. That it starts right back up after stalling leaves me suspicious it may not be the module. Usually when they die out because of heat, they are dead till they cool off, they won't hit a lick till then if at all afterward.

 

Got it. So I need to verify a non-start with a non-spark. Definitely a heat problem which still could point to egr or tcvs or harness/wire or...yes I'm not exactly sure what's wrong with my truck.

 

A little speck of dirt in the carb can cause it to run rough and stall. The fuel tanks on these trucks like to rust out on top, and those little rust flakes can make their way up in the fuel system. The fuel filter can clog with them, and it has a spring inside it, if it gets clogged the fuel pump pressure will push the filter against the spring and the dirt will start going around the filter, get in the carb needle, and make it flood and run rough.

 

Thank Franklin2. I'm pretty meticulous about filters and replace them regularly. Still, though, that gas tank is 37 years old. There was a five year stretch it sat before I bought it. Then a 5 year stretch that I was putting in $5 at a time always on E and keeping track of miles. The last few years I've always tried to keep it full and despite new engine and a new everything but tranny and carb that says a bunch about the 2150 reliability. Had an accelerator pump leak and installed another gasket. Other than that, just left it alone aside from pre and post smog checks. I prefer a 10 deg. timing advance over the 8 on the sticker. At 10 degrees I need to run a bit richer off idle. It's time to learn how to rebuild a carb. I've had the kit for over a year. Now, go get a big can of solvent and soak it. I figure if it works don't mess with it. I appreciate your input. I've just replaced the pickup in the distributor, the coil wire, and the module on the fender. Will go fire it up and report if that did anything.

 

When it's running rough, go around and take the aircleaner off and look down the carb throat with a flashlight(be careful of the fan). If you see liquid fuel dripping into the engine as it's running or just stalled out, then you do have carb problems. You should not see any liquid fuel unless you stab the throttle and the accel pump shoots two streams into the carb.

 

Will do. Started up nice and ran great sitting there. Sun was sinking and didn't want it on the side of the road at night. My eyes are nearly shot. Taking it out in a few to give it a real test.

 

If you find it runs good, and then starts giving trouble when you hit the brakes hard or go around some sharp turns, then it indeed may be dirt from the gas tank that tends to get stirred up when it sloshes around back there. If you go to rebuild the carb and take the top off, you may find sediment in the bottom of the fuel bowl where it has been coming in.

 

Only went 5 miles but so far so good.