new member from GA

[gwotton]

Hello, introducing myself as a new member to the forum. I hope I am posting this message in the correct place! I have a 1984 straight six I bought about 5 years ago. First off, I am a doctor and didn't know the first thing about cars (and don't know too much now). I've enjoyed messing around with this truck and learning some basics after watching hours of youtube how-to videos. So, here's my problem. I just finished replacing the whole cooling system (radiator, water pump, thermostat and housing and even the temperature sensor). However, now the truck is losing power after driving for just a few miles. When I say losing power, I mean the engine just stops. I'm then not able to get the truck to start again right away. It will start again after a few hours however. The truck seems to idle okay, but a little low and I have to rev the gas for awhile until it warms up. I've replaced the fuel pump several times in the past because I thought it wasn't getting fuel to the carb. Anyway, any ideas on where to go from here would be much appreciated.

[ArdWrknTrk]

Welcome!

Unfortunately you've arrived in the midst of our annual gathering, so I expect most of the brain trust is going to be busy today judging trucks, exchanging stories and with the awards banquet.... (today)

I'm not the 300 expert, but it is real interesting that the truck will simply stop, and needs to cool off before it will restart.

Is it that the starter won't turn the engine over?

Or does it turn over fine but won't catch and start running?

Your Carter YFA is one of the simplest carburetors ever.

It should be easy to adjust the choke so you don't have to rev it until it warms up

[grumpin]

Welcome!

[Gary Lewis]

Yes, welcome! Glad you joined.

Where's home? I ask for two reasons. First, we have a map (Bullnose Forum/Member's Map in the menu) and could add you with a city/state or zip. Second, maybe you are close to one of us and we could help.

As for the engine dying, I'm going to guess that's electrical and that you are losing ignition. Jim's question is, as usual, spot on - when you try to start it does it crank but doesn't fire or not crank at all?

I'm not sure when the TFI ignition module was introduced, but that is a module that bolts to the distributor. The 1985 EVTM (Electrical & Vacuum Troubleshooting Manual) shows the 300 had one, but I don't have the 1984 EVTM on the site. I can check after church today to see what the 1984 EVTM shows, but I'll bet yours has one and they are prone to exhibit the same symptoms you are seeing. In fact, Ford lost a class-action suit about that as people had the vehicle dying in the middle of the freeway.

We can get into the fix later if you prove that ignition is the problem. And the way to do that, assuming the engine cranks but won't fire, is to check for spark. The quick and dirty way is to pull a plug wire, stick a screwdriver in the end (or an old plug if you have one), and lay the screwdriver/plug on something metal attached to the engine. If you are using a screwdriver you want the handle to lay on maybe the valve cover and have the shaft maybe .1" away from the valve cover but not touching. If you use an old plug just lay it on the valve cover.

Then have someone crank the engine while watching the screwdriver/plug to see if there's any spark. I don't think there will be, which means the TFI module has gone bad.

Of course, this is while the truck won't start.

[gwotton]

Yes, welcome! Glad you joined.

Where's home? I ask for two reasons. First, we have a map (Bullnose Forum/Member's Map in the menu) and could add you with a city/state or zip. Second, maybe you are close to one of us and we could help.

As for the engine dying, I'm going to guess that's electrical and that you are losing ignition. Jim's question is, as usual, spot on - when you try to start it does it crank but doesn't fire or not crank at all?

I'm not sure when the TFI ignition module was introduced, but that is a module that bolts to the distributor. The 1985 EVTM (Electrical & Vacuum Troubleshooting Manual) shows the 300 had one, but I don't have the 1984 EVTM on the site. I can check after church today to see what the 1984 EVTM shows, but I'll bet yours has one and they are prone to exhibit the same symptoms you are seeing. In fact, Ford lost a class-action suit about that as people had the vehicle dying in the middle of the freeway.

We can get into the fix later if you prove that ignition is the problem. And the way to do that, assuming the engine cranks but won't fire, is to check for spark. The quick and dirty way is to pull a plug wire, stick a screwdriver in the end (or an old plug if you have one), and lay the screwdriver/plug on something metal attached to the engine. If you are using a screwdriver you want the handle to lay on maybe the valve cover and have the shaft maybe .1" away from the valve cover but not touching. If you use an old plug just lay it on the valve cover.

Then have someone crank the engine while watching the screwdriver/plug to see if there's any spark. I don't think there will be, which means the TFI module has gone bad.

Of course, this is while the truck won't start.

I live in Atlanta, GA. My zip code is 30318. Thanks for the initial thoughts. When I start it cold, there is no problem. It is only after a have lost engine power while driving that I am unable to restart it. After a short time driving, the engine loses power. At that time, the engine cranks, but does not turn over. If I leave it awhile, it starts up fine. needless to say, I am not comfortable driving it outside my neighborhood. I will start by testing for a spark. As an aside, I had a friend suggest that it may be an exhaust restriction? I replaced the exhaust pipe and muffler a few years ago...

[ArdWrknTrk]

I live in Atlanta, GA. My zip code is 30318. Thanks for the initial thoughts. When I start it cold, there is no problem. It is only after a have lost engine power while driving that I am unable to restart it. After a short time driving, the engine loses power. At that time, the engine cranks, but does not turn over. If I leave it awhile, it starts up fine. needless to say, I am not comfortable driving it outside my neighborhood. I will start by testing for a spark. As an aside, I had a friend suggest that it may be an exhaust restriction? I replaced the exhaust pipe and muffler a few years ago...

That doesn't really make sense, because it would be stopped up at any time the engine is running, and would go away as soon as you shut it off.

I think Gary may be right and you have the infamous TFI module overheating.

This typically manifestes when you go to accelerate, like merging onto another road and the truck just conk's out.

If this is the case, a new PS TFI module will fix it, but the ultimate solution is to relocate it to the radiator support or inner fender.

[gwotton]

That doesn't really make sense, because it would be stopped up at any time the engine is running, and would go away as soon as you shut it off.

I think Gary may be right and you have the infamous TFI module overheating.

This typically manifestes when you go to accelerate, like merging onto another road and the truck just conk's out.

If this is the case, a new PS TFI module will fix it, but the ultimate solution is to relocate it to the radiator support or inner fender.

How can I locate the module? I'm a novice, but I do not see it mounted on the distributor or on the fender. Am I missing something obvious?

[gwotton]

IMG_3166_(1).jpg

How can I locate the module? I'm a novice, but I do not see it mounted on the distributor or on the fender. Am I missing something obvious?

Update, I just spoke with a guy who did some work on this when I bought it. He said he replaced the distributor with an electronic distributor (pictured above), thus I don't have an ignition module...

[ArdWrknTrk]

Update, I just spoke with a guy who did some work on this when I bought it. He said he replaced the distributor with an electronic distributor (pictured above), thus I don't have an ignition module...

Here's the photo:

You have an HEI distributor, the entire ignition system is there, but they do need WAY more power than is available from the stock Ford wiring.

Perhaps the ignition coil in the cap is overheating?

It's not good to do that repeatedly.

Gary has some instructions for adding a fused relay that will provide enough current.

[Gary Lewis]

Here's the photo:

You have an HEI distributor, the entire ignition system is there, but they do need WAY more power than is available from the stock Ford wiring.

Perhaps the ignition coil in the cap is overheating?

It's not good to do that repeatedly.

Gary has some instructions for adding a fused relay that will provide enough current.

Right, HEI. The instructions are on the page at Documentation/Electrical/Ignition. Then go to the Ignition Simplification tab followed by the One Wire tab. There you'll see a schematic showing how to wire in a relay.

But you might want to check to make sure that the guy that installed it didn't put in a relay. I'd follow the wires coming out of it, the low voltage wires not the spark plug wires, and let us know where they go.

And, you are on the map.