1st time poster here and first time Ford truck owner. I just bought a 1984 f350 pickup with 4.9l six cylinder and 4 speed manual and I am working on tuning it up. All of the smog/emissions equipment was removed from the truck when I got it. As I understand from reading through the forum, the feedback carb runs in "safe" mode with the emissions equipment removed, which seems to be the case on my truck. If I revert to an older non-feedback carb, will there be any issues with the engine controle module, ignition system, etc?

This engine seems to run great at highway speeds, and looks like it's going to be a breeze to work on.

Great forum by the way, lots of great information. Just looking for some guidance from those who have already crossed this bridge. Thanks in advance.

 

That is a common upgrade (degrade?) from the feed back carb. Use an 83 or older carb and possibly recurve the dizzy for non-emissions running and you should be good to go.

 

Welcome to the forums! lots of good info and advice here. and congrats on excellent choice of vehicle!

does it have duraspark or TFI ignition? my dad had an 84 that he swapped from a feedback, but he didn't replace the TFI and didn't have an ignition curve because of it...

 

I think it has duraspark ignition. Is there an easy way to tell? I do know that there is a pickup and ignition (module?) at the distributer base where the points would normally be.

 

I believe the '84 had the EEC-IV management system, feedback carb, and TFI ignition. If it has a module held to the base of the distributor with two allen or torx screws that has several (more than 3, I think 5 ot 6 or maybe more, don't recall offhand) wires coming out of the connector, then it's a TFI ignition. You'll want the older Duraspark distributor and ignition module or a Duraspark distributor / GM HEI homebrew using your TFI coil - gofastforless.com <-- I think this is the right link I am thinking of.

 

I just DE-computerized my 86 Bronco. I used an old manual choke Carter for the carb. I then did the GM HEI/ Ford Duraspark ignition. I trashed the ECM and all the wiring. The truck starts and runs AWESOME. The throttle response is great. My feedback carb and TFI ignition worked fine, but the difference now is night and day, not to mention it's a nice simple set up now.

 

My carb gave me fits, and I swapped it all out for an Offy intake, Edelbrock 500 carb, header, and Duraspark dizzy with Summit ign box. I drive it 6 days a week, and haven't been stranded with it in the past 2 years it's been on there. Not so sure I'd pass a smog/ sniffer test, but it runs great & velvetty smooth.

 

Well, I came up with a non feedback type carb. And I'm pretty sure that the distributor in the truck is a duraspark. Looks like it only has 2 wires coming out of the distributor. Is it typical to remove the egr setup underneath the carb when making this conversion? If so, I assume that I just install a plug the exhaust manifold at the tube that connects to the egr?

This is going to be a much cleaner engine compartment when I get done! Thanks for the help guys.

 

i did the hei module on my capri. it works good enough, but is nothing compared to an aftermarket ignition, which can now be had cheap enough anyways.

sound like you have duraspark, as the tfi has a small module on the side of the dizzy. and tfi never has the vacuem advance pod(which you did not mention, it is a dead giveaway) you may be able to use another duraspark module, which are cheap and reliable.

you could also replace the carb, hook up a timing light and see if you have advance.

 

I just confirmed that the distributor has vacuum advance and the ignition module underneath the rotor button, so I assume that it's the duraspark. After I change out the carb, can I just unhook the "computer" that's mounted on the driver's side fenderwell? I figured that with as many wires that are going to it, it would kill everything to disconnect.

 

yes and no.

that would be a duraspark, but the computer you speak of would be the duraspark module(a duraspark box is around 4x4" and about an inch or so thick). I don't recall if the duraspark has independant timing control, but since yours has vacuem advance I would assume that it does. I will do some digging and see if i can find some info or a wiring diagram or something.

 

Welcome to the site! I noticed that no one has yet recommended the most important first step in understanding the intricacies of your new vehicle. An owners manual from Haynes or Chilton is an invaluable tool and as important as a good set of wrenches! My Haynes book explained all the differences in the various ignition systems that Ford used which help you to identify different parts and components, as well as trouble shooting.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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I know lots of folks on the site have removed their TFI ignitions for a Duraspark, but I have had 2 Fords, an 85 and 86 both with TFI, and I think they work fine. You may also have a positive TFI experiance!<o></o>
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I spent my money on other upgrades.<o></o>
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Good Luck!<o></o>
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Thanks Harfend. I just got a Haynes manual. It has a lot of good information. I've learned though, that no matter how much you read and understand, nothing replaces experience. That's why this forum is such a valuable tool! Thanks for all the help.

 

TFI works great as long as the computer is there to advance the timing.

it seems that you do have duraspark, but it is controlled by the computer. i did have a site pulled up a while back on swapping it for a regular duraspark. but i cant find it now. if i do i will post it up, if not i guess you can try searching, but i'll keep looking.

 

I seem to remember that on a GM HEI, the ignition module controls the coil but is not computer controlled. The duraspark seems to have the same components but the wires from the distributor go to into the harness and I haven't had time to trace them. Looks like it would be pretty simple to eliminate the computer (box on the fender well) unless I'm missing something.

By the way, what is the proper way to release the round electrical connectors in the wiring harness? I did manage to get one loose, but it took forever.