I see a lot of members in here ripping out there TFI ignitions in favor of an earlier Duraspark ignition. Is the Duraspark ignition really a better ignition system than the later TFI ignition system to be considered an "upgrade?" If so, why is it better?

 

It's not a upgrade. The TFI requires computer control to run it properly. The duraspark II is a stand-alone system. When a person decides not to continue trying to keep the computer system going, they revert back to the older system that does not require a computer, which is the duraspark II system.

 

Also, parts to keep the TFI system can get expensive and hard to find sometimes. A Ford TFI ignition module cost $190. You can get cheaper ones at NAPA or other parts stores but there quality is questionable. Mine lasted less than a year (less than 1500 miles), but don't know for sure a Ford one would last any longer.

 

Before you install the TFI ignition module (the one that mounts on the distributor), you are supposed to smear a film of di-electric grease on the back of it. This is essential to keeping the module cool and the life of the module. The distributor was not a good place to mount these, and from what I have read here Ford had a major recall on this. Ford finally moved the ignition module in the 1990s to another part of the engine and mounted it in a heat sink.

As for Duraspark being an "upgrade," I would say it is more a step to the side, but certainly not a step down. The only reason people (myself included) replace the TFI ignition for a Duraspark is to get rid of the infamous feedback carburetor/EEC-IV/TFI ignition system that was used from 1984 - 1986. When you replace the feedback carburetor with a conventional or aftermarket carburetor, the TFI ignition system reverts to a "limp home" locked state because the EEC-IV computer doesn't know what to do without the input from the carburetor. This hurts both economy and power, so retrofitting to an earlier Duraspark ignition is a popular "upgrade" because it restores the function of ignition timing, as it doesn't need the EEC-IV engine computer and all of the other associated sensors that went along with the feedback systems. Duraspark is a stand alone electronic ignition system that was used right before the feedback carburetor, (and later electronic fuel injection) came out.

You could not run a Duraspark ignition with later models that had electronic fuel injection.

 

I did but what I'm getting doesn't seem to be heat related. It backfires and dies about 5-10 minutes after I first start driving for the day. After about 10 minutes tiring to restart it, have it backfiring and dieing it will start up and run fine the rest of the day. Haven't had the chance to pull the codes yet, hope to do that today, but figure it will be the TFI again. That's what it was doing to my brother in law when I got it and the TFI cleared the codes and it ran fin until the other day.

 

I agree fully with what Lariat said, with the minor exception that feedback carbs were used as early as '82 on the 351W's, although those were DS-III and not TFI.

And, to underscore what Lariat said about changing out the feedback carbs w/o changing the ignition system, whether DS-III or TFI, that had been done to my '82 when I got it. And, oddly enough, neither the used car dealership nor the guy that purchased it from them could get the truck to run well at all. I swapped a DS-II for the DS-III and pulled the computer system and that helped immensely.