DS I vs DS II conversion

[Danny G]

OK so the long term plan has been to convert from feed back/computer to Duraspark II.

This comment was made on someone elses thread on the FTE boards:

"you could go to a DS I system and get the benefits HEI and no ballast resistor. Plus you can retain and take full advantage of the TFI coil. "

What do they mean by taking full advantage of the TFI Coil, is a DS I conversion really easier/better than doing the DS II swap with GM HEI module?

Is there any inherent benefits to one over the other? I have an 86 and also read rumor that the DSII provisions may already be present.

[ArdWrknTrk]

The connectors and resistor wire are already present in the trucks harness.

To convert to DSII you need: the module, distributor, coil, and the harness that connects the three.

The efi coil doesn't work as well as the dedicated DSII coil because of resistance vs the load switching transistor in the module.

~

I also expect without the resistor in the DSII harness, the *older can type* coils become saturated and heat up.

(I don't think dwell is limited in the DSII system)

Bill Vose should have all the details, but that is my shade tree interpretation of my own observations.

 

[ArdWrknTrk]

I think the main benefit is they are not only rugged, reliable and stone simple, but that parts are on the shelves of almost every parts store in the nation.

Though, this is beginning to change.

As new chain stores pop up, they never bring in that inventory, because it's so out of date.

[85lebaront2]

I think the main benefit is they are not only rugged, reliable and stone simple, but that parts are on the shelves of almost every parts store in the nation.

Though, this is beginning to change.

As new chain stores pop up, they never bring in that inventory, because it's so out of date.

I will get back to you on this thread later, I have to take advantage of a reasonably warm day and get some things done.

[Gary Lewis]

I have to take advantage of a reasonably warm day and get some things done.

Good idea, Bill. It was 46 when I got up at 5:30 this morn, but it is 33 now and headed to 15 tonight. And it sleeted a bit ago so my trailer is covered. I sent the weather your way.

[LARIAT 85]

OK so the long term plan has been to convert from feed back/computer to Duraspark II.

This comment was made on someone elses thread on the FTE boards:

"you could go to a DS I system and get the benefits HEI and no ballast resistor. Plus you can retain and take full advantage of the TFI coil. "

What do they mean by taking full advantage of the TFI Coil, is a DS I conversion really easier/better than doing the DS II swap with GM HEI module?

Is there any inherent benefits to one over the other? I have an 86 and also read rumor that the DSII provisions may already be present.

DuraSpark I and DuraSpark II were both released in 1977. DuraSpark I was only used on vehicles sold in California, where emissions standards were tighter. The other 49 states used DuraSpark II.

DSI is supposedly "better." But I don't think you would notice the difference between it and DSII. The DSI ignition modules are about twice the cost of a comparable DSII module. Reliability was so bad with the DSI modules, that Ford mechanics apparently referred to it as "NeverSpark."

DuraSpark I was replaced with DuraSpark III in 1980 for California vehicles. Since it was only used for a few years and only in California, you are *not* likely to find a replacement DSI module in stock should you need one.

Duraspark II proved to be much more reliable, which is why it was used right up until 1991. Therefore, replacement parts are much more plentiful and more likely to be in stock.

There would be no advantage (and no reason) to use a GM HEI module in place of a Motorcraft DuraSpark module.

[Danny G]

The connectors and resistor wire are already present in the trucks harness.

To convert to DSII you need: the module, distributor, coil, and the harness that connects the three.

The efi coil doesn't work as well as the dedicated DSII coil because of resistance vs the load switching transistor in the module.

~

I also expect without the resistor in the DSII harness, the *older can type* coils become saturated and heat up.

(I don't think dwell is limited in the DSII system)

Bill Vose should have all the details, but that is my shade tree interpretation of my own observations.

It seems like a straight forward, almost plug and play swap. I remember reading some where (ill check when I'm ready) about a company that has distributors ready to go. Looks like the harness is available as NOS or as aftermarket from painless, coil and the GM HEI.

[ArdWrknTrk]

The connectors and resistor wire are already present in the trucks harness.

To convert to DSII you need: the module, distributor, coil, and the harness that connects the three.

The efi coil doesn't work as well as the dedicated DSII coil because of resistance vs the load switching transistor in the module.

~

I also expect without the resistor in the DSII harness, the *older can type* coils become saturated and heat up.

(I don't think dwell is limited in the DSII system)

Bill Vose should have all the details, but that is my shade tree interpretation of my own observations.

It seems like a straight forward, almost plug and play swap. I remember reading some where (ill check when I'm ready) about a company that has distributors ready to go. Looks like the harness is available as NOS or as aftermarket from painless, coil and the GM HEI.

The distributor socket is the only one not easily available.

And that one can be rigged by using a four pin socket from the Motorcraft pigtail catalog and removing one pin and a clocking fin sticking inside the socket.

In one of my posts I compared the $ Painless harness to readily available parts..... Just like I did with the 3G conversion parts...

It irks me when a "kit" costs more than double what all the bits do.

But then, I like rooting around for stuff and tinkering with it.

I haven't seen a NOS DSII harness, but IDK the part number either.

[85lebaront2]

The connectors and resistor wire are already present in the trucks harness.

To convert to DSII you need: the module, distributor, coil, and the harness that connects the three.

The efi coil doesn't work as well as the dedicated DSII coil because of resistance vs the load switching transistor in the module.

~

I also expect without the resistor in the DSII harness, the *older can type* coils become saturated and heat up.

(I don't think dwell is limited in the DSII system)

Bill Vose should have all the details, but that is my shade tree interpretation of my own observations.

It seems like a straight forward, almost plug and play swap. I remember reading some where (ill check when I'm ready) about a company that has distributors ready to go. Looks like the harness is available as NOS or as aftermarket from painless, coil and the GM HEI.

Ford built the 1985 and 1986 front chassis harness to be able to accommodate several systems, the plain DSII system, a feedback carburetor system or EFI on the 5.0L engines if you look at the left side wiring harness you will see several plugs, some of which seem to make no sense. The DSI and DSII systems along with the computer controlled DSIII require a ballast resistor in the coil feed. This is bypassed during cranking for a stronger spark with the resulting lower system voltage. Ford started some time in the 60s doing away with the resistor block next to the coil and replaced it with a resistance wire, older vehicles had it as a plug in piece in the dash harness. The extra small terminal on the starter relay, the one with a I is the resistor bypass wire on these.

On the 1985/86 trucks, if you examine the ignition circuits you will see a resistance wire between terminals 11 and 12 of the ignition switch. Terminal 11 is hot in run, terminal 12 is hot in start. When the engine is cranked the R/LG ignition feed is powered through the resistance wire from the BR/PK wire from terminal 12 of the ignition switch, this powers the + side of the coil though connector C325 and through the resistance wire the W/LB wire to the R DSII wire. The diagram shows 3 wires to connector C321 (3 pin) on the DSII module, I believe that only 2 are used if I remember correctly, the R/LB to the W and the W/LB to the R, I do not remember a R/LB to a R/LB as it shows. Once the engine starts, and the key is released the coil is still fed by a R/LG wire, but through the resistance wire, the DSII is now receiving full 12V from the W/LB wire to the R wire. C323 on the DSII is the distributor pickup, system ground and ignition coil -.

On the EEC engines, the W/LB and the R/LG wire are connected together in the EEC harness which plugs into C321 and C325, this way the TFI ignition always gets full battery voltage as the resistor is simply bypassed during cranking and running.

In order to install a DSII on your truck, you need a DSII module and the distributor and the wiring from the distributor to the DSII module. If you insist on listening to the HEI crowd, to make it really work properly it needs a #10 wire that can be fed from the battery with a relay as the HEI is a current hog. This can be done using the wiring from the EEC/TFI feed that tie the W/LB and R/LG wires together and use them to turn on the relay, and if you are so inclined, use a late model oil pressure indicator switch (closed with pressure) to ground the relay, that way if you lose oil pressure, either from a failure or engine stall, the ignition feed to the HEI is cut off.

[ArdWrknTrk]

Ford built the 1985 and 1986 front chassis harness to be able to accommodate several systems, the plain DSII system, a feedback carburetor system or EFI on the 5.0L engines if you look at the left side wiring harness you will see several plugs, some of which seem to make no sense. The DSI and DSII systems along with the computer controlled DSIII require a ballast resistor in the coil feed. This is bypassed during cranking for a stronger spark with the resulting lower system voltage. Ford started some time in the 60s doing away with the resistor block next to the coil and replaced it with a resistance wire, older vehicles had it as a plug in piece in the dash harness. The extra small terminal on the starter relay, the one with a I is the resistor bypass wire on these.

On the 1985/86 trucks, if you examine the ignition circuits you will see a resistance wire between terminals 11 and 12 of the ignition switch. Terminal 11 is hot in run, terminal 12 is hot in start. When the engine is cranked the R/LG ignition feed is powered through the resistance wire from the BR/PK wire from terminal 12 of the ignition switch, this powers the + side of the coil though connector C325 and through the resistance wire the W/LB wire to the R DSII wire. The diagram shows 3 wires to connector C321 (3 pin) on the DSII module, I believe that only 2 are used if I remember correctly, the R/LB to the W and the W/LB to the R, I do not remember a R/LB to a R/LB as it shows. Once the engine starts, and the key is released the coil is still fed by a R/LG wire, but through the resistance wire, the DSII is now receiving full 12V from the W/LB wire to the R wire. C323 on the DSII is the distributor pickup, system ground and ignition coil -.

On the EEC engines, the W/LB and the R/LG wire are connected together in the EEC harness which plugs into C321 and C325, this way the TFI ignition always gets full battery voltage as the resistor is simply bypassed during cranking and running.

In order to install a DSII on your truck, you need a DSII module and the distributor and the wiring from the distributor to the DSII module. If you insist on listening to the HEI crowd, to make it really work properly it needs a #10 wire that can be fed from the battery with a relay as the HEI is a current hog. This can be done using the wiring from the EEC/TFI feed that tie the W/LB and R/LG wires together and use them to turn on the relay, and if you are so inclined, use a late model oil pressure indicator switch (closed with pressure) to ground the relay, that way if you lose oil pressure, either from a failure or engine stall, the ignition feed to the HEI is cut off.

^^^^What he said

Gary, this needs to be the DSII tutorial.

Bill is thorough and concise in his description of the components and function of the system that powered hundreds of millions of Ford vehicles between the mid 1970's to 1990

Bravo Bill!