I have been combing these forums for any information I can find on this duraspark conversion, I have found alot of information, and quite sure I can do it. Just not sure if I need to or not. Just got the speedo fixed on my 86 f150 with I6 4 speed granny. My fuel gauge has not been working and still is not, however now my speedo is so I can calculate how much fuel I am burning.
So my dilema is, if fuel burning is not an issue should I do the conversion to simplify things further down the road, or leave it as is. I am certain I have almost everything required for the feedback system to work properly, only missing a few things, one or two vacuum lines are plugged off, but should be fixed pretty easily. One thing I am missing, is the coffee can looking thing on top of the passenger side fenderwell, what is it for and what does it do? I know where one is I can get. I have one of the black vacuum tubes coming off of the feedback sytem that I have not figured out where it goes yet(vacuum diagram is almost unreadable), and two lines coming off of the carb or in that area, havent got to take evrything apart yet, and not sure what all of the things are on the vacuum diagram.
Any help would be appreciated. Thanks,

 

It's a vacuum reservoir (VRESER on the under-hood diagram) and stores vacuum for use in low-to-no-vacuum situations (WOT for example).

I call it the fruit juice can (am I the only one who remembers Hi-C in a can?)

Trucks with AC will have another one in addition to the can, it's a grapefruit-sized plastic ball that stores vacuum for the HVAC vents - keeps from flipping from floor to dash to defrost during no-vacuum situations.

For your other questions, pictures with arrows pointing to the devices in question work well, lots of potential for confusion otherwise.

 

Thanks for the info, I will get some pictures up here tomorrow. Thank you so much for the help.

 

HA! I remember HI-C in a can.....
I want to find one of those larger vac res cans for my 2.3L truck. The softball size res just isn't big enough to keep the A/C blowing out the dash on a few hills around here, unless I drop to 4th.

As for the DS2 swap, I only recommend going thru the process when the FFS (feedback fuel system) is having problems, and cannot be repaired. Then, it's only an option when you live in a testing-free zone.
When working properly, the FFS will actually get better MPG, and leave the air a bit cleaner than even the best tuned DS2/reg carb can think of. Of course, the key to the FFS is, it must all be present and in good shape, in order for the entire system to work as designed.

 

As I'm finding out, the EVTM has some good information on the feedback systems, and EVTMs are cheap these days....

EVTM = Electrical & Vacuum Troubleshooting Manual, a Ford-written factory service manual generally available on eBay these days (be sure to get one for your year truck, they're not generic).

 

Thanks for the info, I got the vacuum system set up about 85%. All of my connections are good now, just dont have a vacuum reservoir. There is not one on the diagram, but I know there is supposed to be one there. I will get it later and just tie it into the tree. It runs alot better now, so hopefully i will be ok. I have the tank down now trying to change out the sending unit, so I will be checking MPG's when I am done. Thanks all.

 

I converted an 85 to Duraspark II. Was fairly simple and passed emissions without a sweat. No EGR and only the necessary vacuum plugged in. still has smog pump but only one cat.

 

The vacuum reservoir needs to be hooked in properly. There is a vacuum line that runs from manifold vacuum over to a tee fitting, but before it gets to the tee there is a check valve in the line. So the supply line with the check valve feeds one leg of the tee, one leg of the tee hooks to the reservoir, and the last leg of the tee feeds the line going to the pass side firewall that feeds the HVAC controls. If you don't hook it up properly, it's not going to do any good. Without the check-valve, the engine will drain the reservoir of all vacuum when you are pulling a hill, rendering it useless.

 

Here's my vacuum hose diagram, the check valve Franklin is referring to is red.