i am 100% sure i got a non-feedback carb, theres absolutly no wires or plugs that could connect to it. the ignition has a vaccume advance on it so im pretty sure its not electronicly controlled. it only has 2 wires going to the coil, and one going to the distributor. i drove it to work and back for the first time yesterday and much to my horror it took 3/4 of a tank. could this be related to timeing or the idle adjustment? my V8 4 barrel carbed trans am gets me to work and back for over a week on a single tank. please tell me this isnt normal gas milage for these engines/trucks?

 

You said that that your distributor has a vacuum advance, and it has a vacuum hose attached to the vacuum advance, correct? Do you have an ignition module attached to the driver's side wheel well? That is the silver box that should have two plugs on it. One of the plugs, which has 4 wires, should be plugged into the distributor, the other plug, with the two wires, is for power to the module. If you have this setup, you have a Duraspark 2 ignition. Probably, whoever had the truck before you, changed it over, as these trucks came stock with the TFI/Electronic Feedback Ignition starting in 1984.
If your distributor has a small square plug with wires, instead of a vacuum advance, you have TFI ignition. Also known as electronic feedback ignition. You cannot run a non-feedback carb with the TFI system. Being that you bought a non-feedback carb. If you find that you DO have a TFI ignition still in place, change it over to the Duraspark 2. The hardest part is getting a wiring harness from a junk yard that is in decent shape. I actually bought one from Ford. The other parts you can get from an auto parts store. BTW, my truck passed emissions with no problems with the DS-2 setup.

Also, if your underhood sticker under is still readable, it will tell you what type of ignition system you are using. Like I said earlier, your truck should have come stock with a TFI ignition. Good luck.

 

yeah, im almost 100% sure i have a duraspark II system and a non-feedback carb. everything works great right now, and i think my fuel guage might be screwed up, because when i fired it up this morning it was at E, after driveing a bit i some how got half a tank. the timeing is next to impossible to set on this thing, seeing as how the fan belt will rip the gun to shreads if you get too close and the fan belts are blocking the indicator. i set it the best i could by sound and test driveing, but i have no clue what its at. do i have to remove the fan to set the timeing or something?

 

No, you shouldn't have to remove anything to set the timing. Your timing indicator should be at about 11 o'clock on the pulley, when you are facing the front of the truck. I hold my light at about the 10 o'clock position, I think. I keep my timing at 6 degrees before top dead center.

 

If the old Feedback carb is rotton and not worth fixing, and you DONT know if the computer is even working anymore, or, if all the additional compter parts are working, then why spend the $300 or so just to get a feedback carb that may or may not work properly?

I think he did the right thing in getting away from the FB version. Mine with the NFB carb is running better than ever, and I ran the FB carb until earlier this year, with no timing advance for over 12 years. It gets good mileage, and has plenty of power for towing vehicles on a trailer up the mountain from South Carolina, which it did about 2 weeks ago.

 

Hey Psyte,

Do you still have the underhood sticker? Also, on the water pump's heater hose outlet tube, do you have a bluish green gizmo(ported Vacuum Switch) with vacuum tubes coming out of it? Or do you have an electronic thing there instead, that has vacuum tubes going to a cluster on the back end of the valve cover? The reason I'm asking is that I noticed that you are in Canada, and I was wondering if the non-feedback/Duraspark II system was still used in the '85 with the I-6. It's very possible. From what I understand, TFI came about because of stricter emissions requirements here in the USA. I do not think that Canada's emissions laws are as strict as here in the USA.

 

Paulz:

You hit it on the head. I never thought about that! He probably didn't have a FB carb to begin with.

 

I hope Psyte still has the underhood sticker, as that would explain everything and satisfy my curiosity. The funny thing is, is that since I changed my '85 over to Duraspark II, it passes emissions better than it did when it had the TFI system. We have pretty strict emissions requirements here in Arizona.

 

sorry about the late reply. from what i can see, there isnt any electronic thing or vacuum ports on the water pump outlets or anything electronic even remotely near the valve cover (other than the ignition components). yes i still have the underhood sticker, but i dont really know what im looking for. it says non-catalyst on the top left side, and has a diagram on the right side that didnt really make any sense to me and some information on setting the timeing and idle speed in the middle. this engine looks about as simple as it can get, the only wires going to the engine are the ones for the starter, and the ignition coil. im sure theirs some for the temperature and oil pressure sensors but i havent come across them yet. im guessing they are somewhere under the engine, or at a lower part. exept for the ticking and occasional popping sound at idle, the engine runs great and fires up at the first turn of the key.

 

Cliffordperformance.com they sell adaptors to mount 2 barrel carbs on the stock intake manifold. I got mine for less than $50 including shipping. You have to measure the distance between the holes where it mounts as they varied through out the years. A good carb to find used is off an older 302 or 351w. The (stock 1 barrel) carbs along with their emissions equipment are a PITA. They are very complicated. 83 was the first year for feedback type on the 300. You can order a new replacement carb from JCwhitney for a pre-73 300-6,, thats pre-emissions. Look around for catalogs from Clifford, broncograveyard, LMC-truck and others. I have owned 8 80s F150s with the 300-6 and by my experience the carbs are nothing but a piece of crap.

 

Hi Psyte,
Does your underhood sticker mention Duraspark-2? Sounds like you do not have any emissions equipment. Do you have emissions testing in Canada? If not, you have an opportunity where you can really get some power out of that 300.
To find out more about your truck, maybe you can try this: write down your vehicle ID number and bring it to, or call, a Ford dealership. Go to, or call, the parts department and see if they can run your vehicle id number to get the information you need.

 

there was no mention of duraspark 2, im sure of that. as far as i know, most major citys around here have emmisions testing, especialy the one i live in. i actualy have both my car and truck insured for kamloops ( same province, but farther east and no testing there)