As far as I know, all of the emissions stuff on my 83 F150 (300 I-6) was working. Yesterday, I broke the Cold Weather Modulator (little round vacuum gizmo that mounts inside the breather). Unable to find one, I just disconnected everything and capped off the vacuum lines. I capped off the vacuum line going to the AIR pump. I did not remove the AIR pump or the belt that drives it yet (really snowing out and temps are cold). Will I be o.k. to run it like this until I can remove the AIR pump?
Secondly, with this stuff removed, will the damper door in the snorkel on the breather continue to operate? There are two hoses going to the bi-metal valve. One comes from the carb to the bi-metal valve in the top of the breather. Another comes from the bi-metal valve to the vacuum motor that controls the damper. I left these intact (or would I be better off to disconnect this stuff as well)?
Not sure, but it does seem to have lot more power with this stuff disconnected. As a side note, the EGR valve is nearly new. If anyone needs it and has a EGR block-off plate, I would be willing to swap.
Thanks in advance!

 

Forgot to mention, this a carbureatored engine that does NOT have a computer. Hope this helps!

 

if you really want to remove the emissions stuff, go all the way. just be warned, when the enviro ***** institute universal smog checks, you'll have to add on later. but if your truck still had the original eq on the smog, if it was still working at all it was robbing tons of power. spend some time when it warms up to remove all of the equipment, that should make everything easier.
i pulled all the eq on mine, and since my vacuum lines were all rotted through, i left it that was for 10,000 miles. i'm replacing a few when i finish the rebuild... maybe.... (mechanical choke, mechanical secondaries, and looking at mech advance DUI distributor) i didn't have any real problems, aside from mileage suffering from the lack of vacuum advance

 

The vaccuum lines going to the distributor are still intact. I'm guessing that they still work. The lines run from the distributor to the carb and I assume operate independently from the smog stuff (?).

 

you're on your own on vacuum lines, i wish i could be of more help. they should operate fine, as long as you plug all other vacuum sources.

 

i eliminated my emissions with an Offy, Holley, EFI manifold combo. My trucks never ran smoother or better. Only two vacuum lines, one for the PCV and one for vacuum advance on the dizzy.

 

Ok, so i have an 85 4.9 with smog/egr removed (way i got it). The Vacuum sensors are disabled too. With this, is there any way to continue running with some adjustments or minimal vac hookups using with stock carb and TFI distributor for best performance or fuel economy? ive gone through forum but answers seem vague. Only because I dont think i have all the parts. Clearly i would have to get vacuum dist. and id rather not mess with the system more. But i picked up some EFI manifolds and i will eventually do Offy but i want to pass emissions at least

thanks,


If you cant find em' grind em'

 

I have an 86m I have been eyeballing that Offy DP intake and a bolt on EFI system myself.

 

You probably have a feedback carb like me. You either need to restore the vac lines per the diagram next to the radiator or do a dura spark conversation to eliminate the computer control. That is what I have gathered so far. I do not have an air pump and the tube to my cats are disconnected. I have restored everything else by finding g NOS parts and buying new silicone vac lines.

 

Hey mountaintruck,
You'll probably have a tough time passing emissions without doing some work to that system. The issue you're going to run into is that the carburetor was computer controlled, as was the timing. Without the proper sensors in place, computer is going to make the carburetor run rich (a safety "LIMP" mode) and prevent the distributor from advancing the timing.

Since you eventually plan on going with a 4bbl carb and the EFI manifolds (which I have passed emissions with easily), I'd at least look into getting a proper ignition to match your setup, since the TFI will not work with either. Either a DuraSpark II or something aftermarket that works off of a vacuum advance. This will help a lot with getting the system to run properly.

Then, from what I've heard, you can remove the solenoids on the feedback carb and use pliers to grab and adjust the idle mixture.

That should get you close.

 

I have a parts truck i was trying to steal the harness off of as it had all the components i needed to mostly restore system (my harness was all hacked up) however most of the insulation is rotted so thats junk unless i splice new stuff; not worth it; i feel stuck with needing conversion. I do have an EGR and pump now though. A side note: I dont even has cats on mine. I think, as strange as it sounds, that this is how it came. I will have to add that at some point.

Thanks!

Hey AbandonedBronco,

I did do some more reading and what you say confirmes this. I just have to get a tractor first in order to remove my head from rear end to get it done right. I wasn't excited to "downgrade" per se to an older setup just because i didnt want to mess with emissions stuff. I was also just concerned whether its more fuel efficient than "functioning" stock setup with emissions. Some users say yes the stock is engineered for it best mpg and others say no that its restricting the system and numbers seem to back it up, But that answer is maybe on another thread, probably. Im glad you pass emissions with your setup. That makes me more confident in my own conversion /removing emissions stuff.

Anyway, have been looking into vacuum dizzy and its like $50. Slap it in there, time it, then bolt manifolds on there and adjust the carb. Just saw your post on a DSII conversion thread BTW (lol) I will see how that works until i can kick out the pile for a new intake/ carb. Your system is pretty close to what im aiming for. Sidetrack: What site did you get your offy?

Thanks!


If you can't find em' grind em'

 

Just to note, the one piece of emissions equipment I do have is a catalytic converter. Not sure you can get away without that.

I definitely wouldn't consider swapping out your ignition for the DuraSpark II a "downgrade". It's considered one of the more efficient and reliable setups you can get. The TFI and feedback carb setup was more of "bandaid" before they could make the switch to fuel injection. It was only used for 3 years.

On your '85, the Duraspark II setup will be plug and play. You'll at minimum need the distributor and ignition module. You'll also need a wiring harness and can either find it in the junk yard, buy it new, or just wire it up yourself if you're okay with that. I made a wiring harness for my setup pretty easily as there's plenty of schematics around. If you get a stock wiring harness, you'll either need to get the correct year coil, or rework the wires to match yours. Not too hard.

I got my Offy DP intake used off of eBay years ago, and then traded it for the Offy C with another member here on the forums. So, I never bought one new. They seem to be jumping up in price about $25 - $50 every six months to a year now, so I'd keep an eye out on eBay, or buy a new one sooner than later, so the price doesn't go up again.

.

 

Yeah, i will add the cat once i modify for the efi manifolds. As far as the harness i would rather get original or new. I have no problem with soldering cables together but, ya know. Where would you buy new (i cant find online)?

 

https://www.ebay.com/itm/Painless-Wi...ca5fc2ec4b4392

 

https://www.summitracing.com/parts/a...oaAmthEALw_wcB



If you use a different aftermarket coil (most of them come with screw/nut posts), then you'll need to just cut off the coil "horseshoe" clip, and wire on some connectors. No big deal.