1986 Ford F250 302 EFI to Carburetor Delete 2

[Phillip G.]

Hey fellas! I decided to make a part 2 because part 1 has 55 replies thanks to everyone.  I've decided to cut all the vacuum & ECM wiring out and just rewire and plumb what's needed for a carbureted engine. I've also decided to go with a pre-electronic ignition setup. I've installed Ekhlin points & condenser in addition to an internally resisted Ekhlin IC-14 ignition coil that measures out at 3.5 ohms so that all should be fine.

At Gary & Jim. after I cut out all the ECM wiring and rewired some of the mess the former owner had, the fuel gauge started working. He had that all wrong per my schematics. I believe for now, I'll just use the electric pumps with a pressure regulator until they fail. Then I'll install an eccentric fuel pump. Question, can you buy just a tank sending unit for these single tank trucks?

[ArdWrknTrk]

Sure you can buy a sender.
The issue with '86 is that it has a big bung, so you have to get one for a 351HO/460 that had the mechanical fuel pump.

JBG seems to have them for a decent price.

[mat in tn]

one for a 4.9 will work also. that makes it quite common.

[ArdWrknTrk]

Does the 4.9 have a return, or do they get a 3 port valve and just a pickup, deadheaded again the float valve?

I thought by '86 (big bung) the 4.9 had an in-tank pump..                                            
   

[mat in tn]

there is not a return. the 85/86 has the big opening to be efi 5.0 compatible with the in-tank pump but the 4.9 did not go efi til 87 so 85/86 got the 84 sender in the large plate. single port.

[Phillip G.]

Jim & Mat, I did think I may have to get one for a different engine as I've done that a lot over the years. So, either 351, 400, or 300 for an '86 will all work it sounds like.

Mat, Im missing something here i think. If the 300 in tank sender doesn't have a fuel return port how does that work?

[ArdWrknTrk]

400 went out in '83, so it has the small bung, and won't fit.
If you have a single line (no return) use the 300/4.9 sender.

[Phillip G.]

Yes, I meant to say 460. Mine has duel lines so I'll need to go with the '86 351/460 sender.

[ArdWrknTrk]

This was the distinction I was trying to make, but Mat said I was wrong.  🤷‍♂️

[mat in tn]

well, there may be an added confusion here. the 85/86 4.9 and 5.8 sending unit has a large plate for the large opening tank and it has a single draw fuel fitting. on the 460, there was offered a "hot fuel" circuit with a continuous fuel return. I'm not certain of the years. this was used with an in-tank low pressure pump/sending unit. this is possibly the best example of how to do a carb setup. I'm certain that you can find info on this here in the doc/info.

[85lebaront2]

Mat, the hot fuel handling package was on 460 powered trucks with AC and predominately ones sold in the South. It was introduced not long after the 460 returned in 1983.

The actual pumps are centrifugal rather than gear or vane style and have a very low pressure, 5-7 psi. The are fed 12V during cranking, and then through a resistance wire once running.

[ArdWrknTrk]

My 460 has a mechanical pump WITH RETURN.
The sending unit is 3/8 feed and 5/16 return....

[mat in tn]

soooo many versions. no wonder there are so many questions. I'm still waiting on parts for the 460 that I'm building and being a mixed batch of parts I'm sure I will be having many more questions myself. at least I can get the block painted and parts cleaned and lined up for assembly. this 460 has the mechanical option with a fuel pump block off plate and in-tank pumps. it's like working on a puzzle with three different boxes spilled together.

[ArdWrknTrk]

There were three different versions of Hot Fuel Handling, that I know of.

It all depends on which switch you have, and how the relays and valve were wired.

[Phillip G.]

It's okay Mat. I take what each of you say and come up with the best options based on everyone's knowledge and my own knowledge.

[ArdWrknTrk]

I certainly didn't mean to be critical, either.

Matt brings decades of experience to this forum.

Very few forums have anything but "cool kids" fishing for page views and likes

[Phillip G.]

No sir, I didn't think that at all. I just didn't want Matt thinking he misdirected me. All these year model changes and variations are hard to remember. I know that from dealing with '67 - '72 trucks for so many years. And the older I get, the harder it becomes. Lol

[ArdWrknTrk]

I think the only "sir" here may be Gary!  😄

There sure are a lot of variations and nuances.

That's what's so great about having all the documentation (and even with that, we find anomalies and omissions everyday!)

[Gary Lewis]

ArdWrknTrk wrote

I think the only "sir" here may be Gary!  😄

There sure are a lot of variations and nuances.

That's what's so great about having all the documentation (and even with that, we find anomalies and omissions everyday!)

Wait!  Just because I'm OLD and have lived in the UK doesn't mean I've been knighted.  

But you are right that we find issues with the Ford documentation frequently.  It is the best we have, but it certainly isn't perfect.

[mat in tn]

on many trucks that I see I catch myself saying "what is that doing there?"  a new option? by the time a truck gets nearly 45 years old there are many times it has had to be "fixed" roadside, improved or otherwise.