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EFI to carb conversion

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  #1  
Old 01-22-2012, 02:23 PM
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EFI to carb conversion

I have a 93 f150 that currently has a fuel injected 302. I put 1,500 internaly into this engine and have been fighting electrical problems since that time. i have replaced multiple sensors and performed multiple electrical tests I am a former technician and am currently a heavy duty diesl tech so im not overly stupid but i only worked on gas for a short time so all this EFI and electronic ignition crap is to some extent beyond me. I am now in dire straights witht his truck and have found multiple wires broken, tied off, missing, burned, etc... also multiple vaccum lines broken, missing, etc.

what I want to do seeing as I now have a hole burnt in a piston and two broken vavle stems is to start from scratch with a new long block assembly and work from there up. I DO NOT WANT TO GO BACK TO EFI. but i have a few questions. i have found the basics like the long block, intake, carb, etc... now my big question is how will i hook up the vaccum advanc on the new carb, what should I do about fuel delivery?, what will I do about gauges? can the stock gauges be used or will i need to install custom gauges? any other advise will be gratly appreciated thanks all!!
 
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Old 01-22-2012, 04:42 PM
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Well most of the stock gauges run off of sensors that also go thru the ECU. Going carb will mean you will essentially need to redo all of that. You didn't mention trans but if its auto you would need a separate trans controller (~$500) It sounds like you are better off selling this truck and starting with a different truck.

You could always do a diesel swap...you mentioned you are a HD diesel tech.....
 
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Old 01-22-2012, 05:42 PM
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The Gauge senders in 93 do not go through the ECM, if you have an AOD or manual then there is no need for a trans controller. The AOD does require a throttle valve control system, Lokar is usually a good source.
 
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Old 01-22-2012, 07:39 PM
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Originally Posted by 85lebaront2
The Gauge senders in 93 do not go through the ECM, if you have an AOD or manual then there is no need for a trans controller. The AOD does require a throttle valve control system, Lokar is usually a good source.
Yep, Lokar carries exactly what you need for a AOD to carb. The 2 TV cables they offer just hooks up to a Holley carb, with the auto trans kickdown. Part # KD-2AODHT, and KD-2AODU. They also offer a braket that holds the throttle cable and kickdown cable for a carbed engine.

Also you don't need a trans controller is you have a C6.
 
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Old 01-22-2012, 07:42 PM
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He has a 93 F150 so I don't think he has a C6 or an AOD. Pretty sure it was either E4OD or 4rw70.
 
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Old 01-23-2012, 08:01 AM
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I've got a m5r2 5 speed

Manual all the way haha she's a pretty truck and I've grown attached to her so last thing I wanna do is see her leave me lol
 
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Old 01-23-2012, 08:53 AM
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Well since you got a manual, to conversion shouldn't be too bad.

You can use the factory gauges, but I would also install manual gauges. (Thats how I got my truck setup). Holley sells fuel pressure regulator with a return, if you want to keep the factory pumps working.

If it was me, I'd get a 650 or 700 cfm Holley double pumper carb. It has the electric choke on it, but doesn't use vacuum to open the 4bbl up. (old school)

Do you have single tank, or dual tanks?
 
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Old 01-23-2012, 10:09 AM
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I say go to the wrecking yard or here RJM Injection Tech — Welcome and get a new harness. will cost you little to nothing. as for vacum lines why dont you give us a chance to help you get thru this. going carb raises some uses and you will find yourself spending some cash for sure. also with the motor toast why not take this chance to swap in a 5.8. hell you could get a complete motor and wiring harness from a wrecked rig for probably $500-800. everything will bolt in and plug in.
 
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Old 01-23-2012, 11:14 AM
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I didn't even think about him dropping in a 5.8. That's a great idea.
 
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Old 01-23-2012, 02:21 PM
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the other issue is regardless of which motor you put in there it must meet that vehicle years emissions standards. and if you have visual inspections in your area you can forget about running a carb.
 
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Old 01-24-2012, 12:01 AM
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Thanks!

Well after the advice and some serious thought I think wht I might do is go ahead and keep the efi running just in case they ever do decide to go back to annual inspections here. I like the idea of dropping a 5.8 in. I figure instead of dumping all the money In the conversion I should probably use that money to get a good used engine, all new accessories (steering pumps, alternator, etc...) and I've got some boxes of parts sitting around that I've bought already. I'm thinking of going with a dual electric cooling fan set up also. And by the time that's done I should have a solid truck again.

Dual tanks btw
 
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Old 11-17-2014, 01:58 PM
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300 inline 6 efi to carb conversion

Hi I have a 89 f150 half ton pickup it had a 300 inline 6 efi that was blown I replaced it with another 300 6 that came out of a 79 f150 I had the motor bored .40 and camed i put a holly 600 and 4 barrel intake on it i also placed a manual fuel pump on the motor the carb is new but the situation is that it will crank and idle fine I can go down the road in 1st 2nd and sometimes 3rd gear once it runs about a minute in 3rd gear it starts puttering really bad like its starving for fuel i placed a clear inline filter by the carb and everytime it happens i get out loom at the filter and its empty then I have to turn the motor over about 30 seconds and the fuel returns back into the filter and it will start again. What could stop the fuel flow when it is running down the road but not idling please help
 
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Old 11-17-2014, 04:25 PM
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Originally Posted by mater1991
...What could stop the fuel flow when it is running down the road but not idling please help
Probably too much restriction in the fuel line somewhere between the tank and the pump. At idle you aren't using much gas, so it's not too hard to get enough. But when you start trying to use more the restricted flow becaomes a problem.

Another possibility is that the tank isn't venting well. Again sort of the same situation where it's too hard to pull enough fuel to keep it going under load, but it can soldier on at idle.
 
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Old 11-17-2014, 04:47 PM
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Oh ok I was also told that the electric fuel pumps could cause a problem with the flow if I run a 3/8 line from the tank to the filter before the manual fuel pump could that be possible?
 
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Old 11-17-2014, 07:07 PM
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So you're trying to suck fuel through the non-powered electric pump using the mechanical pump? I'd guess that would provide some restriction, but I have no idea how much.
 


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