Another EFI to Carb Conversion
Tuned
Joined: Oct 2012
Posts: 440
Likes: 8
I did a MAF swap on my car. Easy as hell, install like 4 new pins (the wires leading to MAF) and relocate like 3 pins already on the car. Took no more than 30 minutes and my car was up and running better than ever. Trucks may be more difficult.
Tuned
Joined: Oct 2012
Posts: 440
Likes: 8
I had thought about doing an EFI to carb conversion on my car. I have aluminum heads, bigger cam, 24 lb/hr injectors, and huge intake plenum. Car wouldn't run worth a damn with speed density. I figured up I'd need approximately $1500 to convert to carb with all new parts, performance parts of course, so your case could be a little cheaper. BUT, I converted to MAF instead for like $400 and had the car running great. Point is, it's cheaper to fix the EFI system than to convert. Also you can dump codes on these trucks and cars with a paper clip.
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
The PCMs in these trucks have issues with the electolytic caps degrading but they're easily replaced, the real achiles heel of any vehicle that is 24yrs old is brittle and corroded electrical wires and connections, I'm now seeing that with my '90 which has developed all kinds of intermittent electrical gremlins so I don't know how much longer I'll be able to keep it on the road. It's one thing when the power windows or locks don't work but when the engine just shuts off while you're driving down the road that's another. I know more than the average guy about the EFI systems in these trucks and the other guys are right it actually is a very simple and very reliable system but I understand your pain with what you feel is now an unreliable truck. I think you should give it another chance though before you throw in the towel, try to learn a bit more about it with help from the guys here and resolve any issues your truck has to make it a reliable driver.
Lead Driver
Joined: Feb 2013
Posts: 5,006
Likes: 72
From: Roseville, MN
....The PCMs in these trucks have issues with the electolytic caps degrading but they're easily replaced, the real achiles heel of any vehicle that is 24yrs old is brittle and corroded electrical wires and connections, I'm now seeing that with my '90 which has developed all kinds of intermittent electrical gremlins so I don't know how much longer I'll be able to keep it on the road. It's one thing when the power windows or locks don't work but when the engine just shuts off while you're driving down the road that's another....
On the other hand, while putting a carb, manifold and HEI distributor isn't a small project by any means, it's a lot less daunting to a lot of us. And the result can easily be a brand new ignition, and an almost completely mechanical fuel system that, while not as good as the EFI system, at least tends to fail gracefully by giving worse performance and almost never just suddenly stranding you.
If I ever swap my truck to a carb it'll be with the idea of doing a big project that will reduce the overall performance of the system but will make it less likely to suddenly stop functioning and strand me.
Posting Guru
Joined: Apr 2011
Posts: 1,119
Likes: 1
From: Hartland, WI
I deal with diagnostics almost on a daily basis, on all makes and models. I'm preferential to EFI since I can watch exactly what every sensor is reading, and know exactly what the computer is seeing. Case in point: Had a Suburban in tonight that was a crank no start. Scrolled through my datastream, found the MAF was reading 2.42 g/sec KOEO. Huh. Should be 0. Unplugged the MAF, fired right up (GM uses a MAP as a redundant). Easy. Do what you feel is necessary to make the truck reliable and easy for you to work on. Techs like myself don't care much to mess with altered vehicles, too many variables.
Posting Guru
Joined: Mar 2013
Posts: 1,726
Likes: 3
I deal with diagnostics almost on a daily basis, on all makes and models. I'm preferential to EFI since I can watch exactly what every sensor is reading, and know exactly what the computer is seeing. Case in point: Had a Suburban in tonight that was a crank no start. Scrolled through my datastream, found the MAF was reading 2.42 g/sec KOEO. Huh. Should be 0. Unplugged the MAF, fired right up (GM uses a MAP as a redundant). Easy. Do what you feel is necessary to make the truck reliable and easy for you to work on. Techs like myself don't care much to mess with altered vehicles, too many variables.
Thread Starter
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Freshman User
Joined: Jul 2013
Posts: 35
Likes: 0
From: St. Charles, MO.
That doesn't add up, a broken EGR sensor won't prevent the motor from running. The only parts that would are the ignition module or a fuel pump and guess what.. you need the same parts to make a carb work unless you go completely stone age and use a mechanical pump and points.. but those things aren't that reliable either.
The PCMs in these trucks have issues with the electolytic caps degrading but they're easily replaced, the real achiles heel of any vehicle that is 24yrs old is brittle and corroded electrical wires and connections, I'm now seeing that with my '90 which has developed all kinds of intermittent electrical gremlins so I don't know how much longer I'll be able to keep it on the road. It's one thing when the power windows or locks don't work but when the engine just shuts off while you're driving down the road that's another. I know more than the average guy about the EFI systems in these trucks and the other guys are right it actually is a very simple and very reliable system but I understand your pain with what you feel is now an unreliable truck. I think you should give it another chance though before you throw in the towel, try to learn a bit more about it with help from the guys here and resolve any issues your truck has to make it a reliable driver.
The PCMs in these trucks have issues with the electolytic caps degrading but they're easily replaced, the real achiles heel of any vehicle that is 24yrs old is brittle and corroded electrical wires and connections, I'm now seeing that with my '90 which has developed all kinds of intermittent electrical gremlins so I don't know how much longer I'll be able to keep it on the road. It's one thing when the power windows or locks don't work but when the engine just shuts off while you're driving down the road that's another. I know more than the average guy about the EFI systems in these trucks and the other guys are right it actually is a very simple and very reliable system but I understand your pain with what you feel is now an unreliable truck. I think you should give it another chance though before you throw in the towel, try to learn a bit more about it with help from the guys here and resolve any issues your truck has to make it a reliable driver.
I'm sure I didn't explain this correctly, but its not that I dislike EFI, I just don' t trust it any longer. Just like you mentioned, nearly every EFI, emissions and ignition connector is either cracked, split or broken. I would be looking at spending an awful lot of FRN's just to get it back to a point where I feel comfortable hopping in and hauling a load of top soil just *****-nilly. Today I do not have that assurance. The advice is well noted but this setup is tired.
Thanks again.
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Senior User
Joined: Jun 2004
Posts: 282
Likes: 0
From: Winchester
Before I get started I would like to state that this conversion is being done and I'm not changing my mind.
This past deer season I drove my stock EFI, 1990 F150 (302) to my hunting spot 200 miles from my home. Did fine on the way there, but left me stranded 100 miles from my house on the way back. I do not carry diagnostic testing equipment, multimeters or test lights with me and only a few tools. I had to call a family member with a trailer to come and haul me back home. So PLEASE, save all of your "why would you convert to carb?" comments out of this post. This is being done. PERIOD!
From my point of view, if being "reliable" means breaking down in the middle of nowhere, guessing at what is wrong with their truck and spending an entire weekend trying to test every single electrical and emissions component on the damn thing, then I don't want reliability. Besides, I only use this truck for hauling stuff around the house and hunting and I am NOT concerned about gas mileage.
With all of that being said, is there a comprehensive guide out there somewhere or has anyone in this group performed an EFI to carb conversion? It seems pretty straight forward, but I would like to see a solution that is both simplistic and functional. And I would like to know where I can find the parts I need to get it done (i.e. throttle cable, coil bracket, etc.)
Any help would be greatly appreciated.
Thanks!
This past deer season I drove my stock EFI, 1990 F150 (302) to my hunting spot 200 miles from my home. Did fine on the way there, but left me stranded 100 miles from my house on the way back. I do not carry diagnostic testing equipment, multimeters or test lights with me and only a few tools. I had to call a family member with a trailer to come and haul me back home. So PLEASE, save all of your "why would you convert to carb?" comments out of this post. This is being done. PERIOD!
From my point of view, if being "reliable" means breaking down in the middle of nowhere, guessing at what is wrong with their truck and spending an entire weekend trying to test every single electrical and emissions component on the damn thing, then I don't want reliability. Besides, I only use this truck for hauling stuff around the house and hunting and I am NOT concerned about gas mileage.
With all of that being said, is there a comprehensive guide out there somewhere or has anyone in this group performed an EFI to carb conversion? It seems pretty straight forward, but I would like to see a solution that is both simplistic and functional. And I would like to know where I can find the parts I need to get it done (i.e. throttle cable, coil bracket, etc.)
Any help would be greatly appreciated.
Thanks!
I converted my 95 Mustang to carb. I got my parts used.
Holley 670 $150
Edelbrock intake $40
Hei Dist new about $100
Fuel pump new 88 ranger low pressure pump , I think about $80 or so
You might be ok with your intank low pressure pump. Your high pressure pump is under the cab. You could install a holley blue pump in place of the high pressure one.
On my mustang for the wiring,I had an extra under hood harness and just cut away the wiring I did not need. That way my gauges all work.
.........and to run the fuel pump I had to ground one wire so it would run with the key in run postion.
You could do this even cheaper than I did. I have seen old 2bl intakes and carbs for under $50 . Good luck with it .
Laughing Gas
Joined: Mar 2006
Posts: 1,164
Likes: 2
From: Tri-Cities, TN
I still haven't heard what transmission the OP is running. That, to me, would be the biggest difference in whether or not the swap is cost effective. Personally, I would repair whatever is needed to get the EFI sorted than go to all the trouble to swap to a carb, but that's just me. Good luck whatever you end up doing!
Tuned
Joined: Oct 2012
Posts: 440
Likes: 8
I converted my 95 Mustang to carb. I got my parts used.
Holley 670 $150
Edelbrock intake $40
Hei Dist new about $100
Fuel pump new 88 ranger low pressure pump , I think about $80 or so
You might be ok with your intank low pressure pump. Your high pressure pump is under the cab. You could install a holley blue pump in place of the high pressure one.
On my mustang for the wiring,I had an extra under hood harness and just cut away the wiring I did not need. That way my gauges all work.
.........and to run the fuel pump I had to ground one wire so it would run with the key in run postion.
You could do this even cheaper than I did. I have seen old 2bl intakes and carbs for under $50 . Good luck with it .
Holley 670 $150
Edelbrock intake $40
Hei Dist new about $100
Fuel pump new 88 ranger low pressure pump , I think about $80 or so
You might be ok with your intank low pressure pump. Your high pressure pump is under the cab. You could install a holley blue pump in place of the high pressure one.
On my mustang for the wiring,I had an extra under hood harness and just cut away the wiring I did not need. That way my gauges all work.
.........and to run the fuel pump I had to ground one wire so it would run with the key in run postion.
You could do this even cheaper than I did. I have seen old 2bl intakes and carbs for under $50 . Good luck with it .
Senior User
Joined: Jun 2004
Posts: 282
Likes: 0
From: Winchester
I was doing a cam swap today and thought about this thread and took a couple of pictures of my harness for you.
http://i77.photobucket.com/albums/j4...ps6305f97c.jpg
above is the stock mustang harness.
http://i77.photobucket.com/albums/j4...ps62c6b299.jpg
This is a after cleaning it up. As you can see I just needed , temp sender, oil sender, tach, 12v running for choke and hei.
Good luck with your conversion.
http://i77.photobucket.com/albums/j4...ps6305f97c.jpg
above is the stock mustang harness.
http://i77.photobucket.com/albums/j4...ps62c6b299.jpg
This is a after cleaning it up. As you can see I just needed , temp sender, oil sender, tach, 12v running for choke and hei.
Good luck with your conversion.
More Turbo
Joined: Dec 2007
Posts: 641
Likes: 3
From: Umicorn UtopiaFantasyLand
Now if only I can find the MAF harness I need, have an A9L computer I need to have reworked(anybody know someone that does that?) and what other parts do we need to accomplish this?
More Turbo
Joined: Nov 2010
Posts: 682
Likes: 15
From: NB, Canada
I agree with the OP to an extent. If I were to build a truck that I wanted to be completely bombproof/reliable, Id build one with a carbuerated 300, Duraspark 2, T18 4 speed, mechanical clutch linkage and a 9" Ford. If something does go, it can always be fixed on the side of the road, when I drove my '79 I always kept a spare alternator, Duraspark module, ignition coil, spare belts, spare hoses, tape, wire ties, and a basic hand tool kit. There's not much else to fail.