'88 W100, what's needed to convert to carb & vacuum distributor?

So, upon having my sons truck diagnosed by a shop, they told me that the ECM was fried. The mechanic is going to call me to discuss further, so info isn't lost in translation from him, through secretary, then to me.

So, basically I was told so far that the mechanic wants to "bypass" the ECM. This was an early idea that I had. IF we end up going this route, what are all systems/considerations that will be effected?

I'm thinking the following will be needed:
-Carbureted intake manifold
-carburetor
-vacuum advance distributor
-fuel pump

I didn't see much of a reason to run a high pressure fuel pump, then regulate it back down to a carb friendly pressure, just to have the potential of a fuel regulator failure causing carb flooding issues! So, either a mechanical or electric fuel pump (I'd prefer mechanical).

Might be a good time to add an "RV" cam & new lifters to the mix, along with a new timing set, as the timing chain has likely stretched, having 154,000 miles on this 318.

What about the transmission? This transmission is a Torqueflite 727, I believe it to be of the non-lock up variety, but I don't know why I think that. I may have looked it up when looking for a transmission rebuild kit and torque converter.

I'm not inquiring about smog laws, or looking for a discussion as to the merits of anything related. I'm simply asking what it would take, mechanically, to get this 1988 318/727 setup to run and function as a NON-computer controlled engine, with a vacuum/mechanical advance distributor, mechanical/electric fuel pump and a carburetor.

My biggest concern would be with the transmission, depending on how much control of it the computer has. I know that it's possible, as guys are putting 3rd gen Hemi's/545RFE's (or whatever trans) and LS based engines and 4L60-e's into new Jeeps and old hot rods. So, how much does it take?

Thank you in advance for any help! I'm searching and reading as we speak!

Nik

are you sure the computer is bad since it didn't sound like it in your other post. personally i would try to get the fuel injection working like it should. with carbs they are simple in some ways but with the way most fuels are these days you are bound to have issues. it is really just a matter of time. you will also need external voltage regulator to control the alternator. i would also just use the electric fuel pump and a regulator. it keeps the fuel system simple. get a regulator with a gauge on it. i had a gauge on my truck fuel line between the pump and carb to see what it was doing before i went fuel injected. the only thing you got to hook up to the tran is the kickdown linkage.

I avoid at all costs outsourcing any vehicle repairs to mechanics. According to the mechanic that has diagnosed it, after throwing a few more parts at it, he is convinced that it is the computer. I see that Summitracing.com has a reman computer for it for $130. I might try that, just to see if it works, then look at going carbureted. I have multiple older trucks that are carbureted and have no issues. I agree that today's fuel is less than ideal, but I'm kind of at my witt's end trying to diagnose this thing. Part of me is relieved that the mechanic is also having trouble identifying the issue, but I really wish that it was something little.

I have had a couple fuel related issues with my carb. If you access to ethanol free fuel and are willing to run it all the time then you might be ok but it seems like it is becoming harder to find. If I was having better luck with my fitech system I would recommend it but I seem to be having quite a bit of bad luck with it especially now that it is starting to get stupid cold out here.

Yeah, I've purchased a Fitech system in the past, but upon hearing about the troubles that some friends have had, I kept mine sealed in the box for a while, waiting to see how some tuning issues worked out. After 3/3 friends experienced issues that made them regret ownership, I returned mine. I have had zero fuel related issues with either of my carbureted vehicles.

Well, to give a little more information for others that may be considering going down this same path, I towed the truck home. I pulled the front accessories off of the truck and inspected the timing chain. With the standard being 1/2" of slack in the chain, we were FAR out of spec with over 1 1/2" of slack in the timing chain. So, my son and I pulled the old clapped out timing set and installed a new double roller timing set. We resealed everything and are nearly finished up with that portion of the job.

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you can do the timing chain on my truck also lol. i wouldn't be surprised if there was that much slack or more. i also got a coolant leak between my timing cover and block and need a new water pump lol. i have been putting it off.

I was not excited about taking the job on, but it was actually pretty quick and went very smoothly.

if it was summer time i would completely agree but it is too cold out here to tackle anything like that. 0*F but feels like -17 with the wind. my hands were going numb the other day when had to snug up the starter. i don't even have a garage or shop to work in.

I began our swap from poor '80's fuel injection technology, to carburetion.

I started with a Weiand Stealth aluminum dual plane intake manifold. It's not listed as being for an '88, but the only difference is that this manifold uses the 1978 & earlier larger thermostat and larger thermostat housing.

Intake:
https://www.summitracing.com/parts/wnd-8022wnd/make/dodge

Water neck:
https://www.summitracing.com/parts/fss-84830/make/dodge/year/1978/model/w150

Gasket set:
https://www.summitracing.com/parts/fel-1213/make/dodge

We are running this GM style HEI blueprinted distributor from Summit racing.

https://www.summitracing.com/parts/sum-850034/make/dodge

I ordered a Quick Fuel Technologies 650 cfm mechanical secondary double pumper carb, but had a 1406 Edelbrock 1406 carb on my '59 that I thought would be a better fit for this application, so I am going to run the Edelbrock.

To handle the fuel delivery, I opted to keep the high pressure electric in-tank fuel pump. So as to not burn up the pump from dead heading pressure into the regulator, I opted to run this Holley fuel pressure regulator that has a return line, back to the tank. I re-routed the hard fuel lines up the firewall and mounted the pressure regulator on the firewall.

https://www.summitracing.com/parts/hly-12-887/

This fuel pressure regulator also has a port for a fuel pressure gauge, so we can make sure that the Edelbrock carb is getting the appropriate fuel pressure. I like to run Edelbrocks at around 5-6 psi.

crazzywolfie said:

if it was summer time i would completely agree but it is too cold out here to tackle anything like that. 0*F but feels like -17 with the wind. my hands were going numb the other day when had to snug up the starter. i don't even have a garage or shop to work in.

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Oh, I get it! There's nothing worse than laying on cold hard concrete outside. Its been getting into the teens here at night and barely over freezing during the day. My '59 and my wife's car got kicked out of the garage for the duration of this project. Luckily I have a heated garage. Makes stuff like this much easier.

It's coming right along. I think that we should be buttoned up today. The only thing that should hold us up is provisions for the throttle cable and lockdown linkage to the transmission. Should be running in the next few hours.

nikwho said:

Oh, I get it! There's nothing worse than laying on cold hard concrete outside. Its been getting into the teens here at night and barely over freezing during the day. My '59 and my wife's car got kicked out of the garage for the duration of this project. Luckily I have a heated garage. Makes stuff like this much easier.

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haha i wish i had a garage. i am temped to ditch the fitech and drop the carb back on at this point. i can't even get my 81 started today which is making me dislike the fitech more. it will sort of start with quick start but not stay running lol.

looks pretty good. definitely not much left to do at this point

I still need to go through the wiring and find my +12v source for the ignition and another for the electric choke. At this point I'm going to leave all of the factory wiring in place. I'm sure that I won't go back to factory EFI in this truck, but I'm not ready to start thinning the wire harness just yet.

I also need to pull lines off of the fuel pressure regulator to see if the pump is running and if I managed to confuse the fuel supply and return lines. I'm not getting fuel pressure and need to figure that out. I've either hooked them up incorrectly, or the computer isn't allowing the fuel pump to run, do to something not being plugged in. I poured some fuel in the carb and fired it up for a moment and it ran well.

I need to find an under hood wiring schematic for this truck. I'll check my manual to see what it has first, then start searching if it doesn't have anything.

Nik

Oh, also the Weiand intake manifold that we went with conflicts with the A/C compressor. Actually, the location of the water neck is what conflicts. I'm okay without AC, but the alternator v-belts also run around the AC compressor. If I delete the AC compressor, I'll need a different alternator mount. I have been thinking about modifying the bracket slightly, to raise the AC compressor. I'd rather keep it, and get the AC system leak resolved and get the AC back into service. I think that I have a plan to raise the AC compressor slightly, and hopefully retain the factory length belts. If I have to run a slightly longer belt, I can live with that.

Nik

you may need to ground the fuel pump relay. the computer usually controls that.

crazzywolfie said:

are you sure the computer is bad since it didn't sound like it in your other post. personally i would try to get the fuel injection working like it should. with carbs they are simple in some ways but with the way most fuels are these days you are bound to have issues. it is really just a matter of time. you will also need external voltage regulator to control the alternator. i would also just use the electric fuel pump and a regulator. it keeps the fuel system simple. get a regulator with a gauge on it. i had a gauge on my truck fuel line between the pump and carb to see what it was doing before i went fuel injected. the only thing you got to hook up to the tran is the kickdown linkage.

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Crazzywolfie, I've been trying to figure out how to get my son's alternator to charge. I ended up doing a search with the keyword "alternator" and your username, since you've helped me so much already! Ironically, I found one that I missed part of right in my own thread! So, I see that you mentioned having to run an external voltage regulator. I will pick one up or order one when I get off work. Do I just grab one for an '87-earlier carbureted truck?

Can you offer any advice on connections/wiring modifications needed? I assume that the ground will stay as is, as will the output wire. What about the other two wires? One (dark blue) currently runs to the ECM and oil pressure switch. The other wire (dark green) currently runs to the voltage regulator. Then, from the voltage regulator shows a dark blue wire going to a ballast resistor.

wiring a voltage regulator to the alt is pretty simple.

Crazzywolfie,
I would like to give you a very heart-felt THANK YOU! This job was certainly large, and you had a very quick response every time that I got held up!

Your intimate familiarity with these trucks is extremely impressive! My 17 YO son is also very grateful! His truck is totally back in service, charging itself, and he is so happy. Plus, he likes all of the performance parts that we added to it. It's still a bit of a dog, but I need to give it a little more timing (we live at 6,800' ASL) and adjust the carb a bit. Though, it has 158K miles and heavy 33" mud terrain tires on it, so my expectations may be too high.

Anyhow, thank you so much for your assistance along the way! It has been invaluable!!!