1978 Chevrolet k20. Its all stock. I drove the truck as a daily driver from 2012-2014. It had an edelbrock carburetor on it and then i put a quadrajet on it. Truck never really had any issues except for the engine would sometimes have power and other times would hesitate. Turned out to be a loose timing chain. That was addressed and it was fine. Anyway the fuel injection bug hit me and i ended up converting it to gm tbi. I did all the wiring and fuel system swap. I modified the computer to be able to burn custom chips and i have all the chip burning hardware and computer programs in order to data log and change the tune in real time. It’s a pretty cool setup. The issue is the truck has left me stranded multiple times over the years. Whether it’s a fuel pump that went out or the multiple times the icm has failed from heat. I ended up mounting the icm on a custom isolated heatsink and that solved the issue. I really appreciate the tunability and theoretical reliability of fuel injection but part of me hates the complexity of the additional wiring and ecm and given the fact it’s hard for me to trust that at any time the fuel pump or some other components won’t go out again. I’m thinking of taking it all off and going back to the analog reliable carburetor. What are yalls opinion.
Thinking of going back to carburetor
- Thread starter joegreen
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It's a little different for me living at 9200' and regularly driving, towing, and playing, in altitudes from 4000' to 11000' with occasional trips to sea level and back. I made a good bunch of change as teen rebuilding carbs, but I fuel inject everything now and I wouldn't look back. I had fuel pump issues with carbs too, along with finding the right jets, adjusting timing with altitude, etc. Not to say I haven't had frustrations with some efi setups, I have.
If altitude isn't a factor and you are more comfortable with a carb then go for it, nothing wrong with that. But let us know how it goes and what you think if you do! I bought a beater 78 K20 plow truck with a quadrajet on it, I'll buy your tbi set up!
If altitude isn't a factor and you are more comfortable with a carb then go for it, nothing wrong with that. But let us know how it goes and what you think if you do! I bought a beater 78 K20 plow truck with a quadrajet on it, I'll buy your tbi set up!
For a daily driver the Q-Jet is an excellent carb.
You only have to make sure it's EXACTLY (can't stress that enough) jetted and tuned for your engine and application.
You only have to make sure it's EXACTLY (can't stress that enough) jetted and tuned for your engine and application.
Thanks for the offer. I would keep my tbi setup. I have a lot of time invested in it and maybe put it on something in the future or keep it on now.
The quadrajet i have is for a 78 k20 and is stock so it should be jetted ok but i would probably buy a wide band 02 setup to help tune it anyway.
Personally I’d probably keep the TBI, for all the tuning ability. That said, it’s not me working on it. TBI was really a stepping stone for getting into EFI, and is lacking compared to PFI. Go simple with the carb, or go more complex and get the power boost with a good PFI setup (‘cuz the Vortec spider was so reliable 
) (maybe rock it old school with TPI? ).
If you do go back to carb, I’d keep the O2 sensor and add meter to the dashboard, so you can watch AFR. Might have value in putting a meter (and vac gauge too) under the hood, why not make it easier when you need to tweak a screw?
I watch some of Thunderhead289’s videos on youtube and I don’t know if he is selling them or not, but he was showing off something he had a hand in, some sort of gizmo that I got the impression could be hooked up to the carb to autotune it. Now the one video I watched really wasn’t more than an O2 hookup to bluetooth and a cell phone app, allowing datalogging of acceleration, O2, RPM so I’m not sure how it can connect to the carb and do anything, not without hooking up servos to twist the screws. IMO that’s a bit complicated and probably not what you want… but I’m mentioning this in case you wouldn’t mind watching a few videos on old trucks, carbs and how to make them happy.
) (maybe rock it old school with TPI? ).If you do go back to carb, I’d keep the O2 sensor and add meter to the dashboard, so you can watch AFR. Might have value in putting a meter (and vac gauge too) under the hood, why not make it easier when you need to tweak a screw?
I watch some of Thunderhead289’s videos on youtube and I don’t know if he is selling them or not, but he was showing off something he had a hand in, some sort of gizmo that I got the impression could be hooked up to the carb to autotune it. Now the one video I watched really wasn’t more than an O2 hookup to bluetooth and a cell phone app, allowing datalogging of acceleration, O2, RPM so I’m not sure how it can connect to the carb and do anything, not without hooking up servos to twist the screws. IMO that’s a bit complicated and probably not what you want… but I’m mentioning this in case you wouldn’t mind watching a few videos on old trucks, carbs and how to make them happy.
Stock is best. since it came with a carb, doesn't have all the teething pains you develop with modifications.
Over a lifetime I've sort of developed this idea that one modification generally turns into more modifications
whereas accepting a vehicle the way it was designed seems to be easier on the psyche and the pocketbook..
I hate carburetors. I’ve had two square body GMs and sold them due to carburetor issues. I know nothing about carbs and nobody around here does either. Several shops couldn’t figure out how to make them run right. Sadly in California fuel injection swaps on 1975+ will fail smog test and so my 77 and 83 would have been a no go. Stick with fuel injection! TBI is plenty reliable. Have had multiple and never any issues. Fuel pumps die, it happens.
yeah, by the late 70's carb tuning on stock vehicles had become so lean they were prone to stumbling..if I remember correctly you had to adjust them using propane and a gas meter... so it was a PITA... and if a person is in the People Republik of California, where they can't get past the emission Nazi's I can see where that would be an issue.
Anything from the last century in NY must be a rarity. Anything surviving from the 70's is a miracle. Was it parked over the winters?
Just get a proper Holley EFI system and enjoy the added power and drivability. TBI was a stop gap and well carbs are nostalgic but really for a daily it's the last thing I'd want especially with altitude changes and seasonal weather.
Probably not. I bought it with a permanent plow frame attached to the front along with plow.
dnewton3
Staff member
The issues you're having aren't related to "fuel injection". The problem is that you're using an acient form of rudimentary injection. Get a modern FI system (Holley, FAST, etc), and you'll not have any issues. The new stuff is often available as a kit (injection system, fuel pump, lines, etc) and the systems are "self-learning". Once you install an O2 sensor and upgrade, all should be much better.
As others have suggested, a current aftermarket EFI is a nice setup.
I love Q-Jets; finding an unmolested one is a good trick. If oyu have the original and it is in good shape, you can do that for next to nothing cost wise.
Long term, I would install a modern system. Good luck!
I love Q-Jets; finding an unmolested one is a good trick. If oyu have the original and it is in good shape, you can do that for next to nothing cost wise.
Long term, I would install a modern system. Good luck!
I personally have quite a bit of experience with carbs and don't have an issue with them. Had a VW with dual Dellortos, twin carb jet ski race motors, 4 carb motorcycles, 2 stroke single carbs..... There are good options available but Edelbrock/Carter isn't one. Q-jets in good condition are hard to find and complex but the vacuum secondaries work great on a stock motor. If you don't live in extreme cold or high altitude a carb is fine. Modern EFI kits are so nice but expensive.
I've heard the Q-jets are as close to FI as you can get...
DynamicEFI has an ecu that might plug right in and get you a couple decades closer to modern and give you a starter tune and lean cruise. Any system of that vintage will have wear issues- but TBI in good working condition has been a rock solid EFI. An older conversion was Edelbrock MPFI- real nice TBI to MPFI system- although the ecu/chip was a pos.
DynamicEFI has an ecu that might plug right in and get you a couple decades closer to modern and give you a starter tune and lean cruise. Any system of that vintage will have wear issues- but TBI in good working condition has been a rock solid EFI. An older conversion was Edelbrock MPFI- real nice TBI to MPFI system- although the ecu/chip was a pos.
Carbs are pretty simple and rarely quit out of the blue if there is a problem. It may not run too good, but at least it runs. If a F.I. has a problem like a bad sensor, it may not run at all.
i have no issue with tbi and have no desire to move to a more modern fuel injection system. I still have all the old parts from the carb setup. I like the tbi because any part can be had from the auto parts store but I dislike the clutter of additional wiring. It’s more me being picky. This isn’t going to be a daily driver but may be in rotation as i enjoy driving it.
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350?
Vortec heads and intake would be my choice. PFI, no spiders.
Vortec heads and intake would be my choice. PFI, no spiders.
