Taking the carburetor off, putting TBI on

[Doober]

The check engine light was on but I figured that was from removing all the smog/emissions junk

:lol: I'm guessing that's why there was no O2 sensor.

 

[dogsht]

I am all for keeping or useing the TBI for a mild performance car especially if you already have access to a tbi unit at no cost. But if you are saying you expect to at least double your mileage just from swapping from a carb to tbi, I don't think you will see that much gain even if you currently have a Holley.

 

[RITTER]

The reason I get single digit gas mileage numbers is because the quadrajet that I am running has that electronic pump selenoid and constantly runs really rich. I don't think that 15-16 mpg is asking for too much with a COMPLETELY stock SBC

 

[dogsht]

Nope 15-16 mpg with a stock 350 sbc should be easy to accomplish in a relative to a truck light & aerodynamic g-body. Heck you can see in my signature that I have gotten 17mpg hwy with 509ci 800 Q-jet with 3.42 gears. With a mix of city & hwy and a little goosing it now & then about 14 mpg. I always thought that wasn't bad for a car with a big motor that also ran 110mph in quarter. Cadillac offered a fuel injected 500 back in 1975/76 but I believe if I converted over to it that I would only pick up about 1 mpg over the Q-jet with an otherwise same setup.

 

[Doober]

Heck I got about 20 on the expressway with my '88 2wd half ton pickup with a TBI 350... and those things have a barn door for a nose 8) my '92 has a 4.3, and with a set of 3.08s in the rear it's gotten as high as 24½ on the expressway... 4½ more than my aunt's '04 Rendezvous with a 3400.

 

[RITTER]

I would be completely satisfied with 16 mpg. This whole, going 140-150 miles on an entire tank of gas is killing me

 

[G_Body_Enthusiast]

The reason I get single digit gas mileage numbers is because the quadrajet that I am running has that electronic pump selenoid and constantly runs really rich. I don't think that 15-16 mpg is asking for too much with a COMPLETELY stock SBC

a non CCC qjet would run better than that. they ruined the qjet with that computer crap. having driven cars with qjets that were CCC and non CCC i can tell you the non CCC seemed to work better. i swear that CCC junk is a noose around the qjet's neck. it was a poorly designed system. carbs were better off without the electronic stuff.

 

[Doober]

On the other hand it was also a very primitive computer setup compared to what's out there today. Even if it was able to monitor & make adjustments as a TBI unit does it would be a lot better.

 

[dan2286]

The reason I get single digit gas mileage numbers is because the quadrajet that I am running has that electronic pump selenoid and constantly runs really rich. I don't think that 15-16 mpg is asking for too much with a COMPLETELY stock SBC

a non CCC qjet would run better than that. they ruined the qjet with that computer crap. having driven cars with qjets that were CCC and non CCC i can tell you the non CCC seemed to work better. i swear that CCC junk is a noose around the qjet's neck. it was a poorly designed system. carbs were better off without the electronic stuff.

I don't know, when mine was running with the ccc system it was running great. I actually got 17-18 mpgs with a 307 and a 3 spd trans. I do know that when those systems have problems, they can be very hard to diagnose.

 

[billyjack]

IMO you're making a good move. While it's certainly not the best option for pure performance, the factory TBI system had a good reputation for reliability, simplicity and excellent driveability characteristics. Hot Rod Magazine had an article years ago in one of their yearbooks extolling the virtues of such a swap, and providing info on wiring harness vendors. I saved the issue in case I do the swap myself someday. If it would help you, I'll be happy to scan and email the article to you.

Bill