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computer controlled quadrajets any good?

J

jkeys0218

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I have an 85 K5 blazer stock 305 with a computer controlled quadrajet that needs a little tlc. But when i went to my local parts guy to get my rebuild kit he said it wasn't worth messing with and that i should go to the scrap yard and find an older non computer controlled model and rebuild that. Im planning on doing a complete engine swap for a tbi 350 within the next year so this really is just temporary so i was wondering if its really worth it. Also if i was to go look around at a junk yard are there any particular years i should look for that would be better?

Sorry if this is in the wrong section or has already been covered i couldn't find any thing but im new here so i may have just missed it.
 
No

Ditch it, get a better carb and when you go FI you can sell it to someone else. Mid to late 70's are pretty good. You're just looking for something without wires other than an electric choke. My cousin's 85 K20 had a basic carb too, so the heavier GVW truck would also be something to check out.

You will want to upgrade your distributor as well. This is another computer controlled device that needs to be swapped. I went through this very thing.

Welcome to ck5
 
I don't have to do the distributor and carb at the same time do I? And do I just cap off the wires and any unused vacuum lines?
 
I have smog checks here, so I made sure the vacuum to the dizzy was good and faked all the other lines. I made the dizzy/carb swap at the same time, just makes sense. You will not get the greatest performance out of that set up, much less one not working perfectly. The theory behind the CCC setups is there, but it all has to work. If not, it's garbage. Running engine mods with that system is also ass backwards.

The computer controls the timing and fuel, using all the sensors and vacuum lines. Going back to 70's technology is the best thing for it. :D
 
If I were to make the current 305 tbi instead of swapping motors would my current distributor work since it's controlled by the current ecm? Also would the new one replace the old or have both? And does the current ecm do anything other than the carb and distributor?

Thanks for all the replies this is helping a lot.
 
Two complete different setups. One will not work with the other. I believe a TBI setup (like factory) would need a TBI dizzy too. Unless you are talking about a setup like Affordable EFI, I think that's fuel only. Not sure.
 
I can't help for sure on the distributor either...I *think* that there were a couple of CCC distributors, but don't quote me on that. If it's got 2 connector terminals on the ignition module, a two pin and three pin terminal, then it might work with TBI.

The CCC ECM does everything a TBI ECM does essentially, just worse...O2 sensor, MAP (Baro) sensor, coolant temp, etc. Only glaring difference is the mixture control solenoid as opposed to injectors, and the secondaries.

You need a complete TBI setup to make your life easy. Trust me. Mixing and matching parts is problematic, and even if you can get it working, you will nickle and dime yourself to death. It's better to buy a complete, unmolested setup up front.
 
im trying to remember but on the Dist I think you only need to replace the internal module to get rid of the computer controlled end of the business. Its been a while since I did this on my 85 but I ran it and passed smog for some time with out the computer.
 
Im thinking now I might just find a used tbi setup and keep my current 305. so if I do that you think I should replace the dizzy too? Is there a guide or walkthrough of some one doing this. And are all the tbi parts the same for a 305 and 350.
 
As many of the TBI distributors are "failing" at this point, you'd probably be better off either getting the newest, lowest mileage used TBI distributor you can get, or buying a brand new one. The brand new ones (although parts store cheapies) are not that expensive when all the parts together as a whole are considered.

Stuff is different for a TBI 305 and 350. 305 was always a "high" compression motor, so timing requirements are going to be different, meaning the calibration in the PROM (the programming that "controls" the ECM/injection setup) will be different. Not only will the timing requirements be different based on that, but also displacement. I can't speak authoritatively on how MUCH different, but it is different, and no matter how it feels or runs, will not be correct.

I can't recall if the 305 injectors were different between the 350 or not. The throttle body itself would be the same. TBI car components (F-body, Camaro/Firebird with V8 TBI) will work for the most part as well, however the wiring is going to be different based on the chassis differences.
 
So the only difference is in the programming? Because fr what I've read most people seem to reprogram them anyway. Also If I were to get an aftermarket system that comes with it's own programmable ecm and put on my 305 then if I switched to a 350 in the future I'd be able to swap everything right?
 
There are a few variables normally. It just depends on what the system is.

The knock sensor is normally different between a 305 and 350, for instance. If the injectors are different, its unlikely 305 injectors will work right on a 350.

I'm kind of beyond my skill set here...I don't know much about injected 305's. It's probably better to just go down the road of building and injecting a 350, so you can plan on getting all the right stuff the first time.

I hate carbs, but I'd rather carb a 305 and spend the money on putting the 350 together and injecting it, than spending money on a 305 and then having to do everything over again (potentially) for the 350.
 
I found a good 94 350 with tbi, harness, ecm for 400 so I think IM just gonna do ths swap now. Will it bolt onto my 700r4 or do I need a new trany too?
 
No reason why you can't use the same transmission. You just have to be sure the T/V cable has the proper place to connect to the throttle.

But you will need a vehicle speed signal.
 
Sorry ive been sick a few days. But thank you everybody for the help.
 
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