86 k5 with the computer carb problems

[Smokinthehippies]

So I'm getting a completely unmolested rust free clean straight k5 from a buddy in a trade. I have no interest in keeping it because I just finished my k20.

Now I'm getting it because they said it was a daily driver until one day the computer controlled carb just crapped out and they parked it.

Now I'd like to get it running just enough to get it running and sell it.

So basically I need some advice on what to look for to get this puppy running and pass smog.

What are the problems with the ccc design? What are the common failure points?
Can I just pop on a quadrajet and be fine?

Any advice on how to go forward here would be peachy as I've never even seen the ccc so I have no idea what I'm looking at.


Also, anyone want a straight full power untouched k5? Or any east coasters need a clean California body?

 

[bubba blazer]

the q-jet in these things are basically the same as older models except they'll have provisions for a few things like a throttle position sensor and a mixture solenoid (which were still available individually through NAPA). the computer does more "monitoring" than anything else and even if its not hooked up the engine should still run (i think it defaults to "rich" mode). the computer also controls the distributor and has an oxygen sensor on the driver's side exhaust manifold. If it's not running, you may want to run through the basics first and if you need to rebuild the carb, it's pretty straightforward. If you need a replacement carb, the number is: 17085508 (350, California, TH700r4)

this is only my personal experience from working on our blazer. hopefully someone with more experience will chime in.

 

[K85 Octane]

You can get it to run without the electronics working, mine did. But to have it run better, throw a late 70s carb on there and be done. Sell it. For the smog thing, dummy the wires that go to the smog/vacuum stuff, and make sure all the vac lines are there, even if they aren't working. The core support diagram doesn't show the wires going to the carb, only vac/smog wires and vacuum hose stuff.

But, my truck ran fine without any of that stuff working when I bought it. Drove home the 250 miles and passed smog a few days later.

 

[dyeager535]

Being in CA, would you run into a problem if you swap the carb for resale? Either way, it SHOULD run without the carb hooked up, but be extremely rich as mentioned. You'd need an earlier distributor as well.

I agree with checking the basics...vacuum lines, cap, rotor, plugs, wires, ignition module, etc. For the thing to just quit running, that doesn't sound like a carb/CCC issue to me. Could be, but ignition module, fuel pump, etc., is far more likely if it just up and died.

 

[bubba blazer]

Depending on where you go (in Cali), the smog check person can be pretty sadistic. I had one double-check my "Check engine" light...yes, just the light to see if it was working and shutting off after the engine ran. Imagine my surprise for failing because my timing was off 3-4 degs...(even though I passed the sniffer). I even explained that the balancer probably rotated b/c the engine had over 220k miles at the time. Filed a complaint with BBB.

Anyhow - if there are things unplugged with the carb and you can't get a good factory service manual. Chilton's #28622 has some good electrical and vacuum diagrams in it that are year specific (For Federal and California models).

 

[dyeager535]

Honestly, IF you can dump it, the CCC is worse than a plain old carb when it stops working. No one tunes them, parts are somewhat pricey as I recall, etc. Only reason to keep it is if it is required by law. Of course going TBI or something even newer would be legal in CA as long as it was done right, but in this case if you aren't keeping it, lot of work and expense that you won't be able to gain much in the way of $$ for, over a properly working carbed setup.

However, being in CA, I'd never take something off and throw it away. Take it off and throw it in a box, just in case.

 

[Smokinthehippies]

the q-jet in these things are basically the same as older models except they'll have provisions for a few things like a throttle position sensor and a mixture solenoid (which were still available individually through NAPA). the computer does more "monitoring" than anything else and even if its not hooked up the engine should still run (i think it defaults to "rich" mode). the computer also controls the distributor and has an oxygen sensor on the driver's side exhaust manifold. If it's not running, you may want to run through the basics first and if you need to rebuild the carb, it's pretty straightforward. If you need a replacement carb, the number is: 17085508 (350, California, TH700r4)

this is only my personal experience from working on our blazer. hopefully someone with more experience will chime in.

thanks for that info.

Being in CA, would you run into a problem if you swap the carb for resale? Either way, it SHOULD run without the carb hooked up, but be extremely rich as mentioned. You'd need an earlier distributor as well.

I agree with checking the basics...vacuum lines, cap, rotor, plugs, wires, ignition module, etc. For the thing to just quit running, that doesn't sound like a carb/CCC issue to me. Could be, but ignition module, fuel pump, etc., is far more likely if it just up and died.

that's gonna be my first step is just start tracing everything and looking for the obvious. its gonna need a lot of time before I even try to turn it over I think

Depending on where you go (in Cali), the smog check person can be pretty sadistic. I had one double-check my "Check engine" light...yes, just the light to see if it was working and shutting off after the engine ran. Imagine my surprise for failing because my timing was off 3-4 degs...(even though I passed the sniffer). I even explained that the balancer probably rotated b/c the engine had over 220k miles at the time. Filed a complaint with BBB.

Anyhow - if there are things unplugged with the carb and you can't get a good factory service manual. Chilton's #28622 has some good electrical and vacuum diagrams in it that are year specific (For Federal and California models).

that's the truth. and good call on the manual. pretty sure I still have mine from my k5 (maybe?) i'll try to dig that out and start doing some reading.

Honestly, IF you can dump it, the CCC is worse than a plain old carb when it stops working. No one tunes them, parts are somewhat pricey as I recall, etc. Only reason to keep it is if it is required by law. Of course going TBI or something even newer would be legal in CA as long as it was done right, but in this case if you aren't keeping it, lot of work and expense that you won't be able to gain much in the way of $$ for, over a properly working carbed setup.

However, being in CA, I'd never take something off and throw it away. Take it off and throw it in a box, just in case.

yeah the problem is out here even if you pass the emmissions its still visual test. which means they can fail you just if it doesn't look correct to them. and if I was going to effort of tbi, i'd probably do it on my rig.
I might just end up selling it as a parts vehicle if I end up skunking out on this.

 

[chulisohombre]

If you sell it I've heard from other Cali members that it is the sellers responsibility to smog it and have all the original engine parts on it with all carb stickers for anything aftermarket. There are still a few counties that don't do smog check but you still have to have it sniffed somewhere I believe to get a new title to the seller. As was said those carbs can run without the computer stuff running but it will default and drop extra fuel to compensate. I don't know if there is a fuel metering valve on that like my dodge has but if it goes bad it won't let fuel into the carb. You can always try some starter fluid to see if it will fire up and go from there.

 

[Smokinthehippies]

If you sell it I've heard from other Cali members that it is the sellers responsibility to smog it and have all the original engine parts on it with all carb stickers for anything aftermarket. There are still a few counties that don't do smog check but you still have to have it sniffed somewhere I believe to get a new title to the seller. As was said those carbs can run without the computer stuff running but it will default and drop extra fuel to compensate. I don't know if there is a fuel metering valve on that like my dodge has but if it goes bad it won't let fuel into the carb. You can always try some starter fluid to see if it will fire up and go from there.

I've gotten past that before by just selling it as parts only. understood by both parties that it wont pass smog. (legally, that doesn't matter as they could still come back on me but it hasn't been an issue yet)

but as of now it looks like a buddy of mine might want it to swap over his cucv equipment.

 

[diesel4me]

Here,most people who had troubles with the computer carbs ditched them and put a pre 1981 carb and distributor in the vehicle and they ran like the good old days.(Gm put the HEI with the EST module setup in with the computer controlled carbs,most engines ran better with the old 4 prong HEI with vacuum advance.. )...here as long as it passed emissions testing the "visual" inspection was usually "passed",seeing few mechanics working the sticker bay could tell the difference by glancing at it--or cared!..long as it didn't flunk emissions you were golden..

Must suck living in parts of CA where they want EVERYTHING 100% stock and perfect....especially on vehicles 40 years old,I think its foolish to expect any emission parts to last that long or work right..