My car is running like crap until it has warmed up for 5-10 minutes. Even then it lacks response. I totally believe its a carb issue. I am planning on headers in the near future also. I am also planning on a speedo upgrade. All of these things are hooked to the comp and all are going to be replaced sometime. Should I just forget the computer and change the carb or will it screw something else up? Is there anything else I need to consider? After I change the carb should I unplug the comp? Will the engine light come on or just be disabled?

 

I'd go forward, not back. Replace the computer-controlled carb (if it is the problem) with fuel injection. TBI would be the easiest route, TPI isn't terribly hard, either.

 

Common '81 mod is to get rid of the computerized system. Here's what you need to do.

Get a non-computerized carb (M4M or 4MV q-jet will fit easiest). I'd like to stress that if you get a q-jet to make sure it doesn't have "M" metering rods, since they're the only kind you can actually buy readily, which sucks.

You'll need to get a vacuum advance HEI distributor. Check ebay because you can get a Procomp HEI for about $85 shipped. Excellent deal and it's a good distributor.

Now in all honesty, your computerized system CAN work fine, but it's such a touchy system most of us hate it. If you want to just make it work for now, check all of your vacuum hoses and make sure there aren't any leaks. Get the Doug Roe book on q-jets and you can rebuild it yourself and it'll work fine.

The benefits of the E4ME and CCC system are as follows:

Simple to tune rich/leaness, the computer does it for you (no more mixing and matching rods and jets)
Timing is easy, just set it between 8 and 12 BTDC and you're done.
Torque Convertor Lock up, saves gas on the highway and keeps the transmission from getting hot.

 

I didnt know about the lock up converter. The rest seems easy enough to get rid of but you may have convinced me not to. What happens to the torque converter without the computer? If I use headers(I want hooker comp sidepipes) do I need the O2 sensor and do they have the provision for them? Does anybody know of anyody that rebuilds the stock carb reasonably? I have heard good things about Lars but dont have his contact info

 

If you ever want to add power, ditch the computer. If you like the stock ride, then leave it in, and fix whatever the problem is.

 

Couple of things on lars, he doesn't work on the E4ME and he's not doing carb rebuilding for about a year.

Without the computer your TH-350C turns in to a TH-350 with lock-up capabilities. You can wire a switch to lock it up manually and there are kits available from like B&M and Bowtie Overdrives to make it easy.

Some headers do have O2 sensor ports, or you can make one in your exhaust pipe that's right behind the header collector.

You can find a decently rebuilt/remanufactured E4ME on ebay.

I took the step "backwards" because of cost and ease. Most people around here know a lot about q-jets so I stuck with it.

If you're not going to do a lot of huge mods the CCC system works fine, UKPaul should chime in soon and make a page long post about his experience with the CCC system.

 

I ditched everything on my 81,new edelbrock profomer 1406 carb and manifold , HEI distributer with vacuum advance hooked up to the maniflod port on the carb and a manual switch hooked into the test plug under the shift console next to the ash tray, you just have to groung the switch wire to loch up the converter..

 

If you want to add power with decent fuel economy, go to a later computer-controlled FI system. Carbs are dino-tech.

 

 

My two cents worth: The CCC system (E4ME, ECM, electronic distributor, coolant and O2 sensors) can keep your fuel mixture set ideally for normal driving efficiency and then let plenty of fuel flow at WOT (wide open throttle) for great performance. It can keep your timing at maximum advance, right to the point of detonation, but never let detonation occur. It will lock up your torque converter for fuel economy and turn on you aux cooling fan to keep that hot vette radiator nice and cool. It can still do all of this even with a new set of performance heads, a performance cam, performance intake, headers and true dual exhaust and performance ignition etc. Whats not to like? I think the main reason people get rid of this system is not because of problems with it, but out of fear of the unknown. They don't understand it and have heard alot of bad info, like how you can't make performance mods. When I looked into exactly what the system does and how it does it, I decided to learn the system and work with it. My '81 has over 300 hp and can spin both of those 255/60R15's with stock 2.78 rear gearing and I get close to 20 MPG in town (and as I continue to tweak things, I think I can do even better). I drive it every day all year long. Long live the '81! God bless, Sensei
P.S. I'll be happy to try and answer any questions you may have.

 

I guess the big reason I am looking at getting rid of it is becuase I have carb issues and the car was cali emmision controled. The smog pump is already gone. I live in Iowa so emmisions are not an issue here. I am not sure how much any of the controls are doing with the pump gone anyway. What happens if I change the carb to an aftermarket one w/o the wiring to the ecm?

 

I bought my 82 with a holley carburator and eldebrock intake already installed.

When I revamped my engine compartment I took it one step farther and removed all traces of the fuel injection wiring and electric fuel pump. it didn't affect the speedo or guages. The only thing that was affected was the lock-up. Like someone else said you can run a toggle switch for that or do like I did get a vacuum operated lock-up switch and be done with it.

I started to retrofit my car with a TPI set up and decided against it because of all the extras needed, I bought a rebuilt Holley carburator for the cost of eight injectors alone.

A lot easier to mess with it and I am TOTALLY happy with my decision.

 

Worst case scenerio is it would flash a light on your dash, but won't hurt a thing as far as running if the carb is set right.

 

The main reason people abandon the CCC system is as basically already stated, lack of information about it. The computer isn't reprogrammable and no one knows how to decode it, yet. In all honesty it isn't a bad setup, it's just a lot more work to make it work right. I abandoned it because I didn't want to have to tinker with a 25 year old computer system. Instead I have to tinker with a 35 year old mechanical system that has tons of information available about it.

 

The CCC system will work fine with the AIR and EGR gone, but if you get rid of the carb you probably will need to go all the way. What carb problems are you having? I have studied this carb extensively and do my own work on mine. I pretty much have it down, it's not really any harder to work on that any other carb, just different. I may be able to help you. God bless, Sensei

 

Trash the 'puter man, and learn how to wrench like the rest of us!! You have to be a rocket scientist to keep make power work with the computer still on.

Come on back to the old ages.....of raw power!!

(I proudly boast that as I sit on blocks )

 

I looked for a long time for information on retuning the ECM. I even got in touch with a GM engineer and there is nothing out there. Appearently GM sold the code to Superchips (I think) and they can do a program for you but it's about $200 each time. This is the only thing bad, it's a one-year-only setup. The CCC system work well stock and it will take some tweeking on the motor, just don't change the vacuum signal much.

As for putting an 02 sensor in Hooker sidepipes, Jet Hot will do it for you and then coat them, but the sensor needs to go in the collector pointing inward which means you need to put a hole in the frame. It's been done by others on the forum.

I eventually decided to go with aftermarket EFI once my car became emissions exempt

 

I can understand and appreciate both points of view (keep the
computer vs trash it). Your call I guess, as to which system
you're more comfortable with and what you're willing to trade in
performance, fuel milage, etc.

FWIW, not that fuel economy is my #1 priority, but I did get a skosh
over 24mpg during a trip to Southern California from Washington
State in my stock '81 a number of years back.

When the motor that's in my '81 gets tired, I'll probably replace it
with something with some more power (heads, intake, cam + exhaust)
but unless something really compels me to do otherwise, I'll keep
the ECM system.

I also have the pleasure of being able to tinker with my '68, which
is dirt-simple comparatively speaking.... Gotta say, I like tinkering with
them both...

Bela P. Havasreti

 

I had nightmares with my CCC. My mechanic swapped out the distributor for a rebuilt, conventional type, and the car runs like an '80 now. Not sure exactly what he did, but it was CHEAP, if that is of sny concern. One problem is that mileage spiked without the lockup (which was a PITA on 1-2 & 2-3 shifts). I would consider getting a manual lockup switch for highway mileage.

Main point is that I retained the original carb.

 

If the CCC system is working OK (or just need a few vac leaks, etc to get it working) then I'd leave it in place unless you want a cam with lots of overlap, lumpy idle, etc. The only reason I'd junk mine is because it's gone pop, or because, like the sensible man above said, to fit FI.
The engine can be modded quite a lot with the CCC system in place, heads, CR, etc can be changed, you just get limited in the choice of cam you can use as there needs to be a minimum vaccum reading at idle (10"mg???), any lower will confuse the life out of the computer.
Lars will not work on the E4ME. Get the factory shop manual for the '81 (maybe also the Roe book on Q-jets) & all is explained on setting up the carb. It seems complicated, but once you start it's not that difficult. There's just a couple of needles bouncing around to control the primary mixture & you just need to limit their movement (as explained in the manual).
Headers will work fine. I got Dynomax ceramic coated ones & bought some reducers with O2 sensor bungs from Summit. I only needed one of them & used it to locate the sensor further downstream. I've not had any problems with the sensor cooling at idle (a potential problem with moving them downstream), but that could be because the ceramic coating keeps the exhaust gas hot? If there are problems then a heated sensor can be fitted. The Secondaries on the E4ME work just like the non-computer controlled ones & with Headers fitted you need to change the stock CH secondary needles to DA (info from Lars & he was bang on).
All the emissions stuff can be removed & the CCC will still work OK. In fact, it'll work better as there's less vac pipes to leak, less wires to get in the way & far less complexity in the system, making it easier to find/fix problems & far less likely for problems to occur.
Hope this is less than a page! (Hi Kalway ).

NB CCC refers to the computer system, not that bunch of guys in Colorado who drink lots of beer!