first off, i know old school carbs and i know ls1's (done 3 of those swaps so far). but i know jack about comp controlled carbs. i just purchased a fairly clean 84 z28 (my stang is too nasty to be a daily driver). the person i bought it form disconnected all the emissions stuff (o2's, egr and smog etc.). anyway, it runs really ruch when i punch it. i have thought about putting an old school carb and dist on it, but i know the ecm controls the tcc etc. so here's my question. is the fact that the o2's are not hooked up why its running rich? i know its not the egr. im going to hook up my scanner and see what codes it has (the engine light is on), but my first thoght is, even w/out the smog stuff i should still use the o2's, no?

Not necessarily, but highly likely. The ECM controls the dwell of the primary rods (amount of time in the jets) based on Throttle Position (TPS) and engine vacuum. More dwell=less fuel. Once the O2 sensor is hot enough the ECM begins constantly re-writing these blocks based on O2 readings. Prior to the O2 heating up but while the CTS setpoint is reached the ECM will use the 'last known good' data. If the ECM has been powered off it will go back to the default block map.

IF all of your other sensors and components are good and everything is working correctly, no adjustments changed, etc. your ECM will be controlling the mixture on either the factory default or 'last known good' map.

The secondaries on these are strictly mechanical. At WOT the ECM commands the primaries full rich and runs the timing up. There's no trim at WOT.

then i have another thought. i have yet to pull the plugs (its beem super hot and i have had to help friend swith their cars the last three days an i only got this car monday), but i think maybe the plugs could be slightly fouled. the reason im thinking that is , it had a miss and the idle was way too low (like 500rpm in park). so, i adjusted the idle and started tracing the wires to make sure there werent two hooked up wrong or something. ......low and behold , the number 3 wire wasnt even connected to the plug!!


so i hooked it up and it ran totally smooth and took it for a ride around the block and the power picked up big time. but when i romp on it it blows a little black smoke. anyway im thinking the one plug wire not being hooked up could have fouled all the plugs wich would intern casue a rich condition since now i wouldnt have a real good spark.

but im still thinkin it would be a good idea to get some o2's an dhook those up along with the broken coolant temp pigtail on the thermostat housing (doesnt that coolant sensor have something to do with fuel as well on these cc carbs?)

most likely the fuel mix solenois in the carb is junk

if yo dont hear rapid clicking iwth key on then its bad

and will run rich like this

common issue.

all you gottta do is replace the solenoid or replace the carb and HEi with 1979 and older ones and remove the pass side computer harness completely

easy

it does not tie in with starter alternator temp oil etc

500 RPMs in drive is the factory idle speed. It's a simple set screw to adjust the idle speed. The ECM doesn't control idle speed directly.

yeah but it was 500rpm in "PARK". it idlled so low the volt gage was barely reading 13. when i set it to 700 in park the volt gauge read 14ish.

and it is clicking. the carb looks good like it was rebuilt not too long ago.

im just trying to find out about this cc carb stuff. i wont spend money swapping to a non cc carb and then a non cc dist. i heard these (cc carbs) run good if everything is correct.

i know i have to go through and do a tune up. i was just trying to learn why or if there was and ecm reasons it could be running rich. and i know the 02's and the ect (at the thermostat) are not hooked up.

i had thought bout throwing an edelbrock carb an intake on it with an msd dist, but i dont want to throw too much money at it. this car is just going to be a daily driver (i have my stang to go fast).

If the coolant temp pigtail is broken and the circuit remains open, the ECM will never recognize the engine as being at operating temperature and will stay in warm-up mode, which is a steady dwell/rich condition.

Always, Always verify the condition, adjustment and proper operation of your ignition system prior to attempting any carburetor changes or adjustments.

It's pretty common for people to hack these poor cars up with absolutely no understanding of what they're doing, thinking "getting rid of all that smog crap" will make the car run better. In fact, the CCC carb system is a very good street/performance system when everything is hooked up and operating properly. What holds factory stock cars back is cam, exhaust, and air cleaner - the carb system will easily support upgrades to all of those (see my vBGarage for a case in point).

I know you said you don't want to spend a lot of money on this, but most likely getting things like O2 sensor and CTS hooked up and working will cost a lot less than converting to a non-CC system.

i probably was rambling an didnt explain clearly. when i said i thought about converting it to non computer controlled, i didnt mean i was going to. i meant because it costs a lot more than just fixing this set up, i would rather get this one running decent.

once i do a tune up i plan on starting with headers (cant decide wich yet) and while doing that im going to clean and paint the block and what not.


and what naf said. yeha that pigtail is broken. is that something you can just buy? or do i have to go to the junk yard to try to find a good one?

and since these one wire 02's arent that expensive, i plan on replaceing them and hooking them up, if nothing more just to try to improve gas milage.

and i was going to go mess with it, but i was outside for about 30 minutes loading up a drag car (and messing with the trailer lights), and im already drenched in sweat so im done for today.

thanks for the replies.

and i never thought i would say it but,......ls1's are sooooo much easier.

It's probably available, but I haven't tried to find one.

There's only one O2 sensor on our cars.

And, yes, find out what trouble code(s) is (are) being set. That will tell you a lot right there.

I've just found an original L69 CCC carburetor for my 84 Trans Am.
I don't have the CCC distributor yet, so I won't start working on it before I find it.
All the Smog components have been removed : AIR pump, EGR, vaccuum canister, everything.
The camshaft has been replaced by an Edelbrock 7102 unit.

Will the Qjet work fine in that case, or should I start looking for the original parts (which I'll do in the future).

You can pick up a pigtail at AZ or one of the others. It's usually hanging in their electrical section.

The qjet will work once it's paired with the proper dist. The smog pump, EGR and evap aren't necessary although lack of EGR can lead to some pinging with a little throttle during low speed cruise. I don't have that problem with my SC though. It has vortec heads, and hence, no EGR, but the gentleman that rebuilt my trans also set it up not to lock the converter below 45. That, or the better heads, may have solved the problem.

A reman dist costs around $100 and will come with a new ignition module; although you'll still have to purchase a cap and rotor-I think anyway. Don't know if you can use the mechanical style, I've never tried.

When the carb wiring etc was unhooked the metering rods failed in the up position, jets were wide open. Sure to run rich like that and very possible the timing was retarded too. Be a big improvement to convert to a standard carb and distributor with a vacuum advance. Does the torque converter still lock up? Can't imagine that working since the ECM would not be in closed loop at all. These were actually pretty good systems when all correct, hate to see them hacked up like this.

tcc locks up fine. just pig rich on wot. i havent touched the car all week cuz its been in the hundreds latley. but im going to see if i can find the pigtail for the temp sender, get an o2 to hook up and see if i can find a heat riser to fix the exhaust leak then do a tune up (got cap and rotor and new coil already) just when i get paid wed im goin to pick up the rest of the stuff (plugs n wires etc).

findin the heat riser is the hard part. the only junk yard close to me only had a couple 3rd gens and they were stripped.

Leonpiper69, I made my own heat riser with some sheet metal and tin snips. Attached it with hose clamps. Worked fine. You are talking about the tube like thing on the exhaust manifold right?

SolarGoldRaptor, you stabbed the EB 7102 stick in a 305? That's a fairly lumpy stick. How does it run? So your question is you want to run a CC Qjet and distro with that cam? The Qjet will feed it but, you'll probably need a different hanger and secondary rods, and modify the opening angle of the air valve to get the full potential with that cam. Not to mention a non-stock air cleaner. But I really want to know how that 305 likes 488/510valve lift and 234/244 @.050 cam.

[quote=csmith3;4203908]Leonpiper69, I made my own heat riser with some sheet metal and tin snips. Attached it with hose clamps. Worked fine. You are talking about the tube like thing on the exhaust manifold right?

no, its the thing between the y pipe and the maifold on the paasenger side. its kinda like a spacer.

It was in there when I bought the car, but I still have the original camshaft and lifters.
It runs pretty good, though rich but that's probably because of the Holley 650cfm carburetor. I've never had a V8 before, but she scares me sometimes !
My plan is to go all original so it will have to go.

[quote=leonpiper69;4203956]I've heard this part reuses the heat from the exhaust smoke to heat the gas/air mixture to fasten cold start.
The problem is that the rod rusts and it get blocked, which can cause problems.

Yeah, Early Fuel Evaporation (EFE) re-routes exhaust gas through the intake manifold to warm the intake charge. The valve shown looks right but it should have a vacuum can attached to it. The usefulness of the valve is debateable. If you don't have it and want to still run the stock exhaust you can use the spacer that was put in its place on the FI engines.

[quote=naf;4201708]You can pick up a pigtail at AZ or one of the others. It's usually hanging in their electrical section.

autozone could get the pigtail for 17.99 (2 or 3 days). but what i found was if you use the sensor from an 87, it has the newer style weathepack connector. and everyato parts store sells them seperate (i.e. sensor and new style pigtail) but the zone has a replacement one listed for the older style for 14 bucks and it is the newer style sensor WITH the connector!!!!

i work for advance and even with my discount it was still cheaper to by them together at the zone