My son and I have been troubleshooting a carb problem on his '82 Camaro for several weeks. We have put in 2 rebuilt carbs because the engine is running too rich (no power; black smoke; backfire through carb; gas evident in intake manifold) but neither helped the problem. New intake (carb) gasket, all vacuum lines are good. As far as we can tell the choke is working-linkage and moving parts all moving freely. +14vdc going to the choke heater coil.

What's baffling is that sometimes the car will run perfect-no hesitation, no black smoke, idles as smooth as a new car! But most of the time when you start it you have to push the throttle down over half way to the floor just to get it to run! When it does decide to run good we test drive around the block a couple times (~1/3 mile) and it will be fine-good power, no hesitation, no smoke. Then, apparently once the engine warms up, it loses power rapidly and starts to exhaust black smoke. It barely makes it up the driveway.

History:
-car had a bad knock when we bought it.
-Had the engine (block) rebuilt; knock was a bad bearing on one of the connecting rods.
-After that the car ran "ok" but was lacking power, hesitant, etc. Found that the cat. converter was plugged. Had that replaced.
-Car ran much better but mechanic that replaced the cat. told us the carb was flooding and that probably diluted the oil which caused the rod bearing to go bad. He suggested we get the carb. replaced asap.
-we've installed two rebuilt carbs since then and neither made a difference. It's still running too rich and although it will run "perfect" very intermittently, most of the time it runs like sh*t. The outside temperature doesn't seem to have any affect on how it runs. It can be warm outside or it can be cool; doesn't make any difference.

We've installed new spark plugs (old ones were fouled of course). Installed new O2 sensor. The timing is set up properly.

Running out of ideas here. If we could just figure out why the car is running too rich it would be a beautiful running car. We paid very little for the car but it is in terrific condition-clean, solid straight body, no rust, excellent interior, etc. It's getting harder to find them in good condition.

Any help would be most appreciated! My son's very close to having a very nice running car and he's being a lot more patient than I am. I'm getting ready to throw in the towel...

 

BTW, is there any way to tell exactly what type carb is supposed to be in the car? We don't know if the original carb was with the car when we bought it or if it was a rebuilt carb. Also, how can we tell if it has Canadian or American emissions (which is something the auto parts store asks us when we order the rebuilt carb). The parts store carries a couple different versions of carbs, one with a 'staight' vent pipe and one with a 'curved' vent pipe. I have no idea which is which. Will a VIN code or engine serial number somehow tell us which is the correct carb for this engine??

 

I was wondering where ya were.
You have my Blazer 2.8 carb set up.
Federal 49 state has no computers nor electronic distributor stuff.
And sounds like you're in Canada?
Am I correct?
This is the AMERICAN SMOG HOSE ROUTING SET UP.
The correct carb is a 2SE
2ESE is the electronic carb, with computer control fuel ratio metering.

 

We're in NC. I think the car has a very basic computer in it. The last mechanic that worked on it (who did the cat. replacement) had to get an updated computer for it so he could troubleshoot the performance problem (which ended up being a plugged cat). I don't think he left that newer computer installed; if he did, he didn't charge us for it.

The carb does have three electrical connectors attached to it: one for the choke (single wire); one at the top w/two wires and one at the front w/two wires. Not sure what those are for.

 

Your carb is electronic!
It's the wires for the air ratio metering.
Perhaps that's why your problem is there.
The emissions map is what you do need.
Shame ya gave away the possible original carb.
Sounds like you've been offered carbs for Blazers the 49 state version (as is my version).

 

How can I tell if the 1st carb I swapped out is the original or not? I still have that one and haven't returned it to the parts store for the core refund yet.

Can you tell me which connector is for the air ratio metering and what sort of voltage is supposed to be on those wires? I assume that control voltage comes from the computer? That does sound like the likely culprit.

Post-edit: Ok, I did a little research and figured out which one is the M/C solenoid and the basics of how it works. The way I understand it is the ECM sends pulses to it and the duty cycle of these pulses determine the mixture. Now, how to measure these pulses or figure out if they're correct???

 

Let's ASSUME you still have original!
From what I've been told the Solinoid "doesn't" go bad, it's the carb that needs the fixing.
On my Blazer one, my big problem was junk inside carb and a very worn down main primary shaft on throttle plate. I rebuilt it & also fixed the primary shaft with new bushings.
What I suggest for ease of work is to find a replacement throttle plate, and rebuild your original body. All that is needed is new gaskets and MAYBE a new float!
IF that mission fails, then replace the electronic solinoid.
Those solinoids I understand are quite pricey.
The values & such like that.
I do no know them.
BUT I would open up the current assumed original and look see what you've got.
I am most sure a decent repair manual may have the electronic values you seek.
AND I would make sure your vacuum hoses set up is "correct".
This could get ya closer to identifying the real problem or eliminating some.
More detective work!

 

I don't think the carb is the problem because the 3rd carb is installed and the car is still running too rich. The original carb ran too rich as did the 2nd and 3rd rebuilt carbs I installed. It has to be something external of the carb apparently.

Maybe the M/C is being told to run rich by the ECM for some reason? Either the ECM is bad or some other input sensor to the ECM is fooling it into thinking the mixture is too lean and so it's commanding the M/C to add more gas to the mix? If that's the case I don't know how the ECM determines if the mix is too lean or too rich other than the O2 sensor, which has been replaced.

 

How is the vacuum hose routing?
Is it like the diagram I offered?
IF not give that hose set up a try and keep going forward.
It could be the signal to the choke that is "stuck".

 

Our hose setup is exactly as in the diagram. We re-checked everything tonight and found we had a couple hoses hooked up wrong. They're all correct now. Didn't make any difference though because when we started the car it's still blowing black smoke and running like crap. Unplugged the M/C connector and it didn't change a thing. +12vdc is on that connector. There's ~14vdc on the choke connector.

Might try to find a used computer next and see if that changes anything. Any idea how much a computer from a junk yard would cost?

 

Try this idea FIRST
New spark plugs & NEW COIL!
See how easy it is to slip in a remote mount coil? Mine is on the firewall back there.
I think you may be running rich due to weak coil!
I would also broaden your search for Blazers/S-Series for the computer, too. AND Lumina/Citations/Those X-Body & Other same type cars, with 2.8 & carbs! FWD rides.
Speak with a someone who has a hollander & see what inerchanges...
My 1985 Firebird?
I'm running a 1985 Corvette computer (cause it works just like a 2.8 Firebird) but using original vehicle prom.
Early rides use lots of same parts!

 

Have you checked to see, if the original ECM is working?

Check your codes with the ALDL port on the car. Connect the two pins and the check engine light should give you a code 12 and/or some error code. If it doesn't then somethings up with the ECM.

Could someone post a picture of the connector and what two pins should be connected? The connector is located on the drives side.

 

Going to check that. I'll post here later what it came up with.