"E"

The smog pump is frozen and most of vaccuum lines are rotten or completely broken off. Are all the lines required to be hooked up even though I going to try and bypass the emission control system? And would I have to replace the carburator?

joe_padavano

I suggest that you fully understand what each component does before you start disconnecting anything, otherwise you'll simply make it run worse. The CCC system controls the primary side mixture on the carb and the ignition timing, so disconnecting the system requires replacing the carb and distributor with older units. While annoying to work around, the majority of the emissions equipment on the 307 doesn't really hurt performance. For example, the EGR valve only opens at part throttle cruise and closes for wide open throttle. The carb secondary side is completely mechanical. The evap canister has no effect on performance. The EFE system is fully open once the engine is warm.

You MUST have all the vacuum hoses in good condition and connected properly, and you MUST adjust the CCC system following the procedure in the factory Chassis Service Manual exactly. Failure to do so will result in a poor-running engine. Do it correctly and the system works great.

Of course, that 307 will never be a powerhouse, even if you remove every piece of emissions equipment. Just be aware that unless you plan to remove everything and convert the carb and distributor to non-computer units, it will likely run like crap.

"E"

Thanks for the advice.

"E"

Maybe it's cheaper for me to just get another pump
I just want it to run without stopping as I move it from place to place get the body work done. I hope to have a pontiac 455 built if it not much needed to put it in

Vyse

Hey joe, what a kind of carb and dist would you recommend if someone were to go that route and remove it completely? Would be used as a daily/cruiser.

joe_padavano

Any Oldsmobile HEI with a vacuum advance can works. You'll want to optimize the advance curve for best performance, but just stabbing one in there works fine. On the carb either use a Qjet set up for a 305 Chevy or an Ebrock 600 CFM. If you are keeping the 200-4R, you may need to swap the primary throttle shaft on your selected Qjet with the one from the original CCC carb to retain the attachment point for the TV cable. Also, the converter lockup function will no longer work with the computer disconnected, so you'll need to install an aftermarket or manual system.

Vyse

alright thanks for the list! so far looking at the
TCI 200-4R / 700R4 Torque Converter Lockup Kit
Olds HEI Dist w/ vacuum advance
And if i cant find a nice 305 qjet itll be a
edelbrock 600 cfm

I'm glad you pointed me in the right direction! thanks

olds 307 and 403

Go Street Demon 625 cfm. It is an improved version of the Thermoquad will new castings. It has the right linkage for the 2004R. Just get there throttle cable bracket. You will gain mileage over the dated AFB design. Very good reviews online for the Street Demon.

Vyse

Am going to look into it right now. THANKS! looking forward to working on the old girl

EDIT- will this fit on the stock manifold? or would i be looking at getting an aftermarket one?

85T

Replace all the lines first, you don't need to have a new pump, if you just move it around.

olds 307 and 403

The carb is dual pattern, it will fit square and spread bore manifolds. It will fit the stock manifold, you may need the $7 adapter plate to prevent a vacuum leak. It is for mounting square bore carbs on a spread bore manifold. Demon made the carb a 3 barrel design to fit both manifolds. It is ver similar to your original Qjet in design and will give similar fuel economy to a Qjet, if both are tuned correctly.

Redog

I have no emissions on my 307 and it will start up rough, huge puff of smoke out of the tailpipe then followed by rough idel until warmed up. I removed the AIR tubes, still have the CCC, computer carb, and computer distrbutor. Still shifts into overdrive. MPG is down a little, but I don't drive the car very often

After that, car runs fine. Still puts down a 18.5 in the 1/4 mile

joe_padavano

I'm not sure I'd call a high-18 second quarter mile "runs fine".

Just sayin'...

Dead Reckon

I had zero emission controls left on my '86 Custom Cruiser with an 85 block and 86 heads / intake, no smog pump, tube system, EGR, ran fine. Got better gas mileage too, 17 in town versus 15, and if you removed the EGR, it's going to run rough. An EGR puts exhaust from the manifold into the intake, thus quickly heating the engine, though that isn't really a good thing if your car isn't running right, can make all kinds of things recirculate. Personally? I'd just patch it with no emission controls and wait until you can swap it, I ran mine for years like that. I think my '77 Delta might have an EGR valve, not sure, but that'll go way when I get an Edelbrock EPS intake and 1406 4bbl carb. Good luck with the project.

joe_padavano

Sorry, but you are confusing the Early Fuel Evaporation (EFE) with Exhaust Gas Recirculation (EGR). EFE is the flapper on the driver's side exhaust manifold that is closed when the engine is cold. This routes exhaust gas through the intake crossover under the carb and out the other side, helping fuel atomization when the engine is cold.

EGR taps off this crossover and does route exhaust gas into the intake, but ONLY under part throttle cruise conditions. Adding this post-combustion gas to the intake charge reduces the amount of combustible charge in the cylinder, cooling the combustion process and reducing NOx emissions. Again, this ONLY happens under part throttle cruise. There is no EGR at idle or under wide open throttle conditions, nor is there any EGR when the engine is cold.

If functioning properly EGR will NOT cause the engine to run rough. If the valve is stuck open or held open by carbon or rust on the seat, this will cause a problem, but it's very easy to fix. Simply removing the EGR valve from an engine designed for it (like the 307) usually causes part throttle pinging unless you recalibrate the carb.

Bottom line is that if the EGR valve isn't leaking, it is unlikely to be the cause of a rough running engine, particularly the "rough idle until warmed up" described by Redog. Most people don't take the time to understand how emissions controls work and simply rip them off. This usually does more harm than good.