Wood

Hey all! Just picked up a pretty solid 1983 delta 88 royale for a steal! Figured I'd save her from the derbies... lol. Anyways, the car has the 307 with about 140,000 miles and all of the original CCC and smog equipment. Fresh 350 trans, lockup convertor & solenoid, amongst various other parts. Engine/carb looks to have been never touched (I think there's an engine under all if those hoses..?) The only thing I've done with the car so far is an oil change, air filter and power steering pump (talk about a cluster**** of an accessory setup..) Car seems to run well with no leaks and no oil burning, WOW! Unfortunately I've only been able to reel in an astounding 8 MPG, Which is an abomination in my mind.
The car throws a CEL Code 45 (rich). The O2 sensor is new and I've disconnected the fuel canistor. The car also seems to have a high idle problem. When cold, the car will kick down and idle fine, however when warm the car has a very high idle (will coast at 30 mph) and does not kick down. I was also told the the car pings on 87(wtf..?) So I have just been filling it with 89.. Ugh. I am not sure where to start diagnostics as this is my first carburated car and I have no idea what I'm looking at underneath that air cleaner.. I understand that when the CEL comes on the car goes into open loop thereby retarding the timing/ unlocking the converter and screwing my gas mileage. A vacuum leak causing a high idle would make sense however I would think that that would lead to a lean condition in the exhaust..
so any input would be greatly appreciated! Being a poor college student I cannot afford to swap to a non CCC setup, but I cannot afford such crappy gas mileage either! Please help, trying to keep this classic on the road, thanks!
-wood

joe_padavano

Welcome.

The CCC system is daunting to many people, and there are virtually no mechanics around today with the patience and/or knowledge to adjust them properly. Start with getting a factory Chassis Service Manual for your car. The CCC system works very well if everything is in good shape and adjusted properly. You MUST follow the adjustment process in the CSM exactly.

I'm guessing the carb likely needs to be rebuilt. Also, plan on manually checking (and MIGHTASWELL replacing) every inch of vacuum line. One improperly connected or cracked line will bring the system to it's knees. In addition, check the systems that are not directly tied to the computer. From personal experience, I can tell you that a bad check valve in the A.I.R. manifolds can allow exhaust gas into the diverter valve. This causes the valve to fail, which allows the A.I.R. pump to blow fresh air directly at the O2 sensor. The sensor reads this as "too lean" and runs the carb full rich. You can check this by using a dwell meter on the green test connector that's in the harness in front of the carb. Read on the six cylinder scale while the engine is running. The CSM tell you what to look for. Good luck.

rocketraider

GM dealers used to keep those AIR check valves and manifolds on the shelf if that tells you anything...

That engine combo should deliver way better than 8 mpg but the way it's behaving tells me you have something that has put the ECM in "limp-home" mode.

I had an 81 Pontiac Safari wagon with that same drivetrain that would consistently deliver 24 mpg as long as it got good fuel. Oxygenated and ethanol gas would drop it to 17- again because those oxygenates were fooling the O2 sensor into a lean condition and causing the carb to run rich. So much for cleaner air- you're burning 30% more fuel to go the same distance, that doesn't make much economic sense to me.

Had to take the alternator and bracket off to tension that PS pump belt, didn't you?

Wood

No, I didn't.. Which is probably why my belts are screaming lately haha. Took me half an hour to figure out how to loosen the p/s tensioner in the first place haha.
Anyways, I replaced most of the vacuum hose today, although I ran out of hose (10 ft of 5/32 is NOT enough and I've also discovered that I have a rebuilt carb! Tag said something along the lines of "rebuilt for gm by a certified rebuilding company" or something like that. Also, I've decided to replace the o2 sensor as it does not look as new as I had initially thought. I cannot get my o2 sensor socket onto the sensor as the sensor body is too close to the frame rail.. Any ideas/tips?
And I thought the air pump hose went into the cat after the o2/sensor, how would a failed valve create a false "lean" condition?
Also, I'm planning on cutting out the catalytic converter as it looks to be original and I do not need to have the car emissions tested. Any forseen problems running without a cat? (Other than a pointless air pump..)

Sugar Bear

A common failure to set a code 45 was a bad canister purge valve. It will be between the thermostat housing and the front of the carb. It is made of black plastic and has approximately four vacuum ports. They would have gasoline in them when bad. Pull it off and see if gas drips out of it. The spark plugs would be black and fuel economy would be bad when these failed.

Also hook up a dwell meter on the SIX cylinder scale to the unattached (it is a test connection) green, single wire plastic connector coming out of the harness in front of the carburetor. It should read 30 degrees on the SIX cylinder scale with the engine up to temperature and idling. If it is far off of 30 degrees the mixture control solenoid is defective or misadjusted.

These carbs ran quite well if one follows EVERY step in adjusting them. As suggested get a factory manual and make ALL of the adjustments.

Wood

Thanks for the response. Is the canistor valve round? I did not notice any gas dripping out/smell when I was replacing the vac lines for it. Are regular vacuum lines alright for that? I noticed some of the lines seemed "heavier duty" around the thermostat housing.

I am worried about dwell meter testing being accurate as this car has a STUPID high idle when warm despite replacing every vacuum line I came across. I have no idea where to even start to look to fix the idle now. Going to try and disconnect the throttle cable to see if that changes anything but I think that wouldn't create a cold/normal idle and a hot/high idle.

P.S where would I be able to find a quality chassis manual?

Sugar Bear

Yes, the valve is round, a search will get pictures of it.

About the high idle, do the throttle plates (front and rear) close all the way? Does the high idle cam on the right side of the carb behind the choke thermostat drop down when the engine is warm? Is the idle speed motor plunger on the left front of the carburetor gummed up and sticking causing the throttle plates to be held open? Are the throttle return springs in place on the carb?

Chassis manual? Sorry, I don't know maybe others can chime in.

joe_padavano

This is why you need the manual.

The A.I.R. system pumps air into the exhaust ports when the system is in open loop mode to help complete combustion of the exhaust before the engine is fully warmed up. Once the system goes to closed loop mode (where the O2 sensor is hot enough to provide useful readings), the system switches the air to the converter (to prevent it from overheating). If one of the exhaust check valves goes bad, hot exhaust gas flows back into this switching valve, which burns it out internally. Fresh air from the A.I.R. pump will now continue to flow into the manifolds in closed loop mode, which the O2 sensor will read as an extreme lean condition.

Wood

Ordered the chassis manual.

On the basis of the high idle, when the engine is hot I can manually close the choke plate and the rpm will drop down after about a 3 second delay. The engine will slightly miss but WILL NOT stall. It keeps running and shows no signs of stalling. Should it be behaving this way?
while running hot


Manually closing the choke plate and still running

Sugar Bear

If the first picture is with the engine fully warm the reason the high idle stays on is because the choke is not opening all the way. Is the engine at operating temp in that picture? Had it been running for 10-15 minutes and with strong heat in the cabin?

If the engine is run 10-15 minutes and is not blowing hot air then it may simply be a bad thermostat causing the problems. If the engine is getting hot then either the choke thermostat is adjusted incorrectly or the crossover passage in the intake manifold that provides heat to the choke thermostat may be blocked by carbon.

As a test, open the choke blade all the way by pushing it until it is straight up and while keeping it straight up have someone tap the gas pedal to see if it comes down to a normal idle.

Lastly, the engine slowing down as you close the choke is normal; but, the choke should be moving the other way i.e., straight up and down as the engine warms causing the high idle cam on the bottom right side of the carburetor to disengage.

Wood

It is not a thermostat problem, car gets nice and hot inside after a few minutes.
After getting home today I checked the choke blade again and it is still not open all of the way.
Sugar bear-
I tried manually opening the choke plate and kicking down the idle, but nothing changed.

Lady72nRob71

Also check to see if these pipe are connected and not broken or perforated. They must pass hot air to the choke thermostat for it to heat up and open the choke.

Sugar Bear

Does the pipe to the choke thermostat get hot? It should get so hot that you cannot touch it. Be careful to not get burned. Try dripping a couple drops of water on it to see if it steams or check it with an infrared thermometer.

What setting is the choke thermostat adjusted to? Look at the black plastic disc on the right side of the carburetor, this is the choke thermostat. What is the relationship between the index mark/line on the thermostat and the raised marks (seven of them) on the aluminum choke thermostat housing. How is it held in with screws or rivets? Can you post a picture of the adjustment?

FMB42

First triple check for vacuum leaks (especially at the carb base) and then check the state of tune (plugs, cap, rotor, timing, wires, PCV valve, etc, etc (you probably already know to do this). And again, the early GM CCC systems, and especially the feedback carbs, are known for being difficult to troubleshoot (seriously, the GM dealerships back in the day couldn't always figure them out).

Wood

You're telling me!
(On an unrelated subject, if anybody has a non-ccc quadrajet and distrubuter lying around, I'd be willing to take it off of your hands... )
Going to take a look at everything mentioned when I get some time this weekend, hopefully the CSM I ordered will arrive by then. This olds is a head turner around here but it certainly has me pulling my hair out!

Sugar Bear

Don't give up, the CCC system runs well, yours is likely just the choke not opening all the way.

Redog

Yeah it's carb related.

If that choke slams shut at a traffic light (idle) the car is going to stall. Just take a screwdriver, wrench, bit driver, or some other metal thingy you have that would fall down in the carb, gently open the plate and stick the item in there and restart the car. It will fire right up.

This has happened to me a lot

olds 307 and 403

I have seen those hot air coils die as well as the electric ones. I prefer the electric ones, more forgiving when setting. The hot air ones have a small range of adjustment or they stay on like yours. Pull the manifold choke tubes, I have seen rusted out tubes that cause your condition. You try warming it up and back of the choke coil till it comes off but you probably need a new choke coil.

Wood

UPDATE:
I discovered that the hot air choke tube is broken off on the plate going into the intake manifold. Any tips on removal/repacement of the choke tubes/plate?
Thanks guys!

Lady72nRob71

I kinda suspected this, as it happened to me on the '72.
The procedure is fairly straightforward, the only problems will be getting to it and if either of the bolts are so rusted they are now a smaller size.
See if these help:
https://classicoldsmobile.com/forums...tml#post313500

https://classicoldsmobile.com/forums...tml#post316059

After removing the stove from the intake, you can see if you can extract the remains of the tube. If not, get another stove. Good used stoves and pipes are still around if you cannot find a new set. Just do not overtighten the fitting at the choke housing and do install a new gasket at the stove.

Wood

Thank you, those threads do help, but now I'm a little nervous about the job! Hopefully removal of the carburetor isn't necessary to get access of the 2 bolts..

Here's the culprit!
IMG_20141227_155041.jpg

I'm having some trouble finding a new replacement..
I did find these reproductions from classic industries for 77-79 403 equipped trans ams:

http://www.classicindustries.com/pro...ts/ta4049.html
http://www.classicindustries.com/pro...ts/ta4047.html

however the long tube going to the back of the carb is not correct. Maybe some tube bending will be needed?
Do you guys think that general setup would work with my 307?
Input, please, before I bite the bullet and order these things..

Sugar Bear

You found it!!! Start soaking the bolts with penetrating oil daily and tap on the bolts with a punch and hammer after soaking them.

I don't know for sure, but think the pipes shown will work. They may need a little tweaking. Don't get the stainless ones as they are difficult to bend. Try to get new bolts also, just standard hardware.

Good luck and keep us updated...

Lady72nRob71

Take a look at the parts for the 350 and 455 engines. The parts place and fusick's has them. Perhaps they are closer to what you need?
The tubing bends easily if you are careful. I made a 455 long tube fit my 350 pretty easily.
It looks like the carb may need to be unbolted and moved aside - hopefully with leaving most connection intact. Get a new gasket for the stove in the intake, too. Beware - those bolts are probably rusted tight so shoot them with PB blaster a day ahead of the job.

Wood

Finally got new choke tubes/stove installed! Also replaced the stove gasket, fuel filter, carb gasket, and pcv hose while everything was apart. I ended up ordering the 403 tubes/stove, and while they were identical to the 307 tubes, the quality was fairly poor IMO. The tubes did not fit into the stove without major modifications.
The choke now fully opens and I have not had any CEL's. Also averaging around 15 mpg with long warm ups in the morning and at night. The idle is now lower when hot, but I believe it is still a bit too high. When the car is warming up, the idle will jump up a few hundred rpm and stay there after idling for a couple minutes. Not sure what would cause a carburetor to do this, however I can live with it for now.
IMG_20150117_161747.jpg
Finally I can enjoy this thing thanks to you guys

Lady72nRob71

That MPG # looks reasonable given cold weather, city driving, and long warmups.
Glad you got her going again.
Great looking car, BTW!

DoubleV

If you feel your idle is a bit high all you need to do is turn it down a hair. The idle being higher than normal during warmup is how it's supposed to be and you can adjust that faster idle too if need be ( without affecting your normal idle ).