ToronadoGuyDenver

I was wondering if anyone had any advanced carburator skills regarding the 4 barrel Quadrajet on a 305. This is for an 1985 Toronado?

I have a brand new Engine and Carburator. When going for emissions, the CO reads incredibly high. It wont pass emissions. I take it to the shop, the charge me $100 and it still reads high. It wasn't as high, but only went down a little.

When getting a 4 barrel quadrajet new, from the factory the settings are sealed and the seal has to be drilled off. I've been told by the emissions people that the car is running too rich.

Does anyone know the exact amount of turns for the settings? Some sort of help would be greatly appreciated.

88 coupe

I normally don't do Chevs on an Olds site, but I normally don't do emissions either.

New? As in not rebuilt, reconditioned, remanufactured, etc?

Is the engine an '85 or newer? Are you sure the carb is correct for that engine, and for your altitude?

They charged you for not fixing it? Do I need to say more?

The cause may or may not be in the carb. If it is, it may not be in the idle circuit.

Your answer will be in small fractions of a turn, and the adjustments will vary from car to car.

I suggest you take it to a shop that specializes in emissions systems. Or you can look for advice about your Chev engine on a Chev site. I've found this one to be informative.

Norm

ToronadoGuyDenver

The Carburator is newly remanufactured. I'm believing at this point that it needs to be rejeted due to the high altitude. The gas is just dumping in the carburator, thus creating high CO.

88 coupe

Big difference between new and remanufactured.

If you had your own working carb rebuilt, you should be able to work with it. If it came from a mass rebuilder, good luck.

If the test is run on a chassis dyno, as is done here in CA, yes. If it's tested at idle, leaner jetting will not affect the outcome.

If it is, leaning the jets will not help. Check the float level, inlet valve, and fuel pressure.

If you exaggerated, disregard my last.

Norm

joe_padavano

First problem is you probably should figure out which engine you have. The Toro was never offered with a Chevy 305, nor was the TH325 trans ever made with a Chevy bellhousing. Either someone did a custom swap with an adapter or (more likely) you really have an Olds 307 (VIN Y).

Assuming this is the case, be sure you have the correct carb. Next, get a factory service manual. The electronic Qjet is extremely sensitive to proper functioning and setup of the carb and all the emissions equipment. A minor problem with a seemingly unrelated system (A.I.R. air injection, for example) can fake the computer into running the carb full rich. You MUST follow the troubleshooting and adjustment process in the FSM exactly. Do not expect to simply bolt on a new carb and go. The good news is that once the system is set up properly, it runs very well.

ToronadoGuyDenver

It is the correct carb. I have the original and the newly remanufactured carburator. I have the factory service manual and I did install the newly remanufactured motor and in fact, the car runs great. Just a little high on the CO and I've taken it to get looked at twice. I'm at a higher altitude and I've known some people to have had to have gotten the carb rejetted.

I have a choice at this point, have the original overhauled by a professional or take it back ino the shop.

joe_padavano

The "jetting" is controlled by the computer, which reads the O2 sensor and varies the duty cycle of the mixture control solenoid automatically. If you're at higher altitude, the system should automatically compensate. I don't even know if you can get different jets for the Electronic Qjet, since is uses special primary metering rods. Have you checked the dwell setting of the mixture control solenoid? There's a green single wire connector in the harness just in front of the carb. Connect a normal dwell meter set to the six cylinder scale. You will read M/C solenoid dwell in degrees. It should be slightly varying around 30 degrees. If it's fixed or if it's off from 30 degrees, you have a problem in one of the systems controlling the carb. Note that this control is very sensitive to adjustment of the throttle position sensor, adjustment of the park/neutral switch, proper functioning of the A.I.R. system, and a host of other parts.

The 307 is also very sensitive to other aspects of the system. For example, always change the oil just before an emissions test. Any residual gasoline that might have leaked past the rings will cause an increase in HC and CO. Be sure the evaporative cannister system is functioning correctly. What's the condition of the catalyst? If you just broke in a new motor, you may have contaminated the cat with oil blowby. Is the PCV system working properly.

If it's any consolation, the VIN Y 307 has the highest emissions failure rate of any engine in the EPA database. The Chevy 305 with the same electronic Qjet is in the number 2 position.

ToronadoGuyDenver

Your the second person who's told me about this wire on the front of the carb.

Another thing, last time I did emissions, the guy for the State, the freee guy who helps you after you've spent too much. Anyway, he told me to look under the dash and look for a computer chip (which they don't make anymore). I went and got one from the junk yard and it passed. Now, it's doing the same thing. While going through this, the State guy told me it was preventing the cycle of the computer from kicking in.

I don't mind spending the money if I can get it right once and for all. I have too dang much money in the engine, etc., to let it go to waist. My next choice might be taking the motor out and taking it to the strip in a little car.

ToronadoGuyDenver

If I get it running properly, I'm going to cherry the car out. New paint, new metal replaced, wheels, shocks, etc. Before I put the motor in, I did up the under carriage. It is a nice ride still.

joe_padavano

OK, the way you wrote that tells me you did NOT adjust the carb per the factory service manual, you just bolted on the rebuild and expected it to work, right? Sorry, but it doesn't work that way. You say you've got the FSM, so read it. You MUST adjust the idle mixture, idle speeds, and TPS in exactly the method and order described in the manual. This must be done on the car, whether the carb is newly rebuilt or not.

Sorry, that's a bunch of crap. Unless you have money to burn, READ THE MANUAL and follow the troubleshooting procedures. There are very simple, no-cost tests to verify if the mixture control solenoid is working, if the O2 sensor is working, and if the TPS is adjusted properly. All it takes is a little time and some patience. Most repair technicians are "parts replacers" and have no concept of diagnosis (especially if someone else is paying for all the parts replacing). It's like the 100 monkeys with 100 typewriters - at some point dumb luck will allow them to "fix" the problem. Again, for people with more money than brains, this may be fine. I can't afford that method of "diagnosis".

ToronadoGuyDenver

Yes, I did just bolt the carburator on, but then took it in to have it adjusted by someone whom I thought knew their job. Therein lies the dilema. I've taken it in twice to two different supposed carb specialists and they've done nothing to improve the problem. So I guess that's what I'm getting at is, I'm tired of paying people to not fix the problem. I wouldn't mind paying if they did it right. I will read over the book and see what I can do. Thanks for your help.

Again, I don't know what to think about the electrical issue? Could some sort of electrical problem cause the computer to not function properly? Is there a way to diagnose that? I'm really not an electrical guy so.....

joe_padavano

This is why I do all my own work.

Unfortunately this electronic Qjet was built right on the ragged edge of passing emissions. It uses a host of vacuum and electronic sensors and actuators, all driven by a computer with a late 1970s processor. There's a reason why this was the last carbureted engine built in the US and the last one was made over 17 years ago, so good luck finding mechanic who understands them. The engine is extremely sensitive to the proper functioning and adjustment of all the various sensors. It's doubtful (but not impossible) for the computer to go bad. More likely it's a sensor feeding it bad data. It is also possible that one of the many, many electrical connectors has become corroded or a wire has broken or chafed through. It's a major pain to check some of these things.

The bottom line is that you must set the idle mixture screws using a dwell meter on the green test connector. Shoot for 30 degrees. You must ensure that the O2 sensor is functioning properly and is not contaminated. You must set the idle speed per the procedure in the manual then adjust the TPS with the throttle at this idle position.

ToronadoGuyDenver

PROM - Diagnosis and/or Replace

Joe and 88Coupe, I appreciate your help and I've begun working on the issue. At least through the book.

What I'm wanting to know is how do you know when to replace the PROM? I got a scanner and the troubleshooting book shows where there have been revised PROMs issued that address the carburetor running too rich. When I attach the scanner, it doesn't give me any codes but it does give me current readings. Just wondering if anyone knows how to find out if I should replace the PROM?

Also, when should the loop be closed and/or open?

Oldsguy

Programmable Read Only Memory. If there are revised PROMs that addressed the carb running too rich that might be a solution, if you know what version your PROM is. If yours isn't one of the later versions then you might be able to correct the problem with the newer PROM. But, it might not be available. If your PROM wasn't working most likely the engine wouldn't run at all, as Joe said, they usually don't fail and if they do the just go. I bet the PROM in your car is doing exaclty what it was programmed to do. Remember what Joe said though, sensors give the computer data and if any of them are giving faulty data then the computer can't do it's job corrrectly. Lots of variables to look at before buying something like a PROM, I bet they aren't cheap.

joe_padavano

Open loop is used before the O2 sensor warms up and during wide open throttle acceleration. Once the O2 sensor reaches operating temperature, it starts sending out a varying voltage signal that is used by the computer to correctly set the pulse width on the mixture control solenoid. This is closed loop since the measurement is used to directly control the mixture. Unfortunately, the O2 sensor can cool off at idle, even with the engine at operating temp, which causes the system to go back to open loop. You can ensure the O2 sensor is at temp by running the engine at 2000 RPM for a couple of minutes. With a dwellmeter hooked up to the green test terminal, you should see the M/C solenoid dwell varying at idle when the O2 sensor is warmed up. If not, there's a problem.

joe_padavano

I should add that the PROM rarely goes bad, so be sure to check EVERYTHING else before spending the money on a PROM.

t0oL

if it's running rich with borderline CO, MAYBE you could wait until the gas tank it really low on gas and add lots of methanol to the gas in the tank.
It has Oxygen already in it and would affect the CO readings until you run out.
Look for methanol in HEET gas line deicer. It's reasonably priced and 3-4-5 little bottles to a really really low tank of gas (like the last gallon) could change the carb from rich to lean, as a methanol carb would use about twice the volume as a gas carb would. The added Oxygen as CH3OH would also aid in producing CO2 instead of CO. A double emissions whammy.

joe_padavano

This was the whole concept behind oxygenated gasoline. It works great in a open-loop carb but on the 307 the O2 sensor will see the lean exhaust and increase the duty cycle on the mixture control solenoid to compensate. In fact, to get off on a little tangent, the whole oxygenated gasoline thing is now moot due to computer controlled cars. Unfortunately, as with any gov't program, once it's in place it's impossible to stop, even if it no longer makes sense. In fact (and talking about double whammies) the use of oxygenated gas not only no longer helps cut emissions, but since the computer richens the mixture to compensate, the mileage goes down so it also INCREASES gas consumption. Thanks, Congress...

Back to this particular 307 - with the carb properly adjusted there should be no need to resort to these tricks (even if they did work with this particular motor). My 307 failed initially, but once I properly tuned it none of the emissions levels were above 50% of the allowable, and most were well below even that.

ToronadoGuyDenver

Well, it's all over. No more fixing up my 1985 Oldsmobile Toronado. I really had it going well but now it's over.

I had my car at a shop for emissions work. While in their care, my car was stolen and the little bastards set it on fire. I can't even see the car at this point because it's being held for arson investigation. The man where I had my car being worked on refuses any liability. I guess I'm just supposed to walk away. That's what he believes. Oh well, bummer. It was a nice car. I put a lot of hard work into fixing it up and a lot of money. The car was fine sitting outside for years, I take it to be worked on and it's gone and I'm just supposed to walk away.

I think I'm going to sue him.

So long everyone and thank you for your help and advice.

cwripinz

...But others may yet find it of value.

In Denver with Same Make/Model Vehicle as OP: 1985 Oldsmobile Toronado with 71K Miles on the 307.

Resurrecting this vehicle that sat for 12 years... Inherited from my Parents' Estate.

Note: Vehicle appeared to run very well... Smooth... No Smoke... Power felt right...

Failing Emissions due to High CO (Carbon Monoxide)...

Replaced/Repaired:
Thermostat
Radiator Cap
Coolant
Radiator Rebuilt (Trans Cooler Leaking Fluid Into Coolant)
Trans Fluid
Trans Filter
Oil
Oil Filter
Air Filter
Plugs
Plug Wires
Cap
Rotor
Coil
Ignition Module
O2 Sensor
EGR Tested Good
Checked Carb Settings (Float, Choke, TPS & MCS)... All Within GM Manual Specs

Reduced CO from 78.4 to 36.7 GPM (Grams Per Mile) on the Dyno Test, Under Load, with above listed repairs. Still Above the 20 GPM Limit. GRRRRRRRRRR!!

After much research, pouring over arcane GM Manuals & various other documentation, interrupted sleep, head scratching and gnashing of teeth, it is, at last, SOLVED!

This Vehicle requires HEAT to kick out of Open Loop Operation and into Closed Loop Operation.

Originally installed NEW 195 Degree (OEM Spec) Stant Super Stat. Could not get a reading above 160 Degrees at T-Stat Housing with an IR Thermometer ($30 at Harbor Freight). NOT SUFFICIENT TO KICK ECU/ECM (COMPUTER) INTO CLOSED LOOP!! What a piece of GARBAGE (T-Stat not Computer). NOTE: Temp Gauge in Vehicle showed 200 Degrees-ish. Gotta look into that at a later date.

Replaced with NAPA Premium 195 Degree T-Stat (THM PM1950025). BINGO! Reading 194 at T-Stat Housing!

HC at .8978 with a 2.0 Limit
NOX at 2.9374 with a 4.500 Limit
CO2 at 507.8848 No Limits in Denver
AND...
CO at 11.9829 with a 20.00 Limit

I have a PAIR of these Toronados. Same Year & Options (4-Wheel Disc Brakes)... Both in Excellent Condition... One with 86K (Passed Emissions with ease) and this one with 71K miles & emissions 'issues'. I was able to take side-by-side (nose-to-nose, actually) readings and discovered the Temperature Discrepancy in this manner. Suspected the Catalytic Converter, but the IR Thermometer showed it to be operating at the correct temperature.

Additional: I have also resurrected the Air Leveling Suspension on these, as well! Very Nice!!

Hope someone finds this info of use... I sure would have!!

RetroRanger

good on you for sticking w it. I cant believe they still sniff test cars that old !

I guess they dont want anymore CO in CO

cwripinz

Yup! It's a Total PITA... Not only a 'sniff' but a full run, under load, on a dyno!

On the other hand, with being this close to the Rockies, we are in a kind of a weather 'trough' and it can result in some nasty inversions, which used to cause Denver to have SEVERE Air Pollution issues. The 'Brown Cloud' was visible for miles & miles and tasted kinda funky, too!

So... it's a trade-off.