I really need help!! I have an 88 oldsmobile cutlass with a 307 motor and quadrajet carb all stock. I'm having problems with the carb running to rich and also the secondary valves not opening. I'm not sure rather to replace it or get it rebuilt. Either way if I need rebuilt what is a reliable shop and If replaced which kind is best? Thanks in advance.. Also im putting up a post in wanted section for an 88 cutlass dashpad an console no matter the color but in good condition

 

How do u know the secondaries aren't opening? can you see them not open when you open up the secondaries? If they are just stuck you may be able to unstick them somehow. Not a carb expert just a thought :P

 

Not sure if u we're trying to be an ******* but ...

The secondaries will not open by free revving the engine. The engine needs to be under a load before they will open. If you are still uncertain if they are opening or not you can take a normal paperclip and clip it onto the secondary diaphragm rod. You will then push it up against the bottom of the secondary diaphragm housing, now you will need to go out and drive the vehicle. When you return you will be able to look at the position of the paperclip on the rod.

 

assuming everything else is working properly on the carb.... the secondaries will partially open by free-revving the engine, you just have to get the engine moving enough air to open them. cheat: grab the secondary throttle lever and crack it wide, the air valves will move.

is your choke fully disengaging?


bill

 

Easy on the name calling this is a family show.From i remember on those they have purge valve that fails and runs rich.

 

Well, I'm no expert, but we need to clarify just what you mean by the secondaries not opening? Do you mean the secondary throttle plates.....or the secondary air valve???

I am not at all familiar with Olds carbs of the late '80's, but I was a MOPAR tech back then, and Mopar used the Quadrajet on police engines after 1985, but all of them I have ever seen had O2 feedback systems, using an oxygen sensor and were computer controlled!

Running rich could be a number of problems, but you will need to do PROPER diagnostics to find the reason/reasons!

Do you have a 1988 OLDS FACTORY SERVICE MANUAL? It would be essential to have to diagnose this problem, in my opinion!

 

The "secondaries" are mechanical. They will open anytime the throttle is pressed sufficiently. The air valves or the vacuum-operated cover plates are the problem. Have you experienced any backfires lately? That is a common reason for vacuum diaphragms being damaged. Cracked or split vacuum hoses can also cause malfunction of vacuum operated devices. Check all of your vacuum hoses for cracks and splits. This could also cause a vacuum operated choke to fail and air valves to not open.

Just a thought or two.

 

Just to be completely correct, the secondary air valves on a Qjet are not vacuum operated, they are opened by mass airflow through the secondary barrels. There is no vacuum actuator the way there is on a vac secondary Holley, for example.

In any case, on early Olds Qjets the choke linkage locks out the secondary air valves when the choke is closed. On the 1980s CCC Qjets, the choke actually locks the secondary throttle plates. If the choke is misadjusted or not opening, the secondary throttle plates will not open (there is an override spring in the linkage so that the accelerator will still move all the way to the floor despite this lockout holding the secondaries closed).

Now, if the secondaries are closed, there won't be any airflow through them, which means that there will be no fuel flow either, so this is NOT the problem of the carb running rich.

The most important thing you need to do here is to get a factory Chassis Service Manual and COMPLETELY read and understand the part about adjusting the CCC system. If you do not follow this exactly, the car will never run right. You also need to completely check every vacuum line on the car, along with ancillary systems like the A.I.R. system. As an example, if the divert valve in the A.I.R. system is not working, the system will blow fresh air directly at the O2 sensor, causing the sensor to think the engine is running lean and thus forcing the ECU to drive the carb full rich.

It takes patience and careful attention to the procedure to get this system to run right. Many people lack the skills or patience to do this.

 

smh...


bill