Please help me out,86 regal failed Smog,Pic of results!

[86laidlow]

Zup guys,took my 86 regal limited with the 5.0 307 4 barrel carb in to the smog station and the car failed.It's a Gross Polluter apparently.The car has new plugs(Delco .60gap)new wires and cap.New o2 sensor and catalytic converter.The car is also equipped with 13" spoke rims and tires(maybe thats also a problem because the engine has to be reved more to reah 25mph?) Anyway here are the results,very high in CO at 25mph and HC,what could it be?please help a brother out,thanks in advance.

 

[85 Cutlass Brougham]

From what I can tell, your state has very low limits on what is acceptable. Nevertheless, it looks to me like it is either a carburetor or timing related issue. Normally, too rich a mixture will cause excess hydrocarbons while too lean a mixture will cause your CO to be too high. However, your car has both issues. I forget what effect ignition timing has as a general rule, but it is probably out of whack too. Does the car have all it's stock emissions equipment installed? Is the check engine light on? I do not think the tire height has affected it too much because of just how tall the gearing is in these cars stock.

To try to adjust the air/fuel mixture on a electronic Quadrajet you need to adjust several things. First off, there is an air bleed screw under a pop riveted cover at the top of the airhorn assembly that controls the idle mixture. This is a reverse adjustment. Tighter is righter, looser is leaner. Then there is the MC solenoid which is adjusted with a special tool. It is accessed under a pressed in plug on the top of the airhorn, The TPS may also be out of adjustment, as could the baseplate mixture screws. I would take it to a shop that knows these carburetors to have it set up right. Make sure they have a 4 gas analyzer so that they can set it up while being monitored to be sure that they are going the right way. A friend of mine used to have this done with his Camaro back when we had smog testing. He'd have it set up, go have it tested, then have it returned to where the car actually ran well. Every year he would repeat the process.

EDIT: I just looked at it again, and it seems the problem is at the 25mph point. Try having the ignition timing reset first. I would also check the MAP sensor as it essentially is the vacuum advance for these cars. The vacuum advance on a non-computer car gives it more timing during light loads for improved efficiency. It may be that it is not getting enough advance to work at it's maximum efficiency under load. I would also check for exhaust leaks on the side of the engine with the O2 sensor. If this is happening, the computer reads a false lean condition and will richen the mixture. This is probably not your problem, but it does not hurt to look. I would also make sure the air injection is working properly. it helps the catalytic converter do it's job by adding more air into the exhaust stream to allow the hot gases to continue burning.

 

[midwestls]

wow, they get serious in Cali. Someone might have some idea's for you. Good luck

 

[86laidlow]

re

hey 85cutlass, the car has all the stock emissions,it is all stock.Like i said the car has new plugs,o2,spark plugs and rotor.the tech at the smog place said it might be the fuel mixture in the carb or the carb may be bad,but you know how it is with these guys,they tell you something so they can fix it,i personally think he failed it or messed with it so it would fail because he asked me to leave it so he could take a lok at it and maybe adjust the fuel mixture.The cars " service engine soon" comes on only when its running at like 65moh and above,but turns off after that.

 

[85 Cutlass Brougham]

Well, there's the key then. If it is coming on at 65mph, it should store a code which can be read to find the problem. Your problem is at speed, but it may not hit the rather high threshold for a fault to register in the computer at low speeds. However, at higher speeds, the problem magnifies itself to the point that it throws a code. Read the code and post it here. You can do that by shorting the ALDL connector next to the ash tray under the dash with a paper clip. THese are terminals A and B. They are in the upper level closest to the passenger's side. The pin out reads "FEGDCBA" from left to right, with terminal G being under F in the second row. However, all you need are A and B. A is a ground, and B is the diagnostic test terminal. Once you have your paper clip inserted, turn the ignition to the on position, but do not start the car. It will now blink all the stored codes using the check engine light, and repeat each of them 3 times before going on to the next one. The first code will be 12. one blink, long pause, two blinks, then a longer pause and it will repeat. This is the operational check code and means nothing more than the system works. After that one blinks 3 times, it will start with the fault codes. Go count the blinks and write it down, then post it here and I will look it up in my GM factory service manual for you.

 

[86laidlow]

re

alright,i got the following codes,41 No Engine Speed Reference Signal and 45 Rich Exhaust,what do these mean?

 

[85 Cutlass Brougham]

The rich condition, that means the carburetor is out of whack or you have incomplete combustion. I am not home right now, but when I get back I will look these two up in the book and post what I find.

 

[dan2286]

For the first code, the computer is supposed to send a small amount of voltage to the sensor, and the sensor will modify that and send it back to the computer so it can determine engine speed. I am not sure how to explain diagnosing this, but if you can get a factory service manual, it will have a diagnostic flow chart for that specific code. I think the first thing you can try is looking for any broken wires or corroded connections coming from the distributor going to the pcm harness.

 

[86laidlow]

re

i dont have a service manual dan,85 cutty if you could let me know what these mean and how to correct them when you get home id really appreciate that,im kinda confused because when i got it,the service engine light came on at low speeds,i checked it out,said it was rich because of the o2 sensor,so i replaced it with a new one,the one it had was the original (car has 60k original miles and it was a real pita :x to get out.after that i disconnected the battery and it went away,no codes,so after that i ran it,20 miles before smogging it,and the service engine light would come on untill i went lower than 65mph or so,I only hope 🙁 i dont have to replace the carb at all,85 cutty if you could tell me how and were to adjust the carb id save some money,as for the rest im gona put seafoam in the car gas tank so that it lowers the numbers alittle specially on the nox readings.Damn,the car has a new catalitic converter,id figured that would be enough to pass the car eventhough the mixture is way off i suppose.

 

[85 Cutlass Brougham]

Honestly, It is very hard to describe how to adjust those carbs. I am not an expert on them by any means, and my advice could make it worse instead of better. Plus, the tools required to adjust it are not normal, and you have to get them from Snap On or Mac. I think the original O2 sensor was not bad, as evidenced by the readings of the new one. To adjust the TPS, you need to drill a small hole beside a small plug that covers the adjuster, then try to pop it out with a hook shaped pic. Then, you need a special tool to set it up right. A normal screwdriver, pliers, socket, etc will not fit down in the hole. It's a GM only tool. I never set my own up, I always paid $20 to a carb guy to do it for me. I have not run a computer carb on my Cutlass since 1997, so I wouldn't even know where to get the tools, if I could get them. Try Napa if you must do it yourself. If you want to try to adjust the air bleed screw, take off the air filter housing and then look at the carb. At the top of the center of the air horn, there will be a small metal plate that is round for most of it, but has tabs that come off of it. It is retained by 2 small pop rivets on the sides. Get those rivets off and underneath is the air bleed screw. This adjusts the idle mixture. Tighten it to richen it, loosen it to lean it out.

Now, the manual says that a code 45 means the ECM has seen:
High Oxygen Sensor Voltage
More than Specified time ( about 2 minutes)
Above a Specified TPS value
Closed loop


Oh, here's an important one: Does the MC Solenoid click rapidly when you turn on the ignition key ( engine off)?

The rest of the test procedure involves a Dwell meter, something that not too many people have, or at least I don't. I am not even that sure what it is as I have only ever seen them in terms of points ignitions. I think it measures the oscillation speed of the M/C solenoid and other such items, so maybe an oscilliscope would be a substitute? Perhaps a geiger counter wired without the gieger mueller tube?

Now, extrapolating what I can from the manual, I would check for major vacuum leaks, check that the M/C solenoid is working, etc. Now I will read the procedure from the other fault and post my findings to see if there is a correlation. I'll put that in another post.