I know this is not a GN but I was wondering if any of you know anything about these carbuerated 3.8L motors. My car chugs really bad and sometimes dies after starting it cold. Is there some sort of choke that needs to be changed? I see they have primary and secondary Choke Pulloffs listed in the Oreillys site but I have no clue where to start. Any ideas? Thanks! -----Jeremy
Question about cold starts for my 85 NA Regal
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According to the Owners Manual for a Cold Start you should press down the accelerator pedal once (coming up on it slow) before trying the ignition.
If your already doing that then you may need to adjust the front vacuum break so the Choke Plate is at the right angle. The procedure is easy enough but you need a hand held vacuum pump and a carburetor angle tool.
You might also want to check the Choke Valve and make sure it's not sticking. In addition check all the vacuum hoses coming into or off the carb and make sure none are leaking.
Try this the next time before you go to start it. Remove the top of the Air Cleaner and move the throttle linkage all the way back real quick and let it go back to rest. You should see the choke plate snap shut. Start the car and get out and look under the hood at the Carb.
As the engine warms up the choke plate should start opening up to let more air in. The rpms should be high as the engine isn't warmed up yet. Don't let it idle high for more than a few minutes without moving the throttle (either at the linkage or using the pedal) as it could harm the engine.
What should happen as once the engine warms up and changes from "open" to "closed" loop the rpms should drop to normal and the engine won't sound like it's racing. Then the computer will take over.
If you don't make it this far (the car is still having the same problem) you will need to check some things out. Carbs don't usually go out of adjustment by themselves other than the TPS or maybe the Choke Coil Spring loosening up.
It could be something as simple as spraying some carb cleaner down the bowl but not near the TPS or any other electrical part on the CarB.
A good book to have is the Rochester Carburetor Manual which will tell you just about everything you wanted to know about these Carbs.
You can usually grab it at any auto parts store.
Greg
According to the Owners Manual for a Cold Start you should press down the accelerator pedal once (coming up on it slow) before trying the ignition.
If your already doing that then you may need to adjust the front vacuum break so the Choke Plate is at the right angle. The procedure is easy enough but you need a hand held vacuum pump and a carburetor angle tool.
You might also want to check the Choke Valve and make sure it's not sticking. In addition check all the vacuum hoses coming into or off the carb and make sure none are leaking.
Try this the next time before you go to start it. Remove the top of the Air Cleaner and move the throttle linkage all the way back real quick and let it go back to rest. You should see the choke plate snap shut. Start the car and get out and look under the hood at the Carb.
As the engine warms up the choke plate should start opening up to let more air in. The rpms should be high as the engine isn't warmed up yet. Don't let it idle high for more than a few minutes without moving the throttle (either at the linkage or using the pedal) as it could harm the engine.
What should happen as once the engine warms up and changes from "open" to "closed" loop the rpms should drop to normal and the engine won't sound like it's racing. Then the computer will take over.
If you don't make it this far (the car is still having the same problem) you will need to check some things out. Carbs don't usually go out of adjustment by themselves other than the TPS or maybe the Choke Coil Spring loosening up.
It could be something as simple as spraying some carb cleaner down the bowl but not near the TPS or any other electrical part on the CarB.
A good book to have is the Rochester Carburetor Manual which will tell you just about everything you wanted to know about these Carbs.
You can usually grab it at any auto parts store.
Greg
WoW!!! Great info! Thanks very much for the help. I will definately try those options out. As far as pressing the gas down prior to starting, I have tried that a few times. It pretty much wants to chug and stall until it warms up. I'm thinking the choke may be stuck. I will definately check that out! I'll keep you posted on my results. -----Jeremy
Okay let me know, I've rebuilt my Dualjet a couple of times now and have gotten better at tuning them than the repair shop was ever able.
Carbuerators are pretty simple devices I've learned and aren't hard to diagnose and repair. It's just tedious and you need some special tools.
Don't flood the engine when you do the gas pedal thing. Usually one good stomp and a easy let up is sufficient. Maybe two. If you have to pump a lot to get it to start then that's delivery problem.
Greg
Carbuerators are pretty simple devices I've learned and aren't hard to diagnose and repair. It's just tedious and you need some special tools.
Don't flood the engine when you do the gas pedal thing. Usually one good stomp and a easy let up is sufficient. Maybe two. If you have to pump a lot to get it to start then that's delivery problem.
Greg
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Did you do your spring cleaning yet
Nah but seriously, I can guarantee that carb is probably as greasy as the rear seal area on that motor:biggrin: . Hose it down with some carb cleaner. then check all the vac lines. get a forty oz., go to work:biggrin:
Nah but seriously, I can guarantee that carb is probably as greasy as the rear seal area on that motor:biggrin: . Hose it down with some carb cleaner. then check all the vac lines. get a forty oz., go to work:biggrin:I had an issue like this once on my old 84 Regal, it was a carbed 3.8 liter.
In the morning I'd set the choke and the car shook and idled rough like if it had a really huge cam in it. It would take a few minutes of having the choke on to clear up.
Turns out the vacuum pull off on the right front corner wasn't doing it's job, and it would continue to let the carb to suffocate the engine 10 seconds after initial start up, instead of pulling the blade open to give it a little more air.
With that, get you a vacuum gauge and test your pull offs. I think there's 2 of them. The diaphragms should move when vacuum is applied. Mine didn't because the diaphragm had a hole in it.
HTH.
In the morning I'd set the choke and the car shook and idled rough like if it had a really huge cam in it. It would take a few minutes of having the choke on to clear up.
Turns out the vacuum pull off on the right front corner wasn't doing it's job, and it would continue to let the carb to suffocate the engine 10 seconds after initial start up, instead of pulling the blade open to give it a little more air.
With that, get you a vacuum gauge and test your pull offs. I think there's 2 of them. The diaphragms should move when vacuum is applied. Mine didn't because the diaphragm had a hole in it.
HTH.
Man this was back in 2005 when I had this problem and I sold the car sometime in 2006. So my memory is cloudy now.
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